Asteroid hyalosis is a degenerative condition of the eye involving small white opacities in the vitreous humor. The cause of asteroid hyalosis is associated with diabetes mellitus, hypertension, hypercholesterolemia, and tumors of the ciliary body. In dogs, asteroid hyalosis is considered to be an age related change. Asteroid hyalosis does not usually severely affect vision Vitrectomy may occasionally be indicated for therapeutic purposes.
Vogt–Koyanagi–Harada syndrome - VKH syndrome - is an immune- mediated disease. The mechanism of the disease is thought to be T helper cell mediated autoimmune attack of melanocytes in the skin and uvea of dogs and humans, and in the central nervous system and inner ear of humans. VKH involves various melanocyte-containing organs, characterized by: →uveitis (inflammation of the inside of the eye), →poliosis (whitening of hair), →vitiligo (loss of pigment in the skin), →meningitis, although dogs with this syndrome rarely develop meningitis. In dogs VKH syndrome most commonly affects young animals. VKH syndrome cause retinal detachment, cataracts, and glaucoma. (Pigment partly disappears from the retinal pigment epithelium and iris. Skin lesions include loss of pigment and hair on the eyelids, nose, and lips.) Treatment is with immunosuppressive drugs such as prednisone and azathioprine.
Entropion is a medical condition in which the eyelid folds inward. It caused by genetic factors and may be congenital, it can also occur secondary to pain in the eye, scarring of the eyelid, or nerve damage. The condition is usually present by six months of age. Treatment is a simple surgery in which excess skin of the outer lids is removed. Prognosis is excellent if surgery is performed before the cornea is damaged. Symptoms: → redness and pain around the eye → sensitivity to light and wind → sagging skin around the eye → excessive tearing
Exophthalmos is a bulging of the eye anteriorly out of the orbit. If left untreated cause blindness, eyelids failing to close during sleep leading to corneal dryness and damage. Another possible complication would be a form of redness called "Superior limbic keratoconjunctivitis," where the area above the cornea becomes inflammed as a result of increased friction when blinking. The process that is causing the displacement of the eye may also compress the optic nerve or ophthalmic artery leading to blindness.
Eye proptosis is a condition resulting in forward displacement of the eye from behind by the eyelids. The condition is also known as eye dislocation and eye luxation. Replaced eyes have a higher rate keratoconjunctivitis sicca and keratitis and often require lifelong treatment. If there is severe damage, the eye is removed in a relatively simple surgery known as enucleation of the eye. The prognosis for a replaced eye is determined by the extent of damage to the cornea and sclera, the presence or absence of a pupillary light reflex, and the presence of ruptured rectus muscles. The rectus muscles normally help hold the eye in place and direct eye movement. Rupture of more than two rectus muscles usually requires that the eye be removed, because there is usually also significant blood vessel and nerve damage.