准分子激光屈光性角膜切削术后10年角膜内皮细胞的观察

Evaluation of corneal endothelial cells ten years after photorefractive keratectomy

ObjectiveTo evaluate and determine the long-term effects of photorefractive keratectomy （PRK） on corneal endothelial cell density and morphology， and investigate their correlation with surgically designed parameters such as ablation depth and laser scan time. MethodsIn this retrospective study， 24 patients （44 eyes） who underwent PRK 10 years earlier and 45 normal eyes of 25 cases without any ophthalmologic surgery were enrolled in this study as the PRK group and the control group， respectively. Noncontact specular microscopy （Topcon， SP3000P， Japan） was used to measure central corneal endothelial cell density and morphology. A Pearson correlation was used to analyze the relationship between corneal endothelial cell density and morphology， and surgically designed parameters. The PRK group was divided into 3 subgroups based on the depth of tissue ablation： low ablation group （ablation depth <60 μm）， moderate ablation group （ablation depth： 60~90 μm） and high ablation group （ablation depth >90 μm）. The differences in corneal endothelial cell density and morphology between these 3 groups and the control group were analyzed. Data were analyzed using independent samples t test， Pearson correlation， ANOVA. ResultsThe differences in average endothelial cell area， endothelial cell density， coefficient of variation of the endothelial cell area and percentage of hexagonal cells between the PRK group and control group were not statistically significant （t=-1.390， 1.323， 0.569， 0.788， P>0.05）. However， there were statistically significant correlations between average endothelial cell area and endothelial cell density and manifest refraction spherical equivalent （MRSE） （r=-0.424， 0.420， P＜0.01）. The 2 parameters were also significantly correlated with attempted ablation depth （r=0.391， -0.388， P＜0.01）. The differences in average endothelial cell area， endothelial cell density， coefficient of variation of the endothelial cell area and percentage of hexagonal cells between the low ablation group， moderate ablation group， high ablation group and control group were not statistically significant （F=2.195， 1.961， 0.817， 1.529， P>0.05）. ConclusionCompared to normal eyes， no significantly abnormal change in central corneal endothelial cell density or morphology was observed 10 years after PRK. MRSE and attempted ablation depth may have an effect on the average endothelial cell area and endothelial cell density.