Equine recurrent uveitis (ERU) is the most common cause of blindness in horses worldwide, causing repeated episodes of painful ocular inflammation that require lifelong management.
ERU causes episodic intense ocular pain — horses with active uveitis squint, tear excessively, and avoid light. The pain of acute episodes is significant; horses may be reluctant to work, eat, or interact normally. The progressive nature means owners face repeated acute crises followed by watchful waiting, with each episode further damaging the eye. The decision about when to enucleate (remove) a painful, blind eye is an important welfare consideration — a cosmetically concerning but functionally beneficial intervention that eliminates chronic pain. Horses adjusted to monocular vision adapt remarkably well. Long-term welfare management of ERU involves minimising UV exposure, prompt treatment of flare-ups, and honest assessment of when the eye causes more suffering than its retention justifies.