Posters

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

Purpose:

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.

Setting:

University of Ottawa Eye Institute, Ottawa, Canada

Methods:

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.

Results:

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).

Conclusions:

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.

Financial Disclosure:

NONE