Health: Enjoy Viewing The Eclipse, But Do So Safely

by Alan Pollock
A crowd uses handheld solar viewers and solar eclipse glasses to safely view a solar eclipse. NATIONAL PARK SERVICE PHOTO A crowd uses handheld solar viewers and solar eclipse glasses to safely view a solar eclipse. NATIONAL PARK SERVICE PHOTO

For some, viewing the April 8 solar eclipse will be a once-in-a-lifetime experience. But without proper safeguards, it could cause a lifetime of vision problems.

The total solar eclipse will happen for two or two-and-a-half hours on Monday afternoon, peaking roughly between 3:25 and 3:35 p.m., and as viewed from Cape Cod, the sun will be about 88 percent occluded at its maximum. (To see the sun fully covered by the moon, one would have to travel to extreme northern New England.) If the weather cooperates, it will be a stunning display, even here.

But experts say it takes some preparation to appreciate the spectacle while avoiding injury. Dr. Michael Rest, chief of emergency medicine at Falmouth Hospital, said there are two separate medical issues that can be caused by unprotected sun-gazing.

“Solar retinopathy is damage to the retina due to the radiation from the sun. The retina is the sensory screen at the back of the eye that converts light into electric nerve signals to the brain. Typically this condition is painless and it develops over hours to days after the damage occurs,” he said. “It may start as purple spots and it can progress to significant loss of vision. A retina specialist can be seen non-emergently, but there is little treatment once the damage has occurred.”

A second condition is solar keratitis, which is burning to the cornea, the outer lens of the eye.

“This is essentially a sunburn, and it can be very painful. The pain usually starts several hours after the injury,” Rest said. It is treated with pain medicines, but can cause cataracts that need to be fixed later on.

Depending on a number of factors, solar retinopathy can cause a reduction in vision that lasts between a few months and a lifetime. Children are particularly at risk, and should be monitored closely during the eclipse, public health officials say. People who have age-related macular degeneration are also at higher risk, as are people who use certain drugs that cause sensitivity to light. There is no cure or treatment, so prevention of solar retinopathy is key.

With the sky likely to darken for more than two hours, it will require some discipline not to take a peek, said Jason Comander, M.D., Ph.D., the director of the inherited retinal disorders service at Mass Eye and Ear.

“That’s a lot of time to fight the temptation to stare at the sun. It’s especially tempting for children,” he said. “I encourage parents to have kids make their own pinhole projector. It’s interactive and fun.”

Aside from watching the eclipse on a TV or computer screen, which takes away some of the wonder, the safest way to view a total eclipse is using a homemade eclipse viewer, and many plans are available online. Generally, they involve a cardboard box to create a dark space, a white piece of paper on one inside wall to make a projection screen, a viewing window to see the screen, and a pinhole aperture, usually in a piece of aluminum foil, that will create an image of the sun on the screen. This method requires a bit of craftiness, but it’s the safest method for viewing the sun.

If that seems a bit ambitious, just use two pieces of white paper with a pinhole poked in one of them to project a tiny eclipse image on the other.

“It’s much safer than staring at the sun… as long as they don’t poke themselves in the eye with the sharpened pencil you give them!” Commander said.

Public health officials say any direct sun-gazing has a risk, but it can be done using proper eclipse glasses. Use only glasses with filters that meet ISO standard 12312-2, and don’t assume that cut-rate versions found online actually meet the standard, even if the printing on the side makes that claim. Buy from a reputable vendor and make sure the lenses have no scratches, punctures or gaps with the frame. In case you’re wondering, regular sunglasses provide no protection, no matter how dark they are.

If there’s anything worse than watching an eclipse with the naked eye, it’s watching through an unfiltered camera, telescope or pair of binoculars, which amplify the damage and can cause instant injury, even if you’re wearing solar glasses.

What if you’ve made no preparations but still want to take part in the fun? Head to the kitchen and grab your collapsible metal colander. Go outdoors and put a sheet of white paper on the ground and hold the colander over the paper to cast a shadow there. Each hole in the strainer will provide a tiny picture of the eclipsing sun.

Learn More:

Free Eclipse Viewing Events

If you’d like to safely spy the total solar eclipse with other enthusiasts, visit Brooks Park on April 8 from 2:30 to 4:30 p.m., where the Brooks Library and the Harwich Observatory will provide equipment for safe viewing. A limited number of eclipse glasses will be available. An event is also happening at Nickerson State Park in Brewster, weather permitting. Activities may include a solar system tour, with a scale model of our solar system posted along a half-mile trail section; eclipse crafts and sundial workshops, and nature observation programs that explore how animals behave during the eclipse.