Keratograph对不同阶段圆锥角膜干眼特征参数的检测及各参数对圆锥角膜的诊断价值

Dry eye features of keratoconus at different stages using Keratograph and its clinical values

目的应用非侵入式眼表综合分析仪Keratograph比较不同阶段圆锥角膜和正常角膜的干眼特征参数,探讨干眼特征参数在圆锥角膜诊断中的作用。方法选取2015年5月至2016年12月就诊于我院的圆锥角膜患者35例(44眼)作为圆锥角膜组,另选拟进行激光角膜屈光手术患者45例(45眼)作为正常角膜组。两组患者年龄差异无统计学意义(P>0.05)。根据Amsler-Krumeich分级法将圆锥角膜患者按照严重程度分为轻度圆锥角膜19眼,中度15眼,重度10眼。利用眼表综合分析仪Keratograph检测患者双眼非侵入式首次泪膜破裂时间(tear break-up time,BUT)、平均BUT、泪河高度及眼红指数。采用ROC曲线分析不同指标对圆锥角膜的诊断价值。结果圆锥角膜组的水平中央曲率、垂直中央曲率、表面变异指数、圆锥角膜指数、角膜后表面高度、眼红指数均高于正常角膜组,差异均有统计学意义(均为P<0.05)。圆锥角膜组的首次BUT、平均BUT、泪河高度均小于正常角膜组,差异均有统计学意义(均为P<0.05)。不同程度圆锥角膜患者的水平中央曲率、垂直中央曲率、表面变异指数、圆锥角膜指数、角膜后表面高度、首次BUT、平均BUT间差异均有统计学有意义(均为P<0.05)。中度组和重度组首次BUT、平均BUT均低于轻度组,差异均有统计学意义(均为P<0.05),但中度组和重度组间差异均无统计学意义(均为P>0.05)。平均BUT与水平中央曲率、垂直中央曲率、表面变异指数、圆锥角膜指数、角膜后表面高度均呈负相关关系(均为P<0.05)。而平均BUT与泪河高度和眼红指数间无相关性(均为P>0.05)。分别将平均BUT、泪河高度、眼红指数和圆锥角膜指数作为诊断指标,作ROC诊断曲线。圆锥角膜指数的ROC曲线下面积最大,AUC为0.985,95%置信区间为0.963~1.000(P<0.001)。此外,ROC曲线下面积平均BUT>泪河高度>眼红指数,诊断效果均差于圆锥角膜指数,差异均有统计学意义(均为P<0.001)。结论眼表综合分析仪Keratograph能够有效地测量角膜的干眼特征参数,其测量参数中平均BUT对圆锥角膜的诊断价值最高,对轻度圆锥角膜患者的诊断更有意义。

Objective To compare the dry-eye features of normal cornea and keratoconus at different stages using non-invasive dry-eye integrated analyzer （Keratograph） and it clinical significance.Methods A case-control study was conducted in 35 patients （44 eyes） with keratoconus who were treated in our hospital from May 2015 to December 2016 as keratoconus group and 45 patients （45 eyes） who received laser corneal refractive surgery as normal cornea group;and subjects in the keratoconus group were subgrouped into mild group （19 eyes）,moderate group （15 eyes） and severe group （10 eyes） according to Amsler-Krumeich grading method.The first tear break-up time （first BUT）,mean BUT,tear meniscus height （TMH） and conjunctival hyperemia scoring （CHS） of the both eyes in all groups were measured by Keratograph,and the diagnostic values of these variables for keratoconus at different stages were analyzed by ROC curve.Results The levels of horizontal central curvature,vertical center curvature,surface variation index,keratoconus index,posterior corneal surface height and CHS of the keratoconus group were higher than those of the normal cornea,and the difference were statistically significant （all P〈0.05）.The non-invasive first BUT,mean BUT and TMH in the keratoconus group were significantly lower than those of the normal cornea group,approaching significant difference （all P〈0.05）.The differences in horizontal central curvature,vertical center curvature,surface variation index,keratoconus index,posterior corneal surface height,first BUT and mean BUT among subgroups of keratoconus patients had statistically significance （all P〈0.05）.The first BUT and mean BUT in the moderate and severe group were lower than those in the mild group,the difference was statistically significant （all P〈0.05）,but there was no significant difference between the moderate and severe group （all P〉0.05）.In addition,the mean BUT was negatively correlated with horizontal central curvature,vertical center curvature,surface variation index,keratoconus index and posterior corneal surface height,but had no significant correlation with TMH and CHS （all P〉0.05）.ROC curve analysis showed that keratoconus index had the highest diagnostic value for keratoconus than other variables （AUC=0.790,95%CI：0.689-0.892;P〈0.001）.Conclusion The Keratograph dry-eye analyzer can effectively measure the dry-eye parameters of the cornea and the mean BUT in the measurement parameters is the most valuable for the diagnosis of keratoconus,and it is more meaningful for the diagnosis of mild keratoconus.