Keeping Your Eyes Safe During a Solar Eclipse
Why a Solar Eclipse Can Damage Your Eyes
The sun emits ultraviolet, visible, and infrared light that can burn the light-sensitive cells in your retina. According to the AAO, looking at an uneclipsed or partially eclipsed sun without proper protection can cause solar retinopathy, a condition that may lead to permanent vision loss.
Your retina has no pain receptors. You can sustain serious damage without feeling any discomfort during the exposure. Many people do not realize they have injured their eyes until hours later, when they notice blurred or distorted central vision.
According to the AAO, solar retinopathy may not cause immediate pain, which is why injuries often go unrecognized until you lose vision. A burn that takes seconds to occur can affect your sight for months or permanently.
During a partial eclipse, enough sunlight remains to cause retinal damage even though the sky appears darker. Your pupils dilate in the reduced light, allowing more harmful radiation to reach the back of your eye.
Many people assume the dimmer sun is safe to glance at. The visible brightness drops, but the UV and infrared output stays high enough to injure retinal tissue.
The AAO stresses that you must use certified solar filters during every phase of a partial eclipse. Only during the brief period of totality in a total solar eclipse can you view the sun without protection.
According to the AAO, during the brief period of totality in a total solar eclipse, you can view the sun without protection. Totality is the short window when the moon covers the sun and the corona becomes visible.
Totality lasts only a few minutes at most, and it ends abruptly. You must put your eclipse glasses back on the instant any sunlight reappears at the edge of the moon.
If you are in the path of a partial eclipse rather than a total eclipse, there is no safe moment to look at the sun without a certified filter.
Safe Ways to Watch an Eclipse
According to the AAO and NEI, the only safe way to look at the sun during an eclipse is through special-purpose solar filters that meet the ISO 12312-2 international safety standard. These are sold as eclipse glasses or hand-held solar viewers.
According to the AAO, eclipse glasses must come from reputable vendors certified to ISO 12312-2. Counterfeit eclipse glasses can look identical to certified ones but fail to block enough radiation. Check the manufacturer name and the ISO certification number printed on the glasses before you use them.
Inspect your eclipse glasses before each use. Discard any pair that has scratches, punctures, or peeling film. Damaged filters may let concentrated sunlight through to your eyes.
According to the AAO, the only safe method for viewing a solar eclipse without certified filters is indirect projection with your back to the sun. A pinhole projector creates a small image of the eclipse on a flat surface without requiring you to face the sun.
You can build a simple pinhole projector with two pieces of cardboard. Punch a small hole in one piece, hold it up to the sun behind you, and watch the projected image on the second piece held in front of you.
Tree canopies create natural pinhole projectors. During an eclipse, you may see crescent-shaped images of the sun scattered on the ground beneath leafy trees.
According to the AAO, ordinary sunglasses, even very dark ones, are not safe for direct solar viewing. They do not block sufficient UV and infrared radiation to protect your retina.
According to the AAO, looking through an unfiltered camera, telescope, binoculars, or smartphone camera while wearing eclipse glasses is still dangerous. Concentrated solar rays can destroy the filter and damage your eye. Only use these devices with a proper solar filter attached to the front lens.
Homemade filters, smoked glass, exposed film, and stacked sunglasses are all unsafe. None of these materials meet the ISO 12312-2 standard required for safe solar viewing.
Recognizing Solar Retinopathy After an Eclipse
Solar retinopathy symptoms often show up several hours after unsafe sun exposure. You may notice a dark or blind spot near the center of your vision, blurred vision, distorted shapes, or changes in the way colors appear.
Some people experience a mild version with a small central blind spot that fades over weeks. Others sustain permanent damage that affects reading, driving, and recognizing faces.
The severity depends on how long you looked at the sun and how much radiation reached your retina. Even a few seconds of unprotected viewing can cause noticeable injury.
Your eye doctor uses optical coherence tomography (OCT) and fundus photography to examine the macula (the central part of the retina) for solar damage. These imaging tests reveal disrupted retinal layers that correspond to the burn site.
Early imaging may show subtle changes even before you notice visual symptoms. If you viewed an eclipse without proper protection, schedule an exam within a day or two regardless of how your vision feels.
Your doctor monitors your recovery over weeks to months. Some patients regain most of their central vision as the retinal cells heal, while others retain a permanent blind spot.
No proven medical or surgical treatment exists for solar retinopathy. The retinal cells must heal on their own over time. Your eye doctor monitors your progress and checks for complications.
Most patients with mild solar retinopathy see improvement within a few weeks to months. Severe cases may result in lasting central vision loss. No eye drop, medication, or laser procedure can speed up retinal recovery from solar burns.
The best treatment is prevention. Using certified solar filters every time you view an eclipse protects you from an injury that no doctor can reverse.
Eclipse Eye Safety Questions
Pointing your phone at the sun without a solar filter can damage the camera sensor, and the bright image on your screen may encourage you to look at the sun. Attach an ISO 12312-2 solar filter over the phone lens if you want to photograph the eclipse safely.
Children need the same ISO 12312-2 certified glasses as adults. The key difference is supervision. Young children may remove their glasses to peek at the sun or wear them wrong, so an adult should watch them during the entire eclipse.
Check for the ISO 12312-2 label, the manufacturer name, and an address printed on the glasses. Buy from vendors listed by recognized astronomical organizations. If the glasses let you see anything other than the sun or a very bright light source, they may not be safe.
No. Windshield glass blocks some UV light but not enough to protect your retina during direct solar viewing. You still need certified eclipse glasses or a solar filter rated to ISO 12312-2.
Many people with mild solar retinopathy recover most of their vision within weeks to months. Severe damage can cause a permanent central blind spot. See your eye doctor as soon as possible after unprotected solar exposure for an accurate assessment.
Solar eclipses occur two to five times per year, but total eclipses visible from any given location are rare. The 2024 AAO patient guidance encourages everyone to keep a pair of certified eclipse glasses ready for future events.
Protect Your Eyes at Every Eclipse
Keep a pair of ISO 12312-2 certified eclipse glasses in a safe place and inspect them before each use. Talk to your eye doctor if you have any concerns about your vision after viewing a solar event.