Having the proper equipment is necessary to safely view a solar eclipse

Texas A&M ophthalmologist offers solar eclipse safety

This rare planetary event can be harmful for your eyes
August 17, 2017

A solar eclipse can be a really cool sight to see, and fairly rare. The last time the United States had a total solar eclipse was 1979, which makes this upcoming solar eclipse one to mark on the calendar (or add as a reminder in your smartphone). However, if you’re not careful, it might cause serious damage to your eyes – or even be the last thing you see clearly.

A physician from Texas A&M College of Medicine explains why a total eclipse of the sun can be damaging to your eyes and what you can do to protect yourself.

The sun and your eyes

Our eyes are sensitive to the sun, and very rarely would someone look at the sun for a prolonged period of time under normal circumstances. We’ve trained ourselves to avoid looking directly at the giant flaming star. Even when we occasionally glance up to see a bird or a plane (or Superman), we instinctively squint or shield the sun with our hand.

However, during an eclipse, the sun is the subject of our gaze, and the very thing that we normally avoid is the center of attention.

“Looking directly at the sun can cause serious damage to your eyes,” said Robert H. Rosa Jr., MD, ophthalmologist and professor of surgery and medical physiology at the Texas A&M College of Medicine. “Staring at the sun, even for a short time, without wearing the appropriate eye protection can damage the macula, which is responsible for our fine vision. It can cause blindness due to solar retinopathy.”

Solar retinopathy, which can occur with or without an eclipse, can produce no significant vision loss, but in some cases, it can cause permanently decreased vision. It is not a painful occurrence, so there may not be any warning signs that you’re damaging your eyes as it is happening.

Children are at greatest risk for solar retinopathy because of their clear crystalline lenses, so parents should be especially careful to make sure their kids are safely viewing the event with protective glasses containing solar filters.

During an eclipse

A truly extraordinary event, a solar eclipse occurs when the moon blocks any part of the sun from our view. During the upcoming event on August 21, there will be a brief window across the United States where a total eclipse occurs and the moon is directly in front of the sun—no longer than two minutes and 40 seconds. The sun’s brightness creates a halo around the moon in front of it, and the stars and planets become more visible in the sky.

If you’re watching a solar eclipse, it’s important to have the proper equipment.

“The only safe way to look directly at the sun, especially during an eclipse, is through special-purpose solar filters,” Rosa said. “The solar filters are commonly used in ‘eclipse glasses’ or in hand-held solar viewers.” Because there have been reports of counterfeit versions being sold leading up to the 2017 eclipse, make sure your glasses or viewers meet the ISO 12312-2 international safety standard. These filters meet specific criteria that ordinary sunglasses, even dark ones, do not meet.

However, even with the glasses on, don’t look through any device that can magnify or intensify the light. “Never look at the uneclipsed or partially eclipsed sun through an unfiltered camera, telescope, binoculars or other similar devices,” Rosa said. “This is important even if you are wearing eclipse glasses or holding a solar viewer at the same time. The intense solar rays coming through the device can damage the solar filters and your eyes.”

During the total eclipse phase, you’ll be able to ditch the special lenses and be able to watch the eclipse safely—as long as you remember to keep your eclipse glasses nearby. This brief period of time may vary depending on your viewing location in the United States.

“When the moon completely covers the sun’s bright face and it suddenly gets dark, you can remove your solar filter to watch this unique experience,” Rosa said. “Then, as soon as the bright sun begins to reappear very slightly, immediately use your solar viewer again to watch the remaining partial phase of the eclipse.”

— Dominic Hernandez

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