Vision and Night Driving Abilities of Elderly Drivers

Abstract

Objective:In this article, we review the impact of vision on older people's night driving abilities. Driving is the preferred and primary mode of transport for older people. It is a complex activity where intact vision is seminal for road safety. Night driving requires mesopic rather than scotopic vision, because there is always some light available when driving at night. Scotopic refers to night vision, photopic refers to vision under well-lit conditions, and mesopic vision is a combination of photopic and scotopic vision in low but not quite dark lighting situations. With increasing age, mesopic vision decreases and glare sensitivity increases, even in the absence of ocular diseases. Because of the increasing number of elderly drivers, more drivers are affected by night vision difficulties. Vision tests, which accurately predict night driving ability, are therefore of great interest.Methods: We reviewed existing literature on age-related influences on vision and vision tests that correlate or predict night driving ability.Results: We identified several studies that investigated the relationship between vision tests and night driving. These studies found correlations between impaired mesopic vision or increased glare sensitivity and impaired night driving, but no correlation was found among other tests; for example, useful field of view or visual field. The correlation between photopic visual acuity, the most commonly used test when assessing elderly drivers, and night driving ability has not yet been fully clarified.Conclusions: Photopic visual acuity alone is not a good predictor of night driving ability. Mesopic visual acuity and glare sensitivity seem relevant for night driving. Due to the small number of studies evaluating predictors for night driving ability, further research is needed.

Nighttime driving: visual, lighting and visibility challenges

“…93 However, while the self-reported visual difficulties of older drivers are well established, there have been only limited numbers of studies that have explored the relationship between the visual characteristics of older drivers and their actual nighttime driving ability and safety. 96 Closed road studies have explored the effect of driver age on nighttime pedestrian detection, finding that older drivers recognised that a pedestrian was present at much shorter distances, and were more likely to fail to detect the pedestrian, than younger drivers. 13,18,19,97 In one study, the mean distance at which older drivers first detected the presence of a pedestrian was only 58% that of younger drivers.…”

The conspicuity of pedestrians at night: a review

“…Traditional measures of high-contrast photopic visual acuity are poor predictors of night-time visual function and driving ability. 46 Alternative tests have been advocated that involve reductions in target contrast and luminance levels to provide information regarding low luminance functional ability, 43,47 as well as insight into visual loss in ocular disease. 44,48 Individual differences in photopic visual acuity do not predict variations in night driving recognition ability, with mesopic measures being better predictors; 18 however, measurement of mesopic visual acuity may be variable due to variations in chart luminance at these low levels, which can significantly affect visual acuity.…”

Google Glass Glare: disability glare produced by a head‐mounted visual display

“…Another important behaviour is that DG is governed by the ratio of the luminance of the glare source to the luminance of the stimulus that the observer is trying to view . The situation is exemplified by the problem of oncoming car headlights when driving at night – this can produce a significant reduction in visual performance due to the low illuminance of the road ahead . The same headlights during daytime would produce negligible DG because of the brightness of the scene.…”

“…10,17 The situation is exemplified by the problem of oncoming car headlights when driving at nightthis can produce a significant reduction in visual performance due to the low illuminance of the road ahead. [18][19][20] The same headlights during daytime would produce negligible DG because of the brightness of the scene. For this reason, when considering the possible glare effects of an HMD, measurements need to be taken across a large range of luminance levels.…”