The day is bright and sunny. Optimal conditions for driving, right? Wrong! Blinding glare from sun and vehicles is a contributing factor to fatal motor vehicle accidents. More than 90 percent of reactions made behind the wheel depend on good vision. A recent survey by Essilor revealed a disturbing fact – 20 percent of eyeglass wearers sometimes drive without their prescription glasses and instead wear non-prescription sunglasses. That means one in five make day-driving unnecessarily treacherous. Another Essilor study found that reaction times improved by one-third of a second for drivers who wear polarized prescription lenses. For a car traveling 80 km/h, one-third of a second allows a driver to stop seven metres sooner, or the length of an intersection. In glare-intense situations, polarized lenses improve vision clarity by 75 percent, compared to ordinary sun lenses.