The cornea is the clear outer layer of the eye (consisting of 5 individual layers) which acts to bend light to help focus it back onto the retina. It also acts as an important outer protective layer of the eye.
Keratoconus is a progressive, degenerative disease of the cornea in which the cornea thins and bulges form a cone-like shape which causes distortion of vision and in severe cases, even perforation of the cornea. The name Keratoconus is derived from the Greek (“kerato” meaning cornea and “konus” meaning cone).
Symptoms of this disorder include distorted night vision, the seeing of light “halos,” decreased distance vision and scarring of the cornea. Vision in glasses in Keratoconus patients is usually very limited often affecting their ability to drive especially if they can’t tolerate contact lenses.
It is thought that Keratoconus has a possible hereditary component and it has been related to conditions like Down’s syndrome, chronic eye rubbing and atopy (the tendency to develop allergic conditions). It usually occurs in both eyes and begins in puberty developing gradually over a period of from 10 to 20 years.
There are about 136,000 cases of keratoconus in the United States (1/2000 Americans). One of these is Emmy and Tony’s award winning actor Mandy Patinkin who plays a doctor on TV’s Chicago Hope and who was diagnosed with Keratoconus in 1982. He had started to notice changes in his vision which led to an evaluation with an Ophthalmologist and his eventual diagnosis and prescription for gas permeable hard contact lenses.
These types of contact lenses can often help improve vision as they flatten the corneas back to a more normal contour. Mandy was able to wear contact lenses for fifteen years but suddenly one day when driving to LaGuardia Airport in New York, he developed extreme pain in his right eye.
He was forced to suddenly stop the car and was rushed to a local hospital. It turned out that his right cornea had ruptured and he urgently needed an emergency corneal transplant.
In Mandy’s case, the corneal graft worked improving his vision in his right eye, but 3 1/2 years later he needed another corneal transplant this time in his left eye. Possible risks of corneal transplants include infection, development of glaucoma, the breaking of sutures and rejection of the transplant. Also, occasionally, there is no improvement in sight.
Two new advances in the treatment of keratoconus are “corneal cross-linking” (CXL) where specialized vitamin drops are applied to the cornea to increase the collagen crosslinks (anchors in the cornea). This increases stability and decreases bulging and INTACS (a procedure where 2 “arc like plastic segments” are inserted into the middle layer of the cornea to help flatten it). Clinical trials are currently ongoing using gene therapy to try to alter abnormal corneal cells.
Written by James D. Okun
James D. Okun, MD is a Phi Beta Kappa graduate of Duke University and the Albert Einstein College of Medicine in New York. He is the author of Erasing Scars: Herpes and Healing and of The History of New Innovations in Modern Medicine.