ABSTRACT
AIM: Firstly to evaluate the changes of corneal sensation and its effect to dry eye syndrome after laser in situ keratomileusis (LASIK); secondly to evaluate the relation between the changes of corneal sensation and the laser ablation depth. ·METHODS: 30 patients (60 eyes) had bilateral LASIK with a superior-hinged flap. Every patient underwent preoperative and postoperative (after one week, one month and three months) evaluations, including corneal sensation, Schirmer's basic tear secretion test, tear breakup time (TBUT), corneal fluorescein stainting, and a questionnaire evaluating dry eye obtained from each patient.·RESULTS: Compared with preoperative level, after one week and one month, the difference of corneal sensation was very significant (P＜ 0.01); after three months, there was no statistical difference (P ＞ 0.05). After one week, there was no statistical difference (P ＞ 0.05) in the subjective dry eye symptoms, after one month, the difference was significant(P=0.025 ＜0.05) and after three months, the difference was very significant (P=0.001 ＜ 0.01). Compared with preoperative level, the basic tear secretion decreased significantly after one week and one month(P＜ 0.01), it did not return to the baseline level after three months (P ＜ 0.01). Tear breakup time decreased significantly after the surgery, and after three months, there was still statistical difference compared with preoperative level (P ＜ 0.01); with cornea fluorescence staining, we found corneal epithelial defect was most serious after one month after LASIK, and did not return to the baseline level after three months (P ＜ 0.01). Linear regression analysis and relevant were used to evaluate the relation between the changes of corneal sensation and the laser ablation depth (r=0.798, P ＜ 0.01). ·CONCLUSION: The central corneal sesation decreased noticeable after LASIK, and it recovered three months postoperatively, but the indicators of dry eye syndrome did not return to their preoperative levels following it. We have found that the decreasation of corneal sensation had positive correlation with the laser ablation depth.