Abstract
Purpose :
Age-related vision change could have substantial impact on the driving abilities of older people especially under mesopic lighting with glare in nighttime driving. However, conventional driving ability evaluation only tests visual acuity in photopic condition. This study investigates how visual acuity (VA), contrast sensitivity function (CSF) and visual field map (VFM) of older drivers change in different lighting conditions and the relationships between the different measurements.
Methods :
Twenty active older drivers (aged 63 to 87 years) participated. All had valid driver’s license, drove at least once per week, and did not use any visual aid for driving. Six had cataract surgery. Each participant completed a battery of visual tasks with their habitual correction for daily driving. Three basic visual functions, VA, CSF and VFM, were measured under photopic and mesopic conditions using the qVA, qCSF and qVFM procedures. VA and CSF were also obtained in the presence of glare under the mesopic condition. The area under log CSF (AULCSF) and volume under the surface of the VFM (VUSVFM) were used as summary metrics of CSF and VFM, respectively. We evaluated correlations between all 28 pairs of outcomes across different conditions and tests with one-tailed, FDR-corrected p-values.
Results :
VA, AULCSF and VUSVFM showed deterioration with age (ps ≤ 0.04), and varied across lighting conditions (ps < 0.001). Except VA between the photopic and glare conditions, all three visual functions exhibited significant correlations across different lighting conditions (r = 0.47 to 0.92; ps < 0.04). For all three lighting conditions, VA and AULCSF were always correlated (r = -0.50 to -0.90; ps < 0.03). In addition, VAs measured in the mesopic condition with and without glare correlated significantly with AULCSF measured under any of the three lighting conditions (r = -0.52 to -0.90; ps < 0.03). No correlation was found between VUSVFM and VA or AULCSF. A trend of stronger correlations was found when examining the subgroup of participants who had cataract surgery.
Conclusions :
Despite the significant correlations between some of the measures, VA, CSF and VFM obtained in the different lighting conditions may each provide useful information about driving ability in older people. Our findings may offer important insights for establishing optimal clinical outcome measures in older drivers.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.