Abstract
Purpose: :
To test a hypothesis that there is regional variation in the effect of experimental glaucoma on ChBF.
Methods: :
Five adult female rhesus macaques underwent unilateral laser trabecular meshwork destruction to induce elevated intraocular pressure (IOP). IOPs were measured weekly thereafter until sacrifice (from 61 to 63 weeks). Mean IOPs were: 41(experimental eyes) and 16 (fellow control eyes) mmHg. During the fluorescent microsphere injection procedure, IOPs were manometrically controlled at 35 (experimental) and 15 (control) mmHg. 5 million 15-µm fluorescent microspheres were injected into the left ventricle. The eyes were fixed in 4% paraformaldehyde. They were then bleached, flat mounted, and photomicrographed. Regional ChBF was then calculated and plotted as previously described (Arch Ophthalmol, 2006;124:860). A MATLAB program was written to align and mathematically compare the results between eyes.
Results: :
Total ChBF was, on average, reduced in the experimentally glaucomatous eyes. The mean blood flow was 893±123 µl/min (SEM) and 481±37 µl/min in the control and glaucomatous eyes, respectively. The regional surface plots of ChBF in the control eyes showed a peak in flow in the macula that tapered towards the periphery. This tapering was more gradual (i.e., the flow was relatively greater) on the nasal (optic nerve) side of the macula compared to the temporal side. Although the ChBF was reduced at all locations in the glaucomatous eyes, the overall shape of the ChBF surface plots were similar in the control and glaucomatous eyes. That is, the reduction of ChBF was proportional throughout the glaucomatous eyes.
Conclusions: :
To our knowledge, this is the first demonstration of reduced ChBF in chronic experimental glaucoma in the non-human primate. It is also the first to show how the marked regional variations in ChBF seen in the normal eye are altered in this model. The reduction in ChBF in chronic experimental glaucoma appears to be proportional throughout the choroid.
Keywords: intraocular pressure • blood supply • choroid