准分子激光屈光性角膜切削术的角膜地形图分析

Corneal topographic analysis after excimer laser photorefractive keratectomy

目的分析准分子激光屈光性角膜切削术后角膜地形图的变化和动态。方法对接受准分子激光屈光性角膜切削术后随诊３个月的６２例（１２２只眼）和随诊６个月的４９例（９６只眼）的角膜地形图变化和动态进行分析。结果中央岛型切削是导致术后早期最佳戴镜矫正视力下降１行以上的重要因素，随着时间的推移，中央岛型切削逐渐演变为其它类型，角膜中央曲率减退，视力逐步提高。角膜地形图分析中，拟似回退指数（ＳｉｍＫ）是反映角膜基质变化的一个指数，其值的变化与年龄无关，而与屈光矫正度数有关，屈光度越大，ＳｉｍＫ越大。结论角膜地形图对分析准分子激光屈光性角膜切削术后角膜的变化是一种有效的工具。

Objective To analyze the changes in corneal topography after excimer laser photorefractive keratectomy (PRK). Methods The topographic changes of 122 eyes (62 patients) and 96 eyes (49 patients) on which PRK was performed were reviewed after 3 and 6 months of follow up respectively. Results The central island pattern had a relationship with the loss of best corrected visual acuity of more than one line in early postoperative period. On subsequent follow up, the central island pattern tended to become to other patterns (semicircular, keyhole and uniform) and the central corneal power decreased, allowing the visual acuity to improve gradually. The simulated K (Sim K) regression index was a useful indication of the changes in the corneal stroma. Sim K was related to the degree of refractive error. The greater the refractive error, the lower the Sim K. Conclusion Corneal topography is a useful tool in the analysis of corneal changes in PRK.