Visual Impairment Becoming Less Likely in Diabetes

Laura Newman, MA

November 19, 2011

November 19, 2011 — The age-adjusted percentage of people with diabetes reporting visual impairment (VI) dropped substantially between 1997 and 2010, from 23.7% in 1997 to 16.7% in 2010, according to National Health Interview Survey (NHIS) data from the Centers for Disease Control and Prevention, published in the November 18 issue of Morbidity and Mortality Weekly Report.

Despite the decrease in the proportion of patients with VI, diabetes is still increasing rapidly in incidence, and the absolute number of people with self-reported VI continues to increase and to put pressure on the healthcare system. Furthermore, the decrease in the percentage of people with diabetes who report VI did not affect all subgroups equally. In particular, blacks with diabetes did not show significantly less VI in 2010 than in 1997.

"A lot of this is really great news," said Carl Regillo, MD, retinal surgeon and director of retinal research at the Wills Eye Institute, Philadelphia, Pennsylvania, in an interview with Medscape Medical News. "I think that we are much better able to treat macular edema and hemorrhage than we were before." Among those advances, Dr. Regillo singled out steroid injections and antivascular endothelial growth factor medications.

"I am also seeing far better control of diabetes today, resulting in slower complication rates," added Dr. Regillo. He said that 15 years ago, "many more patients were not controlling their blood sugar well."

NHIS Data

Nilka Burrows, MPH, and colleagues from the Centers for Disease Control and Prevention, Division of Diabetes Translation, and the Center for Chronic Disease Prevention and Health Promotion, analyzed the survey data. The number of American adults with self-reported diabetes and VI rose from 2.7 million in 1997 to 3.9 million in 2010 (P ≤ .001). To be in this group, people had to say that a physician told them that they had diabetes. This figure includes both type 1 and type 2 diabetes but excludes women with gestational diabetes.

The declines in the age-adjusted prevalence of VI extended to most categories of adults with diabetes. In 2007, smaller proportions of men, women, whites, Hispanics, people aged 45 years or older, people with some college or higher education, and people diagnosed with diabetes for 3 or more years reported deterioration in their vision.

Self-reported VI was defined by an affirmative response to the question: "Do you have any trouble seeing even with glasses or contacts?" Patients were specifically asked whether they had access to an eye-care provider (optometrists, ophthalmologists, or eye doctors) in the past year, but not whether they had been seen by non–professionally trained eye-care personnel.

In an editorial note, the authors write: "The decline in self-reported VI prevalence among persons with diagnosed diabetes during 1997–2010 might be attributable, in part, to better control of VI risk factors (e.g., better blood glucose, blood pressure, and lipid control), improved detection and treatment of eye problems, or other factors. An alternative explanation...is that the large and sustained increase of new cases of diabetes since the 1990s might have led to a large number of persons who have not had diabetes long enough to develop VI."

Self-reported VI decreased significantly in all groups except blacks and people who had had diabetes for less than 3 years. After adjusting for age, investigators found that the finding of less self-reported diabetes and VI held up, regardless of whether patients were taking insulin, were insured within the past year, or had seen an eye-care provider.

Balancing Demand and Access to Eye Care

Overall, access to an eye-care provider did not change significantly. During 1997 to 2010, 63% of patients with diagnosed diabetes reported that they had visited an eye-care provider in the past year.

Paolo Silva, MD, retina specialist at Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, called the 63% rate of patients seeing an eye-care provider "suboptimal" and urged innovative ways to ensure access to regular eye exams. "Telemedicine and incentive plans for doctors might bolster getting patients needed eye exams," he told Medscape Medical News. Yet Dr. Silva also warned that with the diabetes population rising so dramatically, "we have a huge task in workflow." He projected that 2.4 million eyes will soon have to be examined each day, necessitating new ways to manage care.

"It takes at least 5 years before we see changes in the retina in patients with type 1 diabetes," said Dr. Silva. In patients with type 2 diabetes, "we don't know precisely, but it can take between 5 and 10 years," he added. Dr. Silva and others interviewed for the study said that they would not be surprised if the trend reversed in years to come because many more patients will be living longer with diabetes.

"What you really want is a simple way to pick up serious eye complications," said Donald S. Fong, MD, MPH, director, clinical trials research, and physician lead, diabetic retinopathy screening, Kaiser Permanente Southern California, Pasadena, in an interview with Medscape Medical News. At Kaiser, he said, when patients are due for an eye exam when they come in for their primary care visits, "we send them down the hall for photography."

With the growing demand for eye care among people with diabetes, Dr. Fong sees this as a viable way to expand access and detect severe eye problems. "Ninety percent of people with diabetes do not need to be seen by an eye doctor," he said. Dr. Fong pointed out that an important limitation in the NHIS study is that the survey did not query patients about photography or assessments by non–professionally trained eye-care personnel. "It's convenient, it's efficient, and it works," he said. Dr. Fong also noted that during the time period of the study, the definition of diabetes became more stringent. He wondered how the change in definition might have affected the findings.

Neil S. Bressler, MD, the James P. Gills Professor of Ophthalmology and chief of the Wilmer Eye Institute's Retina Division, Johns Hopkins University, Baltimore, Maryland, told Medscape Medical News that "the rising denominator [in diabetes cases] is stretching the system. Whatever it takes to get patients evaluated, get better access, and education, should be supported." Dr. Bressler also commended the NHIS for flagging problems in quality and access. Regarding blacks not sharing in the overall improvements, he said, "We need to know why that is: Is there an access-to-care problem, are blacks less responsive to treatment, or are metabolic issues different for blacks than for other groups? That's why surveys like this are so valuable."

The study authors and the commentators have disclosed no relevant financial relationships.

Morb Mortal Wkly Rep. 2011;60:1549-1553. Full text

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