Hand-held ETDRS device enables accurate, reproducible visual acuity measurements
PHILADELPHIA — A hand-held internally illuminated ETDRS device provided accurate and repeatable visual acuity measurements, according to a study presented here.
“Despite the FDA requiring ETDRS vision in registered trials, still the vast majority of published studies in the ophthalmic literature use Snellen visual acuity,” Ehsan Rahimy, MD, said at the Wills Eye Annual Conference. “There are multiple reasons for the lack of widespread incorporation of the ETDRS system, including the increased time it takes to measure these acuities. … A novel back-lit handheld ETDRS vision meter may allow for reproducible visual acuity measurements at greater convenience for the examiner during clinical studies.”
The ETDRS vision meter is about the size of a disposable camera. It has a battery-powered, high-intensity calibrated light source with a filter to adjust the amount of illumination and a recoiling 40-cm cord to easily measure the examining distance, Rahimy said.
The multicenter prospective study included 134 eyes of 70 patients with retinal disease who underwent visual acuity measurement with the standard ETDRS chart and the ETDRS vision meter.
Mean letters read were 63 with the standard ETDRS chart and 61.2 with the ETDRS vision meter. The mean difference in letter scores between the two devices was 1.8 letters, which was statistically insignificant. Agreement in letter scores between the devices was 0.95.
In addition, agreement between the two devices was independent of underlying retinal disease, Rahimy said.
Disclosure: Rahimy has no relevant financial disclosures.