Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Comparison of three different aberrometers for measurement of optical aberrations

Poster Details

First Author: K. Baig CANADA

Co Author(s):    A. Goulet   Y. Yang   E. Santiago   N. Noordeh           

Abstract Details


To compare the agreement and repeatability of higher order aberration (HOA) measurements in healthy eyes using three different types of aberrometers: iTrace™(Ray Tracer, Tracey Technologies, Houston, TX) iDesign® (Shack-Hartman; Abbott Medical Optics, Santa Ana, CA) and Pentacam.


University of Ottawa Eye Institute, Ottawa, Canada


This prospective study includes 25 participants with normal eyes. Ethics approval was obtained from the Ottawa Hospital Research Ethics Board. Both eyes were tested using iTrace™, iDesign® and Pentacam. A minimum of 3 readings was obtained per eye using each aberrometer. For each aberrometer, the wavefront error is fitted using Zernike Polynomial up to the 8th order to calculate the root-mean-square (RMS). The repeatability of each aberrometer was assessed using Cronbach’s Alpha. Using pupil diameter of 5mm, total eye HOAs up to 4th order were compared between iTrace™ and iDesign®, while corneal HOAs were compared between iTrace™ and Pentacam.


Preliminary results included the first 20 eyes. Scans using iTrace™ and iDesign® were highly reliable (Cronbach’s Alpha ranging from 0.8-1.0), while pentacam scans had limited reliability in most aberrations. Compared to iTrace™ , Pentacam had significant differences in measurements of defocus (0.05±0.09 vs. 0.38±0.25, p<0.01), third order trefoil (-0.02±0.03 vs. 0.05±0.04, p=0.02), coma (-0.01±0.04 vs. 0.05±0.07, p<0.01), and fourth order spherical aberration (0.02±0.01 vs. 0.09±0.06, p<0.01). In terms of total eye HOAs, there were no significant differences between iTrace™ and iDesign® in measurements of any second to fourth order aberrations with the exception of astigmatism (p<0.01).


Preliminary results show a significant difference in measurements of corneal aberrations between the iTrace™ and the Pentacam, where Pentacam tends to underestimate aberrations compared to iTrace™. iTrace™ and iDesign® are comparable in measurements of total eye aberrations.

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