The Effect of Laser in situ Keratomileusis on Low Contrast Vision

PURPOSE: To determine the effects of laser in situ keratomileusis (LASIK) on low contrast visual acuity. METHODS: Thirty eyes of 15 LASIK patients with myopia and astigmatism were evaluated preoperatively, and 1 and 3 months postoperatively. High contrast visual acuity (HCVA), low contrast visual acuity (LCVA), and contrast threshold were determined. RESULTS: Mean spherical correction (SE) was -3.24 +/- 1.90 D; 16 eyes had a mean SE between -1.00 and -3.00 D, and 14 eyes were between -3.25 and -6.50 D. There was no significant change in HCVA observed at 1 and 3 months in any eye. There was a decrease in LCVA in eyes with a correction >3 D SE at 1 month (P=.04), which returned to normal at 3 months (P=.13). There was an increase in the contrast threshold at 1 month (P=.016). When eyes were divided into groups, those with >3D SE correction had an increase in contrast threshold at 1 month (P=.002); no change was seen in eyes with <3D SE correction (P=.15). At 3 months, contrast threshold was similar to baseline values in all eyes (P=.226). CONCLUSION: LASIK transiently decreased low contrast visual function in patients with greater than 3.00 D of myopic correction.