Eyeworld

EW FEATURE 42 by Michelle Dalton EyeWorld Contributing Editor Endothelial keratoplasty preferred choice for Fuchs' dystrophy Surgeons are able to per- form surgery earlier in the progression of the disease, and newer techniques may offer visual outcomes com- parable to full-thickness transplants P atients with Fuchs' dystro- phy present some addi- tional challenges for corneal surgeons—the dis- ease is more slowly pro- gressive than other corneal diseases (such as edema from trauma or her- pes simplex virus), Descemet's mem- brane is typically thicker than in patients without Fuchs,' patients have significant guttata, and, in gen- eral, the location of the portion of the cornea most affected and need- ing replacement is different from those without Fuchs.' "These are patients who are slowly losing their vision, and the timing of when to perform a trans- plant is variable from patient to pa- tient," said Mark A. Terry, M.D., director of corneal services, Devers Eye Institute, and professor of clini- cal ophthalmology, Oregon Health & Science University, Portland. Some patients want to undergo sur- gery as soon as vision begins deterio- rating, while others prefer to wait until their vision has been severely impacted, he said. "Treating Fuchs' was no differ- ent than treating other corneal disorders until endothelial kerato- plasty (EK) came along, which made it much easier," said David T. Vroman, M.D., medical director, Lifepoint Ocular Division, Charleston, S.C., and founder, Carolina Cataract & Laser Center, Ladson, S.C. The first of the EK pro- cedures, deep lamellar EK (DLEK), evolved to the currently used De- scemet's stripping automated EK (DSAEK), which is a partial-thickness technique that replaces only the inner endothelial cell layer. A newer technique, Descemet's membrane EK (DMEK), is based on the idea that stromal dissection is an extraneous step and leaves the patient's cornea closer to its original condition than other techniques. "I used to give patients the op- tion between penetrating kerato- plasty (PK) and the newer techniques," said Francis W. Price Jr., M.D., founder, PriceVision Group, Indianapolis. "But after per- forming DSEK for a month, I real- ized it was so much better than PK, and I stopped giving patients the op- tion. I'd still tell them about PK, but I'd explain why they probably wouldn't want it." One disadvantage is that PK wounds do not heal well. Even 10-15 years after the initial sur- gery, if someone falls or bumps the eye, "the wound can break open, creating a superchoroidal hemor- rhage," Dr. Price said. "With the EK procedure, we fi- nally had a selective transplant for patients who specifically have en- dothelial dysfunction. The bulk of endothelial dysfunction in this country is Fuchs' dystrophy," Dr. Vroman said. Patients with Fuchs' have a bet- ter prognosis post-surgery when compared to most graft patients, said Woodford Van Meter, M.D., professor of ophthalmology, Ken- tucky School of Medicine, Lexing- ton. "Outcomes are not as good for those with Fuchs' as for those with keratoconus, but they are much bet- ter than those with corneal scar- ring," he said. In his experience, patients with Fuchs' dystrophy "liked the EK results better than the PK results with one or two excep- tions." Benefits of EK include the ability to avoid a considerable amount of astigmatism and a much faster rehabilitation time; the down- side is vision may not be as sharp as with a full-thickness transplant, "but patients don't seem to mind," he said. In Asian eyes, DSAEK for pseudophakic bullous keratopathy (PBK) is more common than Fuchs,' mainly because Asians present at a later stage, said Donald T.H. Tan, F.R.C.Ophth., head and senior con- sultant, Singapore National Eye Cen- tre. "Surgery is more challenging in these eyes because there's more haze during surgery and the visual out- comes are not as good," Dr. Tan said, adding that socioeconomics is a pre- dominant reason why people in China, Japan, or India present later than their U.S. or European counter- parts. Adding to the difficulty is the February 2011 CORNEA May 2011 Slit lamp photo with side illumination showing the mid-peripheral cornea in a patient with Fuchs' dystrophy after treatment with DMEK. The central cornea (area 1) is clear and the donor Descemet's membrane and endothelium has replaced that of the recipient. At the graft periphery, donor and recipient Descemet's membrane overlap (area 2). The edge of the stripped recipient Descemet's membrane is scalloped while the edge of the DMEK graft just to the right is smooth and circular. Area 3 is the recipient Descemet's membrane beyond the edge of the graft Source: Marianne Price, Ph.D. DSAEK air bubble Source: Marianne Price, Ph.D. AT A GLANCE • Endothelial keratoplasty has become the procedure of choice for Fuchs' dystrophy • Cell loss hovers around 30% at year 1, but seems to stabilize over 3-5 years • DMEK may result in better visual outcomes, but has numerous obsta- cles to overcome before it's easily reproducible • Eye banks will play a large role in how readily DMEK procedures are accepted

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