Many people notice that driving at night becomes more difficult as they grow older, and for some they have never been comfortable on the road after dark.
Eye Function in Low Light
The majority of the central vision in the human eye requires a certain level of light to function. As the background light level in our surroundings decreases our ability to perceive and react to objects is impaired. The body is equipped with several adaptation mechanisms to enhance our low light vision but these evolutionary responses were never designed for driving.
As light levels decrease the pupil automatically increases in size to allow more light to be collected. It usually takes about one to two seconds for your pupils to figure out where they should be for a given light level. However, it takes a lot longer than two seconds for our eyes to adjust. The receptors in the back of the eye and the brain itself also play a role in our adaptation. Each can undergo dramatic changes in sensitivity in a process that can take up to 15 minutes.
In low light conditions, such as driving at night, the human pupil dilates and the brain becomes more adjusted to the low level of light provided by your headlights. Unfortunately for your visual system you are not alone on the roads. To a dark adapted visual system, oncoming headlights can leave you blinded and unable to see clearly for four to six seconds. To put this into perspective: How far does the average car going 100km/h travel in four to six seconds? Approximately: 140 meters or far enough to cause a serious accident.
As the pupil opens larger and larger the human eye has greater difficulty focusing light in one spot. The loss of one clear point of focus can make your glasses feel as if they are the wrong prescription and blur your vision to an uncomfortable level. Having older glasses or an inaccurate prescription can be particularly devastating to vision in low light conditions.
Vision Tips: Drive Comfortably at Night
- Specialized coatings can reduce the recovery time from oncoming headlights by two to four seconds; cutting the time required in half.
- New generation coatings have been developed that do NOT bind dirt or lift off of the lens. Ensure to always look for the latest technology and get fully coated lenses.
A High Quality Name Brand Lens
- Not all lenses are created equal: the tolerance level of warping by a manufacturer can make night driving a more comfortable experience. Some lenses can distort light just like a fun-house mirror.
Routine Eye Exams
- Having updated, optically correct eyewear designed and fabricated by a reputable dealer can enhance your night driving comfort. Skip the 2 for 1 discount special.
Clean Your Windshield
- Just like cleaning the glasses is important. Having a clean, clear windshield both inside and out can reduce glare a significant amount.
You are the most important person in your eyecare. The decisions you make will influence your vision for the rest of your life. Make wise decisions and that night ride home will be a more comfortable and safe experience.
Visit iris.ca/exam or call 1.800.474.7429 to book an eye exam.
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