Hirata A, Negi A
Department of Ophthalmology, Kumamoto University School of Medicine, Japan.
Graefes Arch Clin Exp Ophthalmol. 1998 Feb;236(2):132-7. doi: 10.1007/s004170050053.
To clarify the mechanism of chorioretinal atrophy, the morphological changes in choriocapillaris (CC) in myopic chick eyes were investigated.
Form deprivation myopia was induced in 40 chicks by unilateral eyelid suturing. Vascular corrosion casts of the choroidal vasculature were examined with scanning electron microscopy (SEM). Structural changes in CC capillaries were also examined with transmission electron microscopy (TEM).
SEM examination of the casts showed that the CC capillaries in the contralateral control eyes formed an extremely dense network with round or oval intercapillary meshes, whereas the capillaries in the myopic eyes were less dense with wider and more irregular intercapillary meshes. As evidenced with morphometrical analysis, CC in the myopic eyes 4 weeks and older exhibited significantly lesser density and capillary diameter and significantly greater center-to-center distance between adjacent intercapillary meshes than in the control eyes. With TEM, most of the capillaries in the myopic eyes were found to be almost devoid of endothelial fenestrations and had narrowed lumina, particularly evident after the 4th week.
These results suggest that the decreased CC density caused in myopic chick eyes may be due partly to capillary atrophy and partly to overall stretch of the capillary network caused by abnormal enlargement of the myopic eyes.
为阐明脉络膜视网膜萎缩的机制，对近视雏鸡眼睛脉络膜毛细血管（CC）的形态变化进行了研究。
通过单侧眼睑缝合诱导40只雏鸡形成形觉剥夺性近视。用扫描电子显微镜（SEM）检查脉络膜血管系统的血管铸型。还用透射电子显微镜（TEM）检查了CC毛细血管的结构变化。
铸型的SEM检查显示，对侧对照眼的CC毛细血管形成了极其密集的网络，毛细血管间网眼呈圆形或椭圆形，而近视眼中的毛细血管密度较低，毛细血管间网眼更宽且更不规则。形态计量分析表明，4周及以上近视眼中的CC密度、毛细血管直径显著小于对照眼，相邻毛细血管间网眼的中心距显著大于对照眼。通过TEM发现，近视眼中的大多数毛细血管几乎没有内皮窗孔，管腔变窄，在第4周后尤为明显。
这些结果表明，近视雏鸡眼中CC密度降低可能部分归因于毛细血管萎缩，部分归因于近视眼球异常增大导致毛细血管网络的整体拉伸。
