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CLINICAL APPROACH TO THE CANINE RED EYE | 2 3 4 Figure 2. Subconjunctival hemorrhage; note diffuse redness with no obvious congestion of bulbar vessels Figure 3. Episcleral injection associated with glaucoma secondary to an anterior luxated lens; note presence of episcleral vessels 90° to the limbus. Figure 4. 360° perilimbal deep corneal vascularization (arrow); note episcleral injection (straight, nonmoveable, perilimbal, episcleral vessels approximately 90° to limbus). 5 6 7 Figure 5. Palpebral and bulbar conjunctival hyperemia and chemosis associated with superficial ulcer secondary to an ectopic cilium (arrow). Superficial corneal neovascularization is present in the dorsal cornea; note long and branching corneal blood vessels. Figure 6. Superficial corneal neovascularization and melanosis, in association with adherent and tenacious mucopurulent discharge secondary to KCS; note long, branching corneal blood vessels, which confirms their superficial location. Figure 7. Hyphema secondary to anterior uveitis; note diffuse bright red color and clot obscuring the pupil. Once an examination and these diagnostics are completed, the eye's condition can be classified as: • Extraocular (conjunctival or corneal) • Intraocular (glaucoma or uveitis) • Ocular manifestation of systemic disease. CORNEAL ULCERS Causes of Red Eye Corneal ulcers result in corneal vascularization, which appears as a "red eye." Corneal blood vessels are an indication of chronic disease and, generally, take 1 to 3 days to proliferate on the corneal surface. Uncomplicated corneal ulcers typically heal in 3 to 5 days; ulcers that do not heal in this time period must be closely evaluated for confounding factors. Underlying disease that can impede healing include: • KCS (low STT values, rapid tear breakup time) • Adenexal disease (entropion, distichia, ectopic cilia) • Chronic corneal exposure (lagophthalmos, exophthalmos). They are often associated with other signs of corneal melanosis (or "pigmentation"). Corneal vascularization can occur with nonulcerative corneal disease, but this article strictly focuses on ulcerative disease. Clinical Note: Blepharospasm is seen with most forms of corneal disease but is a common and nonspecific sign of pain associated with many ocular diseases. Diagnosis & Classification Once an ulcer has been identified with positive fluorescein staining, further classification allows proper therapeutic interventions and prevents catastrophic complications related to lack of treatment. Corneal ulcers are classified as superficial or deep:1 • Superficial corneal ulcer: Has even and superficial fluorescein stain uptake, with no visible loss of stroma,3 and presence of long, branching vessels over the cornea (Figure 5). • Deep corneal ulcer: Has an irregular surface, with loss of corneal stroma, and presence of focal, fine, nonbranching vessels (Figure 8, page 15). Superficial non-healing ulcers: • Indicated by superficial staining with diffuse borders due to stain under running a nonadherent epithelial lip that develops secondary to abnormal wound healing. • Can be associated with KCS (Figure 6), adnexal disease, chronic corneal exposure, or foreign bodies (Figure 9, page 15).3 • Others, however, are believed to occur without concurrent disease and are, therefore, associated with primary corneal disease and referred to as spontaneous chronic corneal epithelial defects (SCCEDs).3 Corneal malacia (melting ulcer): • Presents with visible defects in the corneal surface; corneal malacia4 appears as soft, gelatinous cornea around May/June 2013 Today's Veterinary Practice 13