JAN 2012

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

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40 EW FEATURE February 2011 Retina co-morbidity for the anterior segment surgeon January 2012 Cataract surgery and diabetic retinopathy by Faith A. Hayden EyeWorld Staff Writer AT A GLANCE • Make sure any macular edema is cleared before cataract surgery • Anti-VEGF injections are one of the best ways to treat diabetic macular edema • Multifocal IOLs are not a contraindi- cation for diabetic macular edema patients, but they can bring surgical challenges Experts weigh in on timing and treatment D iabetic patients can be tough cases for cataract surgeons to work with, and managing diabetic retinopathy in prospec- tive and current cataract patients is just one challenge in an already long line. As new data shows, the prob- lem won't be going away anytime soon. According to the 2011 National Diabetes Fact Sheet, which was re- leased January 2011, 25.8 million children and adults in the U.S.— 8.3% of the population—have dia- betes. In adults 65 and order, 10.9 million, or 26.9% of all people in this age group, have diabetes. Fur- thermore, in 2010 alone, 1.9 million new cases of diabetes were diag- nosed in people aged 20 years and older. How can cataract surgeons man- age diabetic macular edema (DME) before, during, and after cataract surgery? And does the timing of the surgery matter for the short- and long-term prognosis? Timing and treatment In deciding when to have patients with baseline DME undergo cataract surgery, David G. Telander, M.D., assistant professor of ophthalmol- ogy, Eye Center, University of Cali- fornia Davis, urged surgeons to wait until the edema is resolved. "You can't argue that's not the best way to do it," he said. "If there's some reason you have to proceed, like the patient can't function nor- mally or he's had chronic edema that rebounds every time you stop treatment, then you have to actively treat him during cataract removal. But those are exceptions. You want A pre-op view of extensive, proliferative diabetic retinopathy with tractional macular detachment and somewhat hazy view secondary to associated cataract to get the edema resolved as much as possible." There are a number of modern- day strategies for treating DME in- cluding anti-VEGF injections, intraocular steroid injections, and laser treatment. "If patients have chronic DME, nowadays they are most likely going to be treated along the way with anti-VEGF agents," said John Loewenstein, M.D., Massachusetts Eye and Ear Infirmary, Boston. "If that's the case, it's probably unlikely that cataract surgery is going to sig- nificantly exasperate their edema, although it can happen. The infor- mation we have to date suggests that coverage with anti-VEGF agents pre- vents the worst of what we used to see. "In the anti-VEGF era," he con- tinued, "we're generally not as con- cerned with patients having cataract surgery as we used to be." Tamer H. Mahmoud, M.D., as- sociate professor of vitreoretinal sur- gery, Duke University Eye Center, Durham, N.C., called attention to a study published in the Journal of Cataract and Refractive Surgery (2008; 34:1001-1006). The authors specifi- cally looked at outcomes in patients with diabetic retinopathy and cataract who had panretinal photo- coagulation (PRP) first and cataract surgery second in one eye, and cataract surgery followed by PRP in the fellow eye. "You'd expect that patients who had PRP initially would have a bet- ter outcome," said Dr. Mahmoud. "But interestingly the study showed the other way around. In patients that had cataract surgery initially followed by PRP, the rate of progres- sion of macular edema was less. And Dr. Mahmoud said these patients need bimanual vitrectomy to segment, delaminate, and remove all the traction. A crisp view is needed for that procedure, and that may necessitate simulta- neous or staged procedure with cataract beforehand their visual outcome was signifi- cantly better at 1 year." Dr. Mahmoud speculated that the reason for this is because sur- geons aren't accurately detecting the severity of the DME before cataract surgery. "Maybe the density of the cataract does not allow a good enough treatment by laser before the procedure because there are those lens opacities in the way," he said. If a patient does have a dense cataract and you suspect he may have DME, Dr. Mahmoud suggested doing a potential acuity meter test, even though it's not always the most reliable. You can also try an optical coherence tomography (OCT), but if it's really bad the OCT might not measure it, Dr. Telander said. "The studies are conflicting, but if there is an effect on DME on con- temporary, uncomplicated phaco, the effect is probably pretty small," said Dr. Loewenstein. "The effect is more likely to be on OCT measure- ment of central macular thickness rather than visual acuity. Also it may be transient. There are some studies that show that the thickening is more likely to occur within 6 weeks after surgery, and then there's no difference between patients with DME and without DME at 6 months." Another study Dr. Mahmoud pointed to was in a 2009 Ophthalmology publication (2009 Jun;116(6):1151-7), which specifi- cally looked at patients with DME at baseline, randomized into two groups. One group had phaco in conjunction with an Avastin (bevacizumab, Genentech, South San Francisco) injection, and the second group had only phaco. A post-op image 1 year after the combined procedure Source: Tamer H. Mahmoud, M.D. "They found that at 3 months both groups improved significantly," he said. "However, the group that had the Avastin injection had signif- icantly better visual acuity at 3 months and a much decreased reti- nal thickness by OCT. How do we explain this? We can explain this by saying that having one of those in- jections at the time of cataract sur- gery or before cataract surgery can improve the short- and long-term outcomes of patients with DME." In addition, after cataract sur- gery, prognosis often depends on how inflammatory the surgery was, said Dr. Telander. "The more inflammatory it is, the more increased macular edema there is," he said. "So if patients al- ready had some DME, it will be worse, and if they didn't have any they can still have it. If they already have DME you should anticipate that it's going to get worse with any inflammation." The trick with multifocal IOLs Dr. Mahmoud can't say for certain that surgeons should not put a mul- tifocal IOL in a diabetic patient after cataract surgery, but he does advise retina surgeons to be aware of the is- sues that could arise. "You need good visualization with a contact lens to be able to de- liver a good focal laser for DME," he explained. "This view will not be the same for the multifocal lenses. One of the options we have for focal lasers nowadays is the PASCAL laser. I think we have to be very careful and do specific studies that look at safety using those types of lasers with diabetic patients with macular edema if a patient has a multifocal lens in the eye because the refrac-

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