注视距离、照度以及视标对早期近视儿童调节反应的影响

摘要

Objective To study the effects of fixation distance luminance and target stimnulus on the accommodative response (AR); to explore the latent effect of these visual environmental factors on the onset and development of myopia.Methods This was a cross-sectional comparative study.The AR of myopic children wearing their best-corrected trial lenses was measured under different fixation conditions that included various distances luminance and word/picture targets.An SRW-50001K infrared autorefractor was used for measurements and AR was then calculated.Results One hundred sixty-eight myopic children were measured successfully and showed an accommodative lag (AL) under all conditions.The ALs of the fixation points of 6 m,1/2 m,1/3 m,1/5 m were -0.19±0.44 D,0.67±0.41 D,0.75±0.55 D,0.93±0.57 D,respectively (F=13.53,P＜0.01).The ALs for a 1/3 m fixation point on word targets under luminances of 173 lx and 5 lx were 0.79±0.35 D and 0.90±0.33 D (t=-2.87,P＜0.01),respectively.The ALs for a 1/3 m fixation point on the target of pictures and words were 0.71±0.37 D and 0.78±0.29 D (t=46.00,P＜0.05),respectively.Conclusion A lower luminance or shorter distance can both increase accommodative lag and words can induce greater accommodative lag than pictures.This study implies that improving these visual environmental factors may slow the onset and progression of myopia.%目的 研究注视距离、照度以及视标刺激对调节反应的影响,继而从调节反应的角度进一步探讨这些视觉环境因素对近视的发生、发展可能的作用.方法 横断面对比研究.一共对168例早期近视儿童进行了测量.近视儿童配戴其最佳矫正试戴镜,利用SRW-5001K红外线电脑验光仪对其分别在不同距离、不同照明条件以及注视文字/图形视标等条件下进行屈光状态的测量,计算其调节滞后量.对不同距离调节反应的数据比较采用配伍设计资料的两因素方差分析,对不同照度、视标刺激调节反应的数据采用配对t检验.结果 注视6 m、1/2 m、1/3 m、1/5 m的调节滞后量分别是(-0.19±0.44)D、(0.67±0.41)D、(0.75±0.55)D、(0.93±0.57)D,差异有统计学意义(F=13.53,P＜0.01).在1/3 m处注视文字视标,在173 lx和5 lx照度下测得其调节滞后量则分别为(0.79±0.35)D、(0.90±0.33)D(t=-2.87,P＜0.01);在1/3 m处注视图形/文字视标,其调节滞后量分别是(0.71±0.37)D、(0.78±0.29)D,差异有统计学意义(t=46.00,P＜0.05).结论 注视距离减少与照度下降均能使调节滞后量增加,文字视标刺激较图形视标刺激产生更大的调节滞后量,提示改善这些视觉环境可能有助于防止近视的发生、发展.