As a surgeon who has the privilege of helping restore vision by performing corneal transplants, this makes March an important month for me. I would not be able to have this privilege, nor would my patients have the fortune of seeing better, without the kindness of eye donors and their families. There are more than 42,000 corneal transplants performed every year in the U.S. Almost half of these transplants are used for partial thickness transplants or endothelial keratoplasty (EK). The Donor Network of Arizona provided 1227 corneas for transplantation in 2011. Corneal disease is the fourth most common cause of visual impairment worldwide in 2002 according to the WHO (world health organization).
How does the cornea affect your vision?
The cornea is the first structure light passes through as it enters your eye. You can think of it as a transparent dome that vaults iris, the tissue inside your eye that gives the eye its color. If you look at your watch it would correspond to the watch glass and the iris to the face of the watch. If the watch glass becomes scratched or opaque you will not be able to see the face of your watch as well. Similarly, if your cornea becomes cloudy, you will not be able to see as well. The effect of a cloudy cornea can be similar to a cataract.
What are the reasons for a cloudy or distorted cornea?
Factors that affect the cornea are varied. They range from an infection of the cornea (corneal ulcer) to inherited diseases. These include corneal dystrophies, which lead to cloudy corneas over time and thinning diseases such as keratoconus, which lead to a distortion of the cornea. Fuchs’ corneal dystrophy or endothelial dystrophy as well as endothelial damage can lead to corneal swelling and cloudiness over time. This is because the endothelium, a layer of cells on the backside of the cornea, prevents swelling by pumping fluid out of the cornea. Fuchs’ dystrophy causes these cells to slowly deteriorate and decrease in number. When you don’t have enough of theses cells, fluid builds up in your cornea leading to swelling.
One of the treatments for the above mentioned conditions is a corneal transplant. The first successful corneal transplant was performed in 1906. Over the last 100 years we have experienced improvements in preservation and surgical techniques. In addition to the full thickness transplant we are now able to selectively replace the parts of the cornea that are not functioning properly. For Fuchs’ endothelial dystrophy as well as for corneal edema only the thin layers of cells/pumps (endothelium) is replaced. This procedure is called DSAEK. In cases where the endothelium is still healthy only the anterior parts of the cornea can be replaced, a procedure called DALK. The same LASER used to create the flap during LASIK procedures can now be used to shape the interface between the patient’s and the donor’s cornea creating a better and more secure fit. These LASER created wounds can be compared to dovetailed joints interlocking in a much more secure fashion.
As the cornea specialist at Barnet Dulaney Perkins I am excited to be able to offer all of these options to patients who need a corneal transplant. Consider helping these patients as well. Consider becoming an eye donor and discuss it with your family. You too can help restore another’s sight.
Robert Fintelmann, MD
Cornea, Vision Correction and Cataract Surgeon