年龄及瞳孔直径对成人正视眼调制传递函数的影响

The influences on modulation transfer function as a function of age and pupil in adult emmetropic eyes

目的探讨年龄及瞳孔直径对成人正视眼调制传递函数（modulation transfer function，MTF）的影响。方法前瞻性临床研究。将102例正视眼按年龄分为3组：A组40眼（20～30岁）、B组30眼（31-40岁）、C组32眼（41～50岁），使用iTrace视觉功能分析仪测量所有正视眼在3．0、4．0,5．0mm瞳孔直径，5、10、15、20、25、30周／度（cpd）六个空间频率状态下的全眼总MTF曲线以及去除低阶像差的MTF曲线。对年龄与两种MTF作相关性分析，用单因素方差分析对不同年龄组、不同瞳孔的两种MTF分别进行比较。结果在不同瞳孔直径所有空间频率下，年龄与总MTF及去除低阶像差的MTF均呈负相关，空间频率5c／d下3组5．0mm瞳孔直径时的总MTF值分别为0．629±0．147、0．440±0．160、0．415±0．184，差异有统计学意义（F=18．773，P=0．000）。其他空间频率及瞳孔直径下，3组的总MTF及去除低阶像差的MTF值差异也均有统计学意义。在所有空间频率下两种MTF均随瞳孔直径的增大而降低。结论成人正视眼的总MTF及去除低阶像差的MTF均随年龄的增长、瞳孔的增大而下降，因此用它们来评价人眼视觉质量时，应当对不同年龄、不同瞳孔大小的人眼采用不同的评价标准。

Objective To explore the influences on modulation transfer function （MTF） as a function of age and pupil in adult emmetropic eyes. Methods It was a prospective clinical study. All the 102 emmetropic eyes were divided into three groups according age： group A, 40 eyes （age 20-30 years） ; group B, 30 eyes （age 31-40 years） ;group C, 30 eyes （age 41-50 years）. The total MTF and subtracted lower order aberration MTF curve were measured in all emmetropic eyes in 3.0 mm, 4. 0 mm and 5.0 mm pupil sizes with a iTraee Visual Function Analyzer at six spatial frequencies（ 5, 10, 15, 20, 25, 30 cpd） . The associateion between age and the two MTFs was analyzed, the two MTFs were compared among different age groups and different pupils using univariate analysis. Results In 3.0 mm, 4. 0 mm and 5. 0 mm pupil sizes and at all six spatial frequencies, there was a negative correlation between age and the two MTFs, there were significant differences among the three groups （F = 18. 773 ,P 〈 0. 05 ）. At all six spatial frequencies, the two MTFs decreased with the increasing pupil. Conclusions The total MTF and subtracted lower order aberration MTF in adult emmetropic eyes decreased with aging and increasing pupil, so when using the two MTFs to evaluate the visual quality of human eyes, we must use different criteria according to the different age and pupil size.