Eyeworld

JAN 2016

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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EW CATARACT 28 January 2016 be able to provide them with better potential vision," Dr. Devgan said. And "always, always, always" explain to the patient that recovery times are going to be longer, their visual recovery may be more event- ful than Mrs. Jones' down the street (more visits, for example), and they may never regain "perfect" vision, Dr. McDonald said. Preoperative plan Because K measurements and IOL powers "are almost linked 1:1, if you've got an irregular corneal surface, you're going to get worse K measurements and here is the danger. If you read the cornea as 2 D lower than it really is, it will affect the IOL power by 2 D," Dr. Devgan said. "Always choose the machine with the lowest K value of all the devices you used, as that will tend to calculate a slightly higher IOL power. Then if there's any post- op variant in the calculations, they'll err on the side of myopia." Some patients may not have any obvious evidence of a corneal irregularity—such as dry eye—that affects vision. "You don't want to necessarily add a multifocal implant for that because a dry irregular tear film can be a tremendously multifocal surface," Dr. Thompson said. He added that the newer diagnostic technologies such as the HD Analyzer (Visiometrics, Terrassa, Spain) and the iTrace (Tracey Technologies, Houston) can measure the health of the tear film and provide enough information to help guide physician choices. If the tear film is rehabilitated, these technologies can quantify if its opti- cal quality has improved enough to consider something like a multifocal lens. Dr. Thompson said they also use laser-assisted cataract surgery in Fuchs' dystrophy patients because it can lessen phacoemulsification time and thus lessen stress on the corneal endothelium. It's not just about informed consent, Dr. Silverstein said. "It's our responsibility. It's not just about handholding, it's about education. At the end of the day, for me, it's an- swering the question, 'Would I have a premium lens implant in my eye if I had these corneal abnormalities?' And if so, which one? There are times that it's perfectly appropriate. There are times that it is contraindi- cated, and it is our responsibility to help guide the patient as we would choose for ourselves." EW appropriate if they have some degree of regular symmetric astigmatism, however." Prep the patient Patients don't understand that dry eye and Fuchs' are chronic condi- tions that can be controlled but not cured, Dr. McDonald said, and that makes patient education not only crucial but difficult. "Some people just can't make the leap that they have to come to terms with it, just like high cho- lesterol or diabetes. I find a lot of patients follow my instructions for a month but don't embrace the chronicity of the disorder," so when the initial prescription runs out (in the case of dry eye treatments), they don't refill, she said. Whenever there is more than one cause of blur, surgeons need to explain both the disease and the cataract to the patient and that multiple preop visits might be neces- sary before the cataract surgery, Dr. Thompson said. For Dr. Devgan, those preop visits are the most crucial aspect of the entire process. "If you do a good job of explain- ing the issues and the slower recov- ery time, everything that happens postop is expected," he said. "If you predict the problem, patients think you're a genius for predicting it, but if you never tell them about the potential problem and it happens, you're a bad guy for causing it." Consider the patient as well as the diseases, Dr. McDonald said. "If you intervene, if you're aggressive and improve their dry eye, will they maintain that health in 2–3 years? Does Alzheimer's run in their family? Crippling arthritis? You need to consider a controllable disease today may not be controllable in a few years. In Fuchs,' maybe they'll be lucky and plateau for a few years, but they are going to get worse eventually." She also avoids multifo- cal lenses in these patients. Be cautious in patients with severe ocular surface disease that cannot be controlled, Dr. Thompson said; these eyes are slightly more prone to melting. Everyone agreed that preop visits with these patients are signifi- cantly longer and more are needed compared to patients without com- promised corneas. "The additional visits are neces- sary to not only stabilize the cornea (in cases of chalazion or Salzmann's nodule), but I'll get a better biome- try and better IOL calculations and An example of dry eye with corneal epithelial defects In this example of Fuchs' dystrophy, the obvious endothelial cell loss in the pupil zone is extensive. This patient is expected to have a more challenging postoperative course. The pterygium looks like it is only affecting the peripheral cornea, but it is actually causing a lot of irregular corneal astigmatism. It must be surgically removed, and the ocular surface will need time to heal before the patient can undergo cataract surgery. Source: Uday Devgan, MD Cataract continued from page 27

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