Head Mounted Display Technology for Low Vision due to Peripheral Field Loss

Abstract

Purpose : Head-mounted display (HMD) technology may assist patients with peripheral field loss (PFL) by expanding their perceived visual field (VF). In a pilot clinical trial, we sought to determine the effect of a commercially available HMD on the vision and mobility of patients with PFL.

Methods : Participants had Usher syndrome, a III4e Goldmann VF with maximum horizontal extent ≤20°, and no other medical conditions affecting mobility. Prior to using Epson Moverio HMD and after a period of adaptation to the device, participants underwent the following tests: ETDRS visual acuity (VA); Pelli-Robson contrast sensitivity (CS); Goldmann VF; visual functioning questionnaires; and gait and mobility testing with and without obstacles. Gait parameters were recorded using inertial measurement units. The VF area was calculated using Adobe Photoshop. Percent preferred walking speed (PPWS) was calculated as the ratio of walking speed with and without obstacles. Data were analyzed using 2-tailed non-parametric tests and the Fisher exact test; we adjusted for inter-eye correlation.

Results : Five participants, 60% female with a median age of 37 years participated in the study. The median VA in the better-seeing eye was 0.30 logMAR without HMD and 0.24 with HMD (p>0.10), while median binocular CS was 1.65 logMAR with and without HMD. The mean and median III4e VF areas without HMD were 445.4 mm² and 553.4 mm² and with HMD were 1162.7 mm² and 1075.6 mm², respectively (Figure 1); this mean increase of 717.3 mm² was statistically significant (95%CI 170.0-1264.6; p=0.01). Scores on visual functioning questionnaires did not change during the study (p>0.10). Walking speed (p>0.10), PPWS (p>0.10), lateral and longitudinal stride variability (p>0.10; Figure 2), and the number of obstacle contacts (p=0.82) were unchanged when participants wore HMD.

Conclusions : Commercially available HMD can substantially increase the perceived VF of patients with severe PFL, though mobility performance was not affected. Future work should be done to customize HMD to the needs of patients with PFL and to study further its impact on activities of daily living, including mobility.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. The black and red III4e isopters represent one participant’s VF without (area, 250.0 mm²) and with (1070.9 mm²) HMD, respectively.

 

Figure 2. The blue and red ellipses represent one participant’s stride variability without and with HMD, respectively.