Keratoconus is an eye condition in which the cornea, the clear front of the eye, becomes thin and develops a cone-shaped bulge. The cornea plays a large role in our vision. As light enters the eye, it is the cornea that directs light rays to land precisely on to the retina. When the cornea is not shaped correctly, light rays will not hit the retina correctly, resulting in poor vision. Keratoconus will most often affect both eyes, but the symptoms can vary from person to person, and even from eye to eye. There are many causes of keratoconus. The most common causes involve genetics and eye rubbing. It is extremely important that patients with keratoconus do not rub their eyes. Eye rubbing will weaken the corneal and cause it to bulge further.
Blurred or distorted vision and frequent changes in eyeglass prescription are generally the first signs.
Common Symptoms include:
• Blurred or distorted vision
• Sensitivity to light
• Glare, halos, or starbursts when looking at lights
• Multiple images
While for many, having keratoconus means nothing more than having to use glasses or contacts, for some this condition can progress to severe levels, greatly affecting vision and quality of life.
As the cornea begins to bulge, it becomes thinner. The thinner the cornea becomes, the weaker it become. The weaker the cornea becomes the more bulging. As this cycle persists the vision gets progressively worse. At some point the cornea may experience breaks in its inner layers causing episodes of pain, light sensitivety, and decreased vision. The cornea will begin to scar in its center causing even further vision loss.
Early keratoconus will cause astigmatism which can be corrected with glasses. As the process progresses, glasses will no longer allow clear vision. At this point the patient will graduate to hard contact lenses. Further along in the disease process, hard contact lenses will no longer correct the vision either because they are not able to fit well on the bulging cornea, or because the scarring in the center of the cornea will inhibit vision even with the hard contact lens on.
There are two surgical interventions which address Keratoconus:
Collagen Crosslinking –
Collagen Crosslinking halts the progression of keratoconus. However, it does not correct the bulging cornea. It is best performed when the patient is still in the early stages of keratoconus and able to see well with glasses or contact lenses.
Penetrating Keratoplasy (Corneal Transplant)
Penetrating Keratoplasty (Corneal Transplant) involves removing the portion of the cornea which is bulging and replacing it with a healthy donor cornea. This surgery is optimal when the vision is affected to the point where the patient no longer sees well in hard contact lenses.