What the corneal nerves do
The cornea is the most densely innervated tissue in the body. Its nerves trigger blinking and tearing when the surface is threatened, and they release factors that maintain the epithelium and drive healing. Without them the surface receives fewer tears, blinks less, heals poorly and gradually breaks down, and because pain is absent the patient may not notice until vision falls.
Causes
- Herpes zoster ophthalmicus (shingles of the eye) and recurrent herpes simplex keratitis, the most common causes
- Diabetes, which damages small nerves throughout the body
- Surgery that cuts corneal nerves: extensive laser correction, corneal transplantation, and, rarely, cataract surgery
- Neurological causes: damage to the trigeminal nerve from tumors, stroke or neurosurgery
- Long term use of certain drops, chemical injury and contact lens overwear
Stages
Stage one is a dry, irregular surface with punctate staining and reduced vision. Stage two is a persistent epithelial defect, an area of missing surface that does not heal for weeks despite treatment, often with rolled edges. Stage three is ulceration into the stroma, with thinning that can progress to perforation. Reduced corneal sensation, tested with a fine filament, is present at every stage and is the diagnostic clue.
Treatment by stage
Stage one: preservative-free lubricants, treatment of any eyelid disease, and stopping toxic drops. Stage two: bandage contact lenses, autologous serum tears made from the patient's own blood, which supply the growth factors the nerves no longer provide, and, since its approval, cenegermin, a nerve growth factor drop given for eight weeks that heals a majority of persistent defects. Stage three: the same, plus protection of the thinned cornea with amniotic membrane grafts, tissue glue or a partial closure of the eyelids, and corneal transplantation if it perforates. Scleral lenses that bathe the cornea in fluid all day protect the surface at any stage. Regaining sensation is possible with corneal neurotization surgery in selected patients.
Why specialist follow-up matters
Because the eye does not hurt, neurotrophic keratitis is easy to underestimate, and it can move from stage one to a perforation without much warning. Patients with a known cause, especially after shingles, are examined regularly, and any persistent defect is treated aggressively from the start.
Is this right for your eyes?
Nothing on this page is a diagnosis. Whether this is what is affecting your vision is decided by a full examination at one of our 4 offices: Pasadena, Huntington Beach, Woodland Hills and Beverly Hills.
About this content: This page was written with the assistance of AI tools and reviewed for medical accuracy by Dr. Bavand Youssefzadeh, DO. It is general information, not medical advice, and does not replace an eye examination. Individual results vary. Read our medical disclaimer.
