Researchers at the University of California studying the effect of wearable head-mounted displays on visual function have found that Google Glass caused blind spots in the upper right area of the visual field, according to results published in the Journal of the American Medical Association.
Three individuals with 6/6 best-corrected visual acuity and normal visual fields were tested after using the Glass device for the manufacturer-recommended acclimatisation period of 60 minutes.
Assessments were then made as to potential obstructions and researchers graded Glass’ display prism position relative to the right eye pupillary axis in three categories: over central pupillary axis; above central pupillary axis but inferior to superior limbus; and finally superior limbus.
The participants were then immediately tested on a Humphrey visual fields analyser – first with Google Glass and then with a control frame of similar colour and temple width.
Researchers said that in all three cases, visual field results highlighted significant scotomas while wearing the device and more than 10 degrees of visual field in the horizontal axis were subtended. Scotoma was not present with control perimetry testing with the study’s control frame.
Images of individuals wearing Google Glass were also assessed to judge how smart glasses were worn by general consumers. Photographs were assessed for prism position relative to the pupil with the same grading scale used for earlier visual fields analysis.
In 132 images suitable for evaluation, the prism covered the pupillary axis in 29.5 per cent of cases, 29.5 per cent covered the eye but not the axis and was superior to the limbus in 41 per cent of instances. The prism was likely to interfere with vision in 59 per cent of cases overall, researchers said.