Age and visual search: expanding the useful field of view.

The useful field of view is defined as the visual area in which information can be acquired within one eye fixation. We studied visual search within this context and found a reduction in the size of the field as a function of age. This loss, however, was recovered partially with practice. Standard acuity and perimetric tests of visual field, although diagnostic of disease, underestimate the degree of difficulty experienced by visually healthy older adults in everyday activities requiring the use of peripheral vision. To aid in predicting such performance, a model incorporating the effects of distractors and secondary task demands was developed.