Researchers found that participants who wore head-mounted display systems like Google Glass had partial peripheral vision obstruction. Tsontcho Ianchulev from the University of California, San Francisco, and colleagues compared performance on visual field tests with a head-mounted device versus regular eyewear to quantify their effect on visual function.

Participants used Google Glass for a 60-minute acclimatisation period. Perimetric visual testing - a measurement of the field of vision - was conducted first with the device followed by a regular eyewear.

Visual field testing demonstrated significant blind spots in all participants while wearing the device - creating a visual field obstruction. An analysis of 132 images indicated that many people wear the device near or overlapping their pupillary axis (a line perpendicular to the surface of the cornea, passing through the centre of the pupil) that induce blind spots and interfere with daily function.

"Since the study is limited by the small number of participants, a larger sample is needed to identify factors that influence scotoma (blind spot) size and depth," the authors concluded. The study appeared in the Journal of the American Medical Association.