VISION AND SAFE DRIVING

October is National Transport Awareness month. While the condition of the roads and the car is critical to safe travel, the driver is equally important. With a high percentage of information on the road being visual and instant decisions being made based on visual cues, good vision is fundamental to driver safety. The eyes are constantly moving, focusing and refocusing as they adjust to the constant flow of input from the eyes. The driver needs to be aware of traffic signals, other cars, pedestrians, changes in light from shady to bright areas, approaching headlights at night and eye fatigue when driving long distances.

Driving requires a combination of complex visual skills.

Visual acuity, the ability to see clearly at distance is a key element for safe driving. If you wear glasses or contact lenses for distance vision, always wear them when driving, even short distances. Make sure your glasses are clean and free of streaks and scratches. While contact lenses provide a less obstructed view of the road and fewer distortions than glasses, wearing them on long drives may cause the eyes to become tired and uncomfortable; keep a pair of glasses in the car so that the contact lenses can be removed if necessary. Have regular eye examinations to ensure that your prescription is up to date.

Being able to see “out of the corner of the eye” without moving the head and while keeping the eyes on the road, peripheral vision, enables the driver to identify other cars on the road, pedestrians, cyclists or objects that may be distracting.

Depth perception is the ability to accurately judge relative distance, particularly between moving objects when driving. This is an important skill for safe driving, specifically when overtaking or changing lanes in traffic. Depth perception depends on effective binocular vision, the ability of the eyes to work together effectively.

Accommodation is the ability to quickly and smoothly change focus at various distances, for example from the dashboard to a traffic light or vice versa.

Be aware of blind spots

Blind spots are specific areas around the car that are invisible to the driver and block other drivers on the road from view. These areas cannot be seen even when looking into any of the rear-view mirrors. They are particularly hazardous when changing lanes or merging with traffic. Most cars have two main blind spots, one on each rear side of the vehicle.

Glare can be distracting and even dangerous

Glare is a distracting and sometimes dangerous excess of bright light and can happen day or night. The eyes must strain to see clearly, causing squinting and eye fatigue. Polarised glasses help to reduce glare and increase visual clarity and comfort. If you need to wear prescription glasses to drive, don’t replace them with non-prescription sunglasses when it is sunny. Rather wear prescription sunglasses or clip-on sunglass lenses over the prescription lenses.

Daylight vision problems can be worse at night

Daylight vision problems are often exacerbated when driving at dawn, dusk or at night. Night vision deteriorates with age and can be more problematic with dry eyes and certain age-related eye conditions. The glare from streetlights, oncoming headlights, and other light sources may reflect from the street surface and present a visibility problem. Looking slightly to the left of oncoming traffic helps to reduce the halo effect from glare and allows the eyes to recover more quickly than looking directly into oncoming headlights. Rainy weather can make night driving more challenging as the wet streets and sidewalks reflect more light than usual. Your optometrist may recommend anti-reflective lenses to help minimise reflected glare.

Give your eyes a break

When driving long distances, stop regularly, and even more often during sunny conditions. Rest your eyes even for just a few minutes.