Solar eclipse 2027 › Eye safety
Watching a solar eclipse safely: how retinal damage happens
Looking directly at the Sun during a partial eclipse can injure the retina. The damage does not hurt while it is happening. Changes in vision may appear hours after the exposure, when it is too late to undo the viewing decision.
What solar retinopathy is
Solar retinopathy is retinal injury caused by looking directly at the Sun. It can affect the macula, the area used for reading, recognising faces and seeing fine detail in the centre of the visual field.
The retina does not produce a pain warning as this injury occurs. During an eclipse the surroundings grow dimmer and glare may feel reduced. That can make it easier to keep looking, but it does not make the visible part of the Sun safe.
Why a Sun that is 99% covered is still unsafe
The uncovered photosphere remains intense enough to harm the retina. A coverage figure describes how much of the solar disc is hidden. It is not a measure of how much danger has been removed.
Outside the path of totality there is no filter-free viewing period at any time. Almería city, for example, reaches 99.99% coverage but is not in totality. Eye protection must remain in place throughout the eclipse there.
The sole exception: complete totality
You may look with the naked eye only inside the path of totality, and only while the solar disc is completely covered. This is the sole exception to the filter rule. It does not apply during a partial or annular eclipse.
- Before totality: keep compliant eclipse glasses on while any bright part of the solar disc remains visible.
- At the start of totality: remove the glasses only after the last points of photospheric light have disappeared and the disc is completely covered.
- At the end of totality: replace the glasses immediately at the first point of returning light, including Baily's beads or the diamond ring.
Do not wait for discomfort. There may be none. The first returning point of light ends naked-eye viewing.
Outside the path, the eclipse remains partial from beginning to end and this exception never exists. Check the path and viewing locations before relying on any totality plan. In Spain, totality occurs between 10:45 and 10:52 CEST where the observing point is inside the path.
Symptoms can appear hours later
Possible symptoms include a dark or blurred patch in the centre of vision, difficulty reading, straight lines appearing distorted, altered colour vision or a persistent after-image. They may begin hours after the exposure rather than during it.
Vision seeming normal immediately afterwards does not rule out injury. The severity and course can vary.
What to do after unsafe exposure
If you notice a change in vision after looking at the Sun, seek prompt assessment from an eye-care professional and explain the exposure. Do not wait for pain as confirmation, and do not rely on a home test.
This page provides general safety information. It does not diagnose an eye condition and does not replace individual medical advice.
Filters and methods that are safe
- Eclipse glasses compliant with ISO 12312-2: this is the same internationally recognised standard used for direct solar viewing filters. The viewer must be intact and come from an identifiable manufacturer.
- Pinhole projection: a small hole projects an image of the Sun onto another surface. Look at the projected image, never through the hole.
- Front-mounted instrument filters: binoculars and telescopes require a suitable solar filter secured over the front of every objective.
Put eclipse glasses on before looking up. If they do not fit securely, use an indirect method. Supervise children throughout every partial phase.
What does not protect your eyes
Sunglasses are not solar filters, however dark they appear. Smoked glass, exposed film, old X-ray material, improvised plastics, clouds and fog are also unsafe for direct viewing.
A phone screen does not protect someone who is also looking at the Sun around the device or through an optical viewfinder. A camera can also be damaged when pointed at the Sun without an appropriate front-mounted solar filter.
Binoculars, telescopes and cameras
The solar filter must always be in front of the objective. Never place a solar filter on the eyepiece. The instrument concentrates sunlight before it reaches that point, which can damage the filter and expose the eye.
Do not wear eclipse glasses while looking through unfiltered binoculars or a telescope. The concentrated light can damage the glasses and the eye. Each objective needs a filter designed and secured for that instrument.
For direct viewers, use the inspection steps in the eclipse-glasses guide. For local timing, consult the Spain times page.
Last updated: 14 August 2026 · Editorial team