Abstract
Abstract: :
Purpose: It has been recently reported that increases in ocular higher–order aberration (HOA) correlate with deterioration of contrast sensitivity function in eyes after corneal refractive surgery. There have been no basic data, however, such as the relation between HOA and contrast sensitivity in normal human eyes. Methods: Measurements were done in 307 eyes of 161 patients, ranging in age between 15 and 52 (30.9 ± 8.0, mean ± SD) years old. They had no ocular diseases except for mild refractive errors. Ocular HOA was measured for a 4–mm pupil using the Hartmann–Shack wavefront analyzer (Topcon KR–9000PW). The root–mean–square (RMS) of the third– and fourth–order Zernike coefficients was used to represent coma– and spherical–like aberration, respectively. Total HOA was calculated as the RMS of the third– and fourth–order coefficients. We measured contrast sensitivity using CSV–1000E (Vector Vision), letter contrast sensitivity using CSV–1000LV, and low contrast visual acuity using CSV–1000LanC10%. From the data of CSV–1000E, the area under the log contrast sensitivity function (AULCSF) was calculated. Results:Snellen visual acuity did not correlate with coma–like (r=0.003, p=0.955), spherical–like (r=–0.053, p=0.370), and total HOA (r=0.086, p=0.144). There was significant correlation between AULCSF and coma–like (r=–0.178, p=0.002) and total HOA (r=–0.246, p<0.001). There was significant correlation between letter contrast sensitivity and coma–like (r=–0.191, p=0.001), spherical–like (r=–0.155, p=0.008), and total HOA (r=–0.164, p=0.005). There was significant correlation between low contrast visual acuity and coma–like (r=0.251, p<0.001), spherical–like (r=0.126, p=0.033), and total HOA (r=0.143, p=0.014). The multivariate analysis indicated that third–order RMS had the largest impact on contrast sensitivity function. Conclusions: In normal human eyes, there is a correlation between contrast sensitivity function and ocular HOA, especially coma aberration.
Keywords: contrast sensitivity • cornea: clinical science • refractive error development