At Home Monitoring

At-Home Monitoring for Early Detection of Wet AMD

Investigational device using shape discrimination hyperacuity shows promise in clinical validation study. Cheryl Guttman Krader reports

Anovel investigational handheld device (KalEYEdoscope) intended for at-home use to identify conversion from dry to wet age-related macular degeneration (AMD) provides a rapid, comfortable, and easy testing solution for a range of patients, according to the findings of a clinical validation study.

The digital device, which was developed by researchers at the University of Michigan, Ann Arbor, Michigan, USA, uses the concept of shape discrimination hyperacuity (SDH) to exploit the fact that patients with wet AMD are able to distinguish distortions, explained Yannis Paulus MD, Assistant Professor, Departments of Ophthalmology and Visual Sciences and Biomedical Engineering.

Users are shown a series of circle-like images on a 1.5-inch OLED screen, and after each is displayed, they are asked to indicate whether the image represents a perfect circle by pushing a button. The test concludes when enough data are obtained to establish the user’s minimum distortion-detection threshold. Data from the testing are collected longitudinally and statistically analysed to determine a change in condition.

The clinical validation trial was designed to evaluate testing duration and user impressions. It included 15 patients with refractive errors ranging from +1.25 D to -7.0 D. The device is designed to accommodate refractive errors of +5.0 D to -10.0 D.

The testing, which was done with a prototype device, was completed by all participants in an average test time of 70 seconds (standard deviation, 9.1 seconds, range 32 to 143 seconds). All of the patients rated the device as comfortable to hold, and they found the testing easy. Asked to rate the difficulty on a Likert scale of 1 (easiest) to 5 (hardest), the average rating was 1.5.

“The average duration of the testing with our device is 67% shorter than for the ForeseeHome monitoring system that is based on Vernier acuity. Furthermore, our device has been meticulously designed and redesigned with patient comfort in mind to facilitate its acceptance and use,” said Dr Paulus.

“We believe the shorter testing time along with the smaller, handheld nature of our device will be valuable for improving patient compliance with the testing.”

Larger prospective clinical trials to target regulatory (US FDA) approval are being planned.

The wide range in testing time documented in the validation study is being looked at in an ongoing larger trial to see if test duration is related to any particular patient characteristics.

Further trials are also necessary to demonstrate that use of the device results in improved outcomes for patients with dry AMD.

Yannis Paulus MD