Retrospective evaluation of alternative vision screening criteria for older and younger drivers.

Visual examinations of 12,400 drivers in Pennsylvania were conducted at the time of their license renewal. Static binocular tests of visual acuity, horizontal visual field, and contrast sensitivity at varying spatial frequencies were given to license renewal operators who were unaware that their vision would be tested when they arrived at a facility where license photographs are processed. Examination results were correlated with involvement in selected crash categories over a 3.67-year period, taking (self-reported) mileage into account. Neither visual acuity nor horizontal visual field measures in isolation were significantly related to crash involvement. The combination of visual acuity, horizontal visual fields, and broad contrast sensitivity criteria was significantly related to increasing crash involvement for drivers aged 66-75 and 76 and over. The implications of including contrast sensitivity measures in driver vision screening protocols are considered.