基于双通道技术的视觉质量分析系统在评估轻度圆锥角膜视觉质量中的应用

探讨视觉质量分析系统（OQAS）测量圆锥角膜眼与正常角膜眼之间视觉质量的差异。方法：横断面研究。选取正常角膜屈光不正患者32例（32眼）作为对照组，圆锥角膜患者27例（27眼）作为圆锥角膜组。采用OQAS测量每组在3、4、5 mm的人工瞳孔直径下的视觉质量参数调制传递函数截止频率（MTFcutoff）、Strehl比、不同对比度下的OQAS值（OV-100、OV-20、OV-9），组间差异采用独立样本t检验或Mann-Whitney U检验，组内差异采用重复测量资料方差分析及Bonferroni校正。结果：圆锥角膜组在人工瞳孔分别为3、4、5 mm时的MTFcutoff、Strehl比、OV-100、OV-20、OV-9均低于对照组（3 mm：t=6.658、6.695、6.660、6.493、6.778；4 mm：t=7.106、6.567、7.109、6.802、6.788； 5 mm：t=6.148、7.254、6.158、6.446、7.210；P均<0.001）。对照组及圆锥角膜组内MTFcutoff、Strehl比、 OV-100、OV-20、OV-9 在不同人工瞳孔大小的组内比较差异有统计学意义（对照组：F=42.205、 28.335、42.559、32.621、30.372；圆锥角膜组：F=15.732、11.533、15.625、13.870、10.495；均 P<0.001）。结论：双通道OQAS测量结果表明圆锥角膜的视觉质量较正常眼明显下降，圆锥角膜及正常眼的视觉质量均随着瞳孔增大而下降。

Objective Assessment of Optical Quality in Mild Keratoconus with a Double-Pass System

To analyze the difference in optical quality between a normal cornea and keratoconus using an optical quality analysis system (OQAS). Methods: This cross-sectional study included 32 normal eyes and 27 keratoconus eyes. Optical qualities were measured by OQAS. Modulation transfer function cutoff frequency (MTFcutoff), Strehl ratio and OQAS values (OV-100, OV-20, OV-9) in artificial pupil diameters of 3 mm, 4 mm and 5 mm were analyzed by independent t test or Mann-Whitney U test, the difference among groups was analyzed by ANOVA for repeated measurement and Bonferroni post hoc t test. Results: MTFcutoff, Strehl ratio and OQAS values of the keratoconus group in artificial pupil diameters of 3 mm, 4 mm and 5 mm were all lower than those of the control group (3 mm: t=6.658, 6.695, 6.660, 6.493, 6.778; 4 mm: t=7.106, 6.567, 7.109, 6.802, 6.788; 5 mm: t=6.148, 7.254, 6.158, 6.446, 7.210; all P<0.001). Both in the control group and in the keratoconus group, the MTFcutoff, Strehl ratio, OV-100, OV-20 and OV-9 varied from artificial pupil diameters (control group: F=42.205, 28.335, 42.559, 32.621, 30.372; keratoconus group: F=15.732, 11.533, 15.625, 13.870, 10.495; all P<0.001). Conclusions: The optical qualities of keratoconus measured by OQAS are worse than normal eyes. Both in keratoconus and normal eyes, the optical qualities decline as pupil size increases.