J S Wolffsohn¹, R C Peterson¹, M Rubinstein², J Lowe²
¹Aston University, Neurosciences Research Institute, Birmingham, United Kingdom; ²Univeristy Hospital, Nottingham, Ophthalmology, Nottingham, United Kingdom
Purpose: To examine the objective and subjective benefits to visual performance of various different electronic vision enhancement systems (EVES) presently on the market compared to the patient's own optical magnifier. Methods: Seventy low vision patients completed a series of tasks to measure: (a) reading speed and acuity; (b) time taken to track from one column of print to the next; (c) time taken to follow a route map and locate a specific feature; (d) and time taken to identify specific information from a medicine bottle label. They used their prescribed conventional optical magnifier, a mouse EVES with the image viewed on a monitor or head-mounted display unit (HMD), or a stand EVES with the image viewed on the same monitor. Results: Fewer subjects could read, and the speed of reading decreased with decreasing print size, with the use of all magnifiers (F=225.6, p<0.001). Reading speed and task performance were generally slower when using the mouse EVES with HMD or the subject's optical magnifier (p<0.05). Conclusion: EVES provide objective and subjective benefits to the visually impaired in some specific tasks, but optical magnification can still provide sufficient magnification and reading speed for many common tasks. The use of HMD technology must be carefully integrated (both optically and ergonomically) into the EVES for patients to receive maximal benefit. maximal benefit.
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