Abstract
Purpose :
We are conducting a clinical trial to compare the effectiveness of a virtual bioptic telescope and virtual projection screen in a head-mounted display (HMD) low vision enhancement system with a wide field of view to currently employed specifications for HMD low vision enhancement technology through patient reported outcome measures. Participants will complete baseline preliminary testing to evaluate various visual function domains including visual information, visual motor, reading, and timed activities of daily living performance. Challenges exist particularly in visual motor function with HMDs due to the lack of binocular disparity using a single camera presenting the same image to both eyes.
Methods :
To examine visual motor function, we conducted a feasibility study with a smartphone app called Hiragani Nazori Lite, which involves tracing a total of 46 Japanese characters on a touchscreen. The time to accurately trace each character was recorded. Testing was performed under two different viewing conditions for both normal subjects and for subjects with vision impairment: 1. with a magnification bubble embedded in a large unmagnified 70° field of view (bubble) and 2. with full-screen magnification in a 37° field of view (legacy).
Results :
Results for the first 5 low vision participants were compared to mean data collected from 9 normal subjects tested under both conditions. Participants had best-corrected visual acuity of <20/50 in the better-seeing eye and bilateral central scotomas. When comparing across all character tasks, all subjects had a slower mean tracing speed with the legacy condition when compared to the normal means. Using the bubble condition, 2 subjects performed better than the normal controls and 3 subjects maintained a slower mean tracing speed when compared to the normal subjects. The time difference from the normal mean ranged from 2.9-16.1 seconds in the legacy condition and -1.3-9.7 seconds in the bubble condition.
Conclusions :
This visual motor smartphone tracing app is responsive to both of the comparative device conditions and can be used to measure device efficacy for visual motor tasks.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.