Official ESCRS | European Society of Cataract & Refractive Surgeons
Vienna 2018 Delegate Registration Programme Exhibition Virtual Exhibition Satellites 2018 Survey


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Normal distribution of iTrace estimated angle alpha in a cataract surgery patient population

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Session Details

Session Title: Presented Poster Session: Training & Quality of Vision

Venue: Poster Village: Pod 3

First Author: : M.Mahr USA

Co Author(s): :    J. Erie                       

Abstract Details


To determine the normal distribution of angle alpha - the difference between the visual axis and the estimated center of the capsular bag and intraocular lens implant.


Mayo Clinic Department of Ophthalmology - Rochester, MN USA


Complete iTrace (Tracey Technologies; Houston, Texas USA) measurements were recorded for 8,773 eyes in a cataract surgery patient population from 2014-7. Data were deidentified, exported, and analyzed using R and RStudio.


Estimated angle alpha orientation as reported by iTrace was asymmetrically distributed. The axis was horizontal in 94%, vertical in 2%, and oblique in 4% of eyes (p<0.01). Angle alpha distance had a mean and median of 0.41mm. The angle alpha distance was <0.35mm in 35%, between 0.35 and 0.45mm in 26%, and 0.45mm or greater in 39% of eyes.


Estimated angle alpha is almost exclusively horizontally oriented (p<0.01). For surgeons who use an angle alpha magnitude cutoff for multifocal IOL eligibility, these normative results can quantify the impact of screening criteria on potential patient eligibility.

Financial Disclosure:


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