Quick Answer: Keratoconus is a progressive condition in which the cornea gradually thins and bulges into a cone-like shape, causing blurred, distorted vision that ordinary glasses cannot fully correct. It often begins in the teens or twenties.

What are the early signs?

• A prescription that keeps changing, with rapidly increasing astigmatism
• Blurred or distorted vision, or ghost images
• Glare, halos and light sensitivity, especially at night
• Frequent eye rubbing, which is best avoided

How is it diagnosed?

Corneal topography maps the curvature of the cornea, and pachymetry measures its thickness. Early detection widens the treatment options.

How is it treated?

Corneal cross-linking (CXL) aims to strengthen the cornea and halt progression. Specialty contact lenses can improve vision as the cornea becomes irregular, and corneal transplantation is reserved for advanced disease. LASIK is generally not suitable for keratoconus.

Learn more in our guide to keratoconus and cross-linking, or see cornea and keratoconus care.