On Aug. 21 a solar eclipse will be visible across the entire United States for the first time since 1918. Many people will travel hundreds of miles to see the totality of the solar eclipse; however, everyone in the United States will be able to see it, even if it is a partial solar eclipse. No matter where you are, an expert at Baylor College of Medicine says when viewing the solar eclipse, it is important to wear proper eye protection to prevent damage to the eye, especially the retina.
“Directly staring into the sun, even for a few seconds, can cause significant permanent damage to your eyes,” said Dr. Christina Weng an assistant professor of ophthalmology at Baylor. “The retina is the back layer of the eye and has a critical role in maintaining good vision. The intense rays from the sun can cause damage to the retina, which could lead to blurred vision or blind spots.”
Looking at the eclipse without proper protection can lead to a condition called solar retinopathy. This is where the retinal tissues are damaged due to the thermal energy from the sun. “Depending on the extent of damage, symptoms can vary from a temporary loss of vision to permanent blindness in both eyes. One can even develop something called a macular hole that requires surgery to repair,” Weng said.
If you will be viewing the eclipse later this month, Weng says you must protect yourself with special filters. “Shade number 14 welder’s glass is a type of filter that has been recommended by the American Society of Retina Specialists, and is available at most welding supply stores,” she said.
NASA endorses eclipse glasses that are certified by the International Organization for Standardization, denoted as ISO-12312-2. There are other less expensive filters available online as well, but it’s important to ensure that they are truly designed to provide full protection against the sun.
The bottom line is that regular sunglasses – even the darkest ones – are not effective for the purposes of viewing the eclipse, Weng said. Regular and polarized sunglasses are designed to filter out UVA and UVB rays, but they do not provide sufficient protection for looking directly at the sun. They simply do not filter out enough visible and infrared light to effectively protect your retinas.
Additionally, remember that most cameras, binoculars, and telescopes are unfiltered, so if you are planning to capture images of the eclipse, you will still need to use a filter in order to protect yourself, she said.
“For those who are planning on watching this incredible event, make sure you are well prepared with the proper eye protection,” Weng said. “Don’t wait until the last minute to attain your filter or eclipse glasses. Whatever type of eye protection you decide to use, make sure you follow instructions properly. Also make sure that children and others around you are familiar with these safety precautions – it is every ophthalmologist’s hope that everyone will enjoy the eclipse safely. Finally, don’t be scared off by horror stories – as long are properly protected, everyone can safely enjoy this rare and striking event. Protect your eyes and enjoy!”
NASA Library Initiative and the Moore Foundation are providing free glasses to be picked up at 4,800 local libraries across the nation.
American Astronomical Society has compiled a list of reputable vendors for protective eye wear.