Beware the sun's rays
The North American eclipse Monday, Aug. 21, will be a natural wonder that may tempt people to look to the skies.
Do not do it, eye care professionals advise, unless you have proper eyewear for viewing this astrological marvel. You could damage your eyes or lose your sight entirely.
"Obviously, the safest way to watch the solar eclipse is on NASA's website or any digital device — online or TV," said Dr. Antoinette Chamoun, an optometrist at Pearle Vision in Red Wing.
"If you really, really, really, really want to watch the eclipse, then safest is with the special purpose solar filters," she said.
You can find guidelines and specifications at aoa.org.
According to eclipse2017.org, the only way to look safely at the sun when it is not in total eclipse is through approved filter material designed and marketed expressly for direct solar viewing. The material for safe viewing glasses is inexpensive and readily available through astronomical supply houses.
The price of not using the filter, however, is high.
Dr. David P. Nelson, president of the Wisconsin Optometric Association, stresses that people can't be too careful in protecting their eyes and especially children's eyes.
"Unlike the mature lens found in an adult eye, a child's lens cannot filter out UV rays as easily, causing damage to the child's retina. When children play outside, they are often excited and may remove their glasses or their glasses may fall off during activities," he said in a news release.
Monday's solar eclipse will span the United States. The moon will cover at least part of the sun for two to three hours, with some areas experiencing complete blockage for up to 2 minutes 40 seconds.
Given good weather, the eclipse will be visible from most Americans' backyards and an estimated 500 million people across North America may witness at least a partial eclipse.
Since Minnesota and Wisconsin are not in the area that will experience complete coverage, wearing glasses specifically designed for viewing an eclipse is critical, he said.
Standard sunglasses, regardless of ultraviolet markings, including UVA and UVB, will not provide enough protection due to the intensity of the rays. The sun's rays may be partially blocked, but the remaining visible rays are intense enough to cause serious eye damage or even loss of vision.
"Eclipse glasses" should have an ISO 12312-2 marking on them to be considered safe for looking at the sun. These glasses should be closely inspected prior to use to ensure the solar filters are free of any scratches or damages, eye care professional advise. If you find an imperfection, discard the glasses.
Do not use binoculars, cameras and telescopes when viewing the eclipse — even if wearing eclipse glasses — as these devices can magnify the sun's rays and negate the effectiveness of the protective eyewear.
"There are a lot of fakes out there and my fear is that patients will watch the solar eclipse and have permanent vision loss," Chamoun warned.
Overexposure to the sun's rays can damage the surface of the eye (photokeratitis) and the back of the eye (solar retinopathy). Symptoms include eye pain, burning or red eyes, light sensitivity, blurred vision, difficulty in recognizing shapes, objects' appearing distorted, headaches, watery eyes, and/or swelling around the eye or eyelid.
"If experiencing any post-exposure symptoms, medical attention should be sought immediately, especially if the condition is worsening with time," Nelson said. "Just as with a sunburn, delayed symptoms can also occur several hours after overexposure."