Randomized Trial Comparing Prediction Accuracy of Two Swept Source Optical Coherence Tomography Biometers
Conditions: Cataract
Sponsor: Multack Eye Care

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
 
Principal Investigator: SAM MULTACK, D.O., FAOCO 
Sub investigator: N/A 
Site: Private Practice and Research Center 
Surgery Center: Tinley Woods Surgery Center 
Measurements: Multack Eye Care @ Laser and Cataract Institute, 22200 Wolf Road, Frankfort, IL 60423 
Post Operative visits: Multack Eye Care @ Laser and Cataract Institute, 22200 Wolf Road, Frankfort, IL 
60423 and Olympia Fields, IL 60461 
Background: Cataract surgery is projected to be the most commonly performed surgical procedure over 
the next 10-15 years. Patient expectations of good visual outcomes have risen with the increase in the 
advancing technology being offered. Cataract surgeons are in need of a clear and consistent process in 
order to deliver the best possible outcomes with the least amount of error.  
Rationale: Biometry data and accurate intraocular lens (IOL) calculations are arguably the most 
important steps in achieving the desired refractive outcomes. There is limited evidence comparing the 
two biometers, Zeiss IOL Master 700 to Alcons Argos.  
Randomized Observational Prospective Trial:  
Hypothesis: The Alcon Argos Biometer’s measurements, when used in conjunction with the Barrett 
Universal II formula, will provide statistically non-inferior outcomes (Mean Absolute Prediction Error of 
Predicted Spherical Equivalents), when compared to the IOL Master 700 utilizing the (PCA) with the 
Barrett Universal II (TK) Formula for IOL power calculations.   
Primary Objective: To assess if the Alcon Argos Biometer utilizing the Barrett Universal II formula for IOL 
calculations can give a non-inferior outcome when compared to the Zeiss IOL master 700 utilizing the 
(PCA) with the Barrett Universal II (TK) formula, when comparing the (mean absolute prediction error of 
the predicted target spherical equivalencies). 
Primary End Point: Mean Absolute Prediction Error (MAPE) of predicted spherical equivalents per 
biometer. (The absolute value of the difference between the Predicted Post-OP MRSE to the Actual 
Achieved Post-OP MRSE for the IOL implanted). 2 biometers (Argos and IOL Master 700). Primary End 
Point (MAPE) will be based on the manifest refraction SE obtained at the postoperative visit day 30 (-
2/+14 days). 
 
 
Secondary End Points:  
a) Percentage of eyes with an Absolute Prediction Error of Predicted SE < or = to (0.5D) with 
Argos vs IOL Master 700 

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
b) Median Absolute Prediction Error of Predicted Spherical Equivalents per biometer 
(The absolute value of the difference between the Predicted Post Op MRSE to the actual 
achieved Post Op MRSE for the IOL implanted) Secondary end points will be based on manifest 
refraction SE obtained at the postoperative visit day 30 (-2/+14 days) 
Exploratory End Points: 
a) Percentage of eyes with an Absolute Prediction Error of Predicted SE < or = to (0.25D) with 
Argos vs IOL Master 700 
Safety: All subjects enrolled in the study will be evaluated for safety. 
Proposed Method: To enroll approximately 80 patients, 80 right eyes in a randomized observational 
prospective study over the course of approximately 4 months (8.5 month estimated total study time), 
randomizing the patients into one of two arms.  
Two Arms:  All scanned by the same technician (Over 2000 scans a year experience) 
A. ARGOS, IOL Master 700, 40 patients, 40 right eyes 
B. IOL Master 700, ARGOS, 40 patients, 40 right eyes 
Randomization of the actual order for biometry measurements will occur utilizing a randomization 
program, with blocking on every 2 or 4 subjects. 
Rationale: Two arms ensure we eliminate dry eye or fatigue bias for each biometer reading by 
randomizing the order of the preoperative biometry measurements. In between measurements patient 
will take a timed 2 min break. No drops will be given prior to measurements, no physical contact with 
the eye will occur prior to any measurements. This will allow for the most accurate keratometry 
readings.  
Barrett Universal Formula II “K” and (TK) are now considered the gold standard in biometry formulas.  
The Barrett Universal II Formula “K” Is available on both biometers, while the Barrett Universal II (TK) is 
only available on the Zeiss IOL Master 700 biometer. 
Surgeon will have access to all biometry readings prior to surgery and at the time of surgery. Surgeon 
will make the lens selection by choosing the IOL (Intraocular lens) power closest to plano for all 
biometers involved. If the two IOL diopter powers are not in consensus, the surgeon will utilize the 
Argos Biometer for the selection.  
We will utilize the Barrett Universal II “K” formula for the Argos, and the Barrett Universal II (TK) for the 
IOL Master 700 to compare the mean absolute prediction error for the predicted spherical equivalents 
by back calculating.  
Utilizing the Barrett Universal II (TK) (Anterior and Posterior corneal measurements) available only on 
the IOL Master 700 and comparing it to the Barrett Universal II “K” on the Alcon Argos biometer will 
allow us to assess if K measurements give non inferior outcomes to the TK Formula.  
The Barrett Universal 2 formula uses a theoretical model eye in which anterior chamber depth (ACD) is related to axial length (AL) and 
keratometry. A relationship between the A-constant and a "lens factor" is also used to determine ACD.1 The important difference between 

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
the Barrett formula and other formulas is that the location of the principle plane of refraction of the IOL is retained as a relevant variable in 
the formula. (1) 
1. 
An improved universal theoretical formula for intraocular lens power prediction. Barrett GD. J Cataract Refract Surg. 1993 
Nov;19(6):713-20. 
Surgery: Surgery will be performed by 1 surgeon, who routinely performs over 20-25 cases weekly. 
Optimized lens settings will be used for each biometer.   
Corneal Incision size: 2.4 mm Alcon Dual Bevel Blade (Temporal) 
Capsulorhexis: Intended size of 4.8mm to 5.2 mm  
Phaco: Alcon Centurion  
Lens: Alcon IQ Acrysof SN60WF only 
Complications: All subjects with any surgical complications will be excluded.  
 
Exclusion Criteria: 
Axial Length < 22.00 and > 26.00 
Corneal Astigmatism > +1.00 Diopters 
CCTS: < 490 and > 600 
Prior Refractive Surgery: RK, PRK, LASIK, INTACTS 
History of contact lens use: Soft lenses within 2 months of surgery, RGP within 60 months of surgery 
Corneal Disease: Keratoconus, Corneal Dystrophies, Any prior corneal Surgery, Prior infections 
Retinal Disease: Macular Pathology, CSCR, CME, Macular Degeneration, Drusen, Retinal Detachment, 
TPPV, SB, prior IVT, Prior PRP or Focal Laser, Diabetic Retinopathy 
History of Uveitis 
POAG: Undergoing any concomitant MIGS procedure- iStent, Omni, iTrack, Hydrus, etc 
Enrollment in any prior clinical trial within 2 years 
Systemic Disease that in the investigator’s opinion may affect outcome  
Currently Pregnant or Breastfeeding 
Severe Dry Eye 
Tear Osmolarity > 320mOsms/L (Moderate)  
Any Surgical Complication(s) 
IOL implanted outside of the capsular bag /capsular damage /weakness /CTR placement 

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
Inclusion Criteria: 
Age: 50-85 years old  
Clinically Significant Cataracts that interfere with daily activities 
Patient is able to understand and able to consent to informed consent 
Patient is able to come to all postoperative visits and agrees to follow up at 30 days -2/+14 days  
Patient undergoing cataract surgery, with implantation of the Alcon SN60WF lens in the capsular bag. 
Study Visit Time Line:   
Visit 1: Screening and initial testing. Initiate dry eye protocol on all subjects 
Dry Eye Protocol: Systane Hydration PF drops (or equivalent) 4 x daily and Warm Packs 10 mins nightly for 14 days 
(+ 5 days maximum). 
Visit 2: Dry eye evaluation to occur at day 14 or greater (+ 5 days maximum), randomization for the 
order (Argos then 700 or 700 then Argos) of bilateral biometry measurements, consents, and study 
enrollment. 
After dry eye protocol, subjects with (Tear Osmolarity > 320mOms/L) will be excluded from the study.  
All enrolled subjects will continue to using Systane Hydration PF drop (or equivalent) 4 x a day for the 
entire duration of the study.  
Subjects will discontinue nightly warm packs the night of surgery. 
 (To minimize the risk of pressure on the eye and potential risk of post operative infection). 
Visit 3: Surgery right eye  
Visit 4: Post Operative Day 1 right eye  
Visit 5: Post Operative Day 6-14 right eye  
Visit 6: Post Operative Day 30 (-2/+14) final manifest refraction right eye  
 
The same Optometrist will perform all refractions on all subjects and will be masked to all biometry data.  
 
Surgeon will be masked to all post-operative manifest refraction results until after study conclusion.  
Initial Screening Testing Visit to include: Best Corrected Distance Visual Acuity, Auto Refraction, 
Manifest Refraction, confrontational fields, pupil reflexes, IOP, slit lamp exam anterior and posterior 
chamber, Tear Osmolarity, Pachymetry, screening for inclusion and exclusion criteria.  
Post Op visits to include: Visual Acuity, IOP, Slit Lamp, final postoperative refraction at visit number 6 
Study Estimated Time for Completion: 
8.5 Months: After fully executed contract, encompassing first patient first visit to last patient last visit, 
plus full analysis, and final report / draft manuscript. 

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
Contract Review: 1 month 
IRB: 1 month 
Enrollment: 4 Months  
8 weeks to measure, 2 weeks of dry eye treatment, 4-6 Week for surgery completion, 4 weeks postoperative final visit -2 +/14 
days  
Data Collection: 30 Days (-2/+14 days)  
Data Analysis: 1 Month  
Final Report/Draft Manuscript with safety information: 1 Month 
Planned Presentations: 
ASCRS Interim Data 2022 and/or AAO Full Data 2022   
 
IAO/COS Illinois Academy of Ophthalmology, Chicago Ophthalmic Society (if not restricted) and/ or  
AOCOO-HNS: American Osteopathic College of Ophthalmology- Annual meeting (if not restricted)  
Planned Publication: 
Peer Reviewed Journal: ASCRS- Journal of Cataract and Refractive Surgery or  
 
 
 
AAO- Journal of Ophthalmology  
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
Biometry Compare Trial 
Protocol # 64989743 
Sample size and statistical analysis: 
 
For this test, a sample size of approximately 70 will provide acceptable power. Up to 10 more 
subjects will be enrolled to account for dropouts. 
 
The endpoint is based on the absolute deviation from target MRSE measured by two biometers 
in the same subject.  The difference is calculated for each subject where the Alcon biometer 
absolute error is subtracted from the XYZ biometer absolute error. A value of zero will reflect 
no difference, where a negative difference indicates that the Alcon biometer has greater error. 
 
We expect the difference to be zero, however, for safety, knowing that the difference can 
fluctuate around zero, we set this at -1/20 D.  In other words, we assume that the Alcon will, on 
average, have 0.05D more absolute error. 
 
We set power at 90%.  We use a one-tailed alpha of 0.025. The standard deviation if the 
difference in the two biometers is assumed to be 0.5 D and the NI Delta is set at 0.25 D.  These 
settings and assumptions result in a required sample size of 68 subjects.  SAS proc power 
output is provided: 
 
 
        Fixed Scenario Elements 
 
Distribution                     Normal 
Method                            Exact 
Lower Equivalence Bound           -0.25 
Upper Equivalence Bound            9999 
Alpha                             0.025 
Mean                              -0.05 
Standard Deviation                  0.5 
Nominal Power                       0.9 
 
 
Computed N Total 
  
Actual          N 
 Power        Total 
 
 0.902         68