From the Guidelines
Glare significantly impairs driving safety by reducing visibility and causing visual discomfort, and patients with mild edema associated with Fuchs dystrophy or opacification related to granular corneal dystrophy may have significant difficulties with driving due to disabling glare, despite having a visual acuity of 20/40 or better 1. When bright light sources like oncoming headlights, sunlight, or reflections hit the eyes, they can temporarily blind drivers, making it difficult to see road hazards, pedestrians, and other vehicles. This effect is worse for older drivers and those with certain eye conditions like cataracts or corneal issues. Some key points to consider when managing glare while driving include:
- Wearing polarized sunglasses during daytime and anti-reflective glasses at night to reduce glare from oncoming headlights and reflections
- Keeping windshields clean to reduce streaks and smudges that can exacerbate glare
- Using sun visors effectively to block direct sunlight and reduce glare
- Maintaining a proper following distance to reduce headlight glare from oncoming traffic
- Considering contact lenses, particularly rigid gas-permeable (RGP) lenses, to improve visual function by creating a smoother and more regular refractive surface 1 Drivers with persistent glare sensitivity should consult an eye care professional, as treatments like cataract surgery or specialized lenses may help. Regular eye exams are important to identify and address underlying conditions that worsen glare sensitivity. Adjusting driving habits by avoiding dawn/dusk driving when possible and taking breaks during bright conditions can also improve safety. Additionally, transportation alternatives and driving retirement should be discussed with patients who experience significant glare sensitivity, as driving retirement can be associated with depression and social isolation 1.
From the Research
Visual Symptoms of Glare and Driving
- The visual symptom of glare can greatly affect driving, particularly at night or in tunnels, where the glare from vehicle headlights can impact motion perception and increase the risk of accidents 2.
- Studies have shown that elderly drivers and patients with beginning cataract may not be able to fulfill the criteria for night driving ability due to contrast and glare sensitivity, even if their visual acuity is sufficient 2.
Effects of Glare on Driving Performance
- Glare can reduce driving performance, especially in older adults, and can lead to decreased detection of signs, pedestrians, and road markings, as well as impaired lane-keeping and avoidance of low-contrast hazards 3.
- The use of blue light-filtering intraocular lenses has been shown to reduce the effects of glare disability on driving performance, particularly in patients with good visual acuity and a valid driver's license 4.
Age-Related Effects of Glare on Motion Perception
- Older adults have increased intraocular straylight compared to younger adults, which can affect motion perception, but glare from a continuous off-axis light source did not further elevate motion perception thresholds in either central or peripheral vision 5.
- However, older adults had elevated thresholds for motion contrast, biological motion, and differences in surround suppression of motion, relative to younger adults, in both glare and no-glare conditions 5.
Driver Judgments of Glare Effects
- Drivers' judgments of the magnitude of disability glare caused by high-beam headlights may not match actual declines in visual performance, with older drivers tend to overestimate their own visual acuity and the effect of glare on their vision 6.
- This misperception of headlight glare may help explain why drivers tend to underuse high beams, and highlights the importance of accurate assessments of visual performance in the presence of glare 6.