Why Direct Viewing Is Dangerous
Looking at a solar eclipse without protection exposes your eyes to intense solar radiation. The sun emits visible light, infrared, and ultraviolet energy that can burn the retina. This injury, called solar retinopathy, can occur in seconds and often causes painless, permanent blind spots.
Why the Eye Focuses the Damage
The eye's lens concentrates sunlight onto a small area at the back of the eye. During an eclipse, the pupil dilates because the scene appears darker, allowing more light in. This combination increases the amount of energy hitting the retina, raising the risk of thermal and photochemical burns.
Safe Viewing Methods
Use eclipse glasses that meet the ISO 12312-2 international safety standard or handheld solar viewers. Inspect filters for scratches before use, and never look through unfiltered cameras, telescopes, or binoculars. For indirect viewing, project the sun's image through a pinhole projector. More guidance is available from NASA at https://science.nasa.gov/eclipses/safety/
