For some people, driving in the dark is uncomfortable, if not downright unpleasant.Fred Lum/The Globe and Mail
After turning the clock back and shortening the day, we spend more time driving in the dark. For many, this is not a problem. But for others, driving in the dark is uncomfortable, if not downright unpleasant.
Recent studies and a new program initiated by two Canadian eye-care professional associations highlight little known conditions that impact many of us when driving at night – halos and glare.
An eye's pupil dilates or grows in size in the dark to allow more light to enter the eye. We can all witness this as our eyes "adjust to the dark." As the pupil dilates, optical quality gets worse and, in many cases, this leads to the perception of halos or rings around headlights and streetlights. Glare can be described as difficulty seeing in bright conditions and can lead to distortion, discomfort or distraction. You may not even realize you are seeing these halos and glare, considering such effects as normal.
Halos and glare are commonly caused by spherical aberration, which is common and cannot be corrected with standard glasses or contact lenses. In fact, experts say many conventional eyeglass and contact lenses actually increase spherical aberration. Halos and glare are also common signals of cataracts. Under normal conditions, the lens at the front of the eye is clear so light can pass through uninterrupted. Cataracts create a cloudy lens, blurring vision and affecting the way you see light.
Other eye problems that prevent the eye from focusing light properly, and thus contribute to halos and glare, include near-sightedness (hard to see things at a distance), farsightedness (hard to see up close) and astigmatism (blurred vision due to the irregular shape of the cornea).
The Canadian Association of Optometrists and the Opticians Association of Canada have launched a program called "Drive Away The Glare" to raise awareness of the problem and that there are solutions.
A recent global study to determine the hierarchy of vision-corrected needs, called NSIGHT (Needs, Symptoms, Incidence, Global Health Trends) revealed that roughly half of all eyeglass and contact lens wearers experience halos and glare more than three times a week. It found that more than 80 per cent of people who experienced halos and glare found them bothersome.
The study, commissioned by Bausch + Lomb, was conducted by the research firm of Market Probe, which surveyed 3,800 people, 15 to 65 years of age, from seven countries (China, Korea, Japan, France, Italy, United Kingdom and the United States) who routinely wear prescription eyeglasses or contact lenses.
Asked to prioritize 40 features within eight categories of potential product features, the study found comfort took a back seat to quality of vision. In descending order of importance, the eight categories of product benefits were vision, health, environment, eye condition, convenience, comfort, personal performance and personal appearance.
The two eye-care professional associations want Canadians to know there are easy solutions to low-light and night vision problems. In addition to a new generation of lenses – whether framed or worn as contacts – there are other steps you can take to reduce the incidence of and issues related to halos and glare.
- When taking long trips at night, schedule plenty of breaks.
- Keep your windshield – inside and out – clean to prevent glare.
- Use your low beams only, when following another vehicle.
- Use your visors to prevent direct sunlight from entering your eyes.
- Continually scan the scene ahead. Do not fix on a certain spot, but look to either side regularly. This will not only alert you to animals, cyclists and pedestrians, but help keep your eyes moist and vision flexible.
- Wear polarized sunglasses during the day.