Eye safety will be a must while viewing Aug. 21 total eclipse of the sun

Weather permitting, Washingtonians soon will get a good view of a full eclipse of the sun — not the whole thing but a good chunk. Here’s hoping that all viewers of this much-anticipated astronomical event take due precautions so they don’t damage their eyesight.

Residents around the nation’s capital can expect to see an 81 percent blockage of the sun at the peak of the Aug. 21 eclipse, not the full solar cover or “totality” that millions of Americans are planning and traveling to view in peak spots that fall in a 70-mile wide swath across the country from Oregon to South Carolina.

Be warned: Don’t think just because the sun overhead is mostly blocked that it is safe even then to stare upwards with unprotected eyes. That might leave a careless viewer in the district with crescent-shaped burns on the back of the eyes, says a vision expert and longtime aficionado who says he has seen 19 eclipses.

Just to review, solar eclipses occur when the moon passes between the Earth and sun. This isn’t that rare an occurrence. But the viewing path for this event will be—this will be the first time in at least a century that a total solar eclipse’s path concentrates on the United States, casting darkness across the continent. It will give astronomers a potentially great view of the sun’s corona, which the Washington Post observes, “emits sprays of hot, ionized particles that can damage electrical grids and satellites and harm astronauts in space.”

FYI, the eclipse for Washingtonians is supposed to begin around 1 on that Monday afternoon and run until around 4.

NASA is having a ball, providing public information about this event, which is forecasted not to occur again in this fashion in the United States until 2045. The space agency is joining other science-based organizations, too, in warning about eye damage for eclipse viewers.

Don’t think that ordinary sunglasses, no matter how dark or pricey, will do. Experts advise fans to don special glasses, which one foundation is trying to provide to libraries 2 million free pairs for distribution to science enthusiasts. (Hint: If you’re buying eclipse glasses, be sure the lenses are marked as meeting an international safety standard, rated ISO 12312-2). Viewers also should mount protective lenses from reputable vendors over telescopes, binoculars, and any other devices they plan to employ for eclipse gazing. Beware, scammers already are hawking phony gear that could injure buyers.

In my practice, I see the detriments of too many Americans’ poor understanding of science and medicine. Let’s hope that this relatively rare event, which fans describe with awe and wonder, will boost interest in space, science, and great vision and health care. As anyone who has impairment or loss knows, good vision is critical to our wellbeing. Sky watching, meantime, has been a fascination for humanity for eons, and I’ve got my fingers crossed that all the build-up for the eclipse won’t disappoint, becoming another flash in the sky like the Comet Kohoutek.