Ischemic hypertension of pigeon eye.
OBJECTIVE
To determine the etiology of open-angle glaucoma in human eyes, we tested the hypothesis that ischemia of the endothelial cells lining Schlemm's canal alters the intraocular pressure (IOP) by affecting the transport of fluids out of the eye.


METHODS
Experiments were conducted on pigeons. After blocking the two major arteries to the aqueous sinus artery of one eye by laser photocoagulation, the episcleral arteries of both eyes were cauterized. The IOP was measured with a Mentor pneumatonometer before, immediately, and several days after blocking the major arteries.


RESULTS
After the episcleral cauterization, the IOP of the laser-treated eye rose significantly and was maintained for at least 3 hours. By day 2, the IOP had recovered to the pre-cauterization level. The IOP of the control eye remained unchanged throughout the experiment.


CONCLUSIONS
These results strongly support the hypothesis that ischemia of the endothelial cells lining Schlemm's canal plays a role in the control of the IOP.
Nakabayashi
M
M
Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
D000818:Animals; D000869:Anterior Eye Segment / Q000098:blood supply*; D010856:Columbidae; D005260:Female; D005902:Glaucoma, Open-Angle / Q000209:etiology; D006988:Hyphema / Q000209:etiology; D007429:Intraocular Pressure; D007511:Ischemia / Q000150:complications*; D017075:Laser Coagulation; D008297:Male; D009798:Ocular Hypertension / Q000209:etiology*; D012590:Sclera / Q000098:blood supply*; D014065:Tonometry, Ocular