Uveitis is diagnosed when your veterinarian sees inflammation of the anterior uvea (the middle of the 3 coats that surround the eye). (cat-health-guide.org)
Diseases and surgery of the canine orbit, cornea & sclera, anterior uvea, and lens, the canine glaucomas, feline ophthalmology, equine ophthalmology, laboratory animal ophthalmology, exotic animal ophthalmology (eyecareforanimals.com)
Uveal melanoma (which is biologically distinct from skin melanoma) arises from the uvea's melanocytes, the pigment cells that give the eye its color. (sciencedaily.com)