Can a corneal ulcer be painless?

Yes, and that is precisely the sign of neurotrophic keratitis: having lost its sensitivity, the cornea ulcerates without pain.

Does corneal sensitivity return after surgery?

Usually yes, gradually, over several months after LASIK. After penetrating keratoplasty, recovery is slower and sometimes incomplete.

Is there a treatment for neurotrophic keratitis?

Yes. Besides protecting the surface and autologous serum, cenegermin, recombinant nerve growth factor, is authorised for stages 2 and 3.

When the cornea feels nothing: understanding neurotrophic keratitis

A corneal ulcer that does not hurt is a disquieting paradox. It is the signature of neurotrophic keratitis, a disease in which the cornea loses its sensitivity — and with it, its ability to repair itself.

Nerves do more than feel

The trigeminal fibres that innervate the cornea do not only transmit pain. They continuously release mediators — substance P, CGRP, nerve growth factor — that maintain the epithelium, stimulate its division and migration, and trigger reflex blinking and tear secretion.

When that innervation disappears, three things happen at once: the epithelium loses its trophic support, blinking becomes rare, and the tear film is impoverished. The cornea dries, ulcerates — and the patient does not notice, since nothing is felt.

Where the loss of sensitivity comes from

Ophthalmic shingles and corneal herpes: the commonest causes. The virus damages the nerve fibres directly.
Diabetes, through the neuropathy that also affects corneal nerves.
Surgery: any corneal incision divides nerves. After LASIK, sensitivity takes months to return; after penetrating keratoplasty, longer.
Trigeminal lesions: acoustic neuroma surgery, stroke, tumour.
Prolonged use of toxic or preserved drops.

Three stages, three different urgencies

Stage 1: the surface is irregular, with punctate keratitis and an unstable tear film, but the epithelium is intact. This is when everything is still simple.

Stage 2: a persistent epithelial defect has set in, often oval, with raised smooth edges — an ulcer that will not close and does not hurt.

Stage 3: the ulcer digs into the stroma, with a risk of melting and perforation.

The practical consequence is that monitoring cannot rely on symptoms. A patient with an insensitive cornea must be examined regularly even when feeling well.

What can be done today

The first step is always to simplify: withdraw unnecessary drops and preservatives, which worsen an already fragile surface.

Then come protection — preservative-free lubricants, bandage lens, and where lid closure is inadequate, a tarsorrhaphy or induced ptosis, both reversible — and substitution: autologous serum drops, which supply the missing growth factors.

For some years a specific treatment has been added: cenegermin, recombinant human nerve growth factor, which targets the mechanism of the disease directly and holds a marketing authorisation for stages 2 and 3. The most severe forms may call for amniotic membrane grafting, and some teams offer surgical corneal neurotisation.

When to seek care without delay. Have the eye examined if you have had ophthalmic shingles, ocular herpes, trigeminal surgery or long-standing diabetes, and you notice a red eye, falling vision or a spot on the cornea — even without any pain. The absence of pain is not reassuring: it is part of the disease.

Frequently asked questions

Can a corneal ulcer be painless?: Yes, and that is precisely the sign of neurotrophic keratitis: having lost its sensitivity, the cornea ulcerates without pain.
Does corneal sensitivity return after surgery?: Usually yes, gradually, over several months after LASIK. After penetrating keratoplasty, recovery is slower and sometimes incomplete.
Is there a treatment for neurotrophic keratitis?: Yes. Besides protecting the surface and autologous serum, cenegermin, recombinant nerve growth factor, is authorised for stages 2 and 3.