开角型青光眼视神经损害的发生机制

The mechanism of optic nerve damage in open angle glaucoma

视杯扩大、视神经纤维损害是原发性开角型青光眼的主要特征．其确切发生机理还不清楚，现有的理论都不能完整地解释所有的临床现象．作者根据已有的青光眼方面的知识，提出如下假说：视神经纤维在视乳头部位的汇聚和向后弯曲自然形成的生理杯是视乳头的最薄弱部位．在眼内压的长期作用下逐步加深扩大．扩大的视杯改变了视神经纤维的走行形态，出现了3次弯曲．在筛孔前缘和视盘边缘发生的弯曲是以坚韧的结缔组织为支点的损伤性屈曲．因而造成轴浆流阻滞，导致下行性视网膜神经节细胞丧失．并应用该假说对高眼压症、正常眼压性青光眼和特征性青光眼视野损害进行了解释．提出采用玻璃体手术填平扩大的视杯．

Primary oPen angle glaucoma is marked by opticdisk cul7Ping and optic nerve damage. But their mechanismremains urlclear and no available theories can fully interpretall the clinical Phellomena. In this paper, a hypothesis on themechanism of glaucomatous ()ptic nerve damage was pr()posedby the author. It is sllggested that physiologic 0ptic disk cup,which na1urally forms by op1ic nerve fiber's convergeflce andbackward bending, is the weakest site of optic nerve head andmay be gradually deepened and enlarged under the long last-ing insll1ts of intraocular pressure. The enlarged optic diskcups have changed the nerve fiber's conformati0n and devel-oped three curves. The i?urves, which form against the pointsof hard connective tissues at the lateral front edges of laminacribr()sa pores and at the optic disk edge, are injurious. Theymay block the axonal transport and resll1t in retr0grade reti-nal ganglion cell loss. ()n this hypothesis, the damage of 0cu-lar hyI)ertension, normal tension glaucoma and characteristicglaucon1atous visual field defect have been re!1sonabIy ex-plalned. A1so on this hypothesis, a new remedy to prevent orpostpone the glaucomatous oI)tic nerve damage by vitrectomy, togcther with impIants t() level up the enlarged optic diskcup, has been suggested.