What is keratoconus?


Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped cornea (clear window of the eye) progressively thins causing a cone-like bulge to develop. Changing the shape of the cornea brings light rays out of focus. As a result, your vision is blurry and distorted, making daily tasks like reading or driving difficult. Keratoconus can cause significant visual impairment.

An eye with a normal cornea. The clear window at the front of the eye.

An eye with keratoconus, where the cornea bulges out like a cone.

What causes keratoconus?


Doctors do not know for sure why people have keratoconus.  It appears to be a combination of allergies, genetic (passed down in families) and other factors. About 1 out of 10 people with keratoconus have a parent who has it too.

Keratoconus is often first diagnosed when people are in their late teens to early 20s. The vision symptoms slowly get worse over a period of about 10 to 20 years and then stabilizes or slows down. Each eye is not necessarily  affected the same

What are keratoconus symptoms?


Keratoconus often affects your two eyes differently. Symptoms can differ in each eye, and they can change over time.


In its earliest stages keratoconus symptoms can include:

• mild blurring of vision

• distortion of vision, where straight lines look wavy

• increased sensitivity to light and glare

• eye redness or swelling


In later stages keratoconus symptoms often include:

• even more blurry and distorted vision

• increased nearsightedness or astigmatism. As a result, you may need a

   new prescriptions for glasses often.

• not being able to wear contact lenses. They may no longer

   fit properly and they are uncomfortable.


Keratoconus usually takes years to progress to late stage. Sometimes keratoconus can get worse quickly. The cornea can swell suddenly and scars can form. When the cornea has scar tissue, it is less smooth and becomes less clear. Vision grows even more distorted and blurry.

How is keratoconus diagnosed?


Keratoconus can be diagnosed during a routine eye exam. Additional tests may be necessary. During Keratometry your eye doctor focuses a circle of light on your cornea and measures the reflection to determine the basic shape of your cornea. Special photographic tests, such as optical coherence tomography and corneal topography, record images of your cornea to create a detailed shape map of your cornea's surface. The tests can also measure the thickness of your cornea. These results aid in the decision of your treatment.

How is keratoconus treated?


Keratoconus treatment also depends on your symptoms. When your symptoms are mild, your vision can be corrected with glasses. Later you may need to wear special hard contact lenses to help keep vision in proper focus.


Other treatment options include:

• Intra-stromal corneal ring segments. This is a very small curved device that your ophthalmologist puts in your cornea with the help of a femto-second laser. These ring segments help flatten the curve of your cornea to improve vision.

• Collagen’ cross-linking. Your ophthalmologist uses a special UV light and eye drops to strengthen the tissues of the cornea. Doing this helps to flatten your cornea, keeping it from bulging further. It also slows down progression.

• Corneal transplant. When symptoms are severe, your ophthalmologist may suggest a corneal transplant. This surgery replaces all or part of your diseased cornea with healthy donor cornea tissue.

Do not rub your eyes!

Avoid vigorous rubbing of your eyes. This can damage thin corneal tissue and make your symptoms worse.

If you have the urge to rub your eyes due to itching, speak to your ophthalmologist about medicines to control your allergies.

For more information or questions:

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