|Seeing in the dark||Nov. 26, 2012|
|Written by: Marilyn Linton, QMI Agency|
|Short days can magnify night vision problems|
“How did it get so late so soon? It’s night before it’s afternoon. December is here before it’s June. My goodness, how the time has flewn.”
Dr. Seuss sure had it right: Now and through to Dec. 21, the longest night of the year, night swallows up the day. Canadians are living in the dark now, and for those of us who struggle with night vision, winter’s long nights present extra challenges.
“Night vision is a problem for all ages,” says Dr. Lareina Yeung, vice-president of the Ontario Association of Optometrists and an optometrist at the Queensway Optometric Centre in Mississauga, Ont.
“The distractions you get at night with halos and glares around lights can be as simple as needing to clean your windshield or glasses,” she says. “If you have a wet icy road, or if it is snowing or raining in the dark, you get reflections off headlights and streetlights that are hitting your eye. The result is that your eye can get a bit confused.
“Driving in the dark is the most common complaint in our office at this time of year,” she adds. “So it’s a good time to raise awareness about night vision and to tell people that night vision problems can also be a sign of eye problems. They should make sure they get their eyes checked out annually.”
Night vision problems are often attributed to older people, but you can have problems at any age, she says. “The younger you are, the larger your pupils are in regular daylight. Then when you get into the dark, your pupils get even larger which lets in more light.”
That result is a condition called spherical aberration, the inability of the eye to focus light rays that come into the eye at different angles –it’s a condition experienced by people of all ages.
For people who wear contact lenses and are troubled by night vision, there are now lenses available to reduce spherical aberration and the reflection problems that result.
“If a patient says they have trouble driving in the dark, they may have the wrong prescription in their glasses or they might even need glasses,” Yeung says. Glasses that have an anti-reflective coating can also help.
With age, night vision declines but the reason could be anything from cataracts to other medical issues such as diabetes. Cataract surgery can restore night vision problems that are a result of the clouding of the lens of the eye.
While night blindness can sometimes be caused by vitamin deficiency, Yeung says eating a diet rich in yellow, orange and green vegetables is important for general eye health.
According to www.driveawaytheglare.ca, a website featuring a campaign launched by the Canadian Association of Optometrists and the Opticians Association of Canada, symptoms of night vision problems include seeing halos and glare which create a distortion of images, sometimes blurring. Halos are bright circles that appear to surround a source of light, such as an oncoming car’s headlights or a street lamp. Glare is light that enters your eye and interferes with your vision.
Night vision problems can be difficult to assess on your own, but Yeung tells her patients it’s not normal to have trouble distinguishing objects in the distance or seeing the lines on the road. “If people begin to realize they are having difficulty distinguishing a traffic light or viewing it as blurry or elongated, then that’s a sign to come in for an eye exam.”
Causes of night vision are numerous and include cataracts, LASIK eye surgery problems, diabetes, and vitamin A or zinc deficiency. But they can also be due to tiredness and existing eye conditions that are not properly diagnosed or corrected.
Driving right in low-light
• Use your low beams when you are less than 60 metres behind another vehicle unless you are passing it
• If taking a long trip, schedule plenty of breaks along the way
• Keep your windshield clean: Built-up dirt worsens the glare of oncoming lights
Yes or no?
Try this mini-quiz from www.driveawaytheglare.ca. A “yes” answer may indicate night vision problems.
• Do you see multiple images of lights at night?
• Do you notice a blur or distraction when you see lights in low-light conditions?
• Do you feel blinded or disoriented by oncoming headlights
• Have you noticed a problem with glare from a computer or TV screen while sitting in low light?
Driving down under
According to the Optometrists Association of Australia, half of the country’s young drivers, aged 18 to 25, find it more difficult to focus on the roads when driving at night; 14% of the survey participants avoided driving at night due to difficulties with vision.
|MORE COLUMNS BY MARILYN LINTON, QMI AGENCY|