无焦放大镜诱导的不等像对立体视功能的影响

Effect of lens induced aniseikonia on stereopsis

目的研究无焦放大镜诱导下的不等像对立体视功能的影响。方法前瞻性随机区组设计实验研究。通过在被检者右眼前放置无焦放大镜，人工诱导2％、3％、5％、8％、10％不等像。用FLY立体视测试图和数字化随机点立体图（DSTC）分别测试在正常双眼视情况下及在2％、3％、5％、8％、10％诱导性不等像条件下的立体视锐度，分析诱导性不等像对立体视功能的影响。采用多组相关样本的秩和检验Friedman检验和Spearman秩相关，两组独立样本的Wilcoxon秩和检验，多组独立样本Kruskal Wallis秩和检验进行分析。结果诱导性不等像对立体视功能具有显著性影响[FLY（X^2=210．113，P〈0．01），DSTC（X^2=162．237，P〈0．01）1；当不等像为2％时立体视功能即受到影响，不等像大于5％时立体视锐度急剧降低。诱导性不等像值与立体视锐度下降呈正相关[FLY（rs=0．776，P=0．000），DSTC（rs=0．626．P=-0．000）1。结论2％不等像视即会损害立体视等双眼视功能，临床实践中应关注不等像的检查和处理。

Objective To study the effect of lens induced aniseikonia on stereopsis with size lenses. Methods A prospective randomized block design was used. Two percent, 3%, 5%, 8% and 10% of aniseikonia were induced by various lens magnification in front of the right eyes of 45 subjects. Stereopsis was then tested utilizing the Stereo Fly Test and Digital Stereoscopic Test Charts （DSTC） under normal binocular vision and induced aniseikonia. The effect of induced aniseikonia on stereopsis then was analyzed based on the data collected. The data was analyzed by Friedman＇s M test, Spearman rank correlation, Wilcoxon rank sum test and Kruskal-Wallis H test. Results Stereopsis was significantly affected by induced aniseikonia [FLY （X^2=210.113, P〈0.01, DSTC （X^2= 162.237, P〈0.01]; stereopsis was measurably reduced by 2% aniseikonia, and drastically reduced when aniseikonia was more than 5%. The decline in stereoacuity was positively correlated with induced aniseikonia [FLY （rs=0.776, P=0.000）, DSTC （rs=0.626, P=0.000）]. Conclusion Stereopsis and other aspects of binocular function are impaired if aniseikonia reaches 2%. An aniseikonia test should be performed more frequently in clinical settings.