[Unilateral trigeminal nerve hypoplasia].

BACKGROUND: Isolated unilateral corneal anaesthesia represents a very rare clinical entity. The underlying cause may be a hypoplasia of the trigeminal nerve.

HISTORY AND CLINICAL FINDINGS: A 7 year old otherwise healthy boy presented with mixed conjunctival injection of the left eye, fluorescein-positive punctuate epithelial keratopathy of the cornea and a central corneal ulcer OS. History revealed intermittent, painless redness of the left eye since the age of 4. Trigeminal defects caused by trauma or infection could be ruled out. Tyndall's phenomena was positive. There was no corneal sensitivity on the left side and facial sensitivity was reduced in all branches of the trigeminal nerve. All other ophthalmologic examination results were normal. Magnetic resonance tomography showed a hypoplastic left trigeminal nerve. Mesenchymal syndromes could be ruled out by neuropediatric examination.

THERAPY AND CLINICAL COURSE: Treatment with prednisolone and antibiotic ointment and eye patching were performed. The ulcer healed completely and artificial tear substitution was given for prophylaxis. Follow-up examinations after 4 and 6 years showed no signs of inflammation. Biomicroscopy showed only mild fluorescein-positive corneal epitheliopathy.

CONCLUSIONS: In cases with painless intermittent keratoconjunctivitis, sometimes associated with corneal ulceration, in early childhood, one should consider acquired or congenital trigeminal anaesthesia. This condition requires life-long corneal ulcer prophylaxis and regular ophthalmologic exams.