A solar eclipse is awe-inspiring, and the temptation to just stare at the source of this spectacle can be powerful. Solar eclipses have been called one of the greatest sights in nature. However, medical experts acknowledge that anytime you look at the sun for longer than a few seconds, it can lead to permanent eye damage. It’s not the eclipse itself that poses a threat. When unprotected eyes look at the sun for more than just a glimpse, the intense visible light and focused infrared radiation can damage or even destroy light-sensitive rod and cone cells inside the retina, or leave permanent scarring.
A solar eclipse is a lineup of the sun, the moon and Earth. The moon, passing directly between the sun and Earth, casts a shadow on our planet. If you’re in the dark part of that shadow (the umbra), you’ll see a total eclipse. Interestingly, the sun and the moon appear the same size. Although the sun is 400 times larger than the moon, it’s also 400 times farther away.
Since the sun is basically a single, large, continuous thermonuclear explosion, the intensity causes people to have a natural aversion to looking directly at it. Most know the headaches and temporary vision distortion that even a glimpse or reflection of direct visible sunlight produces, not to mention the skin and cornea damage ultraviolet radiation from the sun can cause. James Pressly, MD, an ophthalmologist at the GHS Eye Institute, explains that the most common and dangerous is a condition called solar retinopathy, in which retinal burns are produced by staring at even just the partial sun. This causes thermal damage from the visible and infrared rays that are focused onto the retina and pigmented layers of the back of the eye. We don’t usually see a lot of people with solar retinopathy, as the eye will usually tolerate only fleeting glances at the sun, but it is more common following a solar eclipse.
Oddly enough, looking at the sun during an eclipse can be more dangerous than looking at the full sun. The darkness that accompanies an eclipse can override the natural tendency to squint and avert the eyes, making you feel like you can look at the sun for longer. But the increased amount of visible and ultraviolet radiation focused on the retina during that time makes it more likely that you’ll sustain eye damage. Your eyes can be damaged even if only a small sliver of the sun is visible. Right before and right after totality, even the 1 percent of the sun’s surface visible is up to 10,000 times brighter than the full moon. The greatest danger comes from the fact that someone looking at the sun won’t know they are damaging their eyes. Experts warn that there is no pain and no feeling that the damage is being done. It’s only later that an affected person would notice. The damage can last for days, weeks, months or, rarely, it can be permanent.
The National Aeronautics and Space Administration (NASA) and the American Astronomical Society (AAS) recommend that solar-viewing or eclipse glasses meet the current International Organization of Standards: ISO 12312-2. These specifically designed lenses have special filters that block at minimum 99.9999 percent of the sun’s visible and non-visible rays to protect your eyes. Correct use of these types of filters is imperative for your safety.
Note that sunglasses are never a substitute for solar-viewing glasses. Even layering multiple pairs of sunglasses will not protect your eyes from sun damage.
The GHS Eye Institute is taking the lead in its concern for eye protection by making solar eclipse glasses available this week. These glasses, which are approved by NASA and AAS, can be picked up at the Eye Institute’s offices in Greenville (104 Simpson St.), Spartanburg ( 333 S. Pine St.) and Easley (109 Fleetwood Drive, Suite B), while they last. With proper precautions, this type of filter makes it safe to look at the pre- and post-totality portions of the eclipse. For the fleeting few moments during a total eclipse when the entire disk of the sun is completely covered by the moon’s silhouette, it’s safe to look at this spectacular sight with your naked eyes. While viewing an eclipse at totality is safe, it’s important to be aware of when it ends and when the sun starts its return.
Great caution should be exercised to properly monitor children, as a combination of their natural curiosity and lack of knowledge of the consequences may pose a very real danger. Even for those parents, teachers, and caregivers who don’t intend to watch this eclipse, children, especially those who might be outside, should be under close observation for their safety.
Early observers of astronomy sometimes found out about solar retinopathy the hard way. In the most famous case, Isaac Newton tried looking at the Sun in a mirror, essentially blinding himself for three days and experiencing afterimages for months.
Michael Bakich, on his eclipse website, informs us that it has been 38 years since the last eclipse over at least a small part of the continental United States, with the next occurrence on Aug. 21, 2017. For us in South Carolina, the eclipse will start at approximately1:08 p.m., and totality will begin at approximately 2:35 p.m. The exact time will vary as the moon’s shadow progresses across the state. Greenville, Greer, Easley, Greenwood, Laurens, Columbia and Charleston among others, will be in the direct path of totality—but not Spartanburg. The Spartanburg area will observe an “almost-but-not-quite” total eclipse, which will still be awesome.
Here’s a good trivia tidbit: In South Carolina, because of the geography and shape of the continental U.S. and the orbits of the sun, moon and Earth, the moon’s shadow will be moving over 1,500 miles an hour as the moon covers the sun! If that sounds fast, when the shadow begins crossing the country in Western Oregon, it’s anticipated to be 2,955 miles an hour!
While there will be other partial eclipses, the next total solar eclipses over the continental United States will be April 8, 2024. Unfortunately for those of us living around here, it will not be close to our area. After 2017, the next total solar eclipses visible from South Carolina will be in 35 years on March 30, 2052, and then 26 years later on May 11, 2078.
Please call our GHS Eye Institute main number of 864-522-3900 with any questions. We’re here to help.
P.S. To follow up this solar eclipse, the next lunar eclipse that will be visible in South Carolina, according to the TimeandDate.com website, will start at 10:30 p.m. Jan. 20, 2019, and the moon will be totally covered by 12:10 a.m. on Jan. 21, 2019.
Grant Brown is a master optician with the GHS Eye Institute.