Abstract
Purpose :
Reading is the most common functional complaint among patients with vision impairment. Magnification is used to compensate for reduced visual acuity. Using digital image processing, we can employ real-time magnification using mixed reality methods in a head-mounted display (HMD) equipped with a high-resolution video camera. We are conducting a clinical trial to compare the effectiveness of a virtual bioptic telescope and virtual projection screen in an 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 testing measuring visual function, including reading ability.
Methods :
The International Reading Speed Texts (IReST) is an assessment of reading performance consisting of 10 paragraphs of text with approximately 120 words per text. Testing was performed under 2 different viewing conditions: 1. magnification bubble embedded in a large unmagnified 70° field of view (bubble) and 2. full-screen magnification in a 37° field of view (legacy).
Results :
Results for the first 4 low vision participants were compared to the mean data from 9 normal subjects tested under both conditions. Participants had BCVA <20/50 in the better-seeing eye and bilateral central scotomas. The reading speed using the legacy device was slower for all subjects when compared to the normal mean reading speeds for the respective texts. 2 subjects performed better than the normal controls with the bubble condition on a few of the texts. Overall, low vision patients read with a faster reading speed with the bubble condition.
Conclusions :
Although sample numbers are very small, we see a consistent difference in the two comparative device conditions tested. The IReST is responsive to both of the comparative device conditions and can be used to measure device efficacy for reading tasks.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.