Often appearing in the teens or early twenties, keratoconus is a progressive disease in which the normally round cornea thins and begins to bulge into a cone-like shape. This cone shape deflects light as it enters the eye on its way to the light-sensitive retina, causing distorted vision. Keratoconus can occur in one or both eyes.
New research has demonstrated a relationship between malfunction of beneficial enzymes found within the eye’s surface and an accompanying chemical imbalance that leads to toxic damage and thinning of eye tissue. Because keratoconus can be found in extended families, this improper functioning of beneficial enzymes appears to have genetic causes about 5% of the time. Eye damage from keratoconus also can be linked to factors such as overexposure to sunlight, improper fittings of contact lenses, excessive eye rubbing, and continual (chronic) eye irritation.
Signs and Symptoms
Keratoconus can be difficult to detect, because it usually develops so slowly. However, in some cases, it may proceed rapidly. Nearsightedness and astigmatism also may accompany this disease, creating additional problems with distorted and blurred vision. Glare and light sensitivity also may be noticed. Keratoconic patients often have prescription changes each time they visit their eyecare practitioner. It’s not unusual to have a delayed diagnosis of keratoconus, if the practitioner is not familiar with the early-stage symptoms of the disease.
In the mildest form of keratoconus, eyeglasses or soft contact lenses may help. But as the disease progresses and the cornea thins and changes shape even more, glasses or soft contacts will no longer correct your vision.
Other keratoconus treatments include:
Rigid gas permeable contact lenses: if eyeglasses or soft contact lenses cannot control keratoconus, then rigid gas permeable contact lenses are an option to consider. The firmer material of a rigid contact lens vaults over the irregular cornea better than a soft contact lens to improve vision. But rigid contact lenses can be more uncomfortable to wear than a soft lens. Fitting contact lenses on a keratoconic cornea is delicate and time-consuming. You can expect frequent return visits to fine-tune the fit and the prescription. The process will begin again when the cornea thins and distorts even more, altering the contact lens fit and prescription needed for clear, comfortable vision.