近视学龄儿童对比度视力研究  

Study of contrast visual acuity in myopic school children

作　　者：林叶[1] 吕帆[1] 贺极仓 姜珺[1] 

机构地区：[1]温州医学院附属眼视光医院浙江温州 ,325027 [2]美国新英格兰视光学院,美国波士顿

出　　处：《中国实用眼科杂志》2012年第6期686-689,共4页Chinese Journal of Practical Ophthalmology

摘　　要：目的形觉剥夺（或视网膜的影像模糊）是近视发展的危险因素，但基本的模糊图像的视觉处理的机制还不很清楚。测试近视发展不同阶段儿童在不同对比度下的视觉分辨力，探讨学龄儿童近视发展的可能因素。方法筛选年龄8，13岁的儿童78人，等效球镜-0．50-5．00DS，矫正屈光不正，视标背景亮度为250ed／m^2状态下，检查四种对比度视力（100％、25％、10％、5％）。根据前半年的近视进展情况是否重配矫正眼镜，研究对象被分为三组：（1）无进展未重配，（2）稍有进展未重配，（3）有进展重配。根据后半年的近视进展情况，研究对象被重新分为重配和未重配两组。对各组对比度视力进行统计学分析。结果随着对比度从100％到5％，平均对比度视力明显下降（F=129．872，P〈O．012）。对比度视力的下降程度在三组不同近视进展组之间差异有统计学意义（F=3．538，P〈0．032），无进展未重配、稍有进展未重配和有进展重配的平均LogMAR视力分别为0．225±0．098，0．243±0．095和0．266±0．118。后半年重配组相对于未重配组的四种对比度视力均下降（F=1．873，P〈0．009），低对比度视力下降更明显（F=4．538，P〈0．001）。研究发现近视进展和对比度视力下降之间没有显著相关性。结论在不同对比度情况下，近视进展期儿童视觉分辨力相对较差，对比度视力与屈光不正程度数无相关。非光学系统的视觉神经系统改变可能是近视进展期儿童视力下降的主要原因。Objective To investigate possible factor controlling visual performance in school chil- dren, and to test visual resolution under visual condition with varied contrasts for myopic children at different stages of myopia progression. Methods Visual acuity at four different contrasts （100%, 25%, 10% and 5%） was tested against a bright background （250.0cddm2） for 78 myopic children aged 8-13 years old, with refractive error （-0.5D to -5.0D） best corrected. According to myopia pro- gression in the passed half year, the subjects were divided into three groups： （1） stable; （2） slightly progressed but was not re-prescribed; and （3） re-prescribed due to significant myopia progression. Re-grouping of the subjects was also made according to myopia progression during half year fol- low-up period. Difference in contrast VA between groups was statistically analyzed. Results For all subjects, mean contrast visual acuity were significantly decreased as the contrast level was changed from 100% to 5% （F =129.872, P 〈 0.012）. But the decrease in contrast VA was significantly differ- ent between the three myopia progression groups （F =3.538, P 〈 0.032） with the mean changes of 0.225±0.098, 0.243±0.095 and 0.266±0.118 logMAR for the stable, slightly progressed and significant- ly progressed groups respectively. During the half year follow-up period, the progressed group was found to have lower contrast VA across the 4 contrast levels （F =1.873, P 〈 0.009） and exhibited more decreases in VA at low contrast levels （F =4.538, P 〈 0.001） than the stable group. No signifi-cant correlation between the myopia progression and decease in contrast VA was observed. Conclu- sions Progressive myopic children have relatively worse visual resolution at varied contrast condi- tion, and the contrast depended VA change is not associated with the degree of refractive error. Vari- ation in visual neural system, rather than the optical system, might attribute to the degraded visual performance in progr

关 键 词：近视 进展性近视 对比度 视力 

分 类 号：R770.41[医药卫生—眼科]