During a solar eclipse, the sun behaves as it always does, and it is a myth that it emits more dangerous ultraviolet light rays during an eclipse. The amount of invisible ultraviolet (UV) light rays remains the same, but the solar eclipse limits the amount of visible light coming down to Earth. When there is limited light, the iris expands the size of the pupil to allow more light into the eye to see. The damage occurs because the eye is fooled by the celestial phenomenon and allows a potentially dangerous amount of UV light into the eye, which has the very real capacity to damage the retina.
Looking directly at the sun during an eclipse can cause permanent eye damage or severe visual loss, even when 99% of the Suns surface is obscured during the partial phases of a solar eclipse. The remaining crescent Sun is still intense enough to cause a retinal burn, even though illumination levels are comparable to twilight. Failure to use proper observing methods may result in permanent eye damage or severe visual loss.
The condition caused by staring at the sun is known as solar retinopathy. The sun damages the retina, which is the part of your eye that transmits information to the brain. Long exposure to the sun without proper protection will cause scarring of the retina from burns and lead to partial, or even permanent, blindness.
To safely view a solar eclipse, it is important to use proper observing methods. The only safe way to look directly at the sun is through specifically designed solar filters, which are used in both “eclipse glasses” or in solar eclipse viewers you hold up to your eyes. Regular sunglasses are not safe for viewing the solar eclipse. Make sure you purchase solar eclipse filters and glasses from reputable manufacturers, and you shouldn’t be able to see anything through an authentic solar filter except the sun or equally bright light, such as the reflection of sunlight off a mirror.
In summary, sun rays are harmful during an eclipse because the eye is fooled by the celestial phenomenon and allows a potentially dangerous amount of UV light into the eye, which has the very real capacity to damage the retina. To safely view a solar eclipse, it is important to use proper observing methods, such as specifically designed solar filters, and to purchase them from reputable manufacturers.
