A Comparative Study for Mesopic Contrast Sensitivity Between Photorefractive Keratectomy and Laser In Situ Keratomileusis

Abstract

To compare the effect on visual performance of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with mesopic contrast sensitivity. Postoperative visual performance for 40 eyes undergoing PRK and 40 eyes undergoing LASIK was compared with mesopic contrast sensitivity at 1, 3, and 6 months postoperatively. Eyes were divided into two groups (< -6.0 D and > -6.25 D). Mesopic contrast sensitivity was performed with the patient's best-corrected visual acuity of 20/20 or better under photopic conditions. A significant decrease in mesopic contrast sensitivity from preoperative baseline was obtained at all spatial frequencies for the PRK and LASIK groups (P < .05). There was no statistically significant difference at 1 or 3 months postoperatively in both groups (P > .05). At 6 months postoperatively, LASIK significantly decreased mesopic contrast sensitivity more than PRK in myopia with a refractive error of less than -6.0 D, especially at the middle and high spatial frequencies of 6, 9, and 12 cycles per degree (P < .05). However, no statistically significant differences in mesopic contrast sensitivity between PRK and LASIK were found in myopia with a refractive error of greater than -6.25 D (P > .05). In broad-beam excimer laser refractive surgery, PRK seemed to have a more significant effect on mesopic contrast sensitivity than LASIK for myopia with a refractive error of less than -6.0 D at 6 months postoperatively.