Virtual reality (VR) remains under investigation for vision testing and certain ocular therapies including amblyopia, but a research team from Massachusetts reports some deficiencies in this approach. Their study, published in Optometry and Vision Science, suggests that the minimum angular resolution in logMAR found in current VR technology was insufficient for visual acuity testing and may be not be enough for standalone amblyopia treatment.
“While recent advances in virtual reality technology with applications for treatment of amblyopia are amazing, we hope this work serves as a cautionary tale of the current limits of this technology as standalone treatment,” says researcher Marissa Lynn, MD.
Her team looked at the feasibility of VR headsets for vision testing and treatment of binocular vision disorders and low vision, angular resolution (logMAR) and field of view.
The study used two standalone VR devices and four smartphone headsets that were paired with four high resolution smartphones. With each system, the researchers measured eye-to-screen distance, logMAR, field of view and maximum convergence demand.
On average, the smallest letter that could be displayed in VR was 0.41±0.09 (20/51), ranging from 0.59 (20/78) to 0.28 (20/39). Mean field of view was 50.2±4.8°, ranging from 39.6° to 55°. The mean field of view when used as a low vision aid was 23° and 12.7° for 2.2x and 4x, respectively. The mean maximum near convergence demand produced for a 60mm interpupillary distance was a change of 38.6±10.1.
The researchers also found the field of view during movie watching or gaming was about half that reported by manufacturers but adequate for some types of VF testing. Still, they reported use for vergence testing and training remained a concern for headsets with long eye-to-screen distance or interpupillary distances of less than 60mm.
Lynn MH, Lui G, Tomasi M, et al. Measuring virtual reality headset resolution and field of view implications for vision care applications. Optometry and Vision Science. August 6, 2020. [Epub ahead of print].