In vivo confocal microscopy (IVCM) allows detailed examination of the corneal nerves. Damage to V-1 can result in corneal anaesthesia and neurotrophic keratitis. It is not clear whether corneal anaesthesia is related to loss of nerves in the sub-basal plexus or not. We present evidence from patients with uniocular corneal anaesthesia and a normal sub-basal plexus demonstrating a lack of such correlation.

A 57-year-old woman with history of left trigeminal neuralgia for several years had unsuccessful left alcohol trigeminal root injection followed by a left microvascular decompression. Postoperatively she developed persistent dry eye symptoms. Visual acuity (VA) was 6/9. Her left cornea showed superficial punctuate epithelial erosions (SPEE). Corneal sensation (Cochet–Bonnet) was 60 (normal) in her right eye and 0 (absent) in her left eye. IVCM revealed normal stromal and sub-basal nerves with equal density on both sides (figure 1A,B).