Clinical Investigation On The Contrast Sensitivity Of Myopic Patients Treated With Laser In Situ Keratomileusis

Objective To evaluate changes in spatial contrast sensitivity function before and after myopic laser in situkeratomileusis (LASIK). The contrast sensitivity function was measured with using computer program.Methods 51 patients(101 eyes) who underwent LASIK Eyes were divided into two groups(<6.00D and≥6.00D). Best-corrected visual acuity using the Snellen visual acuity chart and spatial contrast sensitivity were tested before and two weeks, one month and three months after LASIK. Corneal microstriae was diagnosed with slitlamp. Results Although 99% patients had normal Snellen visual acuities (>5.0), contrast sensitivity in all spatial frequency had a significant decline in all patients at two weeks(P<0.05). The group(<6.0D) preoperative and postoperative contrast sensitivity did not differ at 1 month in all spatial frequency. The group(≥6.00D) postoperative contrast sensitivity had a significant depress at high spatial frequency(8,16 cpd)at 1 month and 3 months(P<0.05). In the subgroup that had corneal microstriae, there was a significant reduction in the spatial contrast sensitivity at all spatial frequency except for 1 cpd at 3 months(P<0.05).Conclusions Compared to the Snellen visual acuity, contrast sensitivity can reflect visual function under different contrast. Postoperative contrast sensitivity had temporary reduction, but could recover. The contrast sensitivity of high myopia and patients that have corneal microstriae recovered slowly.