Aug 01, 2017 12:00 AM

Author: Moran Eye Center

Are you prepared for the most exciting cosmic spectacle in nearly a century? That would be the upcoming total solar eclipse on August 21, 2017. On that day, the moon will completely cover the sun and the event will sweep across a swath of the entire country for the first time since 1918.

Because the moon will be covering the sun and the sky will darken, some might think it’s a chance to ignore mom’s advice to never look directly into the sun.

But experts at the John A. Moran Eye Center at University of Utah Health warn onlookers not to be tempted. Looking directly at any part of the sun showing during an eclipse can cause eye damage known as solar retinopathy, explains Moran ophthalmologist Jeff Pettey, MD.

“Solar retinopathy can cause vision loss and blind spots that can be long term or even permanent,” says Pettey. “The same risk you would have looking at the sun on a normal day exists during an eclipse. You might not feel any pain as the damage is being done, but vision loss can show up hours later.”

How Does it Happen?

Indirect sunlight enters the eye through the pupil and the lens focuses it onto the retina in the back eye with no problem. But focusing the lens of your eye directly on the sun’s intense ultraviolet and infrared light for an extended period of time can destroy the retina’s photoreceptors—rods and cones that are sensitive to light and dark.

That’s why it’s critical for anyone and everyone viewing the eclipse to protect their eyesight with glasses specifically designed for viewing—or #14 welder’s glasses.

“Unfortunately, sunglasses won’t provide adequate protection,” Pettey notes. “No matter how dark they are, they just don’t block out the damaging rays.”

The Only Safe Ways to Look

Bottom line, there are only three safe ways to look at a solar eclipse. The National Eye Institute offers these safety guidelines for viewing glasses--disposable paper glasses that meet an international standard, indicated by ISO-certified filters. These glasses are widely available and inexpensive and the solar filter is thousands of times darker than regular sunglasses. Just be sure they’re certified.

Or, you can view through binoculars, telescopes or camera lenses, but you must put an ISO filter on the front lens. Not a “built in filter,” (those are only OK for partial eclipses) but a safe, removable ISO filter.  

The other option is turning your back to the sun and watching a projection of the action with a device such as a pinhole projector. 

Whatever safe viewing method you choose, it’s sure to be a sight you won’t forget. Just keep your fingers crossed for clear skies!

vision eclipse sun

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