What is Keratoconus?
A fairly common condition, keratoconus occurs when the middle part of the cornea progressively thins and bulges outwards, forming a cone-like shape. In an eye without keratoconus, the cornea is usually dome-like in shape. This condition reduces your vision and distorts it (astigmatism), making you see blurry (either nearsighted (myopia) or farsighted (hyperopia)). Keratoconus affects about 1 in every 1,000 people.
Keratoconus most often begins in the teenage years, and usually occurs without other eye diseases. In some cases, keratoconus is diagnosed in pediatric patients while in other cases it may not develop until adulthood.
Symptoms of keratoconus start out seeming harmless, as the main complaint is deteriorating vision. Most people complain about a minor blurring and go to see their eye doctor for reading or driving glasses. In some cases, however, vision rapidly deteriorates and night vision becomes extremely poor.
Some people notice the vision in one eye is significantly worse than in the other, but usually the disease affects both eyes. The classic symptom of keratoconus is “ghost” images – called monocular polyopia.
What that means is that instead of just seeing one point of light, the person sees many images, all spread out in a random order. The pattern of distorted light doesn’t tend to change from day to day. Other symptoms include a sensitivity to bright lights, called photophobia, eye strain from squinting to focus on objects, or itchy eyes.
The National Eye Institute (part of the National Institutes of Health) has identified several causes of keratoconus, including genetics and eye rubbing. Interestingly, in patients who have one eye with more advanced keratoconus, patients will frequently report that they rub that eye more often or more intensely than the other eye.
Other potential causes include eye diseases — such as retinitis pigmentosa, retinopathy of prematurity, or vernal keratoconjunctivitis — or systemic diseases, such as Down’s syndrome or Leber’s congenital amaurosis.
Treatment begins with prescription glasses. As the distorted vision (astigmatism) continues to get worse, patients have to be fitted with special contact lenses. These contact lenses require a very precise fit, and need to be updated as the condition worsens.
Without treatment, keratoconus can progress to a point where corneal scarring develops, and the only treatment that will restore vision is a corneal transplant.
Over the past decade, a treatment has been developed that can actually prevent keratoconus from worsening, and this is considered the standard of care treatment in countries throughout the world. This treatment is called Corneal Collagen Crosslinking commonly referred to as “CXL”, and works by strengthening the cornea and halting the condition from worsening. The treatment takes about an hour.
To read more about Corneal Crosslinking, please click here.
CXL was recently approved for use in the United States in 2017, and prior to its approval by the FDA, several institutions nationwide were involved in conducting clinical trials on the procedure in anticipation of U.S. regulatory approval. We are happy to report that our office was one of the clinical study sites involved! The results from around the world have shown that cross-linking is effective, but patients should be aware that there are always risks with any procedure including the risk of infection and inflammation.
If your doctor has determined you need a cornea transplant, it is likely you will still need corrective lenses after the procedure. About 60% of people still have to wear contact lenses after corneal transplants. In some cases, laser vision correction can be performed to reshape the cornea after a corneal transplant procedure.
Another procedure that is sometimes used for keratoconus is called Intacs. These inserts are placed in the cornea and can reshape the cornea. These have been shown to be useful, but they only slow down the progression of keratoconus; they are not a cure and cannot reverse or stop the disease. Although keratoconus is a challenging condition for patients, the recent advances in treatments have greatly improved the long term visual results of patients. Seeking evaluation with an eye care professional to discuss the various options is important, because the sooner that patients initiate treatment (such as with CXL), the more likely a patient will preserve very good useful vision. Visit our CXL page to learn more about Keratoconus Treatments!