Objective To investigate the changes of contrast visual acuity (CVA) under photopic environment in patients with low/moderate myopias treated by femtosecond laser-assisted in situ keratomileusis (FS-LASIK) versus laser assisted subepithelial keratomileusis (LASEK). Methods The FS-LASIK group and the LASEK group consisted of 20 right eyes (20 patients) respectively.The spherical equivalent ranged from -1.00 to -5.00 D. The patients were tested with multi-functional visual acuity tester-100(MFVA-100) at 4 contrast levels (100%, 25%, 10%, 5%) before operation and at 1 week, 1 month, 3 months after operation. Results As for the FS-LASIK group, 5% CVA at 1 week after operation was significantly lower than that before operation under photopic environment [(0.473±0.230) vs (0.291±0.088), P< 0.05], but the levels at 1 month and 3 months after operation showed no statistically significant difference compared with the preoperative [(0.290±0.095) and (0.271±0.115) vs (0.291±0.088), P> 0.05], and there was no statistically significant difference in 100%, 25%, 10% CVA before and after operation at different time points (P> 0.05). As for the LASEK group, CVA at each constrast level at 1 week after operation decreased compared with before operation (P < 0.05), 5% CVA at 1 month after operation did not returned to the preoperative level [(0.589±0.224) vs(0.405±0.118), P< 0.05], and there was no statistically significant difference in 5% CVA before and at 3 months after operation(P> 0.05). Conclusion In mild-to-moderate myopic patients underwent excimer laser corneal refractive surgery, low contrast visual acuity (LCVA) decreases obviously in the early postoperative period. The CVAs of FS-LASIK group and LASEK group return to the preoperative level at 3 months after surgery. 5% CVA can be used as an evaluating indicator of postoperative visual quality.
DownLoad: