Eyeworld

EW FEATURE 44 AT A GLANCE • With increased experience, DMEK is feasible in more types of eyes. • The high rebubble rate in DMEK has improved as techniques and instrumentation have evolved. • Patient discussions about the differ- ent forms of EK should include the surgeon's experience with DSAEK and DMEK. by Rich Daly EyeWorld Contributing Writer All you need to know about cornea transplants • January 2018 New trends in endothelial keratoplasty Surgeons explore whether DSAEK is still better for certain patients and other lingering questions S urgeons have found that the keys to selecting newer corneal transplant procedures involve a solid understanding of techniques, patient selection, and communication. Sophie Deng, MD, professor of ophthalmology, cornea division, University of California, Los Ange- les, has found Descemet's stripping automated endothelial keratoplasty (DSAEK) is a more feasible approach in complex eyes. For instance, patients who benefit most are those with anterior chamber intraocular lenses (ACIOLs), large iridectomy/ sectoral aniridia, iridocorneal adhe- sion, post-vitrectomy, aphakia, and sutured posterior chamber intraocu- lar lenses (PCIOLs). However, with increased experience, Descemet's membrane endothelial keratoplasty (DMEK) is feasible in many of these eyes, Dr. Deng said. Kevin Shah, MD, Eye Consul- tants of Pennsylvania, Wyomissing, Pennsylvania, uses ultra-thin DSAEK for certain patients, typically those who have been vitrectomized, have ACIOLs, glaucoma tube implants, and those who have had previous PKs. "For any cases in which the anterior segment is disrupted and/ or unicameral or there is hardware such as an anterior chamber intraoc- ular lens, a DSAEK is indicated and DMEK would be contraindicated," said Neda Shamie, MD, Advanced Vision Care, Los Angeles, California. "Also, if the view into the anterior chamber is limited, it would make a DMEK surgery far more complex and would pose a relative contrain- dication." By 2016, DSAEK was performed in more than 21,000 cases and DMEK in more than 6,000, said Massimo Busin, MD, professor of ophthalmology, Department of Morphology, Surgery, and Experi- mental Surgery, University of Ferr- ara, Ferrara, Italy. "With few exceptions, DSAEK is still the more popular type of EK and for certain eyes the only avail- able choice," Dr. Busin said. However, Dr. Shah noted that the number of DMEK cases contin- ues to increase annually while the number of DSAEK cases is beginning to decrease. Rebubble rate The high rebubble rate in DMEK has improved as techniques and instrumentation have evolved, Dr. Busin said. "My personal rebubble rate is now less than 10%, and although it's higher than my DSAEK rebubble rates, the benefits in more rapid vi- sion recovery, better visual outcome, and lower rejection rate justify the learning curve," Dr. Busin said. Dr. Deng noted that the rebub- bling procedure is easier to perform than the repositioning in DSAEK. "It takes 5 minutes at the office or minor procedure room," Dr. Deng said. "The rebubble rate seems to be at the same rate observed in DSAEK after the learning curve." Rebubbling is a "minor acci- dent" in the postop course of DMEK and occurs in 5% to more than 50% of cases, depending on many fac- tors, Dr. Busin said. Patients should be advised about this possibility before undergoing DMEK, but they can also be told that uncomplicated rebubbling seldom affects the final outcomes. Ultra-thin option Dr. Shamie said the surgical tech- nique is easier with ultra-thin DSAEK but that the vision quality and optimal vision may still be bet- ter with DMEK in certain patients. "I would suggest having all of these techniques in one's armamen- tarium to be able to customize the treatment to the patient's condition and visual needs," Dr. Shamie said. DMEK patient at 1 day postop Same DMEK patient at 1 week postop, when 20/25 vision had been achieved Source: Sophie Deng, MD continued on page 46 The current data suggest that ultra-thin DSAEK is better than DSAEK, Dr. Deng said, but there is not enough data to compare the procedures directly. Both procedures deliver excel- lent BCVA, Dr. Shah said. For his ultra-thin DSAEK cases, Dr. Shah requests tissue of 40–70 microns. "My DMEK patients have a higher chance of achieving 20/20 BCVA compared to ultra-thin DSAEK," Dr. Shah said. "Also, be- cause of thinner tissue in DMEK, I am seeing a slightly lower rejection rate with DMEK. But again, we need larger studies that evaluate the role of ultra-thin graft thickness with rejection and BCVA." The ideal candidates for DMEK over ultra-thin DSAEK are patients who have a premium IOL. "DMEK works great with toric IOLs and results in a smaller hyper- opic shift compared to ultra-thin DSAEK," Dr. Shah said. Patient communication Patient discussions about the differ- ent forms of EK should include the surgeon's experience with DSAEK and DMEK, Dr. Deng said. "The surgeon should inform the patient that DMEK appears to have better visual outcomes but the air injection rate is higher in the early learning curve," Dr. Deng said. "My experience is that as long as patients understand the risks and benefit of each procedure, they often are will- ing to go with DMEK." Dr. Busin tells patients that DSAEK has a somewhat slower recovery of vision, but less compli- cations. One exception is for the risk of immunologic rejection, which is minimal in DMEK. However, Dr. Shah has found that unless a patient directly asks about the nuances among DMEK, ultra-thin DSAEK, and DSAEK, going into the details about the procedures

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