Today's Veterinary Practice

MAR-APR 2018

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

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PEER REVIEWED 40 ACUTE GLAUCOMA: A TRUE EMERGENCY morphologic changes in response to the persistently high IOP (see CLINICAL SIGNS ). Many dogs present with chronic glaucoma because the acute phase is misdiagnosed or is overlooked completely by the owners. CLINICAL SIGNS OF GLAUCOMA ■ Signs of ocular pain Blepharospasm Epiphora Head shyness Elevated third eyelid Lethargy, decreased appetite, and sleeping more are subtle signs of pain that may be overlooked ■ Ophthalmic examination findings consistent with acute glaucoma: Episcleral congestion and conjunctival hyperemia Corneal edema, present in dogs with IOPs >40 mm Hg A dilated, nonresponsive pupil and negative menace response The pupil size may be normal in cases of mild IOP elevation, or even constricted in cases of glaucoma secondary to anterior uveitis The presence of a consensual pupillary light reflex (PLR; constriction of the contralateral pupil when light is shone into the affected eye) and dazzle reflex These are important keys to diagnosing acute glaucoma because they indicate existing retinal function and the possibility of regaining vision with IOP control Significant and abrupt IOP elevations may lack a consensual PLR, even if vision is salvageable ■ Ophthalmic examination findings consistent with chronic glaucoma: Buphthalmos Chronic corneal disease (Haab's stria, neovascularization, exposure keratitis) Lens subluxation or luxation Retinal degeneration Optic nerve degeneration and cupping DIAGNOSIS OF GLAUCOMA Measurement of IOP is indicated in any patient with a red, painful eye. Normal IOP in dogs is 15 to 25 mm Hg 1–3 and decreases normally with age. A dilated FIGURE 3. Acute glaucoma. The right eye of a 5-year-old female spayed cocker spaniel with acute glaucoma. Note the normal globe size, elevated third eyelid, diffuse corneal edema, and ocular inflammation. FIGURE 4. Chronic glaucoma. The left eye of a 10-year-old male castrated cocker spaniel with chronic glaucoma. Note the buphthalmos, corneal neovascularization, and central corneal scarring secondary to exposure keratitis. Secondary glaucoma results from a physical obstruction to AH drainage, usually occurring at the ICA or pupil.

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