Ophthalmologic Diseases of Small Mammals

Ophthalmic examination of small mammals follows the same principles as in other species. Reference values for tear production and intraocular pressure are provided. Conjunctivitis and epiphora is common in rabbits. Numerous infectious organisms have been isolated from rabbits with conjunctivitis. Dental disease can be a cause for conjunctivitis in rabbits. Treatment consists of topical and oral antimicrobial agents and irrigation of the nasolacrimal system. Underlying dental disease needs to be addressed. Ulcerative keratitis, corneal dystrophy, membranous occlusion of the cornea and eosinophilic keratitis are described. Encephalitozoon cuniculi can cause phacoclastic uveitis in rabbits. A break in the anterior lens capsule exposes lens protein with subsequent anterior uveitis and cataract formation. Cataract surgery can be performed to remove the affected lens. Glaucoma is inherited as an autosomal recessive trait in rabbits. Orbital disease in rabbits may be associated with dental disease. Treatment is often difficult due to the caseous nature of the abscessed material. The most common ophthalmic diseases seen in ferrets include conjunctivitis, corneal endothelial cell degeneration, cataract formation, retinal degeneration and orbital disease. Ophthalmic diseases in guinea pigs include conjunctivitis, dermoids, cataract and osseous metaplasia of the mesectodermal trabecular meshwork. Exophthalmos may be related to dental disease in guinea pigs and chinchillas. Chromodacryorrhea is seen in rats and mice associated with inflammation of the Harderian gland. Sialodacryoadenitis virus is a highly contagious virus that may cause exophthalmos, epiphora and keratoconjunctivitis. Ammonia vapors from soiled bedding can cause keratoconjunctivitis in hamsters.