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Definition

What is keratoconus?

Keratoconus occurs when your cornea — the clear, dome-shaped front surface of your eye — thins and gradually bulges outward into a cone shape.

A cone-shaped cornea causes blurred vision and may cause sensitivity to light and glare. Keratoconus usually affects both eyes and generally begins to first affect people ages 10 to 25. The condition may progress slowly for 10 years or longer.

In the early stages of keratoconus, you can correct vision problems with glasses or soft contact lenses. Later you may have to be fitted with rigid gas permeable contact lenses or other types of lenses. If your condition progresses to an advanced stage, you may need a cornea transplant.

How common is keratoconus?

Keratoconus is common. Please discuss with your doctor for further information.

Symptoms

What are the symptoms of keratoconus?

Signs and symptoms of keratoconus may change as the disease progresses. They include:

  • Blurred or distorted vision
  • Increased sensitivity to bright light and glare, which can cause problems with night driving
  • A need for frequent changes in eyeglass prescriptions
  • Sudden worsening or clouding of vision

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

See your eye doctor (ophthalmologist or optometrist) if your eyesight is worsening rapidly, which might be caused by an irregular curvature of the eye (astigmatism). He or she may also look for signs of keratoconus during routine eye exams.

If you’re considering laser-assisted in-situ keratomileusis (LASIK) eye surgery, your doctor will check for signs of keratoconus before you proceed.

Causes

What causes keratoconus?

Tiny fibers of protein in the eye called collagen help hold the cornea in place and keep it from bulging. When these fibers become weak, they cannot hold the shape and the cornea becomes progressively more cone shaped.

Keratoconus is caused by a decrease in protective antioxidants in the cornea. The cornea cells produce damaging by-products, like exhaust from a car. Normally, antioxidants get rid of them and protect the collagen fibers. If antioxidants levels are low, the collagen weakens and the cornea bulges out.

 

Keratoconus appears to run in families. If you have it and have children, it’s a good idea to have their eyes checked for it starting at age 10. The condition progresses more rapidly in people with certain medical problems, including certain allergic conditions. It could be related to chronic eye rubbing.

Keratoconus usually starts in the teenage years. It can, though, begin in childhood or in people up to about age 30. It’s possible it can occur in people 40 and older, but that is less common.

The changes in the shape of the cornea can happen quickly or may occur over several years. The changes can result in blurred vision, glare and halos at night, and the streaking of lights.

The changes can stop at any time, or they can continue for decades. There is no way to predict how it will progress. In most people who have keratoconus, both eyes are eventually affected, although not always to the same extent. It usually develops in one eye first and then later in the other eye.

With severe keratoconus, the stretched collagen fibers can lead to severe scarring. If the back of the cornea tears, it can swell and take many months for the swelling to go away. This often causes a large corneal scar.

Risk factors

What increases my risk for keratoconus?

There are many risk factors for keratoconus, such as:

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is keratoconus diagnosed?

To diagnose keratoconus, your eye doctor (ophthalmologist) will review your medical and family history and conduct an eye exam. He or she may conduct other tests to determine more details regarding the shape of your cornea. Tests to diagnose keratoconus include:

  • Eye refraction. In this test your eye doctor uses special equipment that measures your eyes to check for vision problems. He or she may ask you to look through a device that contains wheels of different lenses (phoropter) to help judge which combination gives you the sharpest vision. Some doctors may use a hand-held instrument (retinoscope) to evaluate your eyes.
  • Slit-lamp examination. In this test your doctor directs a vertical beam of light on the surface of your eye and uses a low-powered microscope to view your eye. He or she evaluates the shape of your cornea and looks for other potential problems in your eye. The doctor may repeat the test after you’ve had eyedrops applied to dilate your pupils. This helps with viewing the back of your eye.
  • In this test your eye doctor focuses a circle of light on your cornea and measures the reflection to determine the basic shape of your cornea.
  • Computerized corneal mapping. 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.

How is keratoconus treated?

Treatment for keratoconus depends on the severity of your condition and how quickly the condition is progressing.

Mild to moderate keratoconus can be treated with eyeglasses or contact lenses. For most people, the cornea will become stable after a few years. If you have this type, you likely won’t experience severe vision problems or require further treatment.

In some people with keratoconus, the cornea becomes scarred or wearing contact lenses becomes difficult. In these cases, surgery might be necessary.

Lenses

  • Eyeglasses or soft contact lenses. Glasses or soft contact lenses can correct blurry or distorted vision in early keratoconus. But people frequently need to change their prescription for eyeglasses or contacts as the shape of their corneas change.
  • Hard contact lenses. Hard (rigid gas permeable) contact lenses are often the next step in treating progressing keratoconus. Hard lenses may feel uncomfortable at first, but many people adjust to wearing them and they can provide excellent vision. This type of lens can be made to fit your corneas.
  • Piggyback lenses. If rigid lenses are uncomfortable, your doctor may recommend “piggybacking” a hard contact lens on top of a soft one.
  • Hybrid lenses. These contact lenses have a rigid center with a softer ring around the outside for increased comfort. People who can’t tolerate hard contact lenses may prefer hybrid lenses.
  • Scleral lenses. These lenses are useful for very irregular shape changes in your cornea in advanced keratoconus. Instead of resting on the cornea like traditional contact lenses do, scleral lenses sit on the white part of the eye (sclera) and vault over the cornea without touching it.

If you’re using rigid or scleral contact lenses, make sure to have them fitted by an eye doctor with experience in treating keratoconus. You’ll also need to have regular checkups to determine whether the fitting remains satisfactory. An ill-fitting lens can damage your cornea.

Surgery

You may need surgery if you have corneal scarring, extreme thinning of your cornea, poor vision with the strongest prescription lenses or an inability to wear any type of contact lenses. Several surgeries are available, depending on the location of the bulging cone and the severity of your condition.

 

Surgical options include:

  • Corneal inserts. During this surgery, your doctor places tiny, clear, crescent-shaped plastic inserts (intracorneal ring sigments) into your cornea to flatten the cone, support the cornea’s shape and improve vision. Corneal inserts can restore a more normal corneal shape, slow progress of keratoconus and reduce the need for a cornea transplant. This surgery may also make it easier to fit and tolerate contact lenses. The corneal inserts can be removed, so the procedure can be considered a temporary measure. This surgery carries risks, such as infection and injury to the eye.
  • Cornea transplant. If you have corneal scarring or extreme thinning, you’ll likely need a cornea transplant (keratoplasty). Lamellar keratoplasty is a partial-thickness transplant, in which only a section of the cornea’s surface is replaced. Penetrating keratoplasty is a full-cornea transplant. In this procedure, doctors remove a full-thickness portion of your central cornea and replace it with donor tissue. A deep anterior lamellar keratoplasty (DALK) preserves the inside lining of the cornea (endothelium). It helps avoid rejection of this critical inside lining that can occur with a full-thickness transplant. Recovery after keratoplasty can take up to one year, and you may need to continue wearing rigid contact lenses to have clear vision. Full improvement of vision may occur several years after your transplant. Cornea transplant for keratoconus generally is very successful, but possible complications include graft rejection, poor vision, astigmatism, inability to wear contact lenses and infection.

Potential future treatment

A treatment called collagen cross-linking shows promise for people with keratoconus. The process involves using special eyedrops and ultraviolet A (UVA) light to strengthen (cross-link) the tissues of the cornea. The treatment is still in the testing phase in the United States, and additional study is needed before it becomes widely available.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage keratoconus?

If you have any questions, please consult with your doctor to better understand the best solution for you.

 

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: November 1, 2017 | Last Modified: November 1, 2017

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