猴光学离焦性与形觉剥夺性近视眼视网膜形态及超微结构比较

Comparison of retinal morphology and ultrastructure in defocus-induced myopia and form-deprivation myopia in rhesus monkeys

目的对比观察光学离焦性和形觉剥夺两种诱导方法所致恒河猴近视眼视网膜形态与超微结构的变化。方法年龄1.0～1.5个月的健康恒河猴15只,1只眼为实验眼配戴-3.00D镜片(9只眼)或散射镜片(6只眼),造成光学离焦或形觉剥夺;另1只眼作为对照眼。处理后不同时间用角膜地形图、睫状肌麻痹下验光、A超动态观察猴眼屈光状态和眼轴的变化;用相干光断层扫描术(OCT)动态观察视网膜厚度的变化,并与组织学测量值进行比较;3个月后,光镜和电镜下对比观察光学离焦、形觉剥夺性近视眼和对照眼视网膜超微结构的变化。结果15只猴实验眼均形成近视眼,光学离焦和形觉剥夺性近视眼视网膜均可见视杆细胞外节较长,视锥细胞膜盘减少,膜盘间隙增大,视网膜神经上皮层均较对照眼薄(均P<0.05);视网膜神经上皮层和色素上皮层厚度的OCT测量值与经校正后的组织学测量值比较差异均无统计学意义(P>0.05)。结论实验性近视眼视网膜超微结构与对照眼明显不同,但光学离焦和形觉剥夺性近视眼视网膜超微结构变化很相似。这种改变在近视眼发生、发展过程中的意义有待进一步探讨。

Objective To investigate the changes of retinal ultrastructure of defocus-induced myopia and form-deprivation myopia in infant rhesus monkeys. Methods A-3.00 D spectacle lens (n=9) or diffuser lens (n=6) was worn over one eye and a zero-powered lens over the fellow eye in 15 healthy rhesus monkeys ranging in age from 1 to 1.5 months. The eyes were examined periodically with corneal topography, cycloplegic retinoscopy, A-scan ultrasonography, and optical coherence tomography (OCT). Three months later, light and electron microscope were used to observe the changes of the retina. Results In 15 monkeys, all eyes treated with-3.00 D spectacle lens or diffuser lens developed defocus-induced myopia or form-deprivation myopia. Not only defocus-induced myopia, but also form-deprivation myopia showed elongation of rod outer segment, decreased membrane disc of cone outer segment, increased clearance of the membrane disc and decreased thickness of the neurosensory retina (RNL) as compared with the control eyes(P<0.05). There were no significant differences between the mean OCT and histomorphometric thickness of RNL and retinal pigment epithelium (RPE) after the correction of dehydration(P>0.05). Conclusions There are significant differences in retinal ultrastructure between experimental myopic eyes and control eyes. But the morphological changes in the retina of the defocus-induced myopia showed no significant difference as compared with form-deprivation myopia. The role of changes of retinal ultrastructure in the development of myopia needs further studies. OCT can be used to examine the changes of RNL and RPE in experimental myopia in vivo.