配戴硬性透气性角膜接触镜对轻中度圆锥角膜患者视觉质量的影响

目的　探讨配戴硬性透气性角膜接触镜(rigid gas-permeable contact lense，RGPCL)对轻中度圆锥角膜患者视觉质量的影响。方法　选取2018年12月至2019年6月在河南省人民医院门诊确诊为轻中度圆锥角膜的患者20例25眼。轻中度圆锥角膜的诊断标准及分期依据全球圆锥角膜专家共识及圆锥角膜评分标准。应用视觉质量分析系统II(OQAS-II)检查患者在配戴RGPCL前及配戴1个月后各视觉质量参数，包括客观散射指数(objective scatter index,OSI)、调制传递函数截止频率(modulation transfer function cut off frequency,MTFcut off)、斯特列尔比(strehl ratio,SR)，三种模拟对比度下视力OV100%、OV20%、OV9%及19.5 s内不瞬目情况下泪膜散射指数(tear film objective scatter index,TF-OSI)。同时分析各视觉质量参数与角膜前表面中央3 mm光学区K_steep的相关性。结果　配戴RGPCL前与配戴1个月后相比，OSI明显降低，MTFcut off、SR、OV100%、OV20%、OV9%均明显升高，差异均有统计学意义(均为P<0.05)。配戴RGPCL前与配戴1个月后相比，TF-OSI差异无统计学意义(P>0.05)。配戴RGPCL前，OSI及TF-OSI与K_steep呈正相关，MTFcut off、SR、OV100%、OV20%、OV9%与K_steep均呈负相关(均为P<0.05)；配戴RGPCL 1个月后，除TF-OSI与K_steep呈正相关(P<0.05)外，OSI、MTFcut off、SR、OV100%、OV20%、OV9%与K_steep均无相关性(均为P>0.05)。结论　RGPCL可明显提高轻中度圆锥角膜患者的视觉质量。

Assessment of rigid gas-permeable contact lenses on visual quality in mild and moderate keratoconus

Objective　To evaluate the influence of rigid gas-permeable contact lens (RGPCL) on visual quality in patients with mild and moderate keratoconus. Methods　Twenty-five eyes of twenty mild and moderate keratoconus patients were recruited in Henan Provincial People’s Hospital from December 2018 to June 2019. The diagnosis and staging of mild and moderate keratoconus were based on Global Consensus on Keratoconus and Keratoconus Severity Score Ranking Scheme (KSS). The patients were analyzed by optical quality analysis system II (OQAS-II) before and one month after wearing RGPCL respectively, including the value of objective scattering index (OSI), modulation transfer function cut off frequency (MTFcut off), strehl ratio (SR), OQAS values under different contrast(OV100%, OV20% and OV9%), and tear film objective scatter index (TF-OSI) without blinking for 19.5 seconds. Person product moment coefficient was used to evaluate the correlation between the optical quality parameters and K_steep. Results　The OSI decreased significantly and the MTFcut off, SR, OV100%, OV20% and OV9% increased significantly one month after wearing RGPCL, and there were statistically significant difference compared to the pre-treatment (all P<0.05). The TF-OSI showed no statistical difference one month after wearing RGPCL compared to the pre-treatment (P>0.05). The OSI and TF-OSI were positively correlated with K_steep, and the MTFcut off, SR, OV100%, OV20% and OV9% were negatively correlated with K_steep before wearing RGPCL (all P<0.05).The OSI, MTFcut off, SR, OV100%, OV20% and OV9% showed no significant correlation with K_steep one month after wearing RGPCL (all P<0.05) except the TF-OSI was positively correlated with K_steep (P>0.05). Conclusion　RGPCL can significantly improve the visual quality in patients with mild and moderate keratoconus.