## Overview Blepharospasm is the involuntary, forceful closure or squinting of the eyelids caused by spasm of the orbicularis oculi muscle. In horses it is almost always a sign of ocular pain rather than a primary disease. The most common underlying causes are corneal ulcers and uveitis; both can threaten vision if not treated promptly. ## Causes Corneal ulceration, equine recurrent uveitis, conjunctivitis, foreign bodies, and eyelid trauma are frequent triggers. Environmental irritants or bright light can produce milder, transient squinting. Primary neurologic blepharospasm is rare. ## Diagnosis Observation of sustained or frequent eyelid closure, often with tearing, swelling, or cloudiness, is the first clue. A complete ophthalmic examination including fluorescein staining, intraocular pressure measurement, and slit-lamp evaluation identifies the cause. ## Treatment Treatment is directed at the underlying disease: topical antibiotics or antifungals for ulcers, anti-inflammatories and mydriatics for uveitis, and removal of foreign material. Pain relief and protection of the eye (fly mask, stall rest) are supportive. ## Recovery and Prognosis Prognosis depends entirely on the primary lesion. Superficial ulcers often heal well; deep ulcers or uncontrolled uveitis can lead to scarring or blindness. ## Prevention Fly control, prompt attention to any eye discharge or squinting, and regular veterinary eye checks in horses with a history of uveitis reduce complications.
forceful or frequent eyelid closure; excessive tearing; eyelid swelling; light sensitivity; cloudiness or redness of the eye
## Overview Blepharospasm is the involuntary, forceful closure or squinting of the eyelids caused by spasm of the orbicularis oculi muscle. In horses it is almost always a sign of ocular pain rather than a primary disease. The most common underlying causes are corneal ulcers and uveitis; both can threaten vision if not treated promptly. ## Causes Corneal ulceration, equine recurrent uveitis, conjunctivitis, foreign bodies, and eyelid trauma are frequent triggers. Environmental irritants or bright light can produce milder, transient squinting. Primary neurologic blepharospasm is rare. ## Diagnosis Observation of sustained or frequent eyelid closure, often with tearing, swelling, or cloudiness, is the first clue. A complete ophthalmic examination including fluorescein staining, intraocular pressure measurement, and slit-lamp evaluation identifies the cause. ## Treatment Treatment is directed at the underlying disease: topical antibiotics or antifungals for ulcers, anti-inflammatories and mydriatics for uveitis, and removal of foreign material. Pain relief and protection of the eye (fly mask, stall rest) are supportive. ## Recovery and Prognosis Prognosis depends entirely on the primary lesion. Superficial ulcers often heal well; deep ulcers or uncontrolled uveitis can lead to scarring or blindness. ## Prevention Fly control, prompt attention to any eye discharge or squinting, and regular veterinary eye checks in horses with a history of uveitis reduce complications.
forceful or frequent eyelid closure; excessive tearing; eyelid swelling; light sensitivity; cloudiness or redness of the eye