AIM: To provide a reference to improve postoperative effects by screening the related factors causing corneal opacity after sub-Bowman keratomileusis(SBK)by mechanical microkeratome.

METHODS: In this retrospective cases study, 896 eyes underwent sub-Bowman keratomileusis with and they were followed up for 3mo postoperatively. Record was made on whether the corneal opacity occurred. These eyes were divided into 2 groups corneal opacity group and clear cornea group. The gender, age, preoperative intraocular pressure(IOP), preoperative central cornea thickness(CCT), K1, K2, mean K, preoperative spherical equivalent(SE)were statistically analyzed.

RESULTS:There were 52 males and 48 females in haze group, mean age were(24.5±6.1)year, preoperative IOP were(14.26±2.24)mmHg, preoperative CCT were(487.37±18.52)μm, K₁, K₂, mean K were(44.24±1.23)D,(43.33±1.13)D,(43.79±1.15)D, respectively, preoperative SE were(-4.65±1.44)D. There were 412 males and 384 females in without haze group, mean age were(24.3±5.8)year, preoperative IOP were(16.72±7.01)mmHg, preoperative CCT were(533.11±28.74)μm, K₁, K₂, mean K were(43.90±1.47)D,(42.88±1.35)D,(43.39±1.37)D, respectively, preoperative SE were(-5.04±1.96)D. The difference of sex(χ²=0.002, P=0.964), age(t=0.404, P=0.686), preoperative SE(t=1.949, P=0.052)between the 2 groups were insignificant. The difference of preoperative IOP(t=-3.486, P=0.001), preoperative CCT(t=-15.543, P=0.000), K₁(t=2.249, P=0.025), K₂(t=3.172, P=0.002), mean K(t=2.763, P=0.006)between the two groups of haze after mechanical microkeratome SBK.

CONCLUSION: The incidence of corneal opacity is high in patients with thin preoperative CCT, low IOP and high corneal curvature after SBK surgery by microkeratome. Gender, age and preoperative spherical equivalent are not related to the incidence of corneal opacity after SBK surgery.