In less than a week, a total solar eclipse will move across the entire length of North America for the first time since 1979.
The event’s excitement is causing eager astronomers to grab their telescopes, cameras and binoculars and head to states within the path of totality.
But experts are also hoping they remember to pack their “eclipse glasses” and solar filters to help protect them for temporary or permanent blindness.
All it takes is 30 seconds of looking directly at a portion of the sun to cause permanent damage to ones’ eyes, according to NASA and optometrists.
“The rods and cones in the human retina are very sensitive to light,” NASA said on its website. “Even a thin sliver of the sun’s disk covers thousands of these light-sensitive cells.”
According to Dr. Joshua Corben, an optometrist at Corben Optometry in Santa Clarita, eclipse viewers who look directly at the sun can experience one of two consequences.
The first is called Photokeratisis, an eye condition that occurs when eyes are exposed to ultraviolent rays, which can be healed over time.
“It is basically like a sunburn on the eye,” Dr. Corben said.
Corben said this condition can cause a gritty feeling in the eye, light sensitivity, tearing and redness.
However, the second condition, called Solar Retinopathy can cause permanent damage to the eyes and result in partial or complete blindness.
Solar Retinopathy is caused when the radiation of the sun enters through the pupil and goes to the eye’s retina. Once there, it can cause damage to the macula and destroy the cells and photoreceptors, which include rods and cones, according to Corben.
“Inside the macula we have special cells called photoreceptors that allow you to see,” he said. “When you’re staring at the sun there’s no barrier to the sun’s radiation and it damages those cells and they can’t be replaced so you can go blind.”
The effects on Solar Retinopathy happen in both eyes and can have different lasting effects for each person.
“It doesn’t matter how long at you stare at the sun because there’s no time frame [for the injuries to occur],” Corben said. “It’s different for everyone.”
The only safe way to look directly at the sun is through special-purpose solar filters, like eclipse glasses or hand-held solar viewers, according to the National Weather Service (NWS). Homemade filters and ordinary sunglasses are not safe to look at the eclipse.
“You can experience the eclipse safely, but it is vital that you protect your eyes at all times with the proper solar filters,” NASA said on its website. “No matter what recommended technique you use, do not stare continuously at the sun.”
Viewers should not look at the uneclipsed or partially eclipsed sun through an unfiltered camera, telescope, binoculars or other optical devices. They also should not look through such optical devices while using their eclipse glasses or hand-held solar viewers.
Only those in the narrow path of totality—stretching for 70 miles from Salem, Ore. to Charleston, S.C.—can look directly at the eclipse without protection when the sun’s face is completely blocked by the moon.
This path of totality will not happen in Santa Clarita or in any part of California.
If eclipse viewers are interested in ordering their own gear before Monday’s event, they should only buy products from manufacturers that meet the ISO 12312-2 international standard for safety.
The American Astronomical Society’s list of reputable vendors of solar filters and viewers can be found at: https://eclipse.aas.org/resources/solar-filters.
Santa Clarita residents can also get free eclipse glasses, pinhole projectors and educational materials from the Old Town Newhall Library Friday afternoon and Monday morning.
Residents can also visit the Central Park Baseball Fields from 8:30 a.m. to noon to talk to the Astronomy Club of Santa Clarita, watch the eclipse through solar scopes and receive free eclipse glasses.
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