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20 | EYEWORLD DAILY NEWS | MAY 16, 2020 DAILY NEWS ASCRS VIRTUAL ANNUAL MEETING Corneal procedures and diagnostics papers explore EK, PK, and more The study was conducted at the University of Toronto with the purpose of evaluating outcomes of DMEK combined with anterior chamber intra- ocular lens (ACIOL) exchange and transscleral fixation in patients with pseudophakic bullous keratopathy (PBK). Many cornea practices are seeing patients with PBK and ACIOL more frequently, Dr. Santaella said. This is common after complicated cataract surgery when posterior cham- ber placement is not possible, therefore, surgeons choose an ACIOL in order to leave the patient pseudophakic. Years down the road, many of these corneas may experience endo- thelial decompensation. Different surgeons will have different approaches, Dr. Santaella said, but options may include DSAEK with an IOL exchange, DSAEK while leaving the ACIOL in place, or PKP. The study was retrospec- tive and looked at patients who step in DMEK, which can be very difficult in cases of poor visibility, Dr. Nahum stressed. For that purpose, intraoper- ative OCT (iOCT) imaging is useful, he said. It does not touch the cornea, does not obstruct the surgeon's view, and provides high-resolution images, even through a very opaque medium. However, it's expensive and not com- monly available, he said. In comparison, UBM is a small, standalone mobile device that is a fraction of the price of iOCT. It does have lower resolution than iOCT, lightly touches the cornea during examination, and obstructs the surgeon's view during examination, he said, but it can easily determine the graft orientation in seconds, as demonstrated in the study. Gisella Santaella, MD, Toronto, Canada, present- ed "Outcomes of Combined Anterior Chamber Intraocular Lens Exchange and Descemet Membrane Endothelial Kerato- plasty." Currently, the only device to assist in such cases is micro- scope-mounted intraoperative anterior segment OCT, Dr. Nahum said. He then mentioned UBM, which was used in his study on graft orientation. This was a prospective interventional study in five patients undergo- ing DMEK. After centration and partial unfolding of the graft, the blue cannula tip technique was performed. UBM imaging was done by the surgeon or another physician. Dr. Nahum noted that graft orientation was identifiable in all cases. There was no AC leak or graft movement that occurred during UBM. In two of the cases, UBM identified an upside-down graft, and in one of those cases, the blue can- nula tip technique had shown correct orientation. In all cases, postoperative OCT demonstrat- ed correct graft orientation, Dr. Nahum noted. In all cases, the surgery was uneventful. The determination of the graft's orientation is a crucial by Ellen Stodola Editorial Co-Director Throughout EyeWorld Dai- ly News, we will be including coverage of a number of paper sessions, which feature presenta- tions on a variety of topics and studies from around the world. While we're only able to cover a small selection of the many papers featured at the 2020 ASCRS Virtual Annual Meeting, the rest can be found with the other meeting content with the SPS session ID designation. P apers on EK, PK, cross- linking, and more were featured in a paper ses- sion on corneal proce- dures and diagnostics. Yoav Nahum, MD, Tel-Aviv, Israel, presented "Intraopera- tive Ultrasound Biomicroscopy (UBM) for Determining Graft Orientation during Descemet's Membrane Endothelial Kerato- plasty (DMEK)." "During DMEK, the graft orientation has to be deter- mined before fully attaching it to the recipient posterior stro- ma, as transplantation with an upside-down graft will result in primary failure of the graft," Dr. Nahum said. He mentioned techniques to help with this, including the touch techniques that require good visibility (blue cannula tip sign, F/S stamping, punch- ing orientation marks, and ring-shaped peripheral stain- ing) and no-touch techniques that require good visibility (an endoilluminator or a handheld slit lamp). In some cases, he added, there is poor visibility due to corneal opacity, blood, pig- ment, or loss of staining. In these cases, determination of graft orientation can be very difficult and may require AC washout or graft restaining. The different steps of the surgical technique used in the study done by Dr. Santaella and colleagues Source: Gisella Santaella, MD, screenshot from presentation continued on page 22

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