Variations in hyperacuity performance with age.

The term hyperacuity has been applied to a group of stimuli which produce spatial thresholds smaller than those expected given the relatively large receptor spacing and the retinal image quality of the human eye. It is not yet firmly established whether hyperacuity performance declines with increasing age in the same way as most other measures of visual ability. This is perhaps due to the use of varying task configurations and criterion-dependent psychophysical techniques. The present study examines age-related performance in three different hyperacuity tasks using a criterion independent forced-choice method. Both displacement and bisection thresholds were found to increase with age, but there was no significant change in vernier acuity. This indicates that age has a differential effect on thresholds for various hyperacuities depending upon the task requirements. No significant age-related trend was observed in hyperacuity bias, which represents the difference between subjective and true physical alignment.