Handheld device accurate, safe approach to diabetic retinopathy screening

Take-home
An investigational device for diabetic retinopathy screening has a low technical failure rate, completes testing in a few minutes, provides immediate results, and is not associated with adverse events.

By Nancy Groves; Reviewed by April Maa, MD

Atlanta-A handheld diabetic retinopathy screening instrument (RETeval device, LKC Technologies Inc.) is an accurate and promising new testing approach, said April Maa, MD.

Dr. Maa was an investigator in a study comparing the diabetic retinopathy testing performance of the RETeval with gold standard Early Treatment Diabetic Retinopathy Study (ETDRS) 7-field stereo color fundus photography.

“We were really excited because in our trial the device had a 99% negative predictive value for vision-threatening diabetic retinopathy,” said Dr. Maa, staff ophthalmologist at Atlanta Veterans Affairs Medical Center and Emory Eye Center, Emory University School of Medicine, Atlanta. “This means that you are 99% certain that those not referred have no vision-threatening retinopathy.”

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RETeval also had a 17% positive predictive value, 81% sensitivity, and 75% specificity.

Research was conducted at Veterans Affairs Medical Centers in Atlanta and Oklahoma City. Patients were screened for severe or proliferative diabetic changes in the eye or clinically significant macular edema; 467 patients with type 1 or type 2 diabetes completed the study.

Patients were tested first with the RETeval device and then with ETDRS fundus photography. The results showed that the technical failure rate was 0.9% (4/467) for the RETeval device and 11% (51/467) for ETDRS photography (p < 0.001). The RETeval device generated results on 98% (50/51) of the subjects who had ungradable images. No adverse events were reported.

RETeval, a 30 Hz flicker electroretinogram device, represents a new way of looking at diabetic retinopathy screening. “I liken it to an EKG but of the eye. It measures the electrical impulse that’s generated by the back of the eye in response to a flash of light,” said Dr. Maa. Since the implicit time is delayed in a person with diabetic retinopathy, the number obtained through the measurement can be used as an indicator of the disease and of disease severity.

Dr. Maa added that the RETeval has a significant number of advantages compared to fundus photography. “One is that the entire test is performed undilated, which patients really like, and two, it’s very fast. The average testing time for both eyes was 2.3 minutes.”

Results are available instantly and shown on the device’s screen. Also, the device is easy to use. During the study, research coordinators with no experience performing eye tests learned to use the device in about 20 minutes.

“The [device] is undergoing FDA review, and once it gets approved we hope that a lot of primary-care doctors will interested in using this,” Dr. Maa said. “It’s something they can do right there in their office like an EKG.”

In many primary-care practices, eye screening for diabetic patients has lagged behind other monitoring steps such as hemoglobin A1C, cholesterol, and kidney tests, Dr. Maa said. Odds are high that most patients will not follow through on a recommendation to visit an eye-care specialist because of the hassles associated with making yet another appointment and office visit.

The device could be a solution to that problem, since primary-care physicians could readily incorporate the screening into their management plan for diabetic patients, performing the test and having results in a matter of minutes, Dr. Maa explained.

If the results suggest diabetic retinopathy, the primary-care doctor could then provide a referral, and Dr. Maa’s research in screening indicates that patients are more prone to take action when they get test results immediately than if they have to wait for several days.

While Dr. Maa and her colleagues in this study are not involved in other ongoing trials of the device, they are interested in testing it on a broader range of patient with diabetes, not just those with vision-threatening retinopathy. It is also likely that the device will be investigated as a diagnostic tool for other ocular diseases such as glaucoma.

Researchers are also interested in learning more about the false positives, which seem to indicate that the device is picking up other abnormalities that affect retinal function.

April Maa, MD

E: amaa@emory.edu

This article was adapted from Dr. Maa’s presentation during the Euretina meeting at the 2014 congress of the European Society of Cataract and Refractive Surgeons. Dr. Maa received research support from LKC Technologies Inc., which has a grant from the National Eye Institute of the National Institutes of Health.