Which describes the normal canine fundus?

Which describes the normal canine fundus?

• A. Pale pink optic nerve head with highly variable degree of myelin +/- central dark physiologic pit
• B. Tapetum located dorsally with variable presence, color, and size
• C. Pigment of the retinal pigmented epithelium and choroid is common
• D. Holangiotic with 3-4 major venules that cross the optic disc periphery and anastomose to form a circle on the optic disc surface

Answer: (D)

In the normal canine fundus, the retinal blood supply is holangiotic, meaning vessels extend across the retina from the optic disc. A hallmark feature is several large venules (typically three to four) that cross the edge of the optic disc. These vessels then anastomose around the disc to form a circular pattern on the surface—a circumpapillary vascular ring. This vascular arrangement is a classic and reliable descriptor of the healthy canine fundus. Other features like a dorsal tapetum that varies in color and size or pigmentation of the retinal pigment epithelium and choroid can be present and normal, but the distinctive circumpapillary vascular pattern is what most clearly defines the normal canine fundus.

In the normal canine fundus, the retinal blood supply is holangiotic, meaning vessels extend across the retina from the optic disc. A hallmark feature is several large venules (typically three to four) that cross the edge of the optic disc. These vessels then anastomose around the disc to form a circular pattern on the surface—a circumpapillary vascular ring. This vascular arrangement is a classic and reliable descriptor of the healthy canine fundus.

Other features like a dorsal tapetum that varies in color and size or pigmentation of the retinal pigment epithelium and choroid can be present and normal, but the distinctive circumpapillary vascular pattern is what most clearly defines the normal canine fundus.