Use of an augmented-vision device for visual search by patients with tunnel vision.
OBJECTIVE
To study the effect of an augmented-vision device that superimposes minified contour images over natural vision on visual search performance of patients with tunnel vision.


METHODS
Twelve subjects with tunnel vision searched for targets presented outside their visual fields (VFs) on a blank background under three cue conditions (with contour cues provided by the device, with auditory cues, and without cues). Three subjects (VF, 8 degrees -11 degrees wide) carried out the search over a 90 degrees x 74 degrees area, and nine subjects (VF, 7 degrees -16 degrees wide) carried out the search over a 66 degrees x 52 degrees area. Eye and head movements were recorded for performance analyses that included directness of search path, search time, and gaze speed.


RESULTS
Directness of the search path was greatly and significantly improved when the contour or auditory cues were provided in the larger and the smaller area searches. When using the device, a significant reduction in search time (28% approximately 74%) was demonstrated by all three subjects in the larger area search and by subjects with VFs wider than 10 degrees in the smaller area search (average, 22%). Directness and gaze speed accounted for 90% of the variability of search time.


CONCLUSIONS
Although performance improvement with the device for the larger search area was obvious, whether it was helpful for the smaller search area depended on VF and gaze speed. Because improvement in directness was demonstrated, increased gaze speed, which could result from further training and adaptation to the device, might enable patients with small VFs to benefit from the device for visual search tasks.
Luo
Gang
G
Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA. gangluo@vision.eri.harvard.edu
Peli
Eli
E
D005133:Eye Movements; D019416:Head Movements; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008875:Middle Aged; D012682:Sensory Aids; D014786:Vision Disorders / Q000503:physiopathology / Q000628:therapy*; D014794:Visual Fields; D014796:Visual Perception / Q000502:physiology*