正常角膜、亚临床圆锥角膜及圆锥角膜角膜生物力学的临床研究

A Study on Cornea Biomechanical Properties in Keratoconus,Subclinical Keratoconus and Normal Corneas

目的比较正常角膜、亚临床圆锥角膜及圆锥角膜的角膜滞后性(CH)和角膜阻力因子(CRF),探讨CH及CRF与亚临床圆锥角膜的关系及在圆锥角膜诊断中的作用。方法病例对照研究。圆锥角膜25眼作为圆锥角膜组,临床前期圆锥角膜10眼为亚临床圆锥角膜组,欲行近视激光手术者39眼为对照组。用眼反应分析仪(ORA)测定各组眼的CH及CRF,并进行比较分析。组间CH及CRF比较采用单因素方差分析;绘制受试者工作特征(ROC)曲线。结果 CH与CRF在正常对照组为10.14±1.34mmHg和9.68±1.66mmHg、亚临床圆锥角膜组为8.94±0.88mmHg和8.63±1.28mmHg及圆锥角膜组7.56±1.16mmHg和6.68±1.30mmHg(1mmHg=0.133kPa)逐渐下降;CH与CRF在正常对照组明显高于圆锥角膜组及亚临床圆锥角膜组(P<0.01);相关分析中,CH与CRF在正常角膜组与最小角膜厚度相关(r=0.344,P=0.032),在圆锥角膜与亚临床圆锥角膜中与各项角膜参数均不相关(P>0.05)。圆锥角膜的CH和CRF的ROC曲线下面积为0.944±0.26和0.942±0.31,具有统计学意义。结论亚临床圆锥角膜及圆锥角膜的CH和CRF较正常组明显下降,CH和CRF对于圆锥角膜有诊断意义,对于亚临床圆锥角膜有提示作用;对屈光手术患者术前进行角膜生物力学测量有助于检测亚临床圆锥角膜,减少手术并发症。

Objective To compare the corneal hysteresis （CH） and corneal resistance factor （CRF） measured with the ocular response analyzer （ORA） in keratoconus, subclinical keratoconus and normal corneas. Methods It was a case - control study. We randomly selected 39 normal corneals, 10 subclinical keratoconus and 29 keratoconus in the same period in the study. CH and CRF were compared among groups and the areas under ROC curves of the CH and CRF were calculated. Results The mean CH and CRF were 10. 14 ± 1.34mmHg and 9.68 ± 1.66mmHg in normal eyes,8.94 ± 0.88mmHg and 8.63 ± 1.28mmHg in subclinical keratoconus, and 7.56 - 1.16mmHg and 6.68 ± 1.30mmHg（ lmmHg =0. 133kPa） in keratoconus. The difference was statistically significant （ P 〈0. O1 ）. In linear regression analysis, CH and CRF were correlated with minium corneal thickness in normal eyes （ r= 0. 344, P = 0. 032）. The areas under ROC curves of the CH and CRF were 0. 944 ± 0.26 and 0. 942 ± 0. 31. Conclusions The CH and CRF were significantly lower in keartoconic eyes and subclinical keratoconus than in normal eyes. CH and CRF may be as indicators for detecting keratoconus and subclinical keratoconus.