Kim Hyojin, Choi Jun-Sub, Joo Choun-Ki
Department of Visual Optics, Division of Health Science, Baekseok University, Korea.
Cornea. 2006 Aug;25(7):845-8. doi: 10.1097/01.ico.0000224634.72309.43.
To describe the clinical and ultrastructural features of a prominent ectasia of the cornea that occurred 9 years after excimer laser photorefractive keratectomy (PRK).
Analysis of corneal topography and ultrastructural examination by transmission electron microscopy (TEM) were used to assess the ectatic cornea.
The intended laser ablation in the left eye was 74 microm, and the preoperative ultrasonic pachymetry was 536 microm. Orbscan II (V 3.00; Orbtek, Salt Lake City, UT) observations revealed inferior topographic steepening and protrusion of the anterior and posterior corneal surfaces 13 years after the patient underwent PRK. The least thickness of the cornea was 456 microm. TEM showed that the epithelial basement membrane had degenerated into subepithelial stroma, and apoptotic keratocytes with cell debris on the extracellular matrix were observed in the stroma. However, the endothelial cells were normal.
Clinical examination of an eye that had developed corneal ectasia 9 years after PRK showed forward protrusion of both anterior and posterior corneal surfaces. Ultrastructural examination also revealed a degenerated stroma. However, there was no abnormality of the corneal endothelium.
描述准分子激光屈光性角膜切削术（PRK）9年后发生的显著角膜扩张的临床和超微结构特征。
采用角膜地形图分析和透射电子显微镜（TEM）超微结构检查来评估扩张的角膜。
左眼预期的激光消融深度为74微米，术前超声测厚为536微米。Orbscan II（版本3.00；Orbtek，盐湖城，犹他州）观察显示，患者接受PRK 13年后，角膜前、后表面下方出现地形变陡和突出。角膜最薄处为456微米。TEM显示上皮基底膜已退化为上皮下基质，在基质中观察到凋亡的角膜细胞以及细胞外基质上的细胞碎片。然而，内皮细胞正常。
对PRK 9年后发生角膜扩张的眼睛进行临床检查显示角膜前、后表面均向前突出。超微结构检查还显示基质退变。然而，角膜内皮没有异常。
