The University Record, February 21, 2000

Study says diabetics may not need annual eye exams

By Pete Barkey
Health System Public Relations

Patients with higher levels of A1c—a widely used marker for glucose control and the best predictor of diabetes complications—could undergo yearly screenings while others could be screened every two or three years with little or no loss of health benefit, according to the study. Photo by Linda Goings, Biomedical Communications
Researchers at the Department of Veterans Affairs (VA)-Ann Arbor and the U-M say people with the most common type of diabetes may not have to get their eyes screened yearly, as current medical guidelines recommend. Their findings are published in the Feb. 16 issue of the Journal of the American Medical Association.

Annual eye screening for people with type 2 diabetes is frequently proposed as a means of preventing certain eye diseases that can lead to blindness. However, the study found that a significant majority of people with type 2 diabetes derived little additional benefit from annual—as opposed to every second or third year—screening, especially considering the higher costs of yearly screening.

“If glucose control is reasonable and if there is no history of diabetic eye disease, it may not be necessary to get an eye exam every year,” says Sandeep Vijan of the VA and the Department of Internal Medicine. “For many patients, there are minimal benefits with annual versus every second or third year eye exams, but health care costs and patient inconvenience increase substantially.”

Diabetes is a leading cause of blindness in the United States. It’s estimated that more than 9 million people in the United States have been diagnosed with type 2 diabetes, also known as non-insulin-dependent diabetes or adult-onset diabetes. Type 2 diabetes is typically treated with various combinations of diet and exercise, oral medication and insulin injections.

Earlier clinical trials have shown that the risk of developing blindness from proliferative diabetic retinopathy (PDR) or macular edema (ME) can be reduced by a type of laser surgery called photocoagulation. Therefore, screening, detection and treatment for PDR and ME have the potential to significantly reduce the incidence of visual loss in patients with diabetes.

No clinical study has shown that screening directly reduces rates of blindness, but computer-based studies have demonstrated annual screening for PDR and ME can be a cost-effective intervention. Recommendations for annual screening have been widely implemented but compliance rates remain low. However, Vijan says, optimal screening intervals have not been adequately evaluated, especially due to the great variability in diabetic eye disease.

Vijan and his colleagues created a computer-based population of diabetic patients over age 40, based on the National Health and Nutrition Examination Survey, a nationally representative sample of the U.S. population. Patients were grouped by levels of eye disease and blood sugar control. Progression to proliferative retinopathy, macular edema and blindness was followed, based on rates established in previous studies.

The researchers found that, in many groups of patients, very little marginal benefit was gained by annual screening. For some low-risk groups, such as those with good glycemic control and no history of retinopathy, screening every third year was nearly as beneficial as annual screening, while being much more cost-effective. Additionally, diabetic patients routinely make 10 to 12 outpatient visits a year, Vijan says, and insisting on visits that aren’t needed competes with more important care.

“Resources and energies that can be saved from not having annual eye exams for everyone can be directed towards more effective interventions,” Vijan says. “Diabetes is a complex illness which places a high burden on patient time and effort, and streamlining interventions may allow for focus on other important areas, such as blood pressure control and blood sugar control.”

The authors write that if a single screening interval were to be recommended for the entire U.S. population, every-other-year intervals would be the best choice. Vijan says, however, that it would make more sense to base recommendations on individual patient circumstances, such as age, prior disease history and level of glycemic control.

Using this model, he says, multiple screening strategies could be proposed. For example, patients with higher levels of hemoglobin A1c—a widely used marker for glucose control and the best predictor of diabetic complications—could undergo yearly screening. The rest of the diabetic population would then be screened every two or three years, with little or no loss of health benefit and at considerable cost savings.

Vijan says that, in light of this study, organizations that monitor health care quality should strongly reconsider current standards calling for yearly eye exams for diabetic patients. Failure to do so, he says, would encourage inefficiency and require care that well-informed physicians and their patients would not need or want.

Vijan cautions that this study does not mean those with type 2 diabetes don’t need regular screening. “Although annual eye exams are probably not necessary for most patients, getting eyes examined at least every two or three years is still very important. This study should not be interpreted as meaning that eye screening is not an effective intervention. Rather, it is the intensity of the screening that we think should be reconsidered.”

The study was performed by researchers with the Veterans Affairs Center for Practice Management and Outcomes Research and the Department of Internal Medicine. It was supported in part by the Veterans Affairs Health Services Research & Development Center and by the Michigan Diabetes Research and Training Center.