Eyeworld

EW MEETING REPORTER 92 the world cornea doctors no longer retrieve or process corneas before surgery, the exception being South Korea, where the law requires that physicians continue to do so. Elsewhere, Dr. Macsai said, the advantages of eye banking are clear. Since surgeons no longer have to worry about harvesting and processing tissue, they can perform surgery in a matter of minutes. In DSAEK and DMAEK, for instance, Dr. Macsai said that the surgeon sim- ply grips the Descemet's membrane and inserts the tissue into the AC, injects air or gas, and is done. Moreover, she said, it is likely that an eye bank technician precut- ting and processing tissue over and over will be doing it much more efficiently than any surgeon doing it just once or twice a week. Any lingering concerns over the quality of precut tissue should also be laid to rest—Dr. Macsai said that there is no significant difference in the quality of tissue or patient outcomes between surgeon prepared and precut tissue. Precutting saves time and mon- ey, as well as reduces stress in the operating room and the amount of tissue wasted per procedure. There are concerns about ship- ping tissue overseas. However, while one study has shown endothelial cell density (ECD) losses of around 1.75% with precutting and 3.79% "Things have gotten much more complicated in the past decade," she said. Corneal transplantation is no longer restricted to full-thickness penetrating grafts, with surgeons now performing lamellar surgery with partial grafts, sometimes even using scleral tissue for grafts; more- over, rather than being used on the spot, corneal tissue is being stored long term and shipped all around the world. In her plenary lecture, Dr. Macsai made the argument that, these days, following more than 25 years of dramatic surgical innova- tion and advancements in instru- mentation, "Corneal Surgery Begins in the Eye Bank." "The processing of tissue is very high level and quite complicated," Dr. Macsai said. It was because of this that the Eye Bank Association of America (EBAA) established univer- sal medical standards for eye bank- ing—soon to be published in the International Journal of Eye Banking. The standards cover the six eye banking functions: recovery, pro- cessing, storage, evaluation of tissue for transplantation, determination of donor eligibility, and distribution. In addition, eye banks provide infrastructure for gathering postop- erative outcome information up to and including adverse reactions. Given the scope of eye banking and the complexity of modern cor- neal transplant surgery, all around to believe Snow. He used small data to get to the bottom of why chol- era outbreaks were occurring. This led to the eventual demise of the miasmatic theory. The case of the Broad Street tap, Dr. Tu said, is an example of how to approach other human diseases—really, he said, this was "the birth of epidemiology." More than just statistics, epidemi- ology brings together experts from multiple disciplines to collaborate in a small, well-designed study asking appropriate questions based on an understanding of a disease. Fast forward to the present: Turns out, Dr. Tu said, atypical corneal infec- tions are "quite amenable" to this approach. His particular experience, he said, has been with Acanthamoe- ba keratitis—a traditionally rare disease with a reported incidence of two cases per million contact lens wearers per year; easily traceable using special diagnostic modalities requiring specialized, compound medications; and primarily a disease of the eye. It was from outbreaks, he said, that we have learned quite a bit about Acanthamoeba keratitis. Through outbreaks, we have been able to identify contact lens wear as the primary risk factor, ampli- fied by deviations in water quality; study of these outbreaks suggests that environmental risk factors may not be modifiable; and the surge in Acanthamoeba keratitis over the last decade or so may reflect changes in risk factors that may have an effect not only on other ocular infec- tions but also on the general public health. Big data, Dr. Tu said, remains most ideal, but small data and even really small data have their value. Ultimately, he concluded, what is important is that whether big, small, or very small, the data be "good and clean." Cornea surgery begins in the eye bank "It used to be that corneal surgery was quite straightforward," said Marian Macsai, MD, Glenview, Illinois. "We had a problem— keratoconus—we got a cornea, we punched a button, we sewed it into place, badabing badaboom, the eye was rehabilitated." January 2017 continued on page 94 View videos from ACS 2016: EWrePlay.org Amar Agarwal, MD, discusses young donor tissue for pre-Descemet's endothelial keratoplasty. Reporting from the 5th Asia Cornea Society Biennial Scientific Meeting, December 9–11, 2016, Seoul, South Korea Sponsored by

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