Optometrist tips for viewing a solar eclipse safely
A solar eclipse isn’t something that happens every day. So start making plans for 2:02 p.m. on April 8. That’s when the Twin Cities area will see a partial solar eclipse.
A solar eclipse occurs when the sun, moon, and Earth line up. The moon blocks the sun’s rays from hitting us as it passes in between. In the Twin Cities, the sun will be about 74% obstructed. You can check your area here. People a few states away will be treated to a total solar eclipse. That’s when the sun will be entirely blocked for a minute or two. During a total eclipse, it’ll get dark, and the outside air could even drop a few degrees. Sounds like a sight to see, right?
But if you want to go out and see the eclipse, take precautions. Staring at the sun – during a solar eclipse or anytime – can damage your eyes or even cause blindness.
“I think there's this misconception that the sun is stronger during an eclipse, but really it's just that we let our guards down more,” said Andrew J. Ritter, OD, FAAO, an optometrist with M Health Fairview and adjunct assistant professor in the Department of Ophthalmology and Visual Neurosciences at the University of Minnesota Medical School. “We don't take the precautions we normally would and look longer than we normally would. Normally there's more of a squint reflex where if you do stare at the sun, it doesn't feel good, and so you stop.”
Bright lights can damage eyes
At the back of the eye is the retina, which is very sensitive to light. Looking directly at the sun, even briefly, can damage the retina. This potentially permanent damage is called solar retinopathy. It can leave blind spots or distort color perception.
“Once that damage is done, the retina doesn't really heal,” Ritter said. “There’s no treatment for solar retinopathy.”
In milder instances, people might experience blurry vision, see spots, or have a headache after looking into bright light. The symptoms are temporary and might last a few minutes or a few weeks.
How to safely view the eclipse
Your favorite beach-day sunglasses don’t offer enough protection for looking into the sun. Nor is it safe to put sunblock in your eyes – Ritter has heard that one. But you do have a couple options for safely watching the eclipse.
- With special glasses or viewers. They should have a filter marked ISO 12312-2. The American Astronomical Society has a list of reputable sellers. Make sure to watch kids, so they don’t pull their glasses off.
- Through a homemade pinhole viewer. This lets you project the image of the sun onto another surface and it’s a fun science project for kids of all ages. You will need a box, like a cereal or shoe box, scissors, aluminum foil, a pencil, a pin, some tape, and a white piece of paper. Get the NASA-approved instructions.
During a total solar eclipse, people can briefly remove their eye protection when the sun is completely blocked, but in Minnesota, the sun will only be 74% blocked.
“No one in Minnesota should be looking at the eclipse without some sort of protection,” Ritter said.
If you didn’t plan ahead and order approved lenses or make a pinhole viewer, you can still experience the eclipse. Ritter said he and his wife caught a partial eclipse in New Orleans last year and noticed more than the moon.
“When you're looking through the filtered glasses, the only thing you see is the crescent shape of the sun peeking from behind the moon,” he said. “But pay attention to the other shadows. We saw all the shadows coming through the trees that had the same crescent shapes. That was more memorable.”
