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| CLINICAL APPROACH TO THE CANINE RED EYE TAbLE 1. THREE KEY OCuLAR DIsEAsEs THAT MAY CAusE VIsION LOss DISEASE CAUSE OF RED EYE DIAGNOSTICS TREATMENT Corneal Disease or Ulceration Corneal vascularization • Slit-lampexamination • Fluoresceinstaining • Cytology • Culture&sensitivity; Superficial ulcer: • Treatunderlyingdisease • Topicalatropine • Topicalantibiotic • OralNSAID Superficial corneal lesion: Presence of long, branching vessels over the cornea Deep corneal disease: Presence of focal, fine, nonbranching vessels Glaucoma Superficial nonhealing ulcer: • Treatunderlyingdisease • Debridementofulcer • GridkeratotomyorDBD • Tonometry Episcleralinjection Deepcornealvascularization • Gonioscopicexamination • High-resolutionUSorUS (360°perilimbalpattern) biomicroscopy Primary glaucoma: usually associated with a narrow or closed filtration angle Secondary glaucoma: Often seen with uveitis or anteriorlensluxation Anterior Uveitis Episcleralinjection Deepcornealvascularization (360°perilimbalpattern) Hyphema(bloodinanterior chamber) Iris neovascularization Medical: • Prostaglandinanaloguedrops • IVmannitol • OralCAIs Surgical: • Lasercyclophotocoagulation&anterior; chambershunts • Endoscopiclasercyclophotocoagulation • Enucleationorevisceration • Topicalatropine1% • Topicalprednisoloneacetate1%and NsAIDs Dx of Underlying Disease: • SystemicNSAIDs • CBC&serumbiochemistry; • Systemicsteroids(onlyifinfectious • Urinalysis causesruledout) • Tick-bornediseasetiters • Thoracic&abdominal; radiographs • AbdominalUS • Tonometry • OcularUS CAI = carbonic anhydrase inhibitor; CBC = complete blood count; DBD = diamond burr debridement; IV = intravenous; NSAID = nonsteroidal anti-inflammatory drug; US = ultrasound the edges of the ulcer and in the ulcer bed (Figure 8) or stromal loss, both of which are due to activation of matrix metalloproteinases. • Infiltration of the corneal stroma with white blood cells (WBCs; visible as creamy or yellow corneal opacity) often occurs in conjunction with corneal melting or stromal loss; this infiltration is considered highly suggestive of bacterial or fungal infection. Deep corneal ulcer (descemetocele): • Indicated by complete stromal loss and exposure of descemet's membrane • Corneal stain uptake will occur in the walls but not the floor of the ulcer, producing a characteristic donutshaped region of fluorescein stain retention. • Severe condition in which the eye is in grave danger of perforation4; urgent referral to a specialist should be recommended to the client. Clinical Note: Ulcers with greater than 50% stromal loss and malacia require more aggressive medical management; sometimes surgical correction is necessary. Treatment Topical therapy for superficial ulceration is geared toward preventing infection and alleviating pain. Unless the ulcer 14 Today's Veterinary Practice May/June 2013 is infected, topical drugs do not promote healing; therefore, patients should be evaluated for underlying ocular disease (eg, KCS) and treated accordingly and concurrently. Routine corneal cytology is indicated to rule out low-grade infection. Clinical Note: Superficial and uncomplicated ulcers should heal in 3 to 5 days. Management of superficial uncomplicated corneal ulcers consists of:4 • Topical atropine once or twice daily until dilation is achieved to control ciliary muscle spasm and ocular discomfort. Atropine reduces tear production and should be decreased in frequency or discontinued after clinical effect. Most uncomplicated ulcers only require 2 to 3 days of treatment. • Topical broad-spectrum bactericidal antibiotic, such as neomycin and bacitracin in combination with polymyxin B (ointment) or gramicidin (solution), three times daily. • Oral nonsteroidal anti-inflammatory drug (NSAID) for additional comfort. Simple ulcers should be rechecked within 5 days; therapy should be continued until resolution of the ulcer. Management of superficial non-healing ulcers consists of:3 • Treatment of concurrent disease • Medical management