Eyeworld

NOV 2012

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

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38 EW FEATURE February 2011 Cataract/glaucoma combined surgeries November 2012 Using cataract surgery as a treatment for ocular hypertension by Michelle Dalton EyeWorld Contributing Writer AT A GLANCE • Cataract surgery can lower IOP in some patients with elevated pres- sures but should not be considered a primary treatment for glaucoma • Phaco alone seems to reduce IOP by about 16-17%, about the same as adding a secondary medication • Phaco can give patients a "drug holiday" for a couple of years, but should not be considered a permanent fix James D. Brandt, M.D. C T ataract surgery can lower IOP in patients with ocular hypertension (OH), according to results from a large cohort study.1 Steven L. Mansberger, M.D., director, Glaucoma Services, Devers Eye Institute, Portland, Ore., and colleagues determined "someone who has early glaucoma or needs only 10-20% IOP lowering should be considered for cataract surgery," he said, but does stress the results are only applicable for those with OH, a point co-author James D. Brandt, M.D., professor of ophthalmology, and director, Glaucoma Service, University of California-Davis, reiterated. "We only evaluated OH. It is dangerous to extrapolate the findings of this study to those with glaucoma. It's a whole different population, especially those on one or more meds," Dr. Brandt said. The new study is "by far, the cleanest and best data available to date showing what happens when you remove a cataract from someone with elevated IOP," said Tom Samuelson, M.D., Minnesota Eye Consultants, Minneapolis. "When you remove a cataract from an eye with pressures elevated beyond traditional physiological levels, you are far more likely to see a reduction in pressure than when IOP is physiological pre-operatively." In general, "ideas have been changing over the past few years" regarding cataract surgery's role in IOP management, said Leon W. Herndon, M.D., associate professor of ophthalmology, Duke University, Durham, N.C. "Even the old extra- cap procedures lowered pressures." Other papers' results "might Steven L. Mansberger, M.D. hinge on if the patients had ocular hypertension versus glaucoma, their angle structure (possibly com- promised a bit by the lens and its removal results in a more-normal positioning of the iris root following surgery), whether the IOP was meas- ured consistently a few times before surgery and then at approximately the same time, same person doing the measuring, verifying no systemic medication or topical meds that might influence IOP have changed from pre- to post-surgery, among others," said Thomas K. Mundorf, M.D., in private practice, Mundorf Eye Center, Charlotte, N.C. Some papers that did not show an effect "may not have evaluated outflow systems that were dysfunc- tional," Dr. Samuelson said. "If you're starting with an eye with high pres- sure, it's reasonable to assume some aberration in the outflow system. Almost any potential intervention (medical or surgical) has a better chance of showing a favorable effect if you're starting out with an abnor- mal system than one where, for ex- ample, the average IOP was 15 mm Hg. Very few studies have looked primarily at the effects of cataract surgery on IOP when the pre-surgical IOP was high. However, the literature is full of studies on this topic among patients with normal or near normal pre-op IOP. The effect of cataract removal on IOP in these two populations will be different." Clinical relevance Dr. Brandt said that the results are "probably the most accurate estimate of the average effect of cataract sur- gery in patients with elevated pres- sures," although he is careful not to suggest the results would be similar in moderate or severe glaucoma. Dr. Mansberger said for glau- coma patients "with early disease and cataract who require only a small decrease in IOP, I'll consider performing cataract surgery alone. Sometimes you'll be surprised how well controlled the IOP is after cataract surgery." Not everyone will alter how he or she treats patients with elevated pressures, however. Dr. Mundorf noted he has not seen a "consistent lowering of IOP following cataract surgery" in his glaucoma patients Monthly Pulse Keeping a Pulse on Ophthalmology his month's survey illustrates the changing landscape surrounding cataract surgery glaucoma patients. Recent data demonstrates that cataract surgery itself is an IOP- lowering procedure. Accordingly, 26.9% of those surveyed indi- cated that they're more likely to do cataract surgery in glaucoma patients in order to take advantage of the IOP lowering. In patients with early glaucoma, the majority of respon- dents indicated that they might perform cataract alone (52.3%), cataract and iStent (21.7%), or cataract and Trabectome or ECP (11.3%). However in patients with more severe damage, 57.5% would still perform combined trabeculectomy/EX-PRESS with cataract surgery. Given that so many of our glaucoma patients have difficulty using eye drops and that glaucoma patients are more likely to undergo cataract surgery than traditional incisional glaucoma surgery, surgeons might do well to take advantage of the opportunity of cataract surgery to address their patients' IOP-lowering needs. Nathan Radcliffe, M.D., glaucoma editorial board member

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