近视眼角膜后表面高度及其影响因素

Posterior corneal surface hei-ght and influence factors inmyopic eyes

目的探讨近视眼角膜后表面高度的分布特点及其影响因素。方法选取青年近视患者200例(400眼),按屈光度分为4组,应用OrbscanⅡ眼前节分析系统对患者的角膜中央点?最薄点?后表面平均屈光度最大点,以及距中心1.5mm、2.5mm上方、下方、颞上、颞下、鼻上、鼻下、颞侧、鼻侧的后表面高度及相对应的前、后表面曲率、角膜厚度、前房深度进行测量。结果角膜后表面前突极值为(0.024±0.007)mm,多位于颞下(50%)、鼻下(16%)部位。后表面前突极值依次位于后表面平均屈光力最大点(49.75%)、最薄点(33.50%)、旁中心1.5mm颞下(9.25%)和颞侧(8.00%)。后表面平均屈光度最大点、最薄点、中央点3个点的后表面高度在不同近视组中差异无统计学意义(P>0.05)。不同部位角膜后表面高度与其影响因素相关分析:后表面平均屈光度最大点:后表面高度与后表面曲率、角膜厚度负相关(r值分别为-0.118、-0.138,P值分别为0.000、0.006);最薄点:后表面高度与后表面曲率、角膜厚度负相关(r值分别为-0.311、-0.113,P值分别为0.000、0.024);中央点:后表面高度与后表面曲率负相关(r值为-0.622,P值为0.000),与前表面曲率正相关(r值为0.105,P值为0.036)。结论角膜后表面前突极值多位于颞下、鼻下部位,依次位于后表面平均屈光力最大点、最薄点和旁中心1.5mm颞下、颞侧;后表面平均屈光度最大点、最薄点?中央点的后表面高度与近视程度无关;影响后表面高度的因素包括后表面曲率、角膜厚度和前表面曲率。

Objective To investigate the posterior corneal height and its influence factors in myopic eyes. Methods Two hundred myopic subjects （400 eyes） were selected and were divided into four groups according to the diopter. The Orbscan II topography system was used to investigate the posterior corneal surface height, correspond anterior and posterior corneal surface curvature, corneal thickness, anterior chamber depth. All the parameters were measured at central cornea, thinnest point of cornea, posterior corneal surface max mean power site and at 1.5 mm,2.5 mm from center of cornea for superior and inferior part of cornea, superotemporal, inferotemporal, superonasal, inferonasal quarter, temporal and nasal side. Results The posterior corneal surface Diff value was （0.024 ± 0.007 ）mm. The protrusion pole of the posterior corneal surface mostly located in inferotemporal （50%）, inferonasal（ 16% ）. The max protrusion values of the posterior corneal surface were mostly in the posterior sttrface max mean power site （49.75%）, followed by the thinnest point of cornea（ 33.50% ）, inferotemporal （9.25%） and temporal （8.00%） 1.5 mm from center of cornea. At central cornea site, thinnest point of cornea, the posterior sttrface max mean power site, the posterior corneal surface height were no significant difference among groups （P〉0.05 ）. The correlation between the posterior corneal surface height at different sites and influence factors： the posterior surface max mean power site：a negative correlation was built up between the posterior corneal surface height