March 23, 2007

VUSN study shows merits of vision screening

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Amanda Shively, medical assistant, conducts an eye screening on patient Daniel Ashworth at the Vine Hill Clinic. (photo by Susan Urmy)

VUSN study shows merits of vision screening

Diabetic Retinopathy screenings at inner-city clinics can lead to vision-saving treatment for a significant number of patients, according to a study by Vanderbilt University School of Nursing's Cathy Taylor, Dr.P.H., M.S.N., and colleagues.

The Centers for Disease Control and Prevention report that 21 million Americans have diabetes and an additional 40 million to 50 million have pre-diabetes. The CDC estimates that up to 24,000 people with diabetes lose their eyesight each year due to diabetic retinopathy (DR), or changes in the eye's blood vessels associated with excess sugar in the blood. DR typically does not present symptoms until the patient starts losing vision, and in many cases, all vision is lost.

“DR is the leading cause of adult blindness and is almost entirely preventable,” said Taylor. “But the system we have now to detect this disease and other diabetes-type related eye problems is simply not adequate. We pulled elements together in this study to form a new strategy that provides convenient, cost-effective, high quality screens for our patients, most of whom would otherwise not have received this level of preventive care.”

The study, published in Diabetes Care, was conducted at the Vine Hill Community Clinic, a VUSN nurse-practitioner managed primarily care clinic that serves a large indigent population in Nashville.

Adult patients with diabetes were offered an option for an in-clinic DR screening as part of their regularly scheduled appointment or an ophthalmology referral to the Vanderbilt Eye Institute for their eye care. Of the patients that chose to have a digital retinopathy screening at Vine Hill, 11 percent screened positive for sight-threatening eye disease and 37 percent were referred to ophthalmology for further follow up.

“I was surprised at the high number of urgent cases we discovered and that there were nearly twice as many people of color than the number of Caucasians who we referred for specialty care,” said Taylor. “These results underscored how important it is to make this kind of screening more widely available, especially since the health care system is about to get hit with an avalanche of patients with diabetes and the myriad of health concerns that go along with the chronic disease.”

Vine Hill patients who have diabetes are offered the DR screening as part of their routine visit. Technology includes commercially available screening equipment and a laptop computer. A technician dilates the patient's eyes and takes two digital images of each eye that provide a high-clarity image. Images can be magnified to show minute details and electronically stored for comparison with future exams. Each day's worth of images are grouped together and uploaded to the Vanderbilt Eye Clinic, where the scans are reviewed by an expert grader and a retinal specialist. If a client has an abnormality, the patient is called back in and treated. Those patients with normal screenings have a baseline to track changes in their future screening.

This screening approach saves time and money for patients. Screening in the clinic saves the patient time off from work and increases the likelihood the patient will get preventive care. The approach also costs about 25 percent of the typical cost of a full-fledged, dilated eye exam by an ophthalmologist.

“We know that only about half the people with diabetes who need these screenings are getting them now, and ophthalmologists are already feeling the strain of the growing demands of diabetes care,” said Taylor. “This primary care clinic screening approach can filter out the patients who don't need specialty care so the ophthalmologists can use their expertise on those patients with the greatest need.”

In the study, Taylor and her VUSN, VUMC and VHCC colleagues referred about one-third of the subjects for some sort of specialty care by ophthalmologists. The DR screenings are available at Vine Hill Community Clinic, the Casey Clinic and the Veteran's Administration Medical Centers in Nashville and Murfreesboro.

“Ultimately, this strategy allows us to screen more people, save the precious gift of sight and spend specialty care dollars the best way,” said Taylor.