硬性透气性角膜接触镜矫正圆锥角膜不规则散光后对比度视力的观察

Clinical observation of contrast visual acuity after correctting irregular astigmatism for keratoconus by rigid gas-permeable lenses

目的观察硬性透气性角膜接触镜(RGPCL)矫正圆锥角膜完成期患者不规则散光的临床效果。设计病例系列研究。研究对象圆锥角膜完成期患者20例(22眼)。方法采用多功能视力测量仪MFVA100分别测试20例(22眼)圆锥角膜患者裸眼(UCVA)、最佳框架矫正(BSCVA)和RGPCL矫正状态下100%、25%、10%和5%的4种对比度视力。角膜荧光染色法和相干光断层成像术(OCT)观察镜片下泪液的分布情况,判断RGPCL的静态配适状态。用单因素方差分析、LSD法两两比较相同对比度下3组视力之间的差别。主要指标对比度视力。结果 22眼在100%、25%、10%和5%对比度下平均UCVA分别为0.195、0.098、0.053、0.042(P均<0.05),平均BSCVA分别为0.421、0.205、0.116、0.064(P<0.05),平均RGPCL矫正视力分别为0.880、0.520、0.308、0.169(P均<0.05)。在100%、25%、10%和5%四种对比度下RGPCL的矫正视力均优于UCVA和BSCVA(P均=0.000),而在5%对比度下UCVA与BSCVA无显著差异(P=0.142)。22眼RGPCL矫正后荧光素染色裂隙灯钴蓝灯光下见呈稍平坦配适、大曲率子午线上泪液填充较多、边缘部泪液宽度适中。戴镜后用前节OCT扫描中央光学区角膜显示出大、小曲率子午线上镜片下泪液分布厚度不同。结论 RGPCL可矫正圆锥角膜完成期患者的不规则散光,明显提高圆锥角膜患者不同对比度下的矫正视力。

Objective To evaluate the clinical effect of rigid gas permeable contact lens （RGPCL） to correct irregular astigma- tism for keratoconus in advanced stage by examining the visual acuity at four different contrast levels. Design Cases series. Partici- pants Twenty keratoconus patients in advanced stage were enrolled. Methods Keratoconus patients （22 eyes） whose best spectacle- corrected visual acuity （BSCVA） were less than 1.0 and with irregular astigmatism by corneal topography examination. Uncorrected vi- sual acuity （UCVA）, BSCVA and RGPCL corrected visual acuity were examined using MFVA100 at 100%, 25%, 10% and 5% contrast levels. The apical alignment fit （AAF） were observed with slit lamp microscopes and optical coherence tomography （OCT）. ANOVA, LSD methods were used to analyse the differences between 3 groups at the same contrast level. Main Outcome Measures Contrast visual acuity. Results At 100%, 25%, 10% and 5% contrast levels, the mean UCVA were 0.195, 0.098, 0.053, 0.042 （P〈O.05）, the mean BSCVA were 0.421, 0.205, 0.116, 0.064 （P〈0.05）, and the mean RGPCL corrected visual acuity were 0.880, 0.520, 0.308, 0.169 （P〈 0.05） in 22 eyes. The significant difference in 100%, 25%, 10% and 5% contrast visual acuity were found between RGPCL and UCVA or BSCVA （P=0.O00）, but in 5% contrast visual acuity was no significant difference between UCVA and BSCVA （P=0.142）. Conclu- sion RGPCL could significantly increase difference contrast visual acuity of keratoeonus patients in advanced stage, and effectively correct irregular astigmatism resulting from cornea.