Oct 19 2009
Eight-year-old Hannah Terrell of Medford, Oregon, is living life with a new perspective. Last year, it was hard for Hannah to play tag with her friends because she couldn’t see the other children as they ran away. Now she is running across the field and chasing her friends like any other third-grader.
Mark A. Terry, M.D., director of corneal services at Legacy Good Samaritan Devers Eye Institute in Portland, Ore., cleared Hannah’s vision in her right eye with the world’s first successful endothelial keratoplasty (EK) for congenital hereditary endothelial dystrophy (CHED). Dr. Terry will operate on her left eye later this fall.
When Dr. Terry examined Hannah for the first time, she was legally blind in both eyes. He knew an EK was her best hope. The surgery replaces the damaged endothelium, or inner layer of the cornea, with donor tissue through a small incision in the side of the cornea. This tissue adheres to the back surface of the old cornea and clears the corneal swelling, creating a clear window to see through.
“In a traditional corneal transplant, the incision is larger, there are more stitches and the healing process is longer. This can lead to a high risk of amblyopia, or ‘lazy eye,’ in children,” said Dr. Terry. “The healing process would have taken too long with a traditional full thickness transplant to get the best vision for Hannah.”
Dr. Terry developed EK and was the first to perform the surgery in the United States in March 2000. Legacy Good Samaritan Devers Eye Institute has the lowest complication rates at two percent, compared to 20-30 percent nationwide. Dr. Terry further developed EK to its current form of Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK). This is the first time the surgery was successfully performed on a patient with CHED.
CHED is a rare condition that causes corneas to cloud over and vision to blur. The endothelium is responsible for pumping excess water out of the cornea. In CHED, the “pumps” don’t work properly and there is a build-up of water, which clouds the vision like a foggy window. If left untreated in a child under the age of 10, CHED can lead to permanent vision loss.
Before the recent surgery, CHED interfered with Hannah’s depth perception. She took stairs slowly and with extreme caution. “I knew her depth perception was better after surgery when she ran down the stairs without any fear,” said her father, David Terrell. “For the first time, I had to tell her to slow down.”
After Dr. Terry operates on her right eye, the Terrells will have to keep an even closer watch on their daughter. Hannah will no longer have anything holding her back.
Source: http://www.legacyhealth.org/body.cfm?id=330&fr=true