An Optometrist’s Guideto Viewing a Solar Eclipse
When the moon crosses paths between the earth and the sun, one of nature's most spellbinding phenomena occurs—a solar eclipse. While fascinating to observe, gazing directly at an eclipse without proper protection can cause irreparable damage to your eyes.
In this guide, we offer optometrist-approved insights on how to view a solar eclipse without compromising your precious sight.
Quick Overview of Eclipses
The different orbits and motions of the sun, moon and earth determine when and where eclipses occur.
During a solar eclipse, the moon moves directly between the sun and the earth, blocking the sun’s light. However, not all solar eclipses are the same! An annular solar eclipse happens when the moon doesn't fully cover the sun’s disk, leaving a bright ring around it. For this reason, such eclipses are often called "ring of fire" eclipses. A total solar eclipse happens when the moon completely blocks the sun for several minutes.
During a lunar eclipse, the sun, the earth, and moon all line up—with the earth in the middle—and the moon is in the shadow on the earth’s dark side. As the moon moves into the earth’s shadow, it appears dimmer and looks like it has turned red. Lunar eclipses that are visible without a telescope can be either partial or total. Lunar eclipses can be viewed without special eye protection.
How and Why Viewing a Solar Eclipse Can Hurt Your Eyes
While visually spectacular, solar eclipses can hurt your eyes and pose serious risks if viewed improperly. Staring directly at the sun during an eclipse, even very briefly, can lead to solar retinopathy—also known as retinal burns—which is permanent damage to the retina from exposure to harmful radiation.
Your eyes’ retinas contain light-sensitive cells that convert sunlight into signals for the brain, providing sight. Solar ultraviolet (UV) and visible radiation can severely damage these delicate photoreceptor cells, resulting in vision loss in central visual fields—including blind spots and other visual distortions.
Viewing even a thin crescent of sunlight peering out from behind the moon during a partial solar eclipse poses serious risks. Despite most of the sun being covered, that slim glowing edge still emits dangerous ultraviolet and visible radiation that can irreversibly damage your retina in even a second of unprotected viewing.
The harm occurs silently, with no sensation of pain. You likely won't realize your vision has been compromised until a few hours after the eclipse, when symptoms like blurry vision and blind spots emerge.
How to Protect Your Eyes from a Solar Eclipse: Dos and Don’ts
Specialized eyewear is critical for safely observing an eclipse. Regular sunglasses do not adequately shield your eyes from hazardous solar rays. Instead, it’s imperative to choose solar filters or specialized eclipse glasses that meet strict safety standards, blocking 100% of dangerous emissions.
What Not to Wear During a Solar Eclipse
Eye doctors hear two common questions when solar eclipses are about to occur:
"Can I use sunglasses for a solar eclipse?"
"Can I use polarized glasses for a solar eclipse?"
The answer to both questions is an emphatic "No".
Never rely on regular sunglasses or polarized lenses for eye protection when viewing a solar eclipse. These glasses do not fully filter out the dangerous ultraviolet and visible radiation emitted during an eclipse.
You may be tempted to snap a quick picture of the eclipse for future viewing. However, looking at the sun, even through your camera or phone screen, can have the same negative effects on your eye health. Therefore, never use an unfiltered camera, smartphone or telescope to photograph or observe an eclipse, because they concentrate the sun’s rays onto the image sensor or your eyes, amplifying the risk of damage.
Specialized Solar Eclipse Viewing Glasses
To watch a solar eclipse safely, you must use specially-designed solar filters that completely block harmful radiation. Solar viewing glasses are specially designed with filters that block 100% of hazardous ultraviolet and infrared radiation, allowing safe, direct viewing of a solar eclipse. Only use eclipse glasses officially certified to meet the ISO international safety standard, which guarantees adequate eye protection.
Remember to inspect glasses carefully before putting them over your eyes. Look for scratches or damage that could impair their effectiveness. Undamaged, certified solar viewing glasses are essential for witnessing an eclipse because they shield your vision from exposure to damaging rays.
Handheld solar viewers work similarly, using solar filters to block harmful rays. Hold the viewer up to your eyes to see the eclipse safely. Again, confirm that the viewer meets the ISO standard and is in pristine condition for complete protection.
NASA provides a selection of valuable recommendations and guidelines for observing the eclipse in a safe and informed manner.
How to View a Solar Eclipse Safely
Witnessing a solar eclipse is an experience we hope everyone can enjoy during their lifetime, but observing one safely requires caution and proper eye protection.
Whether you have observed an eclipse or not, being proactive about your eye health is critically important. Schedule a comprehensive eye exam so we can assess your vision health and help safeguard it for future eclipses—and your everyday life. With the right eye protection and care, you can enjoy these incredible celestial events for years to come.
From the Newsroom
Information received through Visionworks® content is for informational purposes only and does not constitute medical advice, medical recommendations, diagnosis, or treatment. Always seek the advice of your eye doctor, physician, or other qualified health provider with any questions you may have regarding a medical condition.
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