Vernier acuity and aging.

Purpose/background: Many visual functions change with age. Hyperacuity vernier thresholds, however, seem to remain practically invariant with age.
Methods: We critically review reports on age-related changes in hyperacuity thresholds and present new data using two and three-point vernier hyperacuity thresholds.
Results: It appears as though the vernier (two dot or two line) alignment hyperacuity thresholds are not sensitive to age.
Significance: Based on these studies we propose that hyperacuity (vernier) thresholds be used as a benchmark, or a gold standard for aging studies. This measurement can serve as a valuable control and reference for other clinical studies of aging.