The cornea is the clear skin tissue that composes the outermost layer of the eye. It is responsible for bending the light that enters the eye. Keratoconus is a slow, progressive, thinning of the cornea which causes blurred vision. It is 10 times more common in males than females. Keratoconus is self-limiting meaning that it will advance to a certain state and stop which could be a very mild case or a severe case requiring corneal transplant. Keratoconus will never blind a patient, but it can be a significant inconvenience. Keratoconus is often found more commonly in patients with chronic dermatitis and other skin conditions.
Signs and Symptoms of Keratoconus
Keratoconus usually involves blurred vision in both eyes with one eye being significantly worse. Ghost images around lights are a common initial symptom. Patients usually report inability to see clearly with any glasses prescription as the cornea has changed to an irregular shape which glasses cannot correct.
What Causes Keratoconus
Keratoconus is a genetic disorder and an exact cause has never been determined. It tends to run sporadically in families but often just pops up with no other family members being affected. The irregular thinning of the corneal tissue causes it to become very “football shaped” which induces an irregular astigmatism which then blurs the vision.
How is Keratoconus Diagnosed?
There are several tools that we use to diagnose keratoconus. The first is to check the glasses prescription for high amounts of astigmatism and poor corrected vision particularly in one eye. A keratometer is used to measure the curvature of the cornea and look for excessive steeping. If the corneal curvature is excessively steep, a corneal topographer is then used to make a map of the cornea and if the steep areas are in a keratoconus like pattern, the diagnosis is confirmed. A pachymeter can also be used to measure the thickness of the cornea.
How is Keratoconus Treated?
Keratoconus can be very challenging to treat. Mild cases can sometimes be treated simply with eyeglasses if the patient’s correctable vision is acceptable for them. Often times it is not and contact lenses provide a better option for quality vision. Soft contact lenses for keratoconus are usually not effective. Rigid gas permeable contact lenses can effectively cover up the irregular surface of the cornea and give the eye a new spherical refractive surface. These lenses can be quite uncomfortable and offer variable vision at best. Sometimes glasses have to be worn over top of the contact lenses to provide extra quality vision. New design Scleral Lenses have shown great promise in keratoconus correction. These lenses are very large and cover the entire cornea all the way out to the white sclera. They give better comfort and stable vision but their size can be intimidating at first.
In advanced cases of keratoconus, the cornea may become so thin and irregular that contact lenses do not give adequate vision and a corneal transplant is required. This is a more invasive procedure in which the diseased cornea is replaced with a donor cornea. Several months of healing will be required. Most patients with keratoconus do not require a corneal transplant.
A new procedure called Corneal Cross-linking has been shown to stabilize the cornea in most cases of keratoconus. During this procedure, the top layer of the cornea is removed (it will grow back in a couple days) and a solution of riboflavin is administered to the underlying corneal tissues . Ultraviolet light is then applied to the cornea and this combination encourages formation of new collagen fibers which effectively strengthen and thicken the cornea. Corneal Cross-linking has not yet been FDA approved.
What Steps Should I Take if I Think I Have Keratoconus?
We recommend making an appointment to see Dr. Reinders. He has 22 years of experience treating patients with keratoconus and other related conditions. The sooner we can check your eyes, the better. All doctors agree that waiting and hoping it will get better is not a prescription for success.