Safety and Effectiveness of the PXL-Platinum 330 System for Corneal Collagen Cross-Linking in Eyes With Corneal Thinning Conditions
Phase: PHASE1
Conditions: Keratoconus, Unstable, Bacterial Keratitis, Ectasia of Cornea
Sponsor: Pacific Clear Vision Institute

CONFIDENTIAL 
Safety and Effectiveness of the PXL-Platinum 330 System for Corneal Collagen 
Cross-Linking in Eyes with Corneal Thinning Conditions 
 
 
 
 
PROTOCOL NUMBER: 
 
1005312 
 
DATE: 
 
 
 
05/28/2019 
 
Sponsor: 
 
 
 
Balamurali K. Ambati, MD, PhD 
 
 
 
 
 
Pacific Clear Vision Institute 
 
 
 
 
 
1125 Darlene Lane 
 
 
 
 
 
Eugene, OR 97401 
 
 
Manufacturer: 
 
Peschke Meditrade GmbH 
 
 
Chaesigass 6a 
 
 
 
6331 Huenenberg, Switzerland 
 
 
 
Telephone: 
+41-41-783 1145 
 
FAX:  
+41 41-783-1147 
 
 
MEDICAL MONITOR: 
 
Balamurali K. Ambati, M.D., Ph.D. 
 
 
 
 
 
Pacific Clear Vision Institute 
 
 
 
 
 
1125 Darlene Lane 
 
 
 
 
 
Eugene, OR 97401 
Telephone: 
(541)-343-5000 
FAX:  
(541)-343-9478 
 
 
 

Protocol PXL-330 (v.2.0) CXL for Corneal Thinning  
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Investigator Signature Page 
Study Investigators: 
 
1. 
Balamurali K Ambati, MD 
 
Pacific Clear Vision Institute 
 
1125 Darlene Lane 
 
Eugene, OR 97401 
  
 
2. 
Scott Cherne, MD  
Pacific Clear Vision Institute 
 
1125 Darlene Lane 
 
Eugene, OR 97401 
 
 
 
My signature below certifies that I have read this protocol and agree to conduct the study 
in accordance with the specified procedures. 
 
INVESTIGATOR NAME (Printed): _____________________________ Date:  ______ 
 
INVESTIGATOR SIGNATURE: 
_________________________________________ 

Protocol PXL-330 (v.2.0) CXL for Corneal Thinning  
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TABLE OF CONTENTS 
 
 
1.0 
Background ............................................................................................................ 6 
1.1 
Rationale ............................................................................................................. 6 
1.2 
Prior Experience ................................................................................................. 7 
1.2.1 
Preclinical Studies ......................................................................................... 7 
1.2.2 
Clinical Experience ....................................................................................... 7 
1.3 
Risk Analysis ..................................................................................................... 16 
2.0 
Combination Product Description ....................................................................... 17 
2.1 
PXL Platinum 330 Illumination System ........................................................ 17 
2.2 
Riboflavin Solution ........................................................................................... 18 
3.0 
Objectives .............................................................................................................. 19 
4.0 
Safety and Efficacy Endpoints ............................................................................ 19 
5.0 
Study Design ......................................................................................................... 19 
6.0 
Subject Population ............................................................................................... 20 
6.1 
Inclusion Criteria ............................................................................................. 19 
6.2 
Exclusion Criteria ............................................................................................ 21 
7.0 
Screening for CXL Eligibility .............................................................................. 22 
7.1 
Preoperative Evaluation (Day -30 to Day 0) .................................................. 22 
7.1.1 
Screening Eye Examination ........................................................................ 22 
7.1.2 
Contact Lens Discontinuation ..................................................................... 23 
7.2 
Keratoconus Severity ....................................................................................... 23 
8.0 
Study Procedures.................................................................................................. 24 
8.1 
Examination Schedule ..................................................................................... 24 
8.2 
Outpatient CXL Treatment (Treatment Group) .......................................... 25 
8.2.1 
Surgical Procedure for CXL ....................................................................... 25 
8.2.2 
Subject Preparation ..................................................................................... 25 
8.2.3 
Riboflavin ................................................................................................... 26 
8.2.4 
UVA Light .................................................................................................. 26 
8.2.5 
Concurrent Procedures ................................................................................ 26 
8.2.6 
Postoperative Care ...................................................................................... 27 
8.3 
Follow-Up Visits (1 Day, 1 Week, 1, 3, 6 and 12 months) ............................. 27 
8.4 
Retreatment ...................................................................................................... 27 
8.5 
Safety Monitoring ............................................................................................. 28 
8.6 
Post-Study Procedures ..................................................................................... 28 

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8.8 
PXL Platinum 330 and Riboflavin Accountability ....................................... 29 
8.9 
Early Withdrawal from Study ........................................................................ 29 
8.10 
Study Duration .............................................................................................. 29 
9.0 
Data Analysis and Statistical Considerations ..................................................... 29 
9.1 
Sample Size ....................................................................................................... 29 
9.2 
Accountability ................................................................................................... 30 
9.3 
Screening ........................................................................................................... 31 
9.4 
Subject Characteristics .................................................................................... 31 
9.5 
Primary Efficacy Criteria ................................................................................ 32 
9.5.1 
Keratometry ................................................................................................ 32 
9.6 Secondary Efficacy Criteria ................................................................................. 32 
9.6.1 
Manifest Refraction .................................................................................... 32 
9.6.2 
Visual Acuity .............................................................................................. 32 
9.6.3 
Central Pachymetry ..................................................................................... 32 
9.7 
Clinical Safety Endpoint Criteria ................................................................... 33 
9.7.1 Adverse Events and Complications ................................................................. 33 
9.7.2  
Key Safety Parameters ................................................................................ 33 
9.8 
Refractive Status Vision Profile ...................................................................... 33 
9.9 
Dropouts/Lost-to-Follow-up ............................................................................ 33 
9.10 
Interim Analysis ............................................................................................ 34 
10.0 
Ethical and Regulatory Considerations .............................................................. 34 
10.1 
Informed Consent ......................................................................................... 34 
10.2 
Institutional Review Board .......................................................................... 34 
10.3 
Complications and Adverse Events............................................................. 34 
10.3.1 Serious and Unexpected Drug Adverse Events .......................................... 34 
10.3.2 Serious and Unanticipated Adverse Device Effects ................................... 36 
10.3.3 Non-serious Drug or Device or Anticipated Device Adverse Events ......... 36 
10.4 
Monitoring ..................................................................................................... 36 
10.5 
Source Documents/Case Report Forms ...................................................... 37 
10.6 
Deviation from the Protocol ......................................................................... 37 
APPENDIX A:  Study Flow Chart .................................................................................. 38 
APPENDIX B:  CFR 50.25 - ELEMENTS OF INFORMED CONSENT ................... 39 
APPENDIX C:  World Medical Association Declaration of Helsinki ........................... 40 
A. INTRODUCTION ........................................................................................... 40 
B. BASIC PRINCIPLES FOR ALL MEDICAL RESEARCH ............................ 41 

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C. ADDITIONAL PRINCIPLES FOR MEDICAL RESEARCH COMBINED 
WITH MEDICAL CARE ..................................................................................... 43 
Appendix D:  References ................................................................................................. 44 
 
Appendix E: Information from Manufacturer on Products Used in this Study 
 

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1.0 
BACKGROUND 
This study is being conducted to evaluate the safety and effectiveness of using the PXL 
Platinum 330 system for performing corneal collagen cross-linking (CXL) for the 
treatment of corneal thinning disorders. The PXL Platinum 330 system is a combination 
product consisting of a UVA 365 nm wavelength light source (PXL Platinum 330 
Illumination System) and riboflavin (Peschke-TE 0.25% ophthalmic solution or Peschke-
L 0.23% ophthalmic solution) administered in conjunction with the UVA light as a 
photosensitizer. 
 
The PXL Platinum 330 treatment is intended to induce corneal collagen cross-linking to 
improve the biomechanical properties of the cornea by strengthening the corneal tissue in 
the anterior stroma.  Corneal collagen cross-linking is performed by pretreating the 
cornea with riboflavin 0.1% ophthalmic solution beginning 30 minutes before UVA light 
exposure to saturate the corneal tissue with the riboflavin photosensitizer. The cornea is 
then irradiated with UVA light (365 nm) at an irradiance of 3 mW/cm2 for 30 minutes. 
Exposure of the cornea to this combination of UVA light (365 nm; 3 mW/cm2 irradiation; 
30 minutes duration) after topical administration of riboflavin has been shown to induce 
cross-linking of the corneal collagen fibrils with a resultant increase in tensile strength 
and diameter of the collagen fibrils. Clinically, cross-linking has been shown to stabilize 
the corneal curvature in eyes with progressive keratoconus with no significant change in 
the refractive index of the cornea.  
 
1.1 
Rationale 
Clinical applications of corneal collagen cross-linking include treatment or prophylaxis of 
conditions distinguished by corneal thinning, such as post-LASIK/PRK/SMILE/INTACS 
ectasia, keratoconus, pellucid marginal degeneration, bacterial and fungal keratitis.  
 
Keratoconus is a naturally occurring ocular condition characterized by progressive 
thinning and steepening of the central cornea, resulting in increasing myopia, irregular 
astigmatism, and eventual loss of best spectacle-corrected visual acuity. Rigid contact 
lenses can be used to improve visual acuity in many patients, but keratoconus frequently 
progresses to the point that corneal transplantation is required to restore useful vision.  
Keratoconus may recur following corneal transplantation and require further transplant 
surgery. 
 
Together, keratoconus and post-refractive corneal ectasia are the second most frequent 
indication for corneal transplantation, accounting for about 15% of the corneal transplants 
performed in the United States. Corneal transplantation has inherent risks that could 
result in permanent loss of vision and significantly impact the patient’s quality of life 
during the surgical recovery phase, with lost work time and often permanent changes in 
lifestyle.  Any modality, such as corneal collagen cross-linking, that can delay or prevent 
corneal transplantation in patients with these conditions is of great benefit. 
 
Corneal collagen cross-linking using UVA light with riboflavin photosensitizer to 
strengthen corneal tissue was recently approved in April 2016 with the Avedro KXL 

Protocol PXL-330 (v.2.0) CXL for Corneal Thinning  
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system for slowing or stopping the progression of keratoconus and post-refractive surgery 
ectasia. However, patients with other corneal thinning disorders (pellucid marginal 
degeneration, immune-related corneal melts, bacterial or fungal keratitis, non-progressive 
keratoconus) were not included in the approved indication. Further, the Avedro KXL 
system is a significant burden on patients and clinics due to requirement for epithelial 
scraping (which increases pain, infection risk, and scarring risk), time necessary to 
perform the procedure, expense, and lack of reimbursement.  Lastly, the approved system 
does not offer 30 mW energy (which lowers time required for the procedure) or pulsed 
wave light delivery, which seems to improve outcomes after crosslinking in keratoconus 
due to improve oxygen availability. 1,2,3  
 
1.2 
Prior Experience 
1.2.1 Preclinical Studies 
Preclinical investigations have been performed to: (1) determine the optimal 
photosensitizing agent/dosage and irradiance/exposure time for cross-linking; (2) 
characterize the biomechanical and biochemical effects of cross-linking on corneal 
collagen tissue using rabbit, porcine, and human corneal tissue models; and, (3) 
determine toxicity to keratocytes and endothelial cells (see Section 2.9). 
 
1.2.2 Clinical Experience 
1.2.2.1 Conventional Crosslinking with Dresden Protocol 
UVA/riboflavin corneal collagen cross-linking was first used clinically in 1998. (Unless 
specified otherwise, the treatments referenced below in this subsection all used UVA 
light (365 nm, 3 mW/cm2, 30 minutes) with photosensitizing riboflavin 0.1% (10 mg in 
10 mL dextran-T-500 20% solution) applied after a central corneal abrasion, beginning at 
least 5 minutes before irradiation and continuing every 5 minutes during irradiation.) 
 
Wollensak et al. treated 23 eyes of 22 patients to evaluate the effect of cross-linking on 
patients with moderate or advanced keratoconus. 4 The mean preoperative maximum K-
value (Kmax) was 50.93 D, and the mean preoperative progression of Kmax was 1.42 D 
(±1.18 D) in the 6 months before cross-linking. After cross-linking, there was a mean 
decrease in Kmax of 2.01 D (p=0.001) with follow-up of 3 to 47 months (mean 23.2 
±12.9 months). In five of the untreated contralateral eye controls, the mean Kmax 
progressed an average of 1.48 D in the first year after cross-linking was performed in the 
contralateral eyes. Best spectacle corrected visual acuity (BSCVA) improved by an 
average of 1.26 lines (p=0.026) and manifest refraction spherical equivalent (MRSE) 
improved by an average of 1.14 D (p=0.03) in the treated eyes. No adverse events 
occurred. The postoperative healing process was unremarkable except for slight transient 
stromal edema during the first 3 postoperative days. Corneal and lens transparency, 
                                                 
1 (Moramarco, Iovieno, Sartori, & Fontana, 2015) 
2 (Mazzotta, Traversi, Caragiuli, & Rechichi, 2014) 
3 (Mazzotta, Traversi, Paradiso, Latronico, & Rechichi, 2014) 
4 (Wollensak, Spoerl, & Seiler, 2003) 

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intraocular pressure (IOP), and endothelial cell density (p=0.45) were unchanged after 
treatment compared to baseline.  
 
Similarly, Caporossi et al. reported a 3.6 line increase in uncorrected visual acuity 
(UCVA), a 1.66 line improvement in BSCVA, a mean reduction in Kmax of 2.1 D 
(±0.13), and a 2.5 D reduction in MRSE at 3 months after cross-linking in a series of 10 
eyes in 10 patients with progressive keratoconus. There were no changes in endothelial 
cell density or IOP. 5 
 
Patients treated in an ongoing clinical study at the University of Dresden (Dresden, 
Germany), have experienced outcomes similar to those reported by Wollensak. 6 A 
preliminary analysis of the Dresden keratometry data shows a 1.25 D reduction in 
maximum corneal curvature (K-max) in those eyes that have reached the 6-month 
evaluation timepoint. Progressively increasing corneal curvature is a hallmark of 
keratoconus and corneal ectasia. Based on the preliminary analysis of the Dresden data, 
corneal curvature progression is halted in this series of patients.  The effect is significant 
through 5 years after the CXL treatment and the trend continues to be observed as long as 
7 years after cross-linking. 
 
Table 9.2.1-1:  Change in Maximum Corneal Curvature (K-Max) in Eyes treated with 
CXL 
Time 
N 
Baseline 
Mean 
K-
Max 
(diopters) 
Post-CXL 
Mean 
K-
Max 
(diopters) 
Difference 
in K-Max 
(diopters) 
K- 
Max 
Percent 
Difference 
(%) 
K-Max 
Difference 
(p<0.05) 
K-Max 
% 
Difference 
(p<0.05) 
Baseline 365 53.6044 
 
 
 
. 
. 
6 
Months 
196 53.9003 
52.6523 
-1.24801 
-1.83121 
0.001013 
0.002256 
1 Year 
136 53.7790 
52.3346 
-1.44449 
-2.35446 
0.000025 
0.000039 
2 Years 60 54.0197 
52.4340 
-1.58567 
-2.52731 
0.001214 
0.001250 
4 Years 30 53.4627 
50.7030 
-2.75967 
-4.58245 
0.000396 
0.000342 
5 Years 13 52.2777 
50.0723 
-2.20538 
-3.78418 
0.020667 
0.019656 
6 Years 5 
50.6400 
48.1740 
-2.46600 
-4.81223 
0.064549 
0.067719 
7 Years 4 
52.3825 
49.4500 
-2.93250 
-5.48322 
0.057697 
0.056259 
8 Years 1 
47.3400 
47.1400 
-0.20000 
-0.42248 
. 
. 
 
 
Kohlhaas presented results for 127 of these eyes at the 2005 Congress of the German-
Language Society for Intrakularlinsen Implantation and Refraktive Surgery with a 
                                                 
5 (Caporossi, Baiocchi, Mazzotta, Traversi, & Caporossi, 2006) 
6 ("Data on File. IROC/University of Dresden," 2006) 

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follow-up of up to 60 months. Progression of keratoconus was stopped in all the eyes, 
and 81.7% of them showed a mean decrease of 2.87 D in Kmax. No opacification of the 
lens or change in endothelial cell density was seen in any patient. Long term follow-up 
results in a subset of 60 eyes in the Dresden Clinical Study that underwent cross-linking 
3-5 years ago confirm the lasting effects of cross-linking in that there has been no 
progression of keratoconus in any of the eyes and 51.2% (31/60) of the eyes have a slight 
reversal and flattening of the Kmax. 7 Kohlhaas et al. also reported a patient who 
developed bilateral keratectasia at 4 weeks after LASIK and underwent UVA/riboflavin 
cross-linking 6 months later. 8 In this case, corneal topography remained stable for 18 
months after cross-linking. 
 
Fifty eyes in 36 patients have been enrolled in an Australian randomized study of 
observation-only control versus cross-linking in eyes with progressive keratoconus. 
9Maximum K-readings taken before and at 3 and 6 months after cross-linking showed a 
mean decrease of -1.10 diopters and -1.39 diopters in the treatment group.  In contrast, 
the untreated control eyes show a statistically significant increase 0.70 D and 0.78 D 
increase in K-readings at 3 and 6 months after randomization. The treatment group also 
showed a mean 2.2-line improvement in BSCVA at three and six months, while BSCVA 
in the control group worsened. Similar to the Dresden experience, these data lead to the 
conclusion that corneal cross-linking halts, and even reverses, the progression of 
keratoconus. 
 
More recent studies confirm long-term improvement in eyes treated with crosslinking, 
including 10 year follow-up study as well as a crossover study, and 3 trials in pediatric 
populations. 10,11,12,13,14,15,16,17,18,19,20 
 
With respect to the use of the Dresden protocol with the Peschke system, the relevant 
papers include: 
 Corneal Cross-Linking and Safety Issues  
Open Ophthalmol J. 2011; 5: 14-16. Eberhard S Et al.  
The authors analyzed the current treatment protocol regarding safety during CXL with 
the riboflavin/UVA (370 nm) approach. When the corneal stroma thickness is at least 400 
microns, a homogenous irradiance of UV light of 3mW/cm2 for 30min at 370 nm with 
                                                 
7 (Wollensak, 2006) 
8 (Kohlhaas et al., 2005) 
9 (Snibson, 2007) 
10 (Raiskup, Theuring, Pillunat, & Spoerl, 2015) 
11 (Kumar Kodavoor, Arsiwala, & Ramamurthy, 2014) 
12 (P. Vinciguerra, Albe, Frueh, Trazza, & Epstein, 2012) 
13 (R. Vinciguerra et al., 2013) 
14 (Mazzotta, Balestrazzi, Baiocchi, Traversi, & Caporossi, 2007) 
15 (Zamora & Males, 2009) 
16 (P. Vinciguerra et al., 2009) 
17 (Caporossi, Mazzotta, Baiocchi, & Caporossi, 2010) 
18 (Chatzis & Hafezi, 2012) 
19 (Zotta et al., 2012) 
20 (El Rami et al., 2015) 

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the application of 0.1% riboflavin didn’t damage either corneal endothelium or deeper 
structures such as lens and retina.  
 
 Prospective, randomized, double-blind trial to investigate the efficacy and 
safety of corneal cross-linking to halt the progression of keratoconus. 
BMC Ophthalmology 2015; 15:78. Stefan Lang Et al. 
The efficacy and safety of corneal cross-linking were investigated in a randomized, 
blinded, placebo controlled, multicentre trial. 15 eyes were randomized to the treatment 
troup (corneal epithelial removal, 0.1% riboflavin, UVA 370 nm at 3mW/cm2 for 30 
min) and 14 to the control group (no epithelial removal, fluorescein drops, visible blue 
light for 30 min). Follow-up averaged 1098 days. The treatment group showed a decrease 
in corneal refractive power (on average 0.35 dioptres/year) while the controls showed an 
increase of 0.11 dioptres/year. However, some of the treated patients still progressed, 
whereas some controls improved. The change in visual acuity did not show a statistically 
significant difference between the two groups.  
 
 
1.2.2.2 Accelerated or Pulsed Crosslinking  
 
Pulsed crosslinking seems to be able to enhance functional and structural outcomes due 
to improved oxygen bioavailability during the crosslinking reaction. 21,22,23 The stromal 
demarcation line (commonly accepted as a marker of depth of biomechanical 
strengthening) was deeper with pulsed crosslinking in 2 studies (Moramarco et al. JRS 
2015 and Mazzotta et al. Eye 2014). Mazzotta et al.’s 1 year results (J Ophthalmol 2014) 
show that pulsed crosslinking achieved a 1.2 diopter reduction in corneal keratometry, 
whereas continuous light crosslinking only resulted in a 0.13 diopter reduction.  
 
With respect to the use of the accelerated or pulsed crosslinking using the Peschke 
system, the relevant studies include: 
 
 Accelerated (18mW/cm2) Corneal Collagen Cross-Linking for Progressive 
Keratoconus.  
Cornea. 2015 Nov;34(11):1427-31. Alnawaiseh M Et al. 
The charts and anterior segment data of 20 patients (28 eyes) who were treated with 
accelerated corneal collagen cross-linking (18 mW/cm2; 5 minutes) were reviewed. The 
mean follow-up time was 21.7 months. It found a significant reduction (improvement) of 
Kmax (the steepest radius of curvature of the anterior corneal surface) and stabilization of 
corrected distance visual acuity (CDVA) with no reported complications.  
 
 Accelerated (9-mW/cm2) corneal collagen crosslinking for keratoconus-A 1-
year follow-up. 
Cornea. 2014 Aug;33(8):769-73. Elbaz U Et al. 
                                                 
21 (Moramarco et al., 2015) 
22 (Mazzotta, Traversi, Caragiuli, et al., 2014) 
23 (Mazzotta, Traversi, Paradiso, et al., 2014) 

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16 mild-moderate keratoconus-affected eyes (14 patients) underwent an accelerated 
crosslinking (irradiance of 9 mW/cm2; 10 minutes). At either 6 or 12 month follow-up, 
no statistically significant changes were found in the mean CDVA, mean refractive 
cylinder, or mean manifest refraction spherical equivalent. There was an improvement in 
the uncorrected distance visual acuity (UDVA); a gain of 0.13 logarithm of the minimum 
angle of resolution lines in the mean UDVA (P = 0.012). Ksteep, Kflat, average K (Km), 
corneal astigmatism (Kcyl), and maximal curvature reading at the corneal apex (Kmax) 
were stable. 
 
 Safety of high-intensity corneal collagen crosslinking 
J Cataract Refract Surg. 2014 Aug;40(8):1337-40. George Kymionis Et al.  
10 eyes (9 patients) were treated underwent corneal cross-linking with 9mW/cm2 
irradiance for 10 minutes. 3 months after procedure, endothelial cell density (ECD) did 
not change and CDVA improved but the improvement wasn’t statistically significant. No 
eye lost lines of CDVA. The mean steep K readings decreased significantly.  
 
 One-year outcomes of conventional and accelerated collagen crosslinking in 
progressive keratoconus. 
Sci Rep. 2015 Sep 25;5:14425. Vanissa Chow Et al.  
19 eyes each group underwent conventional (3 mW/cm2, 365-nm UVA, 30 minutes) or 
accelerated (18 mW/cm2, 365-nm UVA, 5 minutes) collagen crosslinking. One year 
postoperatively, there were no inter-group differences in keratometry, UCVA, and best 
corrected visual acuity (BCVA).  
 
 Evaluation of Corneal Stromal Demarcation Line Depth Following Standard 
and a Modified-Accelerated Collagen Cross-linking Protocol. 
Am J Ophthalmol. 2014 Oct;158(4):671-675. George Kymionis Et al.  
26 eyes were treated for 30 minutes with 3 mW/cm2 UVA, while 26 eyes were treated 
for 14 minutes with 9 mW/cm2 UVA. One month postoperatively, corneal stromal 
demarcation line depth was assessed using AS-OCT with no significant difference 
between the two groups.  
 
 Safety profile of accelerated corneal cross-linking versus conventional cross-
linking: a comparative study on ex vivo-cultured limbal epithelial cells. 
Br J Ophthalmol. 2015 Feb;99(2):272-80. Rohit Shetty Et al.  
Day 14 cultured limbal epithelial cells (LECs) were either unexposed (control) or 
exposed to different intensities of UVA irradiance for different durations (3 mW for 30 
min, 9 mW for 10 min, 18 mW for 5 min and 30 mW for 3 min) in the presence and 
absence of riboflavin. When the apoptotic status was evaluated through quantitative real-
time PCR, vital staining, immunofluorescence staining and fluorescence-activated cell 
sorting, it was shownd that the 30 mW UVA irradiation used in accelerated corneal cross-
linking appears to be safe on cultured LECs in comparison with 3 mW used in corneal 
cross-linking. 
 

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 Corneal stroma demarcation line after standard and high-intensity collagen 
crosslinking 
determined 
with 
anterior 
segment 
optical 
coherence 
tomography. 
J Cataract Refract Surg. 2014 May;40(5):736-40. George Kymionis Et al.  
9 eyes were treated for 30 minutes with 3 mW/cm2 UVA  and 12 eyes were treated for 10 
minutes with 9 mW/cm2 of UVA. One month after procedure, the corneal stroma 
demarcation line was significantly deeper after a 30-minute 3 mW/cm2 UVA treatment 
than after a 10-minute  9 mW/cm2 of UVA irradiation. 
 
1.2.2.3. Transepithelial cross-linking: published literature 
Use of epithelial-on, or transepithelial, cross-linking is emerging as an alternative for 
treatment of keratoconus and other corneal thinning disorders.  This approach avoids the 
risks of epithelial debridement, including infection, haze, pain, and scarring.  Published 
studies of transepithelial cross-linking with the Peschke system include: 
 Efficacy and safety of transepithelial corneal collagen crosslinking vs. 
standard corneal collagen crosslinking for keratoconus: a meta-analysis 
BMC Ophthalmology 2017; 17: 262. Li W & Wang B. 
In a meta-analysis of trials evaluating standard vs. trans-epithelial CXL, the trans-
epithelial CXL group gained more improvement in corrected distance visual 
acuity 
 Transepithelial corneal crosslinking in treatment of progressive keratoconus 
Pak J Med Sci. 2017; 33: 570-5. Akbar B et al.  
In a series of 26 eyes of 26 patients, Kmax was reduced over 1 year, and no intra- 
or post-operative complications were noted.  
 Epi-off vs. transepithelial corneal collagen crosslinking for progressive 
corneal ectasia.  
BJO 2017; 101: 503-8. Rush S & Rush R 
In a randomized control trial of 131 eyes followed over 2 years, there was no 
statistically significant difference in best spectacle corrected visual acuity 
between the 2 groups. There were 3 adverse events in the epi-off group, but none 
in the transepithelial group 
 Transepithelial accelerated vs. conventional crosslinking in patients with 
keratoconus.  
Clin Ophthalmol 2019; 13: 445-52. Madeira C et al.  
In a study of 16 eyes with transepithelial vs. 10 eyes of conventional crosslinking, 
there were no significant differences in efficacy 
 Comparision of transepithelial vs. epi-off CXL in progressive keratoconus. 
Taiwan J Ophthalmol 2017; 7: 185-90. Akbar B et al. 
In a comparison of 32 eyes each undergoing transepithelial vs. epi-off CXL, there 
were no differences in visual acuity outcomes between the 2 groups. In epi-off 
CXL, there were 3 eyes with stromal haze which required long-term steroid use, 
but there were no adverse events in the transepithelial CXL group 
 
 
1.2.2.4. Our experience with transepithelial, pulsed, accelerated CXL 

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We initiated a single-site study at our practice in 2017 after approval of the Peace Health 
IRB.  15 patients consented to the study; 2 were screen failures, and 1 has not yet 
undergone treatment. Of the 12 patients who underwent crosslinking, none experienced 
any adverse events (e.g., haze, epithelial sloughing, infection, melt, or scarring).  16 eyes 
of 10 patients have had data collected out to 1 year.  Average demarcation line observed 
has been 243 microns. Mean keratometry declined by 1.35 D in the CXL-only group and 
2.24 D in the Intacs + CXL group.  Patients undergoing concurrent CXL + Intacs have 
experienced 5 letter improvement in ETDRS BCVA, while patients undergoing CXL 
alone have had stabilization in BCVA.  
 
1.2.2.5. Using corneal cross-linking to treat Infectious keratitis 
 
Corneal cross-linking (CXL) therapy was used to treat a 68 year old patient with a central 
2x2-mm corneal epithelial defect with deep stromal infiltration in one eye (OS) with a 
clinical appearance suggesting fungal infection. 24 The patient had visual acuity (VA) of 
CF at 2-ft. Initially, the patient was treated with topical voriconazole, amphotericin B and 
fluconazole drops for 10 days with no response. Then, he was treated with standard 
UVA-riboflavin CXL treatment. 25 After the removal of loose epithelium, riboflavin was 
topically administered for a period of 30 minutes at a 2-minute intervals. Then cornea 
was illuminated with UVA at 365nm wavelength, with an irradiance of 3.0 mW/cm2 for 
30 min. Riboflavin was administered throughout the UV illumination. However, patient 
had a reactivation of the infection 2 weeks post CXL treatment. Patient was given a 
second CXL treatment as described above with adjuvant antimicrobial therapy. The 
antimicrobial therapy was tapered and stopped 3 months post second CXL treatment. No 
reactivation of the corneal ulcer was noted and patient’s VA was CF at 4 ft with complete 
scarring of the lesion.  
 
CXL therapy was used to treat a 57 year old patient with a history of penetrating 
keratoplasty (PK) 12 months ago. 26 He presented with a central corneal ulcer at the graft 
measuring 3 to 3.5mm in one eye (OS). Patient’s VA was CF at 1 ft due to optic nerve 
damage prior to PK. After the cultures came back positive for gram positive cocci 
(MRSA), patient was started on antimicrobial therapy including fortified 5% vancomycin 
topical drops. After 3 days of further deterioration of the clinical picture, CXL therapy 
was administered. After de-epithelization of the area surrounding the ulcer, a mixture of 
0.1% riboflavin in 20% dextran solution was instilled over the cornea every 2 min for 14 
min. Then the cornea was illuminated with UVA at 370nm with an irradiance of 3mW/ 
cm2 for 30 min. Riboflavin drops were administered throughout the UV illumination. 
Topical vancomycin drops were switched to moxifloxacin topical drops five days after 
CXL treatment. Patient’s corneal epithelium was completely re-epithelized five days after 
CXL treatment. Topical antibiotic treatment was stopped at one month post-CXL 
treatment. At the final post-operative examination, the patient’s cornea had minor 
scarring at the ulcer site with strong connection between the graft and recipient cornea. 
No relapses occurred during the total post-operative period of 12 months.  
                                                 
24 (Saglk, Ucakhan, & Kanpolat, 2013) 
25 (Wollensak, Spoerl, et al., 2003) 
26 (Labiris, Giarmoukakis, Larin, Sideroudi, & Kozobolis, 2014) 

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CXL therapy was used in 8 patients with severe corneal ulcers in 8 eyes that had corneal 
melting and were not responding to topical and systemic antimicrobial therapy. 27 After 
de-epithelization of the area around the ulcer, riboflavin drops were instilled over the 
corneas every 3 min for 30 min. Then the corneas were illuminated with UVA at 365nm 
for 30 min with an irradiance of 3.0 mW/cm2. During irradiance, riboflavin drops were 
administered every 3-4 min. After CXL treatment, fortified antimicrobial topical drops, 
cycloplegics, artificial tear drops and systemic doxycycline were used. Topical 
antimicrobial therapy was tapered and stopped at 1 month after re-epithelization of the 
corneas of the patients. All patients had improvement in symptoms such as photophobia 
and pain 24-48hrs post CXL treatment. Hypopyon that was present in 6 eyes completely 
regressed after 2-4 days post CXL treatment in 5 eyes. The progression of corneal 
melting stopped rapidly in all 6 eyes with complete wound-healing at 2-5 weeks post 
CXL treatment. The VA of the patients that ranged from light perception to CF before 
CXL improved to hand motions and 20/100 post CXL treatment at the final post-
operative examination. One eye developed corneal perforation six days after CXL 
treatment and immediate PK was performed.  
 
Price at al did a systemic review in which they looked at 204 eyes diagnosed with 
infectious keratitis, which were treated with the standard UVA-riboflavin CXL therapy 
along with adjuvant microbial therapy. 28,29 Out of the 204 eyes, 109 eyes had mild to 
moderate bacterial keratitis and 73 eyes had completely healed with no complications. 
When the review compared 37 eyes with moderate to severe bacterial keratitis, which 
were treated with CXL and adjuvant antimicrobial therapy, to 35 eyes that were treated 
with topical antimicrobial therapy alone, no difference in visual outcomes were found. 
However, the eyes with moderate bacterial keratitis treated with CXL had shorter wound 
healing time of 17 days compared to the control eyes treated with antimicrobial therapy 
alone. The latter group had a wound healing time of 24 days and longer duration of 
anterior chamber inflammation.  
 
The review looked at 52 eyes with infectious fungal keratitis treated with standard CXL 
treatment with adjuvant antimicrobial therapy. 30,31 28 eyes successfully healed with the 
CXL and adjuvant microbial therapy. The other 20 eyes with fungal keratitis treated with 
CXL and adjuvant microbial therapy did not differ in visual outcomes or wound healing 
times compared to the 21 eyes with fungal keratitis that were treated with antimicrobial 
therapy alone. Four out of six eyes with deep stromal fungal keratitis that were treated 
with CXL along with adjuvant antimicrobial therapy had corneal perforations. However, 
the seven control eyes with deep stromal fungal keratitis, which were treated with topical 
antifungal therapy alone, did not have such complications.  
 
                                                 
27 (Zamani, Panahi-Bazaz, & Assadi, 2015) 
28 (Wollensak, Spoerl, et al., 2003) 
29 (Price & Price, 2016) 
30 (Wollensak, Spoerl, et al., 2003) 
31 (Price & Price, 2016) 

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The review looked at 12 eyes with acanthamoebic keratitis that were treated with the 
standard CXL therapy along with adjuvant antimicrobial therapy. 32,33 11 out of 12 eyes 
healed completely with improved visual outcomes and symptoms. However, when the 
same CXL treatment was used to treat two eyes with Herpes keratitis, patients had 
corneal melting and needed to have tectonic keratoplasty. The review also looked at 16 
eyes with infectious bacterial keratitis and 1 eye with infectious fungal keratitis that were 
treated with standard CXL therapy alone without adjuvant antimicrobial therapy. 15 eyes 
healed without any complications and 2 eyes (both eyes with bacterial keratitis) required 
adjuvant antimicrobial therapy. The review describes one case-report in which one eye 
with fungal keratitis (Aureobasidium pullulans) was treated with accelerated CXL 
therapy alone 6. 34 In this procedure, after the removal of loose epithelium, riboflavin was 
topically administered for a period of 30 minutes at 2-minute intervals. Then cornea was 
illuminated with UVA at 365nm wavelength, with an irradiance of 9.0 mW/cm2 for 10 
min.  Riboflavin drops were administered throughout the UV irradiation. The eye 
successfully healed in 3 days without any complications or recurrences.  
 
1.2.3. Adverse Events 
Adverse events have been reported after cross-linking. Corneal edema occurred in an eye 
with a pretreatment corneal thickness of ~400 microns, presumably caused by UV 
damage to the corneal endothelium. 35 Using confocal microscopy, Mazotta et al. 
evaluated 10 patients treated with UVA/riboflavin for progressive keratoconus and found 
normal epithelial morphology and an absence of subepithelial stromal nerve fibers in the 
central irradiated area at 5 days after cross-linking. 36 Nerve regeneration was observed at 
1 month and nerve fiber recolonization was complete at 6 months with restoration of 
corneal sensitivity. No changes were observed in the peripheral untreated area at any 
time. Recently, Seiler et al. described a thin corneal stromal demarcation line that was 
detectable by slit lamp microscopy at a depth of ~300 microns 2 weeks after cross-linking 
in 14 of 16 eyes evaluated. 37 This demarcation line is believed to be due to a difference 
in the refractive index or reflection properties of untreated and cross-linked corneal 
stroma. When epithelial thickness (~50 microns) is taken into account, the 300 micron 
demarcation line observed by Seiler et al. is consistent with the studies and theoretical 
principles that the selected parameters for UVA/riboflavin treatment produce maximal 
cross-linking to a depth of about 200 microns and that 94% of the UVA light is absorbed 
in the anterior 300 microns of corneal stroma without injury to the endothelium. 
 
Hafezi et al. recently published the results of corneal collagen cross-linking in 10 eyes of 
10 patients who had ectasia after prior LASIK surgery. 38  Anterior stromal haze was 
observed in the early postoperative period in all 10 eyes, with the corneas completely 
clear at the 12 month evaluation. This anterior stromal haze is similar to the subepithelial 
haze that is seen with photorefractive keratectomy (PRK) procedures, but the haze after 
                                                 
32 (Wollensak, Spoerl, et al., 2003) 
33 (Price & Price, 2016) 
34 (Tabibian, Richoz, Riat, Schrenzel, & Hafezi, 2014) 
35 (Seiler) 
36 (Mazzotta et al., 2006) 
37 (Seiler & Hafezi, 2006) 
38 (Hafezi, Kanellopoulos, Wiltfang, & Seiler, 2007) 

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cross-linking is not subepithelial in nature. The anterior stromal haze has also been 
reported anecdotally by the Australian investigators as a typical occurrence after cross-
linking that disappears within 3 to 6 months after the procedure and is thought to be 
related to keratocyte apoptosis (as described in Section 1.3 below) and regeneration after 
cross-linking. 39 
 
Rare cases of persistent epithelial defect or corneal infection have been reported after 
crosslinking, typically after epithelium-off crosslinking which entails scraping of 
epithelium, allowing access for bacteria or other micro-organisms to invade the corneal 
stroma.  
1.3 
Risk Analysis 
Riboflavin, also known as Vitamin B2, is a naturally occurring photosensitizer.  It is the 
precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), two 
coenzymes that are crucial for the metabolism of carbohydrates, fats and proteins into 
energy.  Riboflavin is an essential constituent of all living cells.  It is water soluble and 
only a trace amount is found in the human body. Riboflavin is non-toxic and it is used as 
a coloring agent in food and pharmaceuticals. The intake of riboflavin from food and diet 
supplements ranges from 4 to 10 mg a day. No adverse effects have been associated with 
high intakes of riboflavin from food or supplements.   
 
Pharmacokinetic studies have shown that the maximal amount of riboflavin that is 
absorbed after a single oral dose is 27 mg, regardless of the amount in excess of this that 
is ingested. Excess riboflavin is excreted in urine and, since it is not a fat-soluble vitamin, 
is not stored in fat or other body tissues. No upper limit for riboflavin uptake has been 
established by the Food and Nutrition Board of the Institute of Medicine of the National 
Academy of Sciences due to insufficient human and animal data. A risk assessment 
performed by the UK government has determined that a total intake of 43 mg is not 
expected to result in any adverse effects. 40 
 
The standard concentration of riboflavin used in the riboflavin/UVA treatment is 0.1%. 
The maximum amount of riboflavin to which a patient is exposed during treatment is 
estimated to be 1.6 mg based on the volume of one drop being 0.05 ml and 1 drop being 
instilled every 2 minutes for 30 minutes before, and 30 minutes during, UVA light 
irradiation (32 drops). This is below the 43 mg “safe’ limit by an order of magnitude. 
 
The potential cytotoxicity of UVA light and the UVA/riboflavin exposure on keratocytes 
and endothelial cell function have been characterized in a series of in vitro experiments. 
In each of these experiments, UVA exposure (370 nm, 30 minutes) and riboflavin 
(0.025% solution; equivalent to the corneal concentration after diffusion of a 0.1% 
solution) were administered to mimic conditions of clinical usage. Irradiance levels were 
varied to determine the irradiance threshold for cytotoxic effects. Keratocyte toxicity was 
evaluated in porcine keratocyte cell cultures after exposure to riboflavin alone, UVA light 
alone (irradiance range 2 to 9 mW/cm2), and UVA light plus riboflavin (irradiance range 
                                                 
39 (Wittig & Snibson, 2007) 
40 www.food.gov.uk/multimedia/pdfs/evm.riboflavin.pdf 

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0.4 to 1 mW/cm2). 41 Riboflavin alone had no cytotoxic effect on keratocytes.  The 
cytotoxic threshold for inducing cellular necrosis or apoptosis was 5 mW/cm2 for UVA 
light alone and 0.5 mW/cm2 for the UVA/riboflavin treatment.  Using the Lambert-Beer 
equation, in human corneas the cytotoxic keratocyte UVA irradiance of 0.5 mW/cm2 is 
reached at a stromal depth of 300 microns.  The potential for endothelial cell toxicity was 
evaluated on endothelial cell cultures obtained from porcine cornea that were exposed to 
riboflavin alone and to various UVA irradiances (range 0.1 to 1.6 mW/cm2) with and 
without riboflavin. 42 An abrupt cytotoxic threshold was observed at an irradiance of 4 
mW/cm2 for UVA light alone and was ten-fold lower with an irradiance threshold of 0.35 
mW/cm2 for the UVA/riboflavin treatment. No endothelial cell damage was observed in 
the cells treated with riboflavin alone. Endothelial cell damage is believed to be due to 
oxidative damage caused by the oxygen reactive free radicals (singlet oxygen, superoxide 
anion, hydrogen peroxide) that are generated by the UV light. 43 
 
The lower cytotoxic thresholds observed for the UVA/riboflavin combination in the 
keratocyte and endothelial cell toxicity studies is consistent with the increase in UVA 
absorption in the anterior cornea in the presence of riboflavin. For example, 94% of 
incident UVA light is absorbed in the anterior 400 microns of the corneal stroma in the 
presence of riboflavin, as depicted in the graph below, whereas only 32% is absorbed 
within that depth in the absence of riboflavin. 44 
 
2.0 
COMBINATION PRODUCT DESCRIPTION 
2.1 
PXL Platinum 330 Illumination System 
The PXL Platinum 330 Illumination System is a portable electronic medical device. The 
device’s light emitting diode (LED) is used to deliver a metered dose of UV-A light to a 
targeted treatment area for illuminating the cornea during corneal collagen cross-linking.  
Components of the PXL Platinum 330 System include the LED light source, UV light 
detector, UV detector sensor probe and adapter, wall power supply with DC cord, 
                                                 
41 (Wollensak, Spoerl, Reber, & Seiler, 2004) 
42 (Wollensak, Sporl, Reber, Pillunat, & Funk, 2003) 
43 (Cho, Lee, Choi, & Joo, 1999) 
44 (Sporl, Schreiber, Hellmund, Seiler, & Knuschke, 2000) 
Fig. 7: Anterior stromal UVA absorption with riboflavin 

Protocol PXL-330 (v.2.0) CXL for Corneal Thinning  
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transportation case, safety goggles (to be worn by user), mechanical stand (C-clamp, 
cross clamp, rods), and an instruction manual. System specifications are as follows: 
 
Light Source 
High Power UV-grade LED; LED Laser class 3R 
(EN 60825-1) 
(Mfg. Nichia Co. LTD; Tokyo, Japan)  
Wavelength 
365 nm (± 10 nm) 
Optical Power 
Maximum 10 mW 
Beam Diameter 
7.5 mm to 11.5 mm 
Light Emission 
Continuous wave 
Intensity Setting 
3.0 mW/cm2 (±0.3 mW/cm2) 
Safety Class 
Class II Equipment (EN 60601-1) 
Medical 
Device 
Class 
Class IIa according to MDD 93/42/EEC 
EMI.EMC Class 
Class B (EN 60601-1) 
Power Supply 
SELV (Safety Extra Low Voltage)   9V;   max. 1.7A 
 
The Light Source houses the UVA irradiation mechanism. The LED is preset by the 
manufacturer to emit UVA radiation at a wavelength of 365 nm at variable intensities of 
3, 9, 18, or 30 mW/cm2 (±0.3 mW/cm2). UVA light emission is controlled by an internal 
microprocessor, which controls the electrical current used to drive the UV-LED. No UV 
light will be emitted in case of processor or LED failure. The diameter of the Light 
Source beam aperture is 25 mm and the treatment plane is 50 mm from the beam 
aperture. An aperture wheel mounted in the UVA irradiation beam path is used to 
produce a circular area of irradiation at the treatment plane with an approximate diameter 
of 3 – 12 mm, which is controlled by selecting the corresponding aperture wheel setting 
on the device. An intensity of 30 mW/cm2 and irradiance time of 3 minutes results in a 
standard surface dose of 5.4 J/cm2 surface exposure. With pulsed mode (5 second on, 5 
second off), the treatment time doubles. An eye tracker facilitates patient fixation on the 
light source. The Light Source has an integrated timer that automatically shuts off the 
light emission after the specified duration of exposure. A Power Supply plugged into a 
main electrical wall outlet and into the Light Source via the DC cord powers the Light 
Source.  The On/Off switch (On = ready mode) powers the device; the Start/Stop button 
controls UVA emission; and, status display lights (Red- Internal error, yellow-UV 
emission, Green-Device is powered, but no UV emission) indicate the status of the PXL 
Platinum 330 device. A battery operated UV Light detector, with a built-in low battery 
warning, is used to check the UV light irradiation in the treatment plane before patient 
treatment. The UV Light detector consists of a Sensor Probe and an indicator. The 
Sensor Probe Adapter with a Sensor Probe is permanently mounted to the UV-light 
illumination system to shield the beam aperture and should only be removed for 
treatment. 
 
2.2 
Riboflavin Solution  
We obtain the riboflavin solutions from: 
 

Protocol PXL-330 (v.2.0) CXL for Corneal Thinning  
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19
Peschke-MediTrade GmbH 
Chaesigass 6a  
6331 Huenenberg, Switzerland 
 
Peschke-TE (Riboflavin 0.25% Transepithelial Solution):  The riboflavin solution is 
an isotonic (0.9%) sodium chloride solution containing 0.25% riboflavin, 1% 
hydroxypropylmethylcellulose, and 0.007% benzalkonium chloride, adjusted to a pH of 
7.0, and packaged in 3 mL sterile dropper bottles for topical ophthalmic use. Shelf life is 
24 months. 
 
Peschke-L (Riboflavin 0.23% Solution): This riboflavin solution is an isotonic (.9%) 
sodium 
chloride 
solution 
containing 
disodium 
hydrogenphosphate, 
sodium 
dihydrogenphosphate, and water for injection. It is adjusted to a pH of 7.0, and packaged 
in 2 mL sterile pre-filled syringes, sealed and sterilized for ophthalmic use. Shelf life is 
24 months.  
 
 
3.0 
OBJECTIVES 
The primary objective of this study is to evaluate the safety and effectiveness of corneal 
collagen cross-linking (performed using the PXL-Platinum 330 system) for treating 
corneal curvature and biomechanical anomalies associated with corneal thinning 
conditions, e.g., progressive or nonprogressive keratoconus, pellucid marginal 
degeneration, and treatment of patients with bacterial or fungal keratitis.  
   
 
4.0 
SAFETY AND EFFICACY ENDPOINTS 
The primary efficacy parameter that will be evaluated over time is corneal curvature, as 
measured by maximum keratometry (Kmax) and mean keratometry (Kmean) in the 
randomized eyes.  Study success is defined as a difference of at least 1 diopter in the 
mean change in Kmax or Kmean from baseline to 12 months in the treated eyes. 
Secondary efficacy measurements will include: pachymetry, diopters of astigmatism as 
measured by keratometric cylinder, posterior corneal elevation, best spectacle-corrected 
visual acuity (BSCVA) or contact-lens best-corrected visual acuity, manifest refraction, 
corneal resistance factor, and corneal hysteresis.  
 
Safety assessments will include a tabulation of adverse events, patient symptoms, loss of 
visual acuity, slit lamp examination of the cornea and lens, and contact lens tolerance for 
contact lens wearers. Quality of vision will be assessed using the Refractive Status Vision 
Profile questionnaire. 45 Specific methods of analysis are provided in Section 9.0, Data 
Analysis.  
 
 
5.0 
STUDY DESIGN 
This is a prospective, double-arm, randomized single-site study to determine the safety 
and effectiveness of the PXL Platinum 330 system for performing corneal collagen cross-
                                                 
45 (Schein, Vitale, Cassard, & Steinberg, 2001) 

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linking (CXL) in eyes with corneal thinning. Subjects with a history of keratoconus, 
pellucid marginal degeneration, or non-resolving bacterial or fungal keratitis will be 
evaluated initially for suitability as a candidate for CXL. Subjects that are candidates for 
CXL will be asked to participate in this study and will undergo the required screening 
procedures to determine study eligibility.  Informed consent will be obtained from each 
subject before performance of any required study procedures that are not part of the 
investigator’s routine examination. After completing screening procedures, the diagnosis 
for each eligible eye will be confirmed, and diagnosis classified as mild, moderate or 
severe. 46  
 
Eyes undergoing CXL will have topical anesthetic administered and then have topical 
riboflavin instilled onto the cornea and, after the riboflavin pre-treatment regimen is 
complete, eyes in the treatment group will be exposed to UVA pulsed light 30 mW/cm2 
for 10 minutes (5 seconds, on, 5 seconds off) while eyes in the control group will be 
exposed to UVA continuous light at 9 mW/cm2 for 10 minutes, with topical riboflavin 
continuing to be administered during the illumination time for each group.   
 
The CXL procedures will be performed on an outpatient basis using the PXL Platinum 
330 System (UVA light source and riboflavin solution).  All use of the PXL Platinum 330 
System will be in accordance with this protocol and the general instructions provided by 
the manufacturer (IROC) in the PXL Platinum 330 operator’s manual. 
 
All subjects will be evaluated at screening/baseline, Day 0 (randomization/treatment 
day), and 1 day, 1 week, and 1, 3, 6 and 12 months after treatment.  Topographic 
keratometry, posterior corneal measurements (with Pentacam/Galilei/Orbscan/Cassini), 
corneal topography, manifest refraction, and measurements of best spectacle or contact -
corrected visual acuity, and intraocular pressure will be obtained at baseline and at 
appropriate times after the CXL treatment.  Safety monitoring throughout the study will 
include observations at appropriate times for subjective complaints, complications, 
adverse events, clinically significant findings on ophthalmic examination, dilated fundus 
examination, and slit lamp examination.  Quality of vision and subjective visual 
complaints will be evaluated preoperatively and postoperatively with a vision related 
quality of life questionnaire.   
 
 
6.0 
SUBJECT POPULATION 
This study is a single-center study that will be conducted over 10 years.  Up to 300 
patients with corneal thinning conditions will be enrolled.   
 
6.1 
Inclusion Criteria 
Subjects who have one or both eyes that meet criteria 1 and 1 or more of the 
following criteria will be considered candidates for this study: 
1. 12 years of age or older 
                                                 
46 (McMahon et al., 2006) 

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2. Presence of central or inferior steepening. 
3. Axial topography consistent with keratoconus, post-surgical ectasia, or pellucid 
marginal degeneration 
4. Presence of one or more findings associated with keratoconus or pellucid 
marginal degeneration, such as: 
a. Fleischer ring 
b. Vogt’s striae 
c. Decentered corneal apex 
d. Munson’s sign 
e. Rizzutti’s sign 
f. Apical Corneal scarring consistent with Bowman’s breaks 
g. Scissoring of the retinoscopic reflex 
h. Crab-claw appearance on topography 
5. Steepest keratometry (Kmax) value ≥ 47.20 D 
6. I-S keratometry difference > 1.5 D on the Pentacam/Galilei/Orbscan/Cassini map 
or topography map 
7. Posterior corneal elevation >16 microns 
8. Thinnest corneal point <485 microns 
9. Predicted Post LASIK/PRK stromal ablation depth <350 microns or expected 
keratometry >47.2 D, or patients undergoing PRK/SMILE in keratoconus suspect 
eyes 
10. Bacterial or fungal corneal keratitis persistent and not responding despite > 2 
weeks of standard antimicrobial therapy or with rapid progression of corneal 
thinning, with loss of >25% corneal thickness 
11. Contact Lens Wearers Only:   
a. Removal of contact lenses for the required period of time prior to the 
screening refraction: 
 
Contact Lens Type 
Minimum Discontinuation Time 
Soft 
1 Week 
Soft Extended Wear 
2 Weeks 
Soft Toric 
3 Weeks 
Rigid gas permeable 
2 Weeks per decade of wear 
 
12. Signed written informed consent 
13. Willingness and ability to comply with schedule for follow-up visits 
6.2 
Exclusion Criteria 
All subjects meeting any of the following criteria will be excluded from this study: 
1. Eyes classified as either normal or atypical normal on the severity grading 
scheme. 
2. Corneal pachymetry at the screening exam that is <300 microns at the thinnest 
point in the eye(s) to be treated. 
3. Previous ocular condition (other than refractive error) in the eye(s) to be treated 
that may predispose the eye for future complications, for example: 

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a. History of or active corneal disease (e.g., herpes simplex, herpes zoster 
keratitis, recurrent erosion syndrome, acanthomeoeba, etc.) 
b. Clinically significant corneal scarring in the CXL treatment zone that is 
not related to keratoconus or, in the investigator’s opinion, will interfere 
with the cross-linking procedure. 
4. Pregnancy (including plan to become pregnant) or lactation during the course of 
the study 
5. A known sensitivity to study medications 
6. Patients with nystagmus or any other condition that would prevent a steady gaze 
during the CXL treatment or other diagnostic tests. 
7. Patients with a current condition that, in the physician’s opinion, would interfere 
with or prolong epithelial healing. 
 
7.0 
SCREENING FOR CXL ELIGIBILITY 
A flow chart of study procedures is provided in Appendix A.   
7.1 
Preoperative Evaluation (Day -30 to Day 0) 
All screening examination procedures will be performed by the investigator or trained 
personnel working under the investigator’s supervision. Study candidates who are 
evaluated preoperatively by referring doctors will sign a consent form and have the 
screening procedures repeated preoperatively by the study personnel.  Screening data 
from referring doctors will not be used as the screening data for the study, except to 
document the progression of keratoconus, ectasia, pellucid marginal degeneration or 
corneal infection. Procedures or evaluations that were performed by study personnel 
during their routine clinic evaluation may be used for the screening examination if the 
testing was completed: (1) within 30 days of randomization; (2) in accordance with the 
protocol requirements; (3) all screening tests performed are known to be included in the 
investigator’s usual and customary examination procedures.  Subjects will sign a consent 
form before any clinical protocol procedures or tests specific to the study protocol are 
performed. 
 
7.1.1 Screening Eye Examination  
Potential CXL candidates will undergo a complete eye examination to determine their 
eligibility for study participation.  A complete ocular history, medical history and 
medication history will be obtained.  The complete eye examination and ocular history 
will include: 
 History of contact lens wear or corneal infection 
 History of risk factors for keratoconus 
 UCVA (distance) 
 BSCVA or best-contacted corrected visual acuity (distance) 
 Manifest refraction 
 Pentacam/Galilei/Orbscan/Cassini measurements, including 
o Pachymetry 
o Keratometry 
o Posterior corneal mapping 

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 Corneal topography 
 Intraocular pressure (by Goldmann applanation tonometry) 
 Slit lamp examination of the cornea, anterior chamber and lens 
 Dilated fundus examination 
 RSVP/ Subjective complaint questionnaire 
 
For eyes undergoing CXL treatment, if the CXL treatment is performed more than one 
month after the screening examination, the following measurements will be repeated on 
the day of treatment: 
 
 Topography 
 Pentacam/Galilei/Orbsca/Cassini 
 UCVA (distance) 
 BSCVA (distance) 
 Manifest refraction 
. 
Manifest refractions will be recorded on the source documents in the investigator’s usual 
notation (plus or minus cylinder format). All manifest refractions will be recorded on the 
case report forms in the study using plus cylinder format. Additional instructions for 
these test procedures are provided in Appendix A.  
 
7.1.2 Contact Lens Discontinuation 
Contact lens wearers should discontinue contact lenses at schedule noted above in 
inclusion criteria.  Contact lens wearers should exhibit a stable refraction at the two most 
recent consecutive exams before cross-linking.  A stable refraction is first determined as 
one in which the manifest refraction measurement and the topography (i.e., average SIM 
K readings from the topography) taken at the first visit do not differ by more than 0.75 D 
MRSE from the respective measurements taken at the second exam. If one or more of the 
measurements exhibit a difference greater than 0.75 D MRSE, the subject should either: 
(1) be declared a screening failure; or, (2) additional visits should be completed until 
stability (<0.75D MRSE difference) is attained for each of the three parameters. All exam 
dates for these measurements should be at least 7 days apart.   
 
7.2 
Keratoconus Severity 
Eyes that meet the eligibility criteria for progressive keratoconus will be classified 
according to severity using the grading scheme below adapted from McMahon et al.47  If 
the criteria fall into more than one severity category, the severity rating will be based on 
the keratometry reading. Eyes that are classified as being normal or atypical normal are 
ineligible for the study and will be recorded as screening failures. 
 
 Normal 
                                                 
47 McMahon TT, Szcotka-Flynn L, Barr JT, et al. A new method for grading the severity of keratoconus. 
Cornea. 25(7):794-800; August 2006 

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o Regular axial topography pattern (round, oval, symmetric bow tie, etc.) 
o Normal slit lamp exam 
o Spectacle corrected acuity 20/20 or better 
  Atypical Normal 
o Unusual axial topography explained by slit-lamp exam or history (contact 
lens warpage, cortical scars not typical of keratoconus, history of 
refractive surgery) 
o Normal or diminished spectacle acuity 
 Keratoconus Suspect 
o Suspicious axial topography for keratoconus (isolated area of steepening, 
central steepening > 48 D) but I-S value less than 1.4 
o Normal slit lamp exam 
o BSCVA 20/20 or better 
 Mild Keratoconus 
o Axial topography consistent with keratoconus 
o Flat keratometry reading < 51.00 D 
o Fleischer ring or Vogt striae 
o No corneal scarring 
o BSCVA worse than 20/20 
 Moderate Keratoconus 
o Axial topography consistent with keratoconus 
o Flat keratometry reading between 51.25 D and 56.00 D or astigmatism ≥ 
8.00 D 
o Fleischer ring or Vogt striae 
o May have corneal scarring up to and including CLEK grade 3.0 (any 
scarring up to well-defined stromal scarring consistent with keratoconus) 
o BSCVA 20/30 or worse 
 Severe Keratoconus 
o Axial topography consistent with keratoconus with marked areas of 
steepening 
o Flat keratometry reading > 56.01 D 
o Fleischer ring or Vogt striae 
o May have corneal scarring up to and including CLEK grade 4.0 (any 
scarring up to a dense/opaque stromal scar consistent with keratoconus) 
o BSCVA worse than 20/40  
 
 
8.0 
STUDY PROCEDURES 
Subjects who elect to participate in this study will complete the study as outlined below. 
All tests and measurements will be obtained in accordance with the procedures specified 
in this protocol. 
 
8.1 
Examination Schedule 
The study duration is 12 months following the crosslinking treatment, unless extended 
due to retreatment.  The following examination schedule will be followed:  

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 Preoperative (-30 to -1 days) 
 Operative (Day 0) 
 Day 1 (1 to 3 days) 
 Week 1 (5 to 14 days) 
 Month 1 (3 to 6 weeks) 
 Month 3 (10 to 14 weeks) 
 Month 6 (20 to 28 weeks) 
 Month 12 (40 to 60 weeks) 
 
8.2 
Outpatient CXL Treatment (Treatment Group) 
An interim medical history, ocular history, and medication history will be obtained to 
determine whether any events or changes in health status have occurred that would 
preclude the subject from undergoing CXL treatment at the scheduled time or from 
participating in the study.  Measurements from the complete eye examination that were 
performed during screening may be repeated, at the discretion of the investigator, to 
provide accurate baseline measurements. 
 
Subjects will be prepared for CXL treatment in accordance with the instructions for use 
in the PXL Platinum 330 Illumination System Operator’s Manual. 
 
Prior to the CXL treatment, the staff will confirm that the informed consent form for the 
study has been signed. If the results of any repeat measurements performed on the CXL 
treatment day fail to meet eligibility criteria, the CXL treatment will be postponed or the 
subject will be dropped from the study. 
 
Subjects will remain in the clinic until the CXL treatment has been completed and the 
investigator determines that it is safe for the subject to be discharged from the clinic. 
Generally, the average time from arrival to discharge will be approximately 2 hours. 
 
8.2.1 Surgical Procedure for CXL 
CXL will be performed according to the Instructions for Use provided in the PXL 
Platinum 330 Operator’s Manual. A summary of the general technique for performing 
CXL is summarized below. CXL procedures used for each subject will be documented on 
the source documents. Selected treatment information, including the riboflavin 
administration, irradiance settings, and duration of irradiation exposure will be 
documented. 
 
8.2.2 Subject Preparation 
After topical anesthesia, the surgeon or trained designee will apply topical riboflavin (1 
drop every 2 minutes for 40 minutes with transepithelial treatment). Local anesthetics 
will be administered as needed to maintain patient comfort during the CXL procedure. 
 

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8.2.3 Riboflavin 
Riboflavin will be administered according to the instructions provided by the 
manufacturer. 1 drop of Riboflavin 0.25% ophthalmic solution or 0.23% ophthalmic 
solution will be instilled topically in the eye every 2 minutes for 40 minutes, or instilled 
under a scleral contact lens reservoir for 5 to 10 minutes. At the end of this pre-treatment 
period, the eye will be examined at the slit lamp for the presence of a yellow flare in the 
anterior chamber, indicating adequate riboflavin saturation of the corneal tissue. If the 
yellow flare is not detected, riboflavin will continue to be instilled 1 drop every 2 minutes 
for an additional 10 to 20 minutes, and the anterior chamber will be rechecked for yellow 
flare.  This process will be repeated as necessary.  
 
During irradiation, instillation of riboflavin will be continued every 2 minutes. For a 40-
minute pre-treatment and 5-minute irradiation, the total dose of riboflavin solution is 
approximately 22 drops, or 1.1 ml (1 drop = 0.05 ml; 1.1 mL = 4.4 mg riboflavin). 
8.2.4 UVA Light 
Prior to the first treatment of the day, the PXL Platinum 330 illumination system will be 
assembled and tested according to the manufacturer’s instructions.  The UV irradiance 
dose is the product of the irradiance intensity and the exposure time.  The intensity is a 
fixed parameter of the device. It is checked during the light test and cannot be changed by 
the user. 
 
When the yellow flare in the anterior chamber is confirmed, the eye will be aligned under 
the PXL Platinum 330 light (the treatment plane will be at the correct working distance 
from the PXL Platinum 330 beam aperture when the border of the projected beam is in 
sharp focus).  The correct aperture setting (3-12 mm) will be selected for the size of the 
eye and area needing to be treated, and the eye will be irradiated at 30 mW/cm2, with 
pulsed mode (5 second on, 5 second off) for 10 minutes (for standalone crosslinking 
procedures) or continuous mode for 2 minutes (2 (in concurrent refractive procedures), 
during which time instillation of riboflavin will continue (1 drop every 2 minutes).  
During the treatment, there will be 4 L blow-by oxygen via cannula.  At the end of the 
treatment, the UV light source will automatically switch to the off position.  The operator 
will keep track of irradiation time independently to confirm the actual treatment time. 
 
The eye will be examined at a slit lamp, a drop of antibiotic (4th generation 
fluoroquinolone), and a drop of steroid (prednisolone 1%) will be placed.  If the 
physician notes an epithelial defect, a bandage contact lens can be placed. 
8.2.5 Concurrent Procedures 
If Intacs are indicated based on patient’s condition and status, the physician may perform 
those according to customary procedures. In this case, the crosslinking with riboflavin 
would be performed after Intacs with the UVA light of the PXL Platinum 330 system as 
per section 8.2.4. 

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8.2.6 Postoperative Care 
Prescriptions for postoperative medications and written or verbal postoperative 
instructions will be given to each subject and reviewed prior to discharge. The following 
postoperative medications will be prescribed: 
 Gatifloxacin  0.5% drops for 2 weeks 
 Pred-Forte 1% drops for 2 months on a tapering schedule 
 Preservative-free artificial tears as needed  
 
All postoperative eye drop usage will be recorded in the subject's chart. The dosage 
and/or frequency of any of the above medications may be altered at the discretion of the 
investigator. Other prescription or nonprescription medications, including pain 
medication, may be taken as needed throughout the study.  
 
8.3 
Follow-Up Visits (1 Day, 1 Week, 1, 3, 6 and 12 months) 
A study flow chart summarizing the follow-up examination schedule and required 
procedures to be performed at each study visit is provided in Appendix A. All subjects 
will be seen at 1 day, 1 week, 1, 3, 6 and 12 months after CXL.   
 
The following will be performed at each visit unless noted otherwise. 
 Topography (omit on Day 1 and Week 1) 
 UCVA distance 
 BSCVA distance (omit on Day 1 and week 1) 
 Manifest refraction (omit on Day 1 and week 1) 
 Pentacam/Galilei/Orbscan/Cassini measurements (omit on Day 1 and Week 
1), including 
o Pachymetry 
o Keratometry 
o Posterior corneal evaluation 
 Intraocular pressure (by Goldmann applanation tonometry -- omit on Day 1) 
 Slit lamp examination of the cornea, anterior chamber and lens 
 Dilated fundus exam (Month 12 only) 
 RSVP/subjective complaint questionnaire (omit on Day 1 and Week 1) 
 Documentation of interim medical, medication, and ocular histories. 
 
Reasonable effort will be made by telephone and mail to contact subjects who miss a 
scheduled follow-up visit. 
8.4 
Retreatment  
The CXL treatment is intended to be a one time treatment. If progression is observed at 3, 
6, or 12 months, patient will be offered retreatment with the study device or referral to a 
center with the approved Avedro KXL system. 
 
If a patient receives crosslinking retreatment with the study device, the duration of the 
study will be extended for 6 months after the retreatment. The patient will receive 
additional study visits according to the following schedule: 

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 Retreatment Operative (Day 0) 
 Retreatment Day 1 (1 to 3 days) 
 Retreatment Week 1 (5 to 14 days) 
 Retreatment Month 1 (3 to 6 weeks) 
 Retreatment Month 3 (10 to 14 weeks) 
 Retreatment Month 6 (20 to 28 weeks) 
 
The procedures and assessments at the retreatment visits are the same as those which take 
place at the original post-op visits at the same time points. If a patient is retreated and the 
timing of the visit windows allows, the retreatment visits may be combined with the post-
op visits from the original crosslinking procedure (e.g. if a patient is retreated shortly 
after their 6 month post-op, their 6 month retreatment post-op can be combined with their 
12 month post-op from the original procedure).  
 
In prior ophthalmic experience with retreatment cases, it has been described that there 
can be insufficient or minimal penetration of riboflavin into the cornea. Sufficient 
penetration of riboflavin into the cornea is crucial for the success of the procedure and to 
reduce the risk of keratoconic progression. For retreatment cases, the investigator will 
follow the crosslinking procedure described in section 8.2 unless there is insufficient 
penetration of riboflavin upon slit lamp exam. If riboflavin penetration is insufficient, the 
following alterations to the surgical technique may be made at the investigator's 
discretion:  
 
1) Central corneal epithelial cells can be removed followed by additional riboflavin 
solution soak 
2)  Using 9 mw/cm2 intensity and 10 minutes continuous illumination time 
8.5 
Safety Monitoring 
During the CXL treatment procedure, subjects will be observed closely to detect the 
occurrence of any adverse events or complications that may have occurred.  On the day 
of treatment and at each follow-up visit, it is suggested that the subjects be asked a non-
leading question, such as “How are you seeing?,” to determine whether any 
complications or adverse events might have occurred since the last visit.  The presence or 
absence of adverse events or complications will be documented. 
 
Ophthalmic safety will be evaluated by slit lamp examination of the operated eye, 
measurements of refraction, and measurement of visual acuity.  In the case of an adverse 
event or complication, these tests may be repeated before the next scheduled visit at the 
investigator’s discretion.  Any complications or visual adverse events will be recorded in 
the medical record/case report form.  
8.6 
Post-Study Procedures 
Subjects will be discharged from the study after the 12-month follow-up examination is 
complete.  Clinically significant abnormalities will be followed until the abnormality 
returns to acceptable limits or there is an adequate explanation for the abnormality. 

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8.8 
PXL Platinum 330 and Riboflavin Accountability 
All use of the PXL Platinum 330 Illumination System,  Riboflavin 0.25% Ophthalmic 
Solution, and Riboflavin .23% Ophthalmic Solution will be under the direct supervision 
of the principal investigator or his designee. 
 
8.9 
Early Withdrawal from Study 
Subjects will be advised that they are free to withdraw from the study at any time.  
Subjects experiencing adverse safety events will be followed until the reaction has 
resolved.  Appropriate supportive and/or definitive therapy will be administered as 
required.  The investigator may discontinue a subject if a serious adverse event occurs 
and it is in the subject's best interest not to continue in the study or if the subject moves 
and the subject cannot complete the remainder of the follow-up visits. When a subject 
withdraws early from the study, a final examination will be performed at the time of 
withdrawal if possible. 
 
8.10 
Study Duration 
The study duration is a total of 12 months for all study subjects following the CXL 
treatment. The duration of the study will also be extended for those patients who have 
received retreatment or for subjects who elect to have CXL treatment in an untreated 
fellow eye.  
 
9.0 
DATA ANALYSIS AND STATISTICAL CONSIDERATIONS 
A detailed statistical analysis plan (SAP) will be developed for analysis of all data for this 
study.  Required analyses and target endpoints that will be included in this SAP are 
summarized below.  The methods by which each of these analyses is performed will be 
included in the SAP.  The required analyses and target endpoints include, but are not 
limited to those listed below. 
 
Tabulation of summary statistics, graphical presentations, and statistical analyses will be 
performed using SAS software.  All subjects who are enrolled in this study will be 
included in the safety analysis.  All two sided testing and confidence intervals will use a 
significance level of 5%. The superiority hypotheses will be tested at a significance level 
o 2.5%. 
 
9.1 
Sample Size 
 
9.1.1 Keratoconus, Ectasia, or Pellucid Marginal Degeneration 
 
The primary efficacy hypothesis for the treatment of keratoconus, ectasia, or pellucid 
marginal degeneration is to determine whether there is a difference in the mean change 

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from baseline in the maximal or mean keratometry readings before or after CXL 
treatment at 3, 6, or 12 months.  Since this hypothesis will be tested using a two sample t-
test, Table 9.1-1 presents sample sizes per treatment group for various values of the 
difference between the two means , and the standard deviation,  with the significance 
level = 0.025 and the power =80%.  Previous studies have indicated that at the 12 months 
time period there is a decrease in the K-readings for the CXL group of about 1.2 to 2.0 
diopters.  From previous studies, the standard deviations for the differences in K-readings 
have ranged from 1.5 to 2.5.  Thus these values are used in the following table. 
 
Table 9.1-1 Sample Size Calculations for Keratoconus, Ectasia, or PMD Groups 
 
 
sample 
size 
(per group) 
1.2 
1.5 
39 
 
2.0 
69 
 
2.5 
108 
2.0 
1.5 
14 
 
2.0 
25 
 
2.5 
39 
 
Enrolling 108 patients in each treatment group will enable the detection of a 1.2 diopter  
difference between the treatment groups with a coefficient of variability of 2.5 D. We 
would aim to have 108 patients per group complete the study from both genders. 
 
Since historically there is a 10% discontinuation rate, the sample size is adjusted for a 
10% rate of discontinued and lost-to-follow-up eyes: 
 
 
Adjusted Sample Size (n’) = n/(1-0.10) = n/0.90 
 
 
where: n is the initial estimated sample size  
 
 
 
 
 
 
(n’) = 108/0.90 
 
 
 
 
 
(n’) = 120 
120 eyes per treatment group (KCN,) X 2 genders = 240 patients 
 
9.1.2. Corneal keratitis or Thin Corneas Undergoing Refractive Surgery 
Bacterial 
or 
fungal 
keratitis, 
and 
patients 
with 
thin 
corneas 
undergoing 
LASIK/PRK/SMILE are much rarer conditions.  We would perform descriptive statistics 
only on these groups of patients.  We would like to recruit up to 60 patients in any of 
these groups. 
 
 
9.2 
Accountability 
Accountability by postoperative visit will be calculated as illustrated in Table 9.2-1 
below. 
 
Table 9.2-1: Accountability by Postoperative Visit 

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1 Month 
3 Months 
Available for Analysis2 
n/N1(%)  
 
 
Missed Visit3 
n/N1 (%) 
 
 
Discontinued4 
n/N1 (%) 
 
 
Active5 
n/N1 (%) 
 
 
Lost to follow-up6 
n/N1 (%) 
 
 
% Accountability = Available for Analysis 
(Enrolled - Discontinued - Active) 
 
 
Where,  
1 
Enrolled (N) = total number of subject eyes enrolled in the study.  
2  
Available for analysis = total number of eyes for whom data is available at 
each postoperative interval.  
3  
Missed visit = total number of eyes that missed the visit, but were 
otherwise accounted for. Includes those eyes that missed the visit but were 
seen at a later visit. 
4  
Discontinued = total number of eyes that discontinued follow-up prior to 
completion of the study for any reason (e.g., retreatment, moved away).  
5  
Active (not yet eligible for the interval) = total number of eyes that have 
not yet reached the visit interval.  
6  
Lost to follow-up = total number of eyes for whom a visit at the prescribed 
visit or later was not completed and who are not considered to be active or 
discontinued. 
 
9.3 
Screening 
The screening data for all subjects who were screened but did not meet eligibility criteria 
will not be analyzed or tabulated. 
 
9.4 
Subject Characteristics 
The number of subjects included in the safety and/or effectiveness evaluations, subjects 
completing the study, and the reasons for any withdrawals will be tabulated by counts 
and percents.  Continuous demographic data will be summarized using descriptive 
statistics.  Categorical demographic data will be summarized using counts and percents.   
Risk factors will be tabulated by eye and summarized using descriptive statistics. 

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9.5 
Primary Efficacy Criteria 
9.5.1 Keratometry 
The change in maximum and mean keratometry (Kmax and Kmean) from baseline will 
be evaluated at 3 months and 12 for all eyes.  Data will be summarized using descriptive 
statistics, and the differences in mean changes between the CXL treatment group and the 
control group at 3 months will be evaluated using a two sample t-test to test the following 
hypothesis: 
 
H0:CXL - C = 0 versus HA: CXL - C  > 0  
 
where C is the baseline reading (Kmax or Kmean) and CXL is the 3 or 12 month Kmax 
or Kmean reading.  
 
If it assumed the data from both treatment groups are normally distributed, then the test 
statistic from the ANOVA for testing the above hypothesis is a t-test.  
9.6 Secondary Efficacy Criteria 
9.6.1 Manifest Refraction 
The change in manifest refraction spherical equivalent from baseline will be evaluated at 
3 months.  Data will be summarized using descriptive statistics.  Differences in the mean 
changes from baseline between the two treatment groups will be tested using a two 
sample t-test at each time point.  
 
As a secondary analysis of this endpoint, a repeated measures analysis of variance will be 
conducted to assess the profile of the treatments across time at 1, 3, 6, and 12 months. 
 
9.6.2 Visual Acuity 
Change in BSCVA or best-contact corrected visual acuity and UCVA compared to the 
baseline examination will be evaluated at 3 months postoperatively.  Data will be 
summarized using descriptive statistics. Differences in the mean changes from baseline 
between the two treatment groups will be tested using a two sample t-test. 
 
As a secondary analysis of this endpoint, a repeated measures analysis of variance will be 
conducted to assess the profile of the treatments across time at 1, 3, 6, and 12 months. 
 
 
9.6.3 Central Pachymetry 
The change in central pachymetry from baseline will be evaluated at 3 months 
postoperatively.  Data will be summarized using descriptive statistics. Differences in the 
mean changes from baseline between the two treatment groups will be tested using a two 
sample t-test. 
 

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As a secondary analysis of this endpoint, a repeated measures analysis of variance will be 
conducted to assess the profile of the treatments across time at 1, 3, 6, and 12 months. 
 
9.7 
Clinical Safety Endpoint Criteria 
9.7.1 Adverse Events and Complications 
 
All subject questionnaire data, complications, and adverse events will be tabulated and 
summarized. 
9.7.2  Key Safety Parameters 
For each time point, the following key safety parameters will be estimated for the entire 
cohort.   
1) Percentage of eyes that had a loss of 2 or more lines in BSCVA 
2) Percentage of eyes that had a BSCVA worse than 20/40 
3) Percentage of eyes that had a greater than 2D increase in Kmax or Kmean 
 
 
9.8 
Refractive Status Vision Profile 
The RSVP will be administered pre-treatment at screening to establish the subject’s 
baseline and at 1, 3, 6 and 12 months after CXL.  The change in RSVP from baseline will 
also be evaluated at 1, 3, 6 and 12 months postoperatively. Data will be summarized 
using descriptive statistics. A lower RSVP score indicates less dysfunction.  
 
The secondary safety endpoint will be the difference in the composite score for the RSVP 
administered at 3 months after CXL and the pre-treatment or baseline composite score. 
Therefore, it is desired to determine if the composite score for the RSVP has decreased 
significantly from the preoperative assessment by the 3 month time point. Published 
literature indicates that a difference of 6 points or more on the composite scores is a 
clinically significant change. 48 
 
9.9 
Dropouts/Lost-to-Follow-up 
Patients may drop out at any time during the study.  All treated patients/eyes will be 
included in the safety analysis. 
 
The primary analysis population for the primary analysis will be based on an Intent-to- 
Treat population in which missing differences at 3 months for the CXL treated group will 
be replaced by the smallest maximum difference observed.  A per protocol analysis will 
also be conducted where the missing values are dropped from the analysis. 
 
                                                 
48 (Schein et al., 2001) 

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9.10 
Interim Analysis 
An interim analysis will be performed after all eyes complete the 3-month post-CXL 
visit.  All relevant data summaries will be made according to the regulatory process, 
using appropriate statistical methods.  
 
 
10.0 
ETHICAL AND REGULATORY CONSIDERATIONS 
This study will be conducted in accordance with FDA’s Good Clinical Practice 
regulations.  
10.1 
Informed Consent 
In accordance with the provision of 21 CFR Part 50, each subject will provide written 
informed consent for participation in this study prior to the use of the investigational 
device (Appendix B).   
 
The study will be explained to the prospective subject by the investigator or his designee.  
The nature of the experimental product will be explained together with potential hazards 
of the surgical procedure, including any possible adverse reactions.  The subject will be 
informed that he/she is free to terminate participation in the study for any reason.  One 
copy of the signed consent form will be retained in the medical record.  
 
10.2 
Institutional Review Board 
This protocol and the informed consent form will be approved initially and reviewed 
annually by an Institutional Review Board (IRB) constituted according to FDA 
regulations   Progress reports will be submitted at the completion of the study or at least 
once yearly, whichever comes first, to the IRB.  Serious adverse events will be reported 
to the IRB and the FDA in accordance with applicable FDA regulations for serious 
adverse events. 
10.3 
Complications and Adverse Events 
Adverse events that are observed by the investigator or reported by the subject will be 
recorded on the study source documents/case report forms.  For all adverse events, a 
description of the event, date first observed, any action taken, and its resolution will be 
recorded. 
10.3.1 Serious and Unexpected Drug Adverse Events 
The sponsor and investigator must comply with the applicable sections of 21CFR312.32 
and 21CFR312.64(b) for IND safety reports. In accordance with these regulations, the 
following definitions apply: 
Associated with the use of the drug. There is a reasonable possibility that the experience 
may have been caused by the drug.  

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Disability. A substantial disruption of a person's ability to conduct normal life functions.  
Life-threatening adverse drug experience. Any adverse drug experience that places the 
patient or subject, in the view of the investigator, at immediate risk of death from the 
reaction as it occurred, i.e., it does not include a reaction that, had it occurred in a more 
severe form, might have caused death.  
Serious adverse drug experience: Any adverse drug experience occurring at any dose that 
results in any of the following outcomes: Death, a life-threatening adverse drug 
experience, inpatient hospitalization or prolongation of existing hospitalization, a 
persistent or significant disability/incapacity, or a congenital anomaly/birth defect. 
Important medical events that may not result in death, be life-threatening, or require 
hospitalization may be considered a serious adverse drug experience when, based upon 
appropriate medical judgment, they may jeopardize the patient or subject and may require 
medical or surgical intervention to prevent one of the outcomes listed in this definition. 
Examples of such medical events include allergic bronchospasm requiring intensive 
treatment in an emergency room or at home, blood dyscrasias or convulsions that do not 
result in inpatient hospitalization, or the development of drug dependency or drug abuse.  
Unexpected adverse drug experience: Any adverse drug experience, the specificity or 
severity of which is not consistent with the current investigator brochure; or, if an 
investigator brochure is not required or available, the specificity or severity of which is 
not consistent with the risk information described in the general investigational plan or 
elsewhere in the current application, as amended. For example, under this definition, 
hepatic necrosis would be unexpected (by virtue of greater severity) if the investigator 
brochure only referred to elevated hepatic enzymes or hepatitis. Similarly, cerebral 
thromboembolism and cerebral vasculitis would be unexpected (by virtue of greater 
specificity) if the investigator brochure only listed cerebral vascular accidents. 
"Unexpected," as used in this definition, refers to an adverse drug experience that has not 
been previously observed (e.g., included in the investigator brochure) rather than from 
the perspective of such experience not being anticipated from the pharmacological 
properties of the pharmaceutical product.  
An investigator shall promptly report to the sponsor any adverse effect that may 
reasonably be regarded as caused by, or probably caused by, the drug. If the adverse 
effect is alarming, the investigator shall report the adverse effect immediately. 
Any adverse experience associated with the use of the drug that is both serious and 
unexpected shall be reported by the sponsor to FDA as soon as possible and in no event 
later than 15 calendar days after the sponsor’s initial receipt of the information. Each 
written notification may be submitted on FDA Form 3500A or in a narrative format and 
shall bear prominent identification of its contents, i.e., "IND Safety Report." Each written 
notification to FDA shall be transmitted to the FDA new drug review division in the 
Center for Drug Evaluation and Research or the product review division in the Center for 
Biologics Evaluation and Research that has responsibility for review of the IND. If FDA 

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determines that additional data are needed, the agency may require further data to be 
submitted.  
The sponsor shall also notify FDA by telephone or by facsimile transmission of any 
unexpected fatal or life-threatening experience associated with the use of the drug as soon 
as possible but in no event later than 7 calendar days after the sponsor's initial receipt of 
the information. Each telephone call or facsimile transmission to FDA shall be 
transmitted to the FDA new drug review division in the Center for Drug Evaluation and 
Research or the product review division in the Center for Biologics Evaluation and 
Research that has responsibility for review of the IND. 
In addition to notifying FDA, the sponsor will also notify each investigator of any serious 
and unexpected, fatal, or life-threatening experiences associated with the use of the drug. 
The investigators will promptly report these experiences to the IRB. If the IRB has 
different or specific reporting deadlines, reports should be made to the IRB in accordance 
with the IRB’s requirements. 
10.3.2 Serious and Unanticipated Adverse Device Effects 
An unanticipated adverse device effect is defined as “any serious adverse effect on health 
or safety or any life-threatening problem or death caused by, or associated with, a device 
if that effect, problem, or death was not previously identified in nature, severity, or 
degree of incidence in the investigational plan, or any other unanticipated serious 
problem associated with a device that relates to the rights, safety or welfare of subjects.” 
Since CDER has primary jurisdiction for the regulation of this combination product, 
serious and unanticipated adverse device effects will be reported to FDA and the IRB in 
accordance with the reporting requirements described in Section 10.3.1 above. 
 
10.3.3 Non-serious Drug or Device or Anticipated Device Adverse Events 
Non-serious drug or device adverse events or anticipated device adverse events and 
complications should be documented on the case report forms and tabulated for reporting 
in the annual reports to FDA.  
 
10.4 
Monitoring 
A monitor will be designated by the sponsor to oversee the progress of the investigation.  
The monitor may be an employee of the sponsor or a consultant to the sponsor.  The 
monitor will meet with the investigator and staff before the study, during the study 
annually, and at other appropriate times to ensure compliance with the FDA’s Good 
Clinical Practice requirements and with the protocol specifications.  All records 
pertaining to the study will be made available to the monitor at each review. 
 

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10.5 
Source Documents/Case Report Forms 
Adequate records will be maintained for the study including subject medical and surgical 
records, test reports, work sheets, nursing notes, signed informed consent forms, drug and 
device use records, adverse experience reports and information regarding subject 
discontinuation and reasons for discontinuation.  All original source documentation will 
remain at the investigative site. Study data that are stored at the investigator site in any 
electronic medical records system, including measurements that are obtained 
electronically (e.g., Pentacam, topography), will be printed and retained in the study files. 
 
All study data will be recorded onto case report forms (electronic or paper) designed for 
the study. Copies of the case report forms will be retained with the investigator’s study 
files and the original forms will be filed with the sponsor. 
 
10.6 
Deviation from the Protocol 
The investigator will not deviate from the protocol without prior approval from the IRB 
and the sponsor, unless such deviation is necessary to manage a medical emergency. The 
investigator will notify the IRB and the sponsor of any protocol deviation to protect the 
life, ocular health, or physical well-being of a subject in an emergency.  Such notice shall 
be given as soon as possible, but in no event any later than 5 working days after the 
emergency occurred.   All other revisions and/or amendments to the protocol that affect 
subject treatment, study outcome, or subject safety will be submitted in writing to the 
IRB and the sponsor for approval prior to implementation if the changes or deviations to 
the protocol affect the scientific soundness of the study or the rights, safety, or welfare of 
human subjects.  In this case, the change will not be implemented until IRB approval is 
obtained.  The investigator will maintain a record of all protocol deviations showing the 
dates of, and the reason for, each protocol deviation. 
 
Changes that affect the scientific soundness of the study or the rights, safety, or welfare 
of human subjects may also require FDA and IRB approval prior to implementation.  The 
sponsor and investigator will obtain such approvals, if required.  
 

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APPENDIX A:  STUDY FLOW CHART 
 
Procedure 
Scree
n 
Surgery
49                    POSTOPERATIVE VISITS 
1 
DA
Y 
1 
W
K 
1 
M
O 
3 
M
O 
6 
M
O 
12 
M
O 
Medical History 
X 
X 
X 
X 
X 
X 
X 
X 
Ocular History50 
X 
X 
X 
X 
X 
X 
X 
X 
Medication History 
X 
X 
X 
X 
X 
X 
X 
X 
Demographics 
X 
 
 
 
 
 
 
 
BCVA51 
X 
 
 
X 
X 
X 
X 
X 
UCVA52 
X 
 
X 
X 
X 
X 
X 
X 
Manifest Refraction 
X 
 
 
 
X 
X 
X 
X 
Confocal microscopy (optional) 
X 
 
 
 
 
 
 
X 
Intraocular 
Pressure 
Measurement53 
X 
 
 
X 
X 
X 
X 
X 
Slit Lamp Exam54 
X 
 
X 
X 
X 
X 
X 
X 
Dilated Fundus Examination 
X 
 
 
 
 
 
 
X 
Pentacam/Orbscan/Galilei/Cassi
ni55 
X 
 
 
 
X 
X 
X 
X 
Corneal Topography 
X 
 
 
 
X 
X 
X 
X 
RSVP Subjective Complaint 
Questionnaire 
X 
 
 
 
X 
X 
X 
X 
Sign Consent 
X 
 
 
 
 
 
 
 
Complications 
 
X 
X 
X 
X 
X 
X 
X 
Adverse Events 
 
X 
X 
X 
X 
X 
X 
X 
CXL Treatment 
 
X 
 
 
 
 
 
 
 
Notes for the Examination Schedule (See footnotes below)     
 
                                                 
49 Repeat measurements from the screening exam prior to surgery if needed to provide accurate baseline 
measurements before CXL treatment. 
50 Ocular history should include history of contact lens wear, risk factors for keratoconus, and history of 
refractive surgery. Non-specific questioning should be used at each visit to determine other vision-related 
complaints, complications, or adverse events 
51 Distance BSCVA should be performed using an ETDRS eye chart and recording the total number of 
letters that are seen. 
52 Distance BSCVA should be performed using an ETDRS eye chart and recording the total number of 
letters that are seen 
53 Intraocular pressure measurement by Goldmann applanation tonometry at the slit lamp or by tonopen.  
54 The slit lamp exam should include a complete survey of the anterior segment. The cornea should be 
examined in detail with specific recordings and gradings (0 to 4+ scale, 0=clear) of the following 
information: overall corneal clarity, any abnormalities such as corneal infiltrates. 
55 Pentacam measurements are performed using the Pentacam HR (high resolution). 

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APPENDIX B:  CFR 50.25 - ELEMENTS OF INFORMED CONSENT 
 
BASIC ELEMENTS OF INFORMED CONSENT:  In seeking informed consent, the 
following information shall be provided to each subject. 
 
1. 
A statement that the study involves research, an explanation of the purpose of the 
research and the expected duration of the subject’s participation, a description of 
the procedures to be followed, and identification of any procedures which are 
experimental. 
2. 
A description of any reasonably foreseeable risks or discomforts to the subject. 
3. 
A description of any benefits to the subject or to others which may reasonably be 
 
expected from the research. 
4. 
A disclosure of appropriate alternative procedures or courses of treatment, if any,
 
that might be advantageous to the subject. 
5. 
A statement describing the extent, if any, to which confidentiality of records 
 
identifying the subject will be maintained and that notes the possibility that the 
 
U.S. Food and Drug Administration may inspect records. 
6. 
For research involving more than minimal risk, an explanation as to whether any 
 
compensation and an explanation as to whether any medical treatments are 
 
available if injury occurs and, if so, what they consist of, or where further 
 
information may be obtained. 
7. 
An explanation of whom to contact for answers to pertinent questions about the 
research and research subject’s rights, and whom to contact in the event of a 
research-related injury. 
8. 
A statement that participation is voluntary, that refusal to participate will involve 
no penalty or loss of benefits to which the subject is otherwise entitled, and that 
the subject may discontinue participation at any time without penalty or loss of 
benefits to which the subject is otherwise entitled. 

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APPENDIX C:  WORLD MEDICAL ASSOCIATION DECLARATION OF HELSINKI  
Ethical Principles for Medical Research Involving Human Subjects  
Adopted by the 18th WMA General Assembly Helsinki, Finland, June 1964 and amended 
by the 29th WMA General Assembly, Tokyo, Japan, October 1975 35th WMA General 
Assembly, Venice, Italy, October 1983 41st WMA General Assembly, Hong Kong, 
September 1989 48th WMA General Assembly, Somerset West, Republic of South 
Africa, October 1996 and the 52nd WMA General Assembly, Edinburgh, Scotland, 
October 2000  
 
A. INTRODUCTION  
1. The World Medical Association has developed the Declaration of Helsinki as a 
statement of ethical principles to provide guidance to physicians and other 
participants in medical research involving human subjects. Medical research 
involving human subjects includes research on identifiable human material or 
identifiable data.  
2.  It is the duty of the physician to promote and safeguard the health of the people. The 
physician's knowledge and conscience are dedicated to the fulfillment of this duty.  
3.  The Declaration of Geneva of the World Medical Association binds the physician 
with the words, "The health of my patient will be my first consideration," and the 
International Code of Medical Ethics declares that, "A physician shall act only in the 
patient's interest when providing medical care which might have the effect of 
weakening the physical and mental condition of the patient."  
4.  Medical progress is based on research which ultimately must rest in part on 
experimentation involving human subjects.  
5.  In medical research on human subjects, considerations related to the well-being of the 
human subject should take precedence over the interests of science and society.  
6.  The primary purpose of medical research involving human subjects is to improve 
prophylactic, diagnostic and therapeutic procedures and the understanding of the 
aetiology and pathogenesis of disease. Even the best proven prophylactic, diagnostic, 
and therapeutic methods must continuously be challenged through research for their 
effectiveness, efficiency, accessibility and quality.  
7.  In current medical practice and in medical research, most prophylactic, diagnostic and 
therapeutic procedures involve risks and burdens.  
8.  Medical research is subject to ethical standards that promote respect for all human 
beings and protect their health and rights. Some research populations are vulnerable 
and need special protection. The particular needs of the economically and medically 
disadvantaged must be recognized. Special attention is also required for those who 
cannot give or refuse consent for themselves, for those who may be subject to giving 
consent under duress, for those who will not benefit personally from the research and 
for those for whom the research is combined with care.  
9.  Research Investigators should be aware of the ethical, legal and regulatory 
requirements for research on human subjects in their own countries as well as 
applicable international requirements. No national ethical, legal or regulatory 

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requirement should be allowed to reduce or eliminate any of the protections for 
human subjects set forth in this Declaration.  
 
B. BASIC PRINCIPLES FOR ALL MEDICAL RESEARCH  
10. It is the duty of the physician in medical research to protect the life, health, privacy, 
and dignity of the human subject.  
11. Medical research involving human subjects must conform to generally accepted 
scientific principles, be based on a thorough knowledge of the scientific literature, 
other relevant sources of information, and on adequate laboratory and, where 
appropriate, animal experimentation.  
12. Appropriate caution must be exercised in the conduct of research which may affect 
the environment, and the welfare of animals used for research must be respected.  
13. The design and performance of each experimental procedure involving human 
subjects should be clearly formulated in an experimental protocol. This protocol 
should be submitted for consideration, comment, guidance, and where appropriate, 
approval to a specially appointed ethical review committee, which must be 
independent of the investigator, the sponsor or any other kind of undue influence. 
This independent committee should be in conformity with the laws and regulations of 
the country in which the research experiment is performed. The committee has the 
right to monitor ongoing trials. The researcher has the obligation to provide 
monitoring information to the committee, especially any serious adverse events. The 
researcher should also submit to the committee, for review, information regarding 
funding, sponsors, institutional affiliations, other potential conflicts of interest and 
incentives for subjects.  
14. The research protocol should always contain a statement of the ethical considerations 
involved and should indicate that there is compliance with the principles enunciated 
in this Declaration.  
15. Medical research involving human subjects should be conducted only by 
scientifically qualified persons and under the supervision of a clinically competent 
medical person. The responsibility for the human subject must always rest with a 
medically qualified person and never rest on the subject of the research, even though 
the subject has given consent.  
16. Every medical research project involving human subjects should be preceded by 
careful assessment of predictable risks and burdens in comparison with foreseeable 
benefits to the subject or to others. This does not preclude the participation of healthy 
volunteers in medical research. The design of all studies should be publicly available.  
17. Physicians should abstain from engaging in research projects involving human 
subjects unless they are confident that the risks involved have been adequately 
assessed and can be satisfactorily managed. Physicians should cease any investigation 
if the risks are found to outweigh the potential benefits or if there is conclusive proof 
of positive and beneficial results.  
18. Medical research involving human subjects should only be conducted if the 
importance of the objective outweighs the inherent risks and burdens to the subject. 
This is especially important when the human subjects are healthy volunteers.  

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19. Medical research is only justified if there is a reasonable likelihood that the 
populations in which the research is carried out stand to benefit from the results of the 
research.  
20. The subjects must be volunteers and informed participants in the research project.  
21. The right of research subjects to safeguard their integrity must always be respected. 
Every precaution should be taken to respect the privacy of the subject, the 
confidentiality of the patient's information and to minimize the impact of the study on 
the subject's physical and mental integrity and on the personality of the subject.  
22. In any research on human beings, each potential subject must be adequately informed 
of the aims, methods, sources of funding, any possible conflicts of interest, 
institutional affiliations of the researcher, the anticipated benefits and potential risks 
of the study and the discomfort it may entail. The subject should be informed of the 
right to abstain from participation in the study or to withdraw consent to participate at 
any time without reprisal. After ensuring that the subject has understood the 
information, the physician should then obtain the subject's freely-given informed 
consent, preferably in writing. If the consent cannot be obtained in writing, the non-
written consent must be formally documented and witnessed.  
23. When obtaining informed consent for the research project the physician should be 
particularly cautious if the subject is in a dependent relationship with the physician or 
may consent under duress. In that case the informed consent should be obtained by a 
well-informed physician who is not engaged in the investigation and who is 
completely independent of this relationship.  
24. For a research subject who is legally incompetent, physically or mentally incapable of 
giving consent or is a legally incompetent minor, the investigator must obtain 
informed consent from the legally authorized representative in accordance with 
applicable law. These groups should not be included in research unless the research is 
necessary to promote the health of the population represented and this research cannot 
instead be performed on legally competent persons.  
25. When a subject deemed legally incompetent, such as a minor child, is able to give 
assent to decisions about participation in research, the investigator must obtain that 
assent in addition to the consent of the legally authorized representative.  
26. Research on individuals from whom it is not possible to obtain consent, including 
proxy or advance consent, should be done only if the physical/mental condition that 
prevents obtaining informed consent is a necessary characteristic of the research 
population. The specific reasons for involving research subjects with a condition that 
renders them unable to give informed consent should be stated in the experimental 
protocol for consideration and approval of the review committee. The protocol should 
state that consent to remain in the research should be obtained as soon as possible 
from the individual or a legally authorized surrogate.  
27. Both authors and publishers have ethical obligations. In publication of the results of 
research, the investigators are obliged to preserve the accuracy of the results. 
Negative as well as positive results should be published or otherwise publicly 
available. Sources of funding, institutional affiliations and any possible conflicts of 
interest should be declared in the publication. Reports of experimentation not in 
accordance with the principles laid down in this Declaration should not be accepted 
for publication.  

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C. ADDITIONAL PRINCIPLES FOR MEDICAL RESEARCH COMBINED 
WITH MEDICAL CARE  
28. The physician may combine medical research with medical care, only to the extent 
that the research is justified by its potential prophylactic, diagnostic or therapeutic 
value. When medical research is combined with medical care, additional standards 
apply to protect the patients who are research subjects.  
29. The benefits, risks, burdens and effectiveness of a new method should be tested 
against those of the best current prophylactic, diagnostic, and therapeutic methods. 
This does not exclude the use of placebo, or no treatment, in studies where no proven 
prophylactic, diagnostic or therapeutic method exists.  
30. At the conclusion of the study, every patient entered into the study should be assured 
of access to the best proven prophylactic, diagnostic and therapeutic methods 
identified by the study.  
31. The physician should fully inform the patient which aspects of the care are related to 
the research. The refusal of a patient to participate in a study must never interfere 
with the patient-physician relationship.  
32. In the treatment of a patient, where proven prophylactic, diagnostic and therapeutic 
methods do not exist or have been ineffective, the physician, with informed consent 
from the patient, must be free to use unproven or new prophylactic, diagnostic and 
therapeutic measures, if in the physician's judgment it offers hope of saving life, re-
establishing health or alleviating suffering. Where possible, these measures should be 
made the object of research, designed to evaluate their safety and efficacy. In all 
cases, new information should be recorded and, where appropriate, published. The 
other relevant guidelines of this Declaration should be followed.  
 

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APPENDIX D:  REFERENCES 
 
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J Cataract Refract Surg, 32(5), 837-845. doi:10.1016/j.jcrs.2006.01.091 
Caporossi, A., Mazzotta, C., Baiocchi, S., & Caporossi, T. (2010). Long-term results of 
riboflavin ultraviolet a corneal collagen cross-linking for keratoconus in Italy: the 
Siena 
eye 
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149(4), 
585-593. 
doi:10.1016/j.ajo.2009.10.021 
Chatzis, N., & Hafezi, F. (2012). Progression of keratoconus and efficacy of pediatric 
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Surg, 28(11), 753-758. doi:10.3928/1081597x-20121011-01 
Cho, K. S., Lee, E. H., Choi, J. S., & Joo, C. K. (1999). Reactive oxygen species-induced 
apoptosis and necrosis in bovine corneal endothelial cells. Invest Ophthalmol Vis 
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Data on File. IROC/University of Dresden. (2006).  
El Rami, H., Chelala, E., Dirani, A., Fadlallah, A., Fakhoury, H., Cherfan, C., . . . Jarade, 
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Hafezi, F., Kanellopoulos, J., Wiltfang, R., & Seiler, T. (2007). Corneal collagen 
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laser in situ keratomileusis. J Cataract Refract Surg, 33(12), 2035-2040. 
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Kohlhaas, M., Spoerl, E., Speck, A., Schilde, T., Sandner, D., & Pillunat, L. E. (2005). [A 
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Kumar Kodavoor, S., Arsiwala, A. Z., & Ramamurthy, D. (2014). One-year clinical study 
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Mazzotta, C., Traversi, C., Baiocchi, S., Sergio, P., Caporossi, T., & Caporossi, A. 
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530-535.  
Mazzotta, C., Traversi, C., Caragiuli, S., & Rechichi, M. (2014). Pulsed vs continuous 
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by confocal microscopy and corneal OCT. Eye (Lond), 28(10), 1179-1183. 
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Vinciguerra, R., Romano, M. R., Camesasca, F. I., Azzolini, C., Trazza, S., Morenghi, E., 
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Zamani, M., Panahi-Bazaz, M., & Assadi, M. (2015). Corneal Collagen Cross-linking for 
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Zamora, K. V., & Males, J. J. (2009). Polymicrobial keratitis after a collagen cross-
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28(4), 474-476. doi:10.1097/ICO.0b013e31818d381a 
Zotta, P. G., Moschou, K. A., Diakonis, V. F., Kymionis, G. D., Almaliotis, D. D., 
Karamitsos, A. P., & Karampatakis, V. E. (2012). Corneal collagen cross-linking 
for progressive keratoconus in pediatric patients: a feasibility study. J Refract 
Surg, 28(11), 793-799. doi:10.3928/1081597x-20121011-08