Thursday, April 1, 2010

Transplant Surgery

Some folks do not know what an "ophthalmologist" really does. So whenever people mistake me for an optician at Lens Crafters, I proudly announce that I perform transplant surgery.  Put that in your pipe and smoke it, I chuckle to myself.  Because of their unique position in the body, pristine islands in a sea of blood vessels, corneas receive an immunity necklace.  In professional jargon, they are "immunologically privileged", i.e. white blood cells cannot easily reach a corneal transplant and cause its rejection, because the highways to the cornea are unpaved. Therefore, corneas are the only transplanted organs that do not require systemic immunosuppression or blood-typing.  

Forget "I see dead people."  Recipients of corneal transplants see thanks to dead people!  Cadaveric corneas are harvested from deceased individuals who checked the appropriate box at the DMV.  They are then rushed to an institution on Wall Street called, you got it, an eye bank.  In Optisol storage media, they can be stored for approximately seven days before they are delivered to an operating room.  Meanwhile, they undergo rigorous testing to ensure quality and good health.  There are several eye banks in the country and the world, but the oldest one was established right here in New York.  It was founded by Dr. R. Townley Paton, who pioneered and then performed the first corneal transplant in 1905.  He did not establish The Eye Bank for Sight Restoration until 1944, when he was able to procure proper news-press and funding for his unique project.  Dr. Paton's first donor corneas were obtained from deceased inmates on death row at the nearby Sing-Sing prison and later expanded to deceased law-abiding citizens.  As the New York Eye Bank continued to grow and append surgeons, it sprouted 25 branches throughout the country.  Nowadays, 33,000 corneal transplants are performed in the United States each year.

Who needs corneal transplants?  The most common reasons for a transplant are a pointy cornea condition called keratotconus and a swollen cornea condition called bullous keratopathy.  Corneal scars due to trauma, infection or ulcers are also a hot commodity.  Finally, there are congenital conditions that cause the translucent corneal window to opacify.  These too, qualify for transplant surgery.

The procedure of transplantation is relatively simple: (1) cut out a circle of recipient cornea (2) replace missing circle with cookie-cut donor cornea (3) suture new cornea into its new 'hood and wait for it to jive.  The suture material consists of nylon thread, a fraction of a hair-width (it is only visible under a high-power microscope).  Full visual recovery takes about a year, and the cornea usually lasts approximately 15 years before it fails.  In the meanwhile, topical steroid drops are applied to prevent white-cells from reaching the graft.  There is only a 10% rejection rate in most cases, which, if caught in time, can be reversed.  Several years ago, exciting new technology emerged that allowed for partial corneal transplantation in a procedure called Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK).  This surgery forgoes the need for sutures, promises an even lower rejection rate than conventional transplants, and allows for visual recovery within three months!  It is only appropriate for folks with corneal swelling, though.  To learn more about the fascinating history of the New York Eye Bank, check out their website:

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