圆锥角膜的角膜地形图研究

The study of corneal topography of keratoconus

目的 :探讨圆锥角膜病人角膜地形图的特点 ,为早期诊断圆锥角膜提供客观依据。对角膜屈光术前病人进行严格筛选 ,提高手术的预测性。方法 :7例亚临床期圆锥角膜病人 ,2 6例 (3 8只眼 )进展期圆锥角膜的患者 ,3 0例 (60只眼 )正常眼作为对照组 ,用EyeSyssystem 2 0 0 0计算机辅助的角膜地形图仪检查。检查内容 :(1)地形图形态 ;(2 )角膜中央屈光力 ;(3 )角膜中心下方 3mm处屈光力与角膜中心上方 3mm处屈光力的差值 (I -S) ;(4 )同一个体双眼角膜中心屈光力差值。结果 :亚临床期圆锥角膜角膜下方尤其是颞下方的角膜镜影像呈梨形改变 ,变陡峭的圆锥区域均较局限。进展期圆锥角膜局部区域变陡峭 ,形成一局限性圆锥 ,为乳头状、卵圆形和球形。角膜中央屈光度、同一个体双眼角膜屈光度差值、距角膜中央3 0mmI -S值的差异有显著意义。结论 :角膜地形图仪是诊断单侧亚临床期圆锥角膜的敏感方法 ,可以指导设计角膜接触镜 ,对圆锥角膜的圆锥底进行定位 ,指导手术植孔位置及大小。

Objective:To investigate the characteristics of keratoconus under corneal topography,especially the early stage of keratoconus. Methods:33 cases of keratoconus were examined by corneal topography,in which 7 cases were in subclinical stage,26 cases(38 eyes)progressive.30 volunteers were as control.The topograph morphology,central corneal refractive power,I-S value and the difference of central corneal refractive powers between the bilateral sides were checked. Results:The corneal topograph on inferior part especially inferior temporal part of subclinical keratoconus showed pear shape.In progressive keratoconus,central area became steep to form a cone;the shape was round,oval and papilla-like.Central corneal refractive power and its binocular difference,the I-S value were significant different. Conclusions:Corneal topography seems the most sensitive method to diagnose subclinical keratoconus.The localization of cone bottom by corneal topograph could be used to select the position and size of graft in PKP.