Purpose To investigate relative peripheral refractive error and peripheral astigmatism following conventional laser in situ keratomileusis (LASIK) for myopia.
Methods Using an autorefractor, peripheral refractions (RPRE of M, C, J45, J180) were analyzed along the horizontal visual field between 30 degrees nasally and 30 degrees temporally in 48 myopic eye (presurgical refraction, -5.20±2.24 [M±SD]).
Results 1. After myopic LASIK, there was less hyperopic RPRE at temporal 30⁰ (p<0.01), but less myopic RPRE at nasal 10⁰ (p<0.01). However, there were no significant difference between pre- and post-lasik at nasal 20⁰,30⁰, and temporal 10⁰, 20⁰. 2. In postsurgical myopic LASIK patients, the mean astigmatism magnitude increased with eccentricity, and this increase was greater at temporal visual field. There was a statistical reduction in central and nasal 10⁰ (P<0.01), while a significant growth were found at temporal 20⁰, 30⁰ and nasal 20⁰, 30⁰ (P<0.01).3. Prior to myopic LASIK, the average magnitude of J45 component has a little variation with eccentricity in the myopes. At 3 months after myopic LASIK, J45 was increased significantly at nasal 20⁰ (p<0.01). 4. At 3 months after myopic LASIK, the J180 astigmatism shows nasal-temporal asymmetry, being greater in the nasal than in the temporal field, and has much greater magnitudes than the J180 astigmatism which was measured before the myopic LASIK at all eccentricity (P<0.01) .
Conclusions refraction can be dramatically affected by conventional myopic LASIK. In myopic LASIK, the increased peripheral astigmatism may have adverse effects on peripheral visual tasks. However, conventional laser in situ keratomileusis (LASIK) for myopia can not change the pattern of RPRE of M.