AIM:To observe the effect of timolol on refractive regression after high myopia surgery at different time points in LASIK operation.

METHODS: Prospective study. Totally 180 eyes of 90 patients with high myopia who were admitted to our hospital from August 2015 to August 2016 were randomly divided into control group and observation group. Each group had 45 cases and 90 eyes. Both groups were treated with loxacin eye drops and tobramycin dexamethasone eye drops for 1wk. The control group was treated with timolol eye drops 7d after operation, and the observation group was treated with timolol eye drops 1d after operation. The uncorrected visual acuity, spherical equivalent, intraocular pressure, corneal surface curvature and corneal stroma thickness were measured and compared before and 7d, 1, 3 and 6mo after operation.

RESULTS: There were differences in naked vision and spherical equivalent between the two groups at different time points after operation(P<0.05). At 6mo after operation, the naked vision and spherical equivalent of the observation group were better than those of the control group(0.03±0.01 vs 0.08±0.01; 0.15±0.33D vs -0.17±0.36D; all P<0.05). There was no difference in corneal stroma thickness and corneal surface curvature between the two groups at different time points(P>0.05). The intraocular pressure of the observation group was significantly lower than that of the control group at 7d, 1 and 3mo after operation(all P<0.05). The intraocular pressure of the two groups tended to be stable at 6mo after operation.

CONCLUSION: Early application of timolol after LASIK can effectively reduce intraocular pressure, maintain relatively long-term stability of intraocular pressure, prevent corneal swelling, and thus prevent refractive regression.