If the Sun Is 93 Million Miles Away, Why Can’t We Look Directly at It?
Regardless of where you observe the eclipse, it’s important not to look directly at the sun with the naked eye. To understand why, think of a child using a magnifying glass outside to burn holes in paper. “Focusing the sun’s rays on a single point creates a lot of energy,” Van Gelder said. And the lens in your eye is about four times as powerful as the type of magnifying glass a child might play with, Van Gelder said.
It’s thought that this damage happens when photons (light particles) create free radicals, which are highly reactive molecules that can “poison” cells and kill them, Van Gelder said. The damage occurs in the fovea, a spot in the retina that is responsible for sharp, central vision. As a result, patients with solar retinopathy may have blurry vision or a central blind point in their eyes, according to the AAO.