JMIR Publications

ABSTRACT

Background:

Age-related vision changes significantly contribute to fatal crashes at night in older drivers. However, the effects of lighting conditions on age-related vision changes and associated driving performance remain unclear.

Objective:

This pilot study examined the associations between visual function and driving performance assessed by a high-fidelity driving simulator among drivers 60 and older across three lighting conditions: daytime (photopic), nighttime (mesopic), and nighttime with glare.

Methods:

Active drivers 60 or older participated in visual function assessments and simulated driving on a high-fidelity driving simulator. Visual acuity (VA), contrast sensitivity function (CSF), and visual field map (VFM) were measured using the qVA, qCSF, and qVFM procedures under photopic and mesopic conditions. VA and CSF were also obtained in the presence of glare in the mesopic condition. Two summary metrics, the area under the log CSF (AULCSF) and volume under the surface of VFM (VUSVFM), quantified CSF and VFM. Driving performance measures [average speed, standard deviation of speed (SDSpeed), standard deviation of lane position (SDLP). and reaction time] were assessed under daytime, nighttime, and nighttime with glare conditions. Pearson correlations determined the associations between visual function and driving performance across the three lighting conditions.

Results:

Of the 20 drivers included, the average age was 70.3 years; 55% were males. Poor photopic VA was significantly correlated with greater SDLP while driving during the day (r = 0.31, p < 0.0001), at night with (r = 0.25, p = 0.0004) and without (r = 0.28, p = 0.0001) glare, respectively. Poor photopic AULCSF was significantly correlated with greater SDLP across the three lighting conditions, a larger SDSpeed (r = -0.15, p =0.0466), and longer reaction time (r = -0.24, p =0.0048) while driving at night. Poor photopic VUSFVM was significantly correlated with a longer reaction time (r = -0.16, p = 0.0357) while driving during the day and larger SDLP (r = -0.25, p = 0.0003) while driving at night with glare. For functional vision in the mesopic condition, poor VA, AULCSF, and VUSFVM were significantly correlated with a greater SDLP and/or longer reaction time while driving at night with or without glare. For functional vision in the mesopic condition with glare, poor VA and AULCSF were significantly correlated with a longer reaction time in all three lighting conditions.

Conclusions:

Visual functions differentially affect driving performance in different lighting conditions among older drivers, with more substantial impacts on driving during nighttime, especially in glare. Additional research with larger sample sizes is needed to confirm these results.