Eyeworld

EW GLAUCOMA 68 June 2016 by Tony Realini, MD, MPH Approaches to glaucoma screening I n 2013, the U.S. Preventive Services Task Force, an indepen- dent panel of evidence-based medicine experts, concluded that there was insufficient evidence to recommend large-scale screening efforts to identify undiag- nosed glaucoma in the community. The group opined that effective screening methodology was lacking and that the benefit of detecting early field defects remains unclear. Glaucoma specialists take a dif- ferent view of glaucoma screening. At the 2016 American Glaucoma Society annual meeting, the topic of glaucoma screening was revisited. Screening is important The burden of undiagnosed glau- coma is significant. "About half of people with glaucoma are unaware that they have the disease," said David Friedman, MD, Baltimore. Among people at highest risk, the numbers are even worse. "In Hispan- ics, 62–76% of glaucoma is undiag- nosed, and in the developing world, up to 90% of people with glaucoma are unaware they have the disease." Dana Blumberg, MD, MPH, New York, agreed, and pointed out that the problem will only get worse with time. "High risk populations— such as blacks and Hispanics—are growing and aging. These are the groups at highest risk for glaucoma and glaucoma-related blindness." Community or opportunistic screening? Most glaucoma specialists support screening efforts, but there are challenges. One challenge is who to screen. Should we go out into the community or should we look with- in our own offices? "Screening is difficult," Dr. Friedman conceded. "The disease has no symptoms until in the ad- vanced stages." Still, he thinks that community-based screening has value. "We need to start screening for glaucoma in the communities around us." He pointed out that they are most interested in screening people at high risk for having glaucoma, and many in this group tend to underutilize health care services overall. Thus, if we don't go out and look for them, they are unlikely to come to us, he pointed out. "The population is aging, and if we don't get people with glaucoma under care, we're going to see more and more blindness," he said. Conversely, Anne L. Coleman, MD, PhD, Los Angeles, suggested that we look within our own prac- tices. She cited the results of several epidemiological studies showing that up to 50% of people newly diagnosed with glaucoma in screen- ing programs had seen an eyecare provider in the previous 12 months and the opportunity to make the di- agnosis had been missed. "We need to reduce the risk of missed glauco- ma," she said. Who is missed? There are several clinical attributes that play a role in missing the diag- nosis of glaucoma. "More than half of all glaucoma occurs in eyes with IOP in the normal range," Dr. Cole- man said. He said that elevated IOP serves as a reminder to the clinician to conduct a careful examination of the optic nerve for subtle signs of glaucomatous optic neuropathy. In eyes with normal IOP, we may be less likely to pay such close atten- tion to the optic nerve examination. Also, disc size can mislead us. "Glaucoma is missed more often if the optic nerve head is small," he said. He pointed out that small nerves should have small cups. A small nerve with a 0.4 cup might have early glaucoma, but would look Uncovering undiagnosed glaucoma cases to reduce blindness G laucoma usually doesn't have any symptoms until there is visual loss. If our goal is to treat patients before they have noticeable damage, we have to find them when they are asymptomatic. This is screening. Meanwhile, something like one-half of the people with glaucoma aren't aware they have it. This means hundreds of thousands of people are going blind without knowing it. These facts seem to call for large-scale screening programs to find people with glaucoma and begin treatment. But glaucoma screening has been problematic. Although a large number of people have undiagnosed glaucoma nation- wide, there may not be many—or any—at a local health fair, and the few who do have it may still be missed. It is easy to fail to detect glaucoma—whether in a community screening or in your office—because none of the tests are definitive every time. For ex- ample, many glaucoma patients will have a normal pressure on a single test, visual field testing is too time consuming and variable, and OCT is not reliable as a screening tool. In this "Glaucoma editor's corner of the world," we are fortunate to have Alan Robin, MD, David Friedman, MD, Dana Blumberg, MD, Anne Coleman, MD, and Constance Okeke, MD, give us their views on the current state of glaucoma screening. This is an all-star cast of glaucoma epide- miologists, and they share their insights on the pros and cons of screening. My own view is that we need a differ- ent test for screening. We need innovation to create a test that is simple, quick, and "fun." It would be based on visual field loss since this is the most definite sign of glau- coma. It could be a video-game type format and would need to work on a smartphone. Until we have better screening tools, the most we can do as ophthalmologists is to not miss the glaucoma in the patients that we see every day. This is its own challenge because the usual testing can be equivocal in the early stages. We also need to remind our glaucoma patients to have their relatives get checked. Helping to detect glaucoma in people who don't know they have it is one of the most important things we do. Reay Brown, MD, glaucoma editor Dr. Okeke shares this heredity poster that she created with Alcon to help doctors and patients start the conversation about family awareness. Source: Alcon Glaucoma editor's corner of the world

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