Overview
In keratoconus the cornea progressively thins and its normally dome-like shape bulges forward into a cone. That irregular surface scatters light, producing distortion and ghosting that a standard spectacle lens cannot fully correct.
It usually starts in the teens or twenties and progresses over a decade or so before stabilising. Early detection matters enormously now, because cross-linking can halt progression — but it cannot undo damage already done.
What are the common symptoms?
- Blurred and distorted vision that glasses do not fully fix
- A prescription that changes often, with rapidly increasing astigmatism
- Ghosting or multiple images from one eye
- Streaking and haloes around lights, and poor night vision
- Light sensitivity, and frequent eye rubbing
What causes it, and who is at risk?
- Vigorous, habitual eye rubbing — the strongest modifiable risk factor
- Genetic predisposition and family history
- Allergic eye disease, which drives the rubbing
- Associations with Down syndrome, sleep apnoea and connective tissue disorders
How is it treated?
Two separate goals: stop it getting worse, and get vision back. Stopping eye rubbing is part of both.
- Corneal cross-linking to stiffen the cornea and halt progression
- Rigid gas-permeable, hybrid or scleral contact lenses, which create a smooth optical surface over the irregular cornea
- Glasses in mild cases only
- Intracorneal ring segments to flatten the cone
- Corneal transplant in advanced cases — a minority
- Aggressive treatment of any underlying allergy
When to get seen quickly
Sudden severe pain, marked blurring and a whitening of the cornea can indicate corneal hydrops, where the inner layer splits. It needs prompt attention.
This page is general information, not a diagnosis. Only an eye care professional who has examined you can tell you what is actually going on.