London Vision Clinic, London, United Kingdom.
J Refract Surg. 2010 Aug;26(8):555-64. doi: 10.3928/1081597X-20091105-02.
To characterize the epithelial thickness profile in a population of eyes after LASIK for hyperopia or hyperopic astigmatism.
The epithelial thickness profile was measured in vivo by Artemis very high-frequency (VHF) digital ultrasound scanning (ArcScan Inc) across the central 10-mm diameter of the cornea on 65 eyes at least 3 months after hyperopic LASIK using a 7-mm ablation zone with the MEL 80 excimer laser (Carl Zeiss Meditec). Maps of the average, standard deviation, minimum, maximum, and range of epithelial thickness were plotted. The cross-sectional hemi-meridional epithelial thickness profile was calculated using annular averaging. Linear regression analysis was performed to evaluate correlations between epithelial thickness, spherical equivalent refraction treated, and maximum simulated keratometry.
The mean thinnest epithelial thickness was 39.7 +/- 5.6 microm and the mean thickest epithelial thickness was 89.3 +/- 14.6 microm. The average epithelial thickness profile showed an epithelial doughnut pattern characterized by localized central thinning within the 4-mm diameter zone surrounded by an annulus of thick epithelium, with the thickest epithelium at the 3.4-mm radius. The epithelium was on average 10-microm thicker temporally than nasally at the 3.4-mm radius. Central epithelium was thinner and paracentral epithelium was thicker for higher hyperopic corrections and steeper maximum simulated keratometry.
Three-dimensional high-resolution ultrasound mapping of epithelial thickness profile after LASIK for hyperopia demonstrated thinner epithelium centrally and thicker epithelium paracentrally. Presumably, the paracentral epithelial thickening compensated in part for the stromal tissue removed by the hyperopic ablation, whereas the central epithelial thinning compensated for the localized increase in corneal curvature.
描述远视或远视散光 LASIK 术后人群的角膜上皮厚度分布特征。
使用 Artemis 甚高频（VHF）数字超声扫描（ArcScan Inc），对 65 只至少在远视 LASIK 术后 3 个月的眼，在角膜中央直径 10mm 范围内，对 MEL 80 准分子激光（卡尔蔡司医学系统）7mm 消融区进行活体测量上皮厚度。绘制平均上皮厚度、标准偏差、最小、最大和上皮厚度范围的图。使用环形平均法计算角膜横断半球形上皮厚度分布。采用线性回归分析评估上皮厚度、治疗的等效球镜和最大模拟角膜曲率之间的相关性。
平均最薄上皮厚度为 39.7 ± 5.6μm，平均最厚上皮厚度为 89.3 ± 14.6μm。平均上皮厚度分布呈上皮甜甜圈模式，特点是在 4mm 直径区域内有局部中央变薄，周围有一层厚的上皮环，最厚的上皮在 3.4mm 半径处。上皮在 3.4mm 半径处，颞侧比鼻侧厚 10μm。中央上皮较薄，旁中央上皮较厚，用于矫正更高的远视和更陡峭的最大模拟角膜曲率。
远视 LASIK 术后上皮厚度的三维高分辨率超声测绘显示，中央上皮较薄，旁中央上皮较厚。推测旁中央上皮增厚部分补偿了远视消融去除的基质组织，而中央上皮变薄部分补偿了角膜曲率的局部增加。
