Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208-3107, USA.
Invest Ophthalmol Vis Sci. 2011 May 1;52(6):3398-403. doi: 10.1167/iovs.10-6560.
To investigate the effects of argon laser photocoagulation on the choroidal circulation in cats.
Three sizes of argon laser lesions designed to damage the outer retina were created in six cats: larger than 1 mm, 500 μm, and 200 μm. At least 1 month after the lesions, damage to the choroidal vasculature was studied in two ways. First, scanning laser ophthalmoscopy was used to obtain infrared reflectance (IR) photographs and indocyanine green (ICG) angiograms. Second, fluorescent microspheres (15 μm) were injected into the left ventricle. The globes were fixed, the choroid was flat mounted, and images were taken with a fluorescence microscope. Retinal histology was assessed in comparable lesions.
Histology showed that the inner retina was preserved, but the choroid, tapetum, and outer retina were damaged. ICG angiograms revealed choriocapillaris loss in large lesions and in some 500-μm lesions, whereas the larger vessels were preserved; in 200 μm lesions, choriocapillaris loss was not detectable. However, in all lesions, the distribution of microspheres revealed little if any choriocapillaris flow. In larger lesions, the damaged region was surrounded by an area in which the number of microspheres was higher than in the lesion but lower than in the normal retina.
Under lesions that destroyed photoreceptors, the choriocapillaris was also compromised, even when no change could be detected with ICG angiography. Panretinal photocoagulation is designed to increase retinal PO2 by allowing choroidal oxygen to reach the inner retina, but its effectiveness may be limited by damage to the choriocapillaris.
研究氩激光光凝对猫脉络膜循环的影响。
在 6 只猫中创建了三种大小的氩激光损伤，旨在损伤外视网膜：大于 1 毫米、500 μm 和 200 μm。至少在损伤后 1 个月，通过两种方法研究脉络膜血管损伤。首先，使用扫描激光检眼镜获得红外反射（IR）照片和吲哚菁绿（ICG）血管造影。其次，将荧光微球（15 μm）注入左心室。固定眼球，平铺脉络膜，并用荧光显微镜拍摄图像。在可比的病变中评估视网膜组织学。
组织学显示内视网膜保留，但脉络膜、脉络膜毯和外视网膜受损。ICG 血管造影显示大病变和一些 500-μm 病变中的脉络膜毛细血管丧失，而较大的血管则保留；在 200 μm 的病变中，无法检测到脉络膜毛细血管丧失。然而，在所有病变中，微球的分布表明脉络膜毛细血管血流很少或没有。在较大的病变中，受损区域被一个微球数量高于病变但低于正常视网膜的区域包围。
在破坏光感受器的病变下，脉络膜毛细血管也受到损害，即使 ICG 血管造影无法检测到任何变化。全视网膜光凝旨在通过允许脉络膜氧到达内视网膜来增加视网膜 PO2，但由于脉络膜毛细血管的损伤，其效果可能受到限制。
