Publication Exclusive: DMEK will eventually show superiority in hands of expert surgeons

The Eye Bank Association of America was founded in 1961 with 25 member eye banks. Today, 78 member eye banks harvest approximately 120,000 corneas per year in a high-quality, highly regulated and expensive undertaking. With this network of eye banks and modern transportation capability, along with advanced corneal preservation media that sustain endothelial viability for up to 14 days, corneal transplantation, at least in the U.S., is now an elective procedure. The days of waiting lists and weekend emergency transplants are long gone.

Rounding off, approximately 50,000 transplants are performed in the U.S. each year. Eye Bank Association of America member eye banks also export approximately 20,000 corneas for use outside the U.S. every year. While corneal blindness in the U.S. amenable to keratoplasty essentially no longer exists, the story is extremely different in areas of the world where an inadequate eye banking network, unavailability of trained corneal surgeons and economic barriers leave several million people who might respond to a corneal transplant blind and disabled.

In the U.S., a study by the Lewin Group found the cost of a corneal transplant, including tissue, facility, anesthesia, surgeon and postoperative care, is approximately $15,000. We corneal surgeons know that we are only a very small part of this cost, in most cases less than 10%. In the same study, the calculated “value” to society of treating a patient disabled by corneal disease with a keratoplasty was $250,000 for those younger than 65 years and somewhat less as patients age and life expectancy declines. Corneal transplantation is therefore not only life-changing for patients, but also a great value for society.

The biggest change in the field of keratoplasty over the last decade has been the transition from penetrating keratoplasty to lamellar keratoplasty, especially for endothelial dysfunction, including aphakic and pseudophakic bullous keratopathy and Fuchs’ dystrophy. Approximately 20,000 of the 50,000 corneal transplants performed in the U.S. each year are now some form of lamellar endothelial keratoplasty.

The first meaningful transition, now pretty much complete in the U.S., was from PK to what most today call Descemet’s stripping endothelial keratoplasty. Our group of four, soon to be five, corneal surgeons made this transition nearly 5 years ago, and overall today we find DSEK preferable for most patients with endothelial dysfunction. Still, my personal impression affirmed by a substantial set of data collected and published by Doug Coster, MD, from a well-managed Australian Registry is not clearly in favor of DSEK over PK. While DSEK is much easier on the surgeon and the patient than PK, there is a significant learning curve, and postoperative interventions such as re-bubbling are a hassle for all. In addition, at 12 months and later postoperative, visual acuities achieved, especially if the PK patient is allowed to wear a gas permeable hard contact lens, are often superior with PK. In favor of DSEK, there is much more rapid visual recovery and less astigmatism, the hassle of suture removal and suture-related complications is reduced or eliminated, and there may be a slightly lower rejection rate. However, many patients with long-standing corneal edema also develop stromal or anterior corneal surface haze and/or significant epithelial basement membrane dystrophy. Depending on the corneal surgeon, some choose to treat these patients with DSEK combined with superficial keratectomy or phototherapeutic keratectomy when the surface disease is significant, while others choose PK. Both, in my opinion, are reasonable approaches.

Click here to read the publication exclusive, Lindstrom's perspective, published in Ocular Surgery News U.S. Edition, April 10, 2015.