Your cornea focuses light into your eye. Keratoconus is the thinning of the cornea and bulging out like a cone. Light rays become unfocused when the shape of the cornea changes. As a result, your vision may become blurry and distorted, making daily tasks like reading or driving difficult.

An eye with keratoconus is shown in the images above and below.

What causes keratoconus?

The cause of this disease has not been discovered; however, it appears to be genetic. About 1 in 10 people with keratoconus have a parent who has it too.

Keratoconus beings when people are in their late 20s. Over time, the vision symptoms slowly get worse.

What are keratoconus symptoms?

Keratoconus often affects both eyes; however, vision between the two eyes can differ greatly and change over time. Symptoms also be different in each eye and change over time.

In the early stages of keratoconus symptoms could be as follows:

  • blurring of vision
  • slightly distorted vision
  • increased sensitivity to light 
  • eye redness or swelling

As time goes by keratoconus symptoms can become worse in later stages and often include:

  • more blurry and distorted vision
  • increased nearsightedness or astigmatism leading to a potential new eyeglass prescription 
  • inability to wear contact lenses

Keratoconus usually takes long to develop or switch stages; however, for some, it can get worse quickly. The cornea may suddenly swell and begin to scar, causing it loses smoothness and becomes less clear. As a result, vision grows blurrier and more distorted.

How is keratoconus diagnosed?

Keratoconus is diagnosed in a routine eye exam. Your ophthalmologist will examine your cornea and measure its curve, if there is a change in shape, you likely have Keratoconus. Your doctor may also map your cornea’s surface using a special technology, the image gathered through this will show the condition of the cornea’s surface.

How is keratoconus treated?

Keratoconus treatment varies based on your symptoms. When symptoms are mild, your vision can be corrected with eyeglasses; however, contact lenses may be the only solution to help keep vision in proper focus in later stages.

Other ways that your eye doctor may treat keratoconus:

  • Intacs:  a small curved device that your eye surgeon will place inside your cornea to flatten the curve of your cornea and improve vision.
  • Collagen cross-linking: UV light and eye drops are used to strengthen the cornea and flatten or stiffen it to prevent further bulging.
  • Corneal transplant: if symptoms are severe, your eye doctor may suggest a corneal transplant. 

Try to avoid rubbing your eyes if you suffer from Keratoconus. Doing so can damage corneal tissue and make your symptoms worse. If you have itchy eyes that make rubbing necessary, speak to your ophthalmologist about medications to control your allergies.


With keratoconus, the cornea becomes less dense and bulges out like a cone, affecting vision.

Keratoconus treatment depends on your symptoms. With mild symptoms, eyeglasses can correct your vision. With more severe symptoms, there are other treatment options that can include hard contact lenses, medication or surgery. In some cases, a cornea transplant may be needed.

With keratoconus, it is essential to see your ophthalmologist regularly for check-ups.

For questions about your vision or eyes, speak with your ophthalmologist.