A 9-year-old male neutered domestic shorthaired cat was referred to The Veterinary Eye Clinic in Wheat Ridge, Colo., for evaluation of acute, progressive uveitis in both eyes and glaucoma in the right eye. The cat went outside occasionally to hunt. It had no known history of trauma or travel and was receiving no medications, and its vaccination status was current for feline viral rhinotracheitis, calicivirus infection, panleukopenia, and rabies.
One month before referral, the cat had been presented to an emergency clinic because of acute hyphema in the right eye and uveitis in both eyes. The cat was mildly lethargic, and its temperature was 102.4 F. The intraocular pressure (IOP) was 16 mm Hg in both eyes (normal = 15 to 35 mm Hg).1 Trauma was suspected, and one drop of prednisone acetate was prescribed for use in both eyes four times a day.
The referring veterinarian saw the cat for a recheck examination two days later, and the IOP was 45 mm Hg in the right eye and 5 mm Hg in the left eye. Hyphema had developed in the left eye, and hypopyon was present in the right eye. Neither eye had fluorescein stain uptake. The cat had also become more lethargic and exhibited inappetence.
A serum chemistry profile had revealed a high normal globulin concentration (5.4 g/dl; reference range = 2.8 to 5.4 g/dl). A complete blood count had shown a mild lymphocytosis (9,860/µl; reference range = 400 to 6,800/µl). The cat's blood pressure was normal, and a thoracic radiographic examination revealed no abnormalities. The results of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) tests (SNAP FIV/FeLV Combo—Idexx) were negative.
Trauma, infectious disease, or idiopathic uveitis with secondary glaucoma were the top differential diagnoses. Treatment prescribed by the referring veterinarian included intravenous mannitol (1 g/kg) administered over 30 minutes and subcutaneous triamcinolone acetonide (0.25 mg/kg given once). A topical carbonic anhydrase inhibitor, dorzolamide (one drop in each eye twice a day), and oral prednisolone (1 mg/kg once a day) were also prescribed, and the cat was discharged.
Over the next 20 days, the IOP in the right eye decreased and the cat's ocular pain seemed to diminish. However, on a recheck 21 days after initial presentation, the IOP was 37 mm Hg in the right eye and 8 mm Hg in the left eye. The patient had become blind in right eye and had bilateral uveitis. The pupils had become irregularly shaped because of posterior synechiae (adhesions between the iris and the anterior lens capsule).2 The cat also exhibited inappetence. The cat was then referred to a veterinary ophthalmologist.
The initial ocular examination at The Veterinary Eye Clinic revealed that the right eye was blind and had buphthalmos with iris bombé and posterior synechiae (Figure 1). (Iris bombé occurs when there is forward bowing of the iris and synechiae that seal the iris to the lens so aqueous humor cannot pass through the pupil into the anterior chamber.) The base of the iris had obstructed the filtration angle because of forward bowing of the iris, causing obstructive glaucoma.3 Fibrin and a blood clot were present in the right pupil (Figure 2). Ulcerative keratitis had developed, likely from exposure, in the right eye. Pars planitis (inflammation of the posterior portion of the ciliary body) was also evident.
1. The cat's right eye exhibited buphthalmos, and the left pupil was irregularly shaped.