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How to Safely View the Solar Eclipse

Make sure you’re ready for April 8

Solar Eclipse

On Monday, April 8, a solar eclipse will be visible (weather permitting) across the U.S. Anyone within a 115-mile-wide path cutting from Texas through Maine will experience a total eclipse. A partial eclipse will be visible in the Allentown area beginning at 2:08 p.m. It will peak at 3:23 p.m. and conclude at 4:35 p.m.

If you plan to observe the solar eclipse at any time during those 2 hours and 27 minutes, Lehigh Valley Health Network encourages you to review these important safety tips.

Be sure to protect your vision

A total solar eclipse occurs when the moon passes between the sun and Earth, blocking the face of the sun for a few minutes. As a result, the sky darkens. While it’s easier to look directly at the sun during an eclipse, it’s dangerous. In very little time, your vision can be seriously damaged, and you won’t notice a thing until it’s too late.

According to NASA and the American Astronomical Society (AAS), the only way to look at the sun safely during an eclipse is with special filters that meet the international safety standard for direct solar viewing known as ISO 12312-2. Unfortunately, there are always people who ignore this guidance — and suffer the consequences. A solar eclipse on Aug. 21, 2017, also cut a wide swath across the U.S. A survey of eyecare professionals following it showed that about 100 people suffered eclipse-related eye damage as a result of looking directly at the sun without proper eye protection.

Use only authentic, certified protection

You should never look directly at the sun with unprotected eyes, whether there is an eclipse or not. And don’t trust ordinary sunglasses to protect you. They won’t, no matter how dark they are. Not even if you wear multiple pairs. Homemade filters of any kind should also not be trusted.

To view the sun safely, you need special-purpose solar filters, such as “eclipse glasses” or handheld solar viewers. The price of these can range widely, but many of the options are very inexpensive. The critical thing is to make sure you buy from a reputable manufacturer. There are companies selling counterfeit products that do not meet ISO 12312-2 standards. As a result, the AAS advises against searching for eclipse glasses on the internet and buying whatever pops up in search results. Instead, see the list of reputable vendors that AAS has compiled.

Always read the instructions

Don’t neglect to read any instructions that come with your eclipse glasses or filters. There can be details you shouldn’t miss. If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld filter in front of them. After looking at the sun, turn away before removing your glasses. Never remove them while looking at the sun. Always closely supervise children.

Note that solar filters should never be used with telescopes, binoculars, cameras or other optical devices. These devices require specially designed filters. If you’re uncertain about the safety of a filter, don’t use it. If you have an appropriate filter, note that it must be attached to the front of any telescope, binoculars, camera lens or similar viewing instrument. Solar filters provided with inexpensive telescopes and designed to thread into or fit over eyepieces are not safe. Throw them away.

Always inspect your glasses or filters before use

Always inspect your eclipse glasses or handheld filters before use. If they are torn, scratched, punctured or otherwise damaged in any way, throw them out. Also check the expiration date as filters are composed of materials that can degrade over time.

Be careful about cleaning your eclipse glasses or handheld filters. If the manufacturer has provided a cloth for cleaning, that’s safe to use. So are soft, nonabrasive tissues or cloths. But do not use wet wipes, baby wipes, water, glass cleaner, or any other liquids to clean cardboard eclipse glasses or handheld filters. If the cardboard gets wet, it will swell and likely detach from the lenses.

What if you don’t have eclipse glasses or filters?

If you don’t have eclipse glasses or a handheld filter, you can view the eclipse indirectly through a pinhole viewer. This simple device lets you project an image of the sun onto another surface, like a piece of paper or a wall. Such an image of the sun is safe to look at. NASA provides instructions on how to make and use a pinhole projector.

A welding filter with a shade number of 13 or 14 can also be used to view a solar eclipse, but note that the image will be green rather than yellow-orange or white. Do not use adjustable and/or auto-darkening welding helmets or similar products.

What happens if you do look at the sun during an eclipse?

When exposed to intense sunlight as during a solar eclipse, the cells in your retinas can be damaged. The condition is called “solar retinopathy” or "eclipse blindness." Symptoms can appear within a few hours or a few days. They can include:

  • Blurry vision
  • Reduced acuity
  • Sensitivity to light
  • A blind spot in one or both eyes
  • Changes in the way you see colors 
  • Distortion of shapes or objects
  • Headaches

If you notice changes in your vision after viewing a solar eclipse, see an eye doctor promptly.

Remember skin safety, too

If you’re watching an entire eclipse, you may be in direct sunlight for hours. Remember to wear sunscreen and protective clothing to prevent damage to your skin.

What about animals?

Fortunately, there’s no need to worry about your pets or any animals in the wild when it comes to a solar eclipse. Animals don't normally look up into the sun. However, they might be made uneasy by the darkening sky and the accompanying drop in temperature. If you have concerns, keep your pets indoors.

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Ophthalmology specialists at Lehigh Valley Health Network (LVHN) have a passion for helping people see the world more clearly. From routine eye exams to intricate cataract surgery, we care for people with a wide range of routine and complex eye concerns, at three convenient locations.

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