Handheld ETDRS device may eliminate need for dedicated test lane
SAN DIEGO — A handheld ETDRS device may offer benefits of convenience and portability, as well as the ability to assess ETDRS visual acuity without a dedicated testing lane, according to a speaker here.
“A critical and often overlooked aspect of how we handle our clinical research is the means by which we quantify results and, ultimately, how we translate these results over to real-world clinical practice,” Ehsan Rahimy, MD, said at the American Society of Retina Specialists meeting.
Visual acuity is the gold standard primary endpoint in ophthalmic clinical trials, but despite the U.S. Food and Drug Administration requirement for using ETDRS charts to measure visual acuity, the majority of published clinical studies still report Snellen acuities, Rahimy said.
A novel backlit handheld ETDRS device (AMA Optics) may allow for reproducible visual acuity measurements at greater convenience to the examiner during clinical studies. The device uses the same standardized letter optotype, geometric line progression and letters of equal difficulty as the ETDRS chart.
In a two-center, prospective study, visual acuity was measured in 70 patients with retina pathology using both the standard ETDRS chart and the handheld ETDRS device by masked, independent examiners. Examination was performed in the same room under identical illumination and testing conditions.
Mean difference in measured visual acuity per eye between methods was 1.8 letters, which was not statistically significant.
“Equally important is that the agreement noted was independent of the underlying retinal disease,” Rahimy said.
Limitations of the test were that time to complete each test was not recorded, repeatability of results was not performed, each patient’s subjective evaluation of each test was not surveyed and the spectrum of diseases encountered was not comprehensive for all types of retinal disease, according to Rahimy.
Disclosure:Rahimy receives financial support in part by an Innovation Grant awarded through Wills Eye Hospital.