Eyeworld

EW CORNEA 24 January 2011 by Faith A. Hayden EyeWorld Staff Writer Novel strategy could help to solve cornea shortage? W hat's the most efficient method to instantly double the quantity of something? Take one and split it in two. That's the think- ing behind a novel surgical proce- dure developed by researchers out of the University of Erlangen-Nurem- berg, Erlangen and Nuremberg, Ger- many, to address the increasing global need for cornea tissue. Although cornea tissue is the most common form of tissue trans- planted—on average, 50,000 surger- ies are performed in the U.S. alone, according to Eye Bank Association of American statistics—there is an over- whelming need for donor tissue in many parts of the world, including Africa and Asia. Many eye banks try to tackle this problem through edu- cation and outreach, but those ef- forts just aren't enough to keep up with the demand. Doctors at the Eye Bank Erlan- gen, University of Erlangen-Nurem- berg, found they were facing similar issues. "We have our own cornea bank here in our clinic. Although we've made quite a large effort to get more cornea tissue, it's becoming in- creasingly more difficult to get enough tissue to serve all of the pa- tients on our waiting list," said Claus Cursiefen, M.D., director, Eye Bank Erlangen, and one of the re- searchers for the study. "The wait list is getting longer and longer." Dr. Cursiefen and coworkers knew of a recent, revolutionary de- velopment in cornea surgery where instead of replacing a patients' entire cornea, surgeons replaced only the section that was diseased. "This technique basically allows the cornea being used to be split into two parts," Dr. Cursiefen said. "We thought maybe we could combine patients in such a way that we could use the anterior portion of the donor cornea for one patient and the posterior portion for the other." To test this theory, researchers used a combination of deep anterior lamellar keratoplasty (DALK) and Descement's membrane endothelial keratoplasty (DMEK) surgeries, two highly complicated procedures, on 12 donor corneas. In DMEK only the corneal endothelial "pump cells" and their basement membrane (< 15 µm) are transplanted to patients with isolated diseases of corneal en- dothelium. In contrast, in DALK sur- gery, the remaining 98% of the donor tissue is transplanted to pa- tients with healthy endothelium, but scarring of the anterior cornea occurs. The researchers reported a suc- cess rate of 83% but have since im- proved that number to nearly 90%. Two of the 12 cases used in the study had to be converted to pene- trating keratoplasty (the current standard technique). Six months after surgery, the mean best specta- cle-corrected visual acuity was 20/35. "Post-operative complications after DALK included Descement's folds in three eyes and epitheliopa- thy in two eyes," the team wrote in the study. "After DMEK, partial graft detachment occurred in five eyes and was managed successfully with intracameral air reinjection. All corneas remained clear up to six months after surgery." Although Dr. Cursiefen and coworkers were generally successful and had encouraging results, the method does come with challenges and pitfalls. Before surgeons could Bare Descemet's recipient membrane in DALK; splitting donor corneas may allow surgeons the ability to perform more DALK procedures in more patients Part of the DALK procedure is removing any overlying stromal tissue. Source: Mark Terry, M.D., Devers Eye Institute Alcon, Novartis Agree to Merger Terms A lcon's board of directors has approved the merger terms with Novartis. The company will pay $168 per share for the Alcon shares it already does not own. The merger consideration will be comprised of Novartis shares and, if needed, a cash contingent value amount. The merger will make Alcon the second largest division within Novartis, and expected to return a number of benefits such as an expanded ability to develop novel eye care products, as well as enhanced product development and branding opportunities for contact lenses and solutions. "This merger will create a stronger eye care business with broader com- mercial reach and enhanced capabilities to develop more new and innovative eye care products that address unmet clinical needs in eye care," said Kevin Buehler, Alcon's president and chief executive officer, in a press release. "The combination of Alcon's deep understanding of the eye care specialty and the broad expertise and scale of Novartis will allow us to address virtually all key areas of eye care with quality products and will position the Alcon business for faster growth." Alcon and Novartis expect the merger to be finished during the first half of 2011.

• Cover