Benefits of electronic vision enhancement systems (EVES) for the visually impaired.

PURPOSE: To examine whether objective performance of near tasks is improved with various electronic vision enhancement systems (EVES) compared with the subject's own optical magnifier.

DESIGN: Experimental study, randomized, within-patient design.

METHODS: This was a prospective study, conducted in a hospital ophthalmology low-vision clinic. The patient population comprised 70 sequential visually impaired subjects. The magnifying devices examined were: patient's optimum optical magnifier; magnification and field-of-view matched mouse EVES with monitor or head-mounted display (HMD) viewing; and stand EVES with monitor viewing. The tasks performed were: reading speed and acuity; time taken to track from one column of print to the next; follow a route map, and locate a specific feature; and identification of specific information from a medicine label.

RESULTS: Mouse EVES with HMD viewing caused lower reading speeds than stand EVES with monitor viewing (F = 38.7, P <.001). Reading with the optical magnifier was slower than with the mouse or stand EVES with monitor viewing at smaller print sizes (P <.05). The column location task was faster with the optical magnifier than with any of the EVES (F = 10.3, P <.001). The map tracking and medicine label identification task was slower with the mouse EVES with HMD viewing than with the other magnifiers (P <.01). Previous EVES experience had no effect on task performance (P >.05), but subjects with previous optical magnifier experience were significantly slower at performing the medicine label identification task with all of the EVES (P <.05).

CONCLUSIONS: Although EVES provide objective benefits to the visually impaired in reading speed and acuity, together with some specific near tasks, some can be performed just as fast using optical magnification.