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LIFEWAVES: Giving up night driving sometimes a difficult decision to make
When you are driving at night does it feel as if the headlights of oncoming cars are much brighter than they used to be? Do you have to squint a bit until an oncoming car passes?
Many of today’s car lights are backed with highly reflective material or have powerful halogen lights which cause a glare that can make it difficult to see lane markings, fog lines and oncoming cars.
Then there is the issue of driving on some of our country roads at night, especially when a sport utility vehicle approaches with its bright lights raised up higher than cars’ lights.
Does any of this sound familiar? If so, you and I are experiencing a problem with our night vision called “night blindness.” We may be able to drive well during the day, but at night it may be different.
My eye doctor and I discussed this a year ago, its causes and the rate at which it develops. He told me poor night vision is one of the most common problems people bring him and that it usually begins to occur in our mid to late 40s, but that even someone as young as 20 can develop it. It continues to progress enough to be detected in an eye exam by the time we are 60 or so.
There are two main causes of night blindness – internal and external. Think of a camera. When you take a picture the light passes through the lens, the shutter opens and closes quickly to let the light in and the image is captured on a piece of film, or on a digital screen, recording what the camera “saw.”
When we look at an object, the light passes through our eye’s cornea and on to the pupil in the center of the iris. The pupil adjusts to the amount of light available, passes the image through the eye’s lens, onto the retina (film) and to the brain.
If the lens of your camera gets scratched, pitted or dirty, the camera records a poor image. Over time, the lens in our eyes get cloudy and light just does not pass through it as it used to so the brain gets a poor image. Why?
Because the eye’s lens begins to breaks down over time and starts to look a bit like chicken broth acting as a filter to what we are seeing. In some people, over time this can lead to the formation of cataracts which, luckily, can be removed so vision is improved.
Also, as we age, the eye’s lens becomes stiffer which causes poor adaptation to light. Our pupils dilate to be able to take in more light at night, have to contract quickly when an oncoming headlight hits it and then readjust after the car has passed. Stiffer lenses just cannot adapt quickly causing us problems.
Then there are external causes. We see this a lot on the Plateau on rural roads that do not have streetlights. Add in rain splatters on the windshield, fog, faded center and fog lines and it is confusing. When you consider all these internal and external causes, a night driving experienced can be frightening to us and possibly dangerous to other drivers.
Sometime in our 70s or 80s we are not going to be able to drive safely at night. We are going to have to be smart enough to limit ourselves. I know it hurts like heck to say you or I cannot drive anymore at night, especially if we are the one everyone else depends on. It is a sign of the beginning of the loss of independence, but at the same time it is a problem that could cause great harm if not addressed.
Seniors, when it is time to give up driving at night, let’s step out gracefully and let others take over this role. We can be positive role models to our children and grandchildren.