People may risk serious eye damage if they look at the partial phases of the upcoming total solar eclipse without proper protection.
The “only time it’s safe to look directly at the event” is during “totality,” when the sun is blocked in its entirety by the moon, Dr. Ralph Chou, an eclipse watcher and professor emeritus at the School of Optometry & Vision Science at the University of Waterloo in Ontario, told Fox News.
Not everyone will be able to see the total solar eclipse, though many people may be able to see a partial eclipse.
Chou emphasized that if you’re in an area where only a partial eclipse can be viewed, there’s never a safe time to look straight-on at the sun.
Eclipse blindness “describes the injury that occurs when a person looks at the sun without a protective filter during the eclipse,” Chou said.
If someone watches the sun without protection, light hits the fovea — a part of the retina which helps humans with fine detail and color vision — and “overwhelms with the sheer volume of light coming in,” he said. Chou likened the intense amount of light hitting photoreceptors to ocular “force-feeding.”
“Structures that respond to the light break down,” and they begin to release oxidizing chemicals like peroxide “that will attack what’s left of the cell,” in what’s known as a photochemical injury, Chou said. If enough damage is accumulated, the cell’s function will be impaired and it may eventually die.