Assessing driving self-restriction in relation to vision performance was the objective of a study by West et al. (A-37). The researchers studied 629 current drivers ages 55 and older for 2 years.

The variables of interest were driving behavior, health, physical function, and vision function.

The subjects were part of a larger vision study at the Smith-Kettlewell Eye Research Institute.

A conclusion of the study was that older adults with early changes in spatial vision function and depth perception appear to recognize their limitations and restrict their driving. What was the target population? The sampled population?