Scientists of the University of California, San Francisco, compared performance on visual field tests with a head-mounted device over regular eyewear to quantify their effect on visual function. Three healthy individuals with 20/20 best-corrected visual acuity and normal baseline visual fields were tested in April 2014.
Participants used a wearable device (Google Glass), following manufacturer’s instructions, for a 60-minute period.
Perimetric visual testing (a measurement of the field of vision) was conducted first with the device, followed by a control frame (regular eyewear) of similar colour and temple width.
Visual field testing demonstrated significant scotomas (blind spots) in all three participants while wearing the device, creating a clinically meaningful visual field obstruction in the upper right quadrant.
Defects were induced by the Google Glass frame hardware design only and were not related to a distracting effect of software-related interference.
The authors noted that the study is limited by the small number of participants, who may not be representative of all users, and that a larger sample is needed to identify factors that influence scotoma size and depth.
“Additional studies are needed to understand the effects of these devices on visual function, particularly as their use becomes increasingly common,” the authors concluded.