角膜地形图仪在疑似圆锥角膜患者诊断及鉴别诊断中的应用

Application of corneal topography in diagnosis of suspected keratoconus

目的探讨疑似圆锥角膜患者角膜地形图的特异性敏感指标。方法在拟行准分子屈光手术的患者中筛选出18例(27眼)疑似圆锥角膜和23例(41眼)亚临床圆锥角膜患者,检测其Orbscan-Ⅱ参数并进行对照分析。结果疑似角膜圆锥组角膜中央屈光力、双眼角膜屈光力差值、Sim K、上/下方屈光度差值、角膜前表面和后表面Diff值、3.0mm Zone Irreg和3.0mmZone Astig Pwr分别为(44.96±2.47)D、(1.86±1.17)D、43.45±5.31、(0.93±0.83)D、(0.017±0.021)mm、(0.039±0.021)mm、2.12±1.67、1.75±0.86,与亚临床期角膜圆锥组比较,差异均有统计学意义(均为P<0.05);角膜最薄点分布差异表现为疑似圆锥角膜组以颞下象限(59.2%)更为多见,亚临床期圆锥角膜多分布在鼻下象限(56.1%)。结论疑似圆锥角膜患者角膜地形图参数存在特异性;各参数的差异可为鉴别疑似角膜圆锥和亚临床期角膜圆锥提供一定的依据。

Objective To investigate the specific sensitive indicators of corneal topography in patients with suspected keratoconus.Methods A contrast study of Orbscan-Ⅱ was performed on 18 cases（27 eyes）with suspected keratoconus and 23 cases（41 eyes）with subclinical keratoconus,which were selected from patients taking laser refractive surgery.Results Central corneal refractive power,difference of central corneal refractive power between both two eyes,Sim K value,difference of inferior-superior diopter,Diff value of anterior surface and posterior surface of cornea,3.0 mm Zone Irreg value and Astig Pwr value were（44.96±2.47）D,（1.86±1.17）D,43.45±5.31,（0.93±0.83）D,（0.017±0.021）mm,（0.039±0.021）mm,2.12±1.67 and 1.75±0.86 in patients with suspected keratoconus,and significant differences were found compared with those in patients with subclinical keratoconus（all P0.05）.Corneal thinnest points were the most at inferior temporal quadrant（59.2%）in patients with suspected keratoconus and inferior nasal quadrant（56.1%）in patients with subclinical keratoconus.Conclusions Parameters of corneal topography was specific in patients with suspected keratoconus.The differences of parameters can provide an evidence for discriminating suspected keratoconus and subclinical keratoconus.