WHOLE EYE, CORNEAL AND INTERNAL ABERRATIONS INDUCED BY CORNEAL REFRACTIVE THERAPY

Title WHOLE EYE, CORNEAL AND INTERNAL ABERRATIONS INDUCED BY CORNEAL REFRACTIVE THERAPY
Author, Co-Author C Joslin, Shelley Wu, Timothy McMahon, Mahnaz Shahidi
Topic
Year
2003
Day
Thursday
Program Number
Room
Affiliation
University of Illinois Chicago
Abstract PURPOSE: To evaluate the whole eye, corneal and internal (posterior corneal, ocular media and crystalline lens) aberrations induced by Corneal Refractive Therapy (CRT; Paragon Vision Sciences, AZ).

METHODS: 12 eyes of six myopic subjects (-2.25 to -6.00 D; -3.23 ± 1.06 D; mean ± SD) were fit with CRT contact lenses. Whole-eye aberrations were measured in dilated subjects using a Hartmann-Shack (HS) aberrometer. Corneal aberrations were measured using elevations maps from Keratron corneal topography (Optikon, Italy) and converted to wavefront error using CTView (Sarver and Associates, FL). The average of nine HS and two topography exams taken at baseline and one month after treatment were used. Six-mm pupil sizes for topography measurements were calculated to match 6-mm pupil sizes in whole-eye aberrations. Internal aberrations were calculated by subtracting corneal from whole eye coefficients.

RESULTS: Mean myopia reduction was 3.00 ± 0.88 D. CRT induced whole eye, corneal and internal aberrations. Whole eye higher order (3rd - 6th) RMS values increased following CRT (0.35 ± 0.13 to 0.80 ± 0.37 microns; p =0.0005, paired two-tailed t-test); as did corneal (0.27 ± 0.10 to 0.63 ± 0.39; p =0.005) and internal higher order RMS values (0.34 ± 0.11 to 0.62 ± 0.42; p =0.02). The Zernike coefficient most affected by CRT was spherical aberration (Z40), which significantly increased for all eyes in whole eye (0.12 ± 0.15 to 0.46 ± 0.21 microns; p <0.0005), corneal surface (0.13 ± 0.054 to 0.29 ± 0.92; p <0.0005), and internal aberrations (-0.014 ± 0.17 to 0.17 ± 0.17; p =0.0005).

CONCLUSIONS: CRT increases higher order and spherical aberrations of the whole eye and corneal surface. Furthermore, CRT increases internal optical aberrations, specifically spherical aberration, which is consistent with posterior corneal flattening. These results suggest that CRT affects also the posterior corneal surface shape.

ADDITIONAL COMMENTS: Suppport: NIH/NEI EY01792 (UIC), EY14275 (MS), and EY12656 (TTM), Research to Prevent Blindness, Inc., an unrestricted grant from Paragon Vision Sciences (CEJ)
Affiliation of Co-Authors University of Illinois Chicago, University of Illinois Chicago, University of Illinois Chicago
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