AIM: To comprehensively evaluate of visual quality after epipolis laser in situ keratomileusis(EPI-LASIK)in mild to moderate myopia.

METHODS: Sixty cases(120 eyes)undergone EPI-LASIK with equivalent diopter(SE)were divided into two groups: mild myopia group(60 eyes)and moderate myopia group(60 eyes). Objective visual acuity, aberration, contrast sensitivity and glare sensitivity were measured before and 1wk; 1, 6mo after operation, and made comparative analysis.

RESULTS: Postoperative uncorrected visual acuity(UCVA)of two groups were better than that of preoperative(P<0.05). Postoperative 6mo, there were significant differences on total high RMS between two groups(P<0.05). Before operation and 6mo after operation, higher-order aberrations had statistically significant difference between two groups(P<0.05). After 1wk and 1mo, there were statistical significances at the five frequencies between two groups(P<0.05). After 6mo, the mild myopia group returned to preoperative levels, however, moderate myopia group in the high frequency region(18.0c/d)had significant difference with before surgery(P<0.05). 1wk after surgery, there were statistically significant differences on the 3.0, 6.0, 12.0, 18.0c/d frequency in both groups(all P<0.05), 1mo after surgery, there were significant difference at 12.0, 18.0c/d frequencies(all P<0.05), after 6mo, both groups returned to preoperative levels, showed no significant difference.

CONCLUSION: Visual quality is poorer in mild myopia patients than that in moderate myopia at early stage after EPI-LASIK. Better visual quality is observed at mid-late stage.