Keratoconus

Keratoconus

Definition: Keratoconus is a condition where the cornea thins and gradually bulges forward, assuming a cone-like shape.

Causes: The cause of keratoconus is likely multifactorial, with genetics playing part of the causative role. Some non-genetic factors, like constant eye rubbing, have also been implicated in the cause of keratoconus. Keratoconus may develop in the setting of other diseases, such as Down’s Syndrome and Marfan’s Syndrome.

Symptoms: The abnormal, cone-like curvature changes the cornea's refractive power in an irregular way, producing mild or even moderate to severe astigmatism and blurriness. Symptoms often begin in to a mild degree in the teens or twenties, and may slowly worsen over the next several decades. The astigmatism may slowly worsen or, occasionally, a scar may slowly form in the middle of the cornea, decreasing vision. Occasionally, the thinning in keratoconus disrupts the delicate layer of cornea responsible for keeping it clear, causing the cornea to suddenly swell and the eye to become very irritated. This acute swelling, called corneal hydrops, usually resolves over several weeks, but can leave a corneal scar behind, causing decreased vision.

Treatment: In its earliest stages, keratoconus can be treated with glasses. As the astigmatism worsens, patients are fitted with special contact lenses to reduce the distortion and improve vision. In some patients, the condition may progress to the point where glasses or contact lenses are not effective in improving vision, and a corneal transplant may be required to gain improved vision. Another option, which is less invasive than a corneal transplant, is called Intacs. The Intacs procedure involves placing very small plastic rings into the cornea, which help normalize its shape. Conductive keratoplasty may be used in conjunction with Intacs to help decrease the corneal astigmatism.

Prognosis: Keratoconus generally first appears in the teens through early thirties. It may slowly progress over the next 10 to 20 years, but often stops progressing by late middle age. Most people with keratoconus can be effectively treated with glasses or contact lenses. However, about 20% of keratoconus patients eventually require surgery to help correct their vision.