Bilateral idiopathic oculomotor neuropathy in a cat

Idiopathic oculomotor neuropathy is a well‐recognised syndrome in people, and it has also been described in dogs. In dogs, the disease appears to have a good prognosis; however, only reports of a unilateral presentation exist. Evidence of oculomotor dysfunction in cats has been previously associated with intracranial neoplasia, with a poor prognosis. This case report describes the clinical and imaging findings and outcome of a 12‐year‐old, male, neutered, domestic shorthair cat with bilateral mydriasis, unresponsive to light, as the sole clinical sign. Thorough diagnostic investigations led to a diagnosis of bilateral idiopathic oculomotor neuropathy. No treatment was prescribed, and there was no change in the clinical signs with 9‐month follow‐up. To the authors’ knowledge, this is the first report of bilateral idiopathic oculomotor neuropathy in a cat, which, based on this case, suggests a good prognosis with minimal adverse impact on the patient.