Treatment effects of 0.5% timolol on refractive regression in eyes after laser in situ keratomileusis

Objective To assess the effects of 0.5% timolol on refractive outcomes in eyes with myopia regression after laser in situ keratomileusis (LASIK). Methods Thirty eyes of 16 patients (8 eyes of males, 22 eyes of females) undergoing LASIK for myopia from July 2001 to November 2009 were included in this study. 0.5% timolol was applied consecutively to regressive eyes twice daily until the uncorrected visual acuity (UCVA) improved two lines or more. Comparisons of the UCVA, best corrected visual acuity (BCVA), manifest refraction (spherical equivalent, SE), Pentacam corneal topography and intraocular pressure (IOP) with a Goldmann applanation tonometer were obtained before, during and after treatment was suspended. Data were analyzed with Wilcoxon rank-sum test.Results The IOP decreased significantly (Z=-3.17, P=0.002). The manifest refraction (spherical equivalent, SE), refractive power of the corneal, visual acuity improved significantly (Z=-4.70,-3.36, -4.57; P＜0.01 for all). The difference in the central corneal thickness was not statistically significant (Z=-0. 16, P=0.876). The IOP increased significantly after treatment was suspended (Z=-3.06, P=0.002). The spherical equivalent, corneal refractive power increased significantly (Z=-2.52,P=0.012; Z=-2.12, P=0.034). The visual acuity decreased significantly (Z=-1.98, P=0.047). The difference in the central corneal thickness was not statistically significant (Z=-0.59, P=0.556).Conclusion The administration of 0.5% timolol is effective in reducing myopia regression after LASIK. Myopia regression may still recur once treatment stops so long-term use of the IOP-lowering treatment is needed.\r\n\r\nKey words: \r\nTimolol;  Regression;  Keratomileusis,laser in situ;  Intraocular pressure