Effect of Soft and Rigid Gas-permeable Contact Lenses and Aging on Wavefront Aberrations

Abstract

Abstract: : Purpose: It is reported that wavefront aberrations (WAs) change with age. But it is not well investigated about the effect of contact lenses (CLs) on WAs in different age groups. We studied the effect of soft contact lenses (SCLs) and rigid gas-permeable contact lenses (RGPCLs) on corneal and ocular WAs and compared between young and elderly groups. Methods: Fourteen normal eyes with the age of forties and ten normal eyes with the age of twenties were included in the study. Corneal and ocular WA of uncorrected eyes, eyes with null-powered SCLs, and those with null-powered RGPCL were analyzed with Hartmann-Shack wavefront sensor and with a composite device of corneal topographic analyzer (Wavefront analyzer, Topcon Corp, Tokyo, Japan). The coefficient of astigmatism (C₂²), and RMS of the third-order and of the fourth-order wavefront aberrations (TFWA) were compared among the CLs. The internal WA was estimated by subtracting the corneal WA from the ocular WA. Results: In the forties, corneal TFWA with SCL (0.115 ± 0.026µm) was significantly larger than that of uncorrected eyes (0.095 ± 0.026µm) (p<0.01, paired -t). No other significant differences were obtained in corneal and ocular TFWA among the three conditions in two age groups. Corneal C₂² was -0.238 µm in uncorrected eyes, -0.169µm with SCL, -0.026µm with RGPCL in the forties, and -0.587µm, -0.536µm, -0.145µm in the twenties, respectively. Corneal with-the-rule astigmatism (C₂² with negative sign) was corrected by RGPCL, but not by SCL. Ocular C₂² was 0.135µm, 0.194µm, 0.342µm in the forties, and -0.318µm, -0.291µm, 0.103µm in the twenties, respectively. Ocular against-the-rule astigmatism (C₂² with positive sign) significantly increased by RGPCL in forties (p<0.01). The internal C₂² were 0.373µm, 0.364µm, 0.368µm in the forties, and 0.269µm, and 0.244µm, 0.248µm in the twenties, respectively. The internal C₂² of uncorrected eyes was significantly larger in the forties than in the twenties (p<0.01). Conclusions: Both corneal and ocular TFWA did not change either with SCL or with RGPCL in both age groups except in the forties with SCL. By correcting the corneal with-the-rule astigmatism by RGPCL, ocular against-the-rule astigmatism significantly increased in forties. The results suggest that caution should be taken to prescribe the RGPCL to elderly patients.

Keywords: contact lens • optical properties • aging: visual performance