Keratoconus
What is keratoconus?
Keratoconus is an eye problem where the cornea (clear front surface of the eye) becomes too thin. The cornea should be round like a dome, but in keratoconus, it bulges out like a cone. This bulging and thinning causes blurry vision. People with keratoconus might have to get their glasses or contacts changed more often than normal.
Keratoconus happens in about 1 out of every 2,000 people. It can happen to anyone but is more common in people from Asia. Most people with keratoconus find out they have it when they are in puberty or in their late teens. It usually happens in both eyes but can be different in each eye. After it starts, keratoconus usually gets worse over 10-20 years and then stops.
Fig. 1: Keratoconus
What causes keratoconus?
Doctors are not sure what causes keratoconus. Many problems are linked with keratoconus. Eye rubbing is often seen in people with this problem. It can run in families – if your parent or brother or sister has it, then you are more likely to get it too. The main problem in keratoconus is that the cornea and the tissue inside it (collagen) is weak and thin.
People with asthma, eczema, or allergies, and other health problems (Down Syndrome, Marfan’s syndrome, and Leber’s congenital amaurosis) are more likely to get keratoconus.
What are the signs & symptoms of keratoconus?
Main signs and symptoms are:
- Blurry vision that gets worse over time
- More nearsightedness (trouble seeing things far away)
- Irregular astigmatism (a loss of the normal shape of the eye that causes things to look wavy or double)
- Blurry vision especially at night
- Being sensitive to light (photophobia)
- Seeing double or “ghost images”
- Seeing streaks around lights
Most of the time, keratoconus doesn’t hurt. If a blister forms in the cornea (called hydrops), it can cause eye pain and redness. Scarring in the cornea can lead to blurry vision that cannot be fixed with glasses or contacts.
How is keratoconus found by doctors?
An eye doctor (ophthalmologist) looks for signs of keratoconus with detailed eye exam. They check vision and use special tools to look at the eyes closely. They may also use a special test (corneal topography) which creates a 3D map of the cornea's surface. This test can show thinning and other signs of keratoconus.
How is keratoconus treated?
Keratoconus is often worse in children than adults.
Mild cases of keratoconus can often be treated with glasses or soft contact lenses. Most people need hard contact lenses for the best vision.
A newer treatment called collagen crosslinking (CXL) helps make the eye stronger. The doctor uses special drops (riboflavin) and a special (UV) light on the front of the eye. This treatment can form stronger collagen and help with the bulging in the cornea. People might need to see a specialist and have general anesthesia to get crosslinking treatment.
Some people need surgery to replace the cornea (transplant) if other treatments don’t help. About 10-25% of people with keratoconus need this treatment.
After any treatment, regular follow-up care is important to check for any problems.
If you have keratoconus, you should NOT get LASIK because it can make the eyes worse.
Where can I learn more about keratoconus?
Updated: 10/2024
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