Combined Phacoemulsification and Viscocanalostomy With Ologen Implant Versus Combined Phacoemulsification and Viscocanalostomy
Phase: NA
Conditions: Primary Open-angle Glaucoma
Sponsor: Zagazig University

 
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Combined phacoemulsification and viscocanalostomy 
with Ologen implant versus combined 
phacoemulsification and viscocanalostomy 
 
Document Date: 1/5/2013 

 
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Introduction 
Surgical treatment of glaucoma is indicated in cases of failure of medical treatment. 
Trabeculectomy is considered the standard surgical treatment of glaucoma. Non-
penetrating glaucoma surgeries, e.g. viscocanalostomy and deep sclerectomy, are becoming 
good alternatives. Viscocanalostomy has fewer complications than trabeculectomy, e.g. bleb 
leak, hypotony and bleb-related infections. [1–4]  
Since the prevalence of both cataract and glaucoma increases with age, phakic patients who 
are scheduled for glaucoma surgery may also require cataract extraction, or patients 
scheduled for cataract surgery may be scheduled for combined surgery. Improvement of 
phacoemulsification techniques and stable anterior chamber depth with non-penetrating 
glaucoma procedures may favor combined viscocanalostomy and cataract surgery in 
patients with glaucoma and a coexisting cataract. [4]  
A biodegradable porous collagen-glycosaminoglycan copolymer matrix implant (Ologen®) is 
a simple chemical analog of extracellular matrices and has been used as an adjuvant to 
increase the long-term success of trabeculectomy. The degradation time of this type of 
implant is around 180 days; this implant consists of porcine based, lyophilized, crosslinked 
type I atelocollagen (≥ 90%) and glycosaminoglycans (≤ 10%). During trabeculectomy 
surgery it is placed subconjunctivally and acts as a spacer to mechanically separate the 
subconjunctival and episcleral tissues to decrease subconjunctival fibrosis.[1,3] 

 
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Rationale 
Primary open angle glaucoma is the second leading cause of blindness worldwide which 
needs effective attention otherwise it will lead to progressive optic nerve damage and 
eventual blindness. 
The current surgical treatment of choice for medically uncontrolled glaucoma in association 
with cataract is combined phaco-trabeculectomy. However, this procedure is associated 
with both early and late postoperative complications.  
Combined Non-penetrating glaucoma surgeries with phacoemulsification have been 
developed offering both surgeon and patient a safer, more convenient option.  
With the use of Collagen implant with phaco-viscocanalostomy, it is expected to improve 
the pressure lowering effect of this procedure and increasing the success rate.  
Research Question 
Does phacoemulsification and viscocanalostomy with ologen implant have a better 
outcome, in patients with both cataract and primary open angle glaucoma, regarding 
postoperative IOP control and low complications rate, compared to phacoemulsification and 
viscocanalostomy alone? 
Hypothesis 
Our hypothesis is that using Ologen implant as a spacer in the subscleral reservoir in phaco-
viscocanalostomy reduces fibrosis and increase the success rate of this operation. 
Aim of the Work 
The Aim of this study is to evaluate the use of Ologen implant as an adjuvant in phaco-
viscocanalostomy 
in 
patients 
with 
coexisting 
cataract 
and 
glaucoma. 

 
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Objectives 
1. To estimate the number of patients with postoperative IOP ≤ 21 mmHg after phaco-
viscocanalostomy with ologen implant compared to phaco-viscocanalostomy alone 2 
years after surgery. 
2. To measure complete and qualified success rates after phaco-viscocanalostomy with 
ologen implant compared to phaco-viscocanalostomy alone 2 years after surgery. 
3. To report and describe early and late postoperative complications after phaco-
viscocanalostomy with ologen implant compared to phaco-viscocanalostomy alone 2 
years after surgery. 
Subjects and Methods 
Before initiating this study, the protocol, the informed consent form and any other written 
information to be given to patients was reviewed and approved by the Ethics Committee of 
the Alpha vision center. 
The investigator will explain to each patient the nature of the study, its purpose, the 
procedures involved, the expected duration, the potential risks, benefits involved, and any 
discomfort may be caused. 
Each patient will be informed that participation is voluntary, that he or she may withdraw 
from the study at any time and without giving reasons. The withdrawal will not affect the 
subsequent medical or conservative treatment or relationship with the treating surgeon. 
Technical Design 
Center: Alpha vision center 
Design: A prospective randomized controlled clinical trial. 

 
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Subjects: Patients will be collected from the outpatient clinic of Alpha vision center. The 
patient will be randomly assigned using simple randomization method to receive either 
Phacoemulsification and viscocanalostomy or Phacoemulsification and viscocanalostomy 
with Ologen implant.  
Study sample: Based on previous studies by Shaarawy and Mermoud [5], the mean IOP at 
the first postoperative day was 6.4 (SD=3)mmHg for the DS-treated eyes, and 3.7 
(SD=2)mmHg for the DSCI-treated eyes,  the minimum total sample size of 32 will be 
sufficient to detect a power of 80% and a significance level of 5%. To allow for 25% losses, 
the sample was further increased to 81.  Sample size estimation was performed by G power 
statistical package. 
Inclusion criterion:  
The inclusion criteria are the presence of significant cataract interfering with vision (visual 
acuity ≤ 0.5) in the presence POAG. Patients are included if cataract is associated with 
uncontrolled glaucoma, (IOP > 21 mmHg despite maximally tolerated medical therapy) or if 
the IOP is ≤ 21 mmHg with use of at least two antiglaucoma drugs with medication 
intolerance, poor patient compliance, patients cannot attend medical supervision or have 
visual field deterioration. 
Exclusion criteria: 
Patients will be excluded if they have closed-angle glaucoma, other types of open angle 
glaucoma (OAG), e.g. pigmentary glaucoma, inflammatory glaucoma or neovascular 
glaucoma, previous ocular trauma or surgery, lens subluxation or other eye diseases 
affecting the vision, e.g. anterior uveitis. Patients were also excluded if there is a large 
perforation of the Descemet’s membrane with iris prolapse during surgery (cases with 
microperforation, which is defined as small perforation with no associated iris prolapse, occurring 

 
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during surgery will not be excluded) or if they have other intraoperative complications that 
might affect the IOP, e.g. vitreous loss. 
Operational Design: 
Patient histories will be taken including age, gender, previous ocular surgery, trauma or any 
previous ocular inflammation, e.g. keratitis, iridocyclitis, etc. Slit-lamp examination will be 
done for examination of anterior chamber angle, determination of the type of glaucoma and 
the degree of cataract, measuring IOP (using Goldmann applanation tonometer), 
assessment of optic nerve head and retinal examination, if possible. Visual acuity (VA) was 
expressed in decimal fraction.  
Surgical procedures:  
All operations will be carried out by one surgeon using peribulbar anesthesia.  
After phacoemulsification, a traction suture in the cornea is made using 8-0 polyglactin 910 
(Vicryl®, Ethicon Inc, Bridgewater, NJ, USA). 
A fornix based conjunctival flap is fashioned and no cautery is applied. Hemostasis is only 
achieved by using a microsponge soaked with 1/100,000 adrenaline. A superficial scleral flap 
of 5 x 5 mm is made and dissection is done 2 mm into the clear cornea. A smaller deeper 
flap of 4 x 4 mm is made until deroofing of Schlemm’s canal is achieved. Decompression of 
the eye is done through one of the paracentesis incisions, then blunt dissection with a 
microsponge is done to create a descematic window that extended over Descemet's 
membrane until 1 to 2 mm inside the clear cornea. Subsequently, the sides of the deep flap 
is freed from the adjacent sclera by Vannas scissors and the deep flap is cut by the same 
scissors.  
The juxtacanalicular trabeculum is removed and then the two openings of Schlemm’s canal 
are cannulated on both sides using a viscocanalostomy cannula (Eagle labs, Rancho 

 
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Cucamonga, CA, USA) and high-viscosity sodium hyaluronate (Healon GV; Abbott Medical 
Optic Inc., Santa Ana, CA, USA) is injected into the canal on both sides.  
In the Phacovisco group, the superficial flap is closely sutured using four interrupted 10-0 
nylon sutures, and then Healon GV is injected into the subscleral lake.  
In the OloPhacovisco group, a 4 x 4 mm piece of Ologen® (Model: 862051 “12mm(D) x 1mm 
(H)”) (Aeon Astron Europe B.V., Leiden, The Netherlands) is fashioned to be nearly of the 
same size as the cut deep scleral flap to fit inside the subscleral reservoir (Fig 2). Then the 
superficial flap is sutured tightly over it using four interrupted 10-0 nylon sutures (Ethilon®, 
Ethicon Inc, Bridgewater, NJ, USA). Some air is injected from the paracentesis inside the eye. 
Then conjunctiva is closed using 8-0 polyglactin 910 sutures (Vicryl®, Ethicon Inc, 
Bridgewater, NJ, USA). 
Postoperative management included topical administration of 0.5% moxifloxacin drops with 
a tapered schedule of 1% prednisolone acetate. Antiglaucoma medication is ceased after 
surgery in all cases.  
Follow-up: 
Postoperatively, follow-up examination will be done on days 1, 7, 14 and 30, then every 2 
months for 2 years. The follow-up examination includes assessment of IOP, VA and slit-lamp 
examination. Postoperative complications will be recorded. Signs of inflammation, such as 
cell infiltration and flare, is recorded and graded from 0 to 4.  
Nd:YAG laser goniopuncture is considered in all cases with elevated postoperative IOP 
above 21 mmHg after discontinuation of corticosteroid eye drops for at least 14 days. The 
Nd:YAG goniopuncture is performed using an Ellex Super Q YAG laser machine (Ellex 
Medical Lasers Ltd., Mawson Lakes, SA, Australia) and the gonioscopy mirror of Goldman 
three mirror universal laser lens (Ocular, Bellevue, Washington, USA) with a laser power 

 
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setting of about 3 to 6 mJ and using about 2 to 15 shots aiming at the opening of the 
trabeculo-Descement window, the number of laser shots needed to open the Descemet’s 
membrane was counted and recorded in each group. Antiglaucoma drugs will be prescribed 
if the IOP is elevated above 21 mmHg after considering Nd:YAG laser goniopuncture. 
The main outcome measures are the IOP at the 2-year follow-up and the overall success, 
which included complete success when IOP is ≤ 21 mmHg without any antiglaucoma drugs, 
and qualified success if IOP is ≤ 21 mmHg with the use of a single antiglaucoma medication. 
Failure is considered if IOP ≤ 21 mmHg cannot be reached even with the use of a single 
antiglaucoma medication and after performing Nd:YAG laser goniopuncture, at any follow-
up visit. The secondary outcome measures were surgical complications, the use and results 
of Nd:YAG laser goniopuncture and visual acuity results. The last data for failed cases were 
used for further statistical analysis. 
RESULTS 
Collected data will be presented in Tables and analyzed by computer software using 
appropriate statistical methods. 
DISCUSSION 
Discussion will be done on results compared to relevant literatures and scientific researches 
to explain the reasons for getting such results. 
Conclusion and Recommendations 
Conclusion and Recommendations will be derived from the findings of the study. 

 
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Statistical analysis plan: 
The data will be analyzed using the software Statistical Package for Social Science (SPSS) 
version 16.0 (SPSS Inc., Chicago, Illinois, USA). Continuous variables will be expressed as 
mean ± SD and compared using student t tests; two tailed test will be used to detect 
significance between the two groups and one tailed t test will be used to detect the 
significance before and after intervention in the same group. Mann-Whitney U test will be 
used for nonparametric analysis. Categorical variables will be expressed as percentages and 
will be analyzed using the chi square (χ2) test. A value < 0.05 will be considered statistically 
significant. 
References 
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mitomycin-C as an adjuvant in trabeculectomy: a 24-month, randomized clinical trial. 
Eye (Lond). 2011;25:1598–1606. 
2. Narayanaswamy A, Perera SA, Htoon HM, et al. Efficacy and safety of collagen matrix 
implants in phacotrabeculectomy and comparison with mitomycin C augmented 
phacotrabeculectomy at 1 year. Clin Experiment Ophthalmol. 2013;41:552–560. 
3. Johnson MS, Sarkisian Jr SR. Using a collagen matrix implant (Ologen) versus mitomycin-
C as a wound healing modulator in trabeculectomy with the Ex-PRESS mini glaucoma 
device: a 12-month retrospective review. J Glaucoma. 2014;23:649–652. 
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recent results. J Glaucoma. 2008;17:139–146. 

 
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5. Shaarawy T, Mermoud A. Deep sclerectomy in one eye vs deep sclerectomy with 
collagen implant in the contralateral eye of the same patient: long-term follow-up. Eye 
(Lond) 2005;19: 298-302.