We’ve all been told by our parents to never look directly at the Sun. But why? What is it about the Sun that damages our eyes so much? To answer that question, first we need to talk about the electromagnetic spectrum.
The light that our eyes can see is referred to as visible radiation. Different colors represent different wavelengths of light, and when white light passes through a prism (i.e. the album art for Pink Floyd’s The Dark Side of the Moon), the different wavelengths emerge from the prism at different locations. When we see a rainbow, we are seeing the white light from the Sun being refracted through water vapor in the atmosphere. The water vapor acts as a prism, bending the white light into the ROYGBIV colors we see.
The Sun also produces radiation outside the bounds of the visible spectrum. Ultraviolet radiation and high energy blue light cause retinal damage across all species. Ultraviolet rays stimulate growths in the eye known as pingueculae and pterygia. These growths can cause distorted vision, and issues with the cornea in the eye. If you look directly at the Sun, your eye will receive a very high dose of UV radiation. High doses cause something called photokeratitis, which is a very painful inflammation of the cornea. Severe photokeratitis is also known as snow blindness. Snow blindness causes temporary vision loss for 24-48 hours. The term snow blindness comes from the most common cause of the injury: unprotected eyes looking at snow. Snow is extremely reflective, and bounces the UV radiation right back up into your eyes.
During the eclipse the UV radiation will creep out from behind the Moon. Even if the Sun is 99% covered enough UV radiation will make it around the Moon to hurt your eyes. This is why it’s very important to have solar eclipse glasses on during the entire total solar eclipse except for during the few minutes of totality. To buy solar eclipse shades to protect your eyes visit our online store here!