Congenital trigeminal anaesthesia: a rare preventable cause of visual loss in children.

Congenital trigeminal anaesthesia (CTA) is a rare condition characterised by a congenital deficit involving all or part of the sensory component of the trigeminal nerve in children. It is a heterogeneous condition that can present in isolation or is associated with congenital abnormalities affecting the mesoderm, ectoderm and/or brainstem. The authors report a case of a 4-year-old girl who presented with reduced visual acuity, painless bilateral keratitis and painless non-healing lesions on the face, who was confirmed to have CTA on detailed neurophysiological investigations. She also had associated unilateral renal dysplasia and Duane syndrome. The authors also discuss an up-to-date review of the published cases of CTA in literature, the first of which was reported as early as 1984.