调节滞后与儿童近视关系的研究

A study of the relationship between accommodative hysteresis and early-onset myopia

目的 :观察并评价调节滞后与儿童近视关系 ,探讨儿童近视发病机理。方法 :使用分光镜动态检影法测定 38名年龄 6～ 14岁在学儿童 (平均年龄 10 .1岁 )的张力性调节值与调节滞后值。其中 19名为正视 ,19名为近视。通过注视昏暗照明下置于眼前 40厘米的DOG视标 (0 .2cpd)打开调节环 ,于持续聚焦于一 3D目标5分钟之前及之后立即测定张力性调节值 ,取前后差值作为调节滞后值。统计分析采用组间样本t检验方法。结果 :本研究中近视儿童的调节滞后值为 0 .11± 0 .33D ,正视儿童该值为 0 .30± 0 .45D ,两者差异无统计学意义 (P >0 .0 5 )。结论 :环境因素如近距离工作在早发性近视发展中起较小作用。早发性近视与迟发性近视具有不同的发病机理。

Objective:The objective of the study was to compare the accommodative hysteresis of emmetropic and myopic children and to evaluate the relationship between accommodative hysteresis and early-onset myopia.Methods:38 schoolchildren aged 6～14 years (average age = 10.1 years) participated in the experiment. Measurements of tonic accommodation and accommodative hysteresis were taken before and immediately after focusing on a target placed 3D away for 5 min. The accommodative loop was opened by viewing a DOG target (0.2 cpd) placed 40cm away from subjects in a dim environment. The difference between the pre-task and post-task values was defined as accommodative hysteresis.Results:The myopic children in our study tend to have lower accommodative hysteresis values than emmetropic children after the same near work. But analysis of variance indicated that no significant differences were found in accommodative hysteresis between the emmetropic and myopic groups.Conclusion:Environmental factors such as near work play a less important role than hereditary factors in the development of early-onset myopia. Our results indicate that early-onset myopia and late-onset myopia have different myopic etiologies.