Short posterior ciliary artery anatomy in normal and acutely glaucomatous dogs

To quantify the total number and luminal areas of the short posterior ciliary arteries (SPCA) surrounding the canine optic nerve at the level of the sclera/lamina cribrosa in normal dogs and compare this data to dogs with a history of acute (≤7 days) glaucoma.

Twelve normal globes were obtained through Harlan Laboratories, the UW-Madison School of Veterinary Medicine necropsy service and via enucleation submissions to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Ten globes with a history of acute glaucoma were obtained from submissions to the COPLOW. Optic nerves were cross-sectioned in 20 micron steps, and five distinct levels were identified: the retinal nerve fiber layer; the retinal pigmented epithelium and neural canal opening; the choroid/pre-lamina; the sclera/lamina cribrosa; and the retro-lamina. At the level of the sclera/lamina cribrosa, SPCA profiles were counted and the luminal area was measured using Cell Sens software. Normal and glaucomatous globes were compared using ANOVA.

Statistically significant smaller luminal areas and fewer numbers of arteries were recorded between normal and glaucomatous globes.

The glaucomatous eyes in this study have SPCA with decreased lumina, suggestive of a vascular pathology present at the early stages of clinical glaucoma. Smaller lumina may be a contributing factor to the ischemia, necrosis, and the eventual full-thickness retinal atrophy often seen in glaucomatous dogs.