Ophthalmology Challenge: A greyhound with red eyes


Ophthalmology Challenge: A greyhound with red eyes

A 4-year-old spayed female greyhound was presented to Colorado State University Veterinary Teaching Hospital for evaluation of redness in both eyes, a possible corneal ulcer in the right eye, and a scratch in the skin of the medial canthus of the left eye. The owner reported that a recent fight had caused the ocular and periocular lesions. The dog was a retired racing greyhound and had been with its current owners for two years. No other health-related complaints were noted.

Physical and ocular examinations

FIGURE 1. At presentation, the greyhound eyes appear cloudy from corneal neovascularization and granulation tissue-like ingrowths. FIGURE 2. A close-up of the dog left eye shows corneal neovascularization and granulation-like tissue extending across the cornea from the lateral limbus (solid arrow). Note the small areas of infiltrate a few millimeters in front of the advancing neovascularization (dashed arrow).
The results of the physical examination were normal except for the eyes. Vision was present in both eyes as determined by menace reflex and tracking tests, and the pupillary light and blink reflexes were normal. Intraocular pressures were normal at 10 mm Hg in the right eye and 11 mm Hg in the left (normal = 10 to 20 mm Hg). Schirmer tear test results were also normal at 15 mm at 60 seconds in both eyes (normal ≥ 15 mm/min). The bulbar and palpebral conjunctival vessels of both eyes were mildly injected. Reddish-pink, slightly raised tissue and blood vessels were present at the midlateral limbus of each eye and appeared to be extending from the conjunctiva or sclera (Figures 1 & 2). On the left eye, the tissue extended about 5 mm onto the cornea and measured about 4 mm from top to bottom. The tissue on the right eye was more prominent and extended 7 mm onto the cornea. Both areas were well-vascularized, and on biomicroscopic examination, the masses did not appear to extend deeply into the corneas. No miosis or aqueous flare was seen in either eye, and the results of the fundic examinations were normal. Slight fluorescein dye retention occurred in the crevices of the raised tissue in both eyes. This nonspecific stain retention was due to the irregularity of the tissue and not true corneal ulceration. An 8-mm superficial scratch was present on the skin of the medial canthus of the left eye. The scratch did not extend to the left globe and was healing well.

Differential diagnoses and additional testing

Differential diagnoses for the dog's ocular problems included chronic superficial keratitis, granulation tissue secondary to irritation or foreign bodies, neoplasia, and metabolic infiltrates (e.g. lipids, minerals). Keratoconjunctivitis sicca is another differential diagnosis in dogs presenting with these clinical signs, but it was ruled out because of the normal Schirmer tear test results. By carefully inspecting the conjunctiva and conjunctival fornices and evaluating the dog's ability to blink and completely close its eyelids over the corneas we were able to rule out exposure keratopathy or foreign bodies. The results of a complete blood count and serum chemistry profile were normal, indicating that neither hypercholesterolemia nor hypertriglyceridemia led to corneal lipid or cholesterol deposition. After applying a topical anesthetic to both eyes, we obtained a scraping of the tissue in each eye with a Kimura spatula and submitted the material for cytologic evaluation. The results showed numerous normal epithelial cells, lymphocytes, neutrophils, and occasional mast cells.

Diagnosis and treatment

The cytologic evaluation results combined with the other findings led to a diagnosis of chronic superficial keratitis (CSK). We prescribed prednisolone acetate 1% ophthalmic drops three times a day in both eyes for an indefinite period. In addition, we augmented the corticosteroid therapy by administering 0.2% cyclosporine ophthalmic ointment (Optimmune—Schering Plough Animal Health) twice a day in both eyes.