Extraocular muscle dysinnervation disorder resembling Duane retraction syndrome in a 9-month-old French Bulldog.

Abstract

A 9-month-old French Bulldog was presented with a chronic history of lateral strabismus and intermittent third eyelid protrusion in the left eye. The neuro-ophthalmological examination revealed mild ptosis of the left upper eyelid, mild lateral strabismus, and external ophthalmoparesis of the left eye. Retraction and ventral deviation of the left eye globe with protrusion of the third eyelid and elevation of the upper eyelid were elicited on attempted voluntary adduction of the left eye. Hematology, serum biochemistry, serology for infectious diseases, magnetic resonance of the head, and cerebrospinal fluid analysis did not reveal significant abnormalities. Forced duction test did not show signs of mechanical restriction in ocular motility. A suspected congenital cranial dysinnervation disorder resembling Duane retraction syndrome in humans was diagnosed based on the typical clinical signs and exclusion of structural abnormalities. The clinical signs remained stable for 9 months until the time of writing this report.