Keratoconus

What it is

The cornea is the clear dome at the front of the eye. In keratoconus it gradually thins and bulges forward into a cone. The irregular shape bends light unevenly, causing blurry and distorted vision that glasses often cannot fully correct. It usually starts in the teens or early twenties and can progress for 10 to 20 years.

Symptoms

• Blurry or distorted vision, often worse in one eye
• Rapidly increasing astigmatism and frequent prescription changes
• Glare, halos and streaks around lights at night
• Light sensitivity
• Seeing multiple images from one eye

Who is at risk

• People who rub their eyes hard and often
• People with a family history of keratoconus
• People with allergies, eczema or asthma
• People with certain conditions, such as Down syndrome or connective tissue disorders

How it is diagnosed

Corneal mapping (topography or tomography) shows the shape and thickness of the cornea and can detect keratoconus early, often before glasses stop working well.

Treatment

• Glasses or soft contact lenses in early stages
• Rigid gas-permeable, hybrid or scleral lenses that give the eye a smooth optical surface
• Corneal cross-linking, which uses riboflavin drops and ultraviolet light to strengthen the cornea and can stop progression
• Corneal ring segments to flatten the cone in some cases
• Corneal transplant for advanced keratoconus

Catching it early and halting it with cross-linking can preserve much better vision. Sudden pain and clouding in an eye with keratoconus can be corneal swelling (hydrops) and needs prompt care.

Questions people ask

Can I have LASIK if I have keratoconus?

Generally no. LASIK thins the cornea further and can make keratoconus worse. Other options such as cross-linking and implantable lenses may be considered.

Does eye rubbing cause keratoconus?

Frequent, hard eye rubbing is strongly linked to keratoconus getting worse. If your eyes itch, treat the allergy instead of rubbing.

Sources

1. American Academy of Ophthalmology, What is keratoconus?