Prof. Chou explained that long-term damage from a solar eclipse is very rare and occurs under certain conditions.
The symptoms may not show up until 12 hours after viewing the eclipse, according to an NPR interview with Ralph Chou, professor emeritus of optometry and vision science at the University of Waterloo in Ontario, Canada.
He looked at it for just 20 seconds, he estimates.
Changes to vision or light sensitivity may not be noticeable until the following day or longer, he added. The warnings were all over social media, on the news, and spread by word of mouth, urging you to get special eclipse glasses or make a viewing device using a box and some tinfoil.
The only way to safely look at an eclipse is through specially designed solar glasses, viewers and lens filters to block the sun's harmful rays, eye experts said. Damage can either be temporary or permanent, and there's no pain associated with it.
But that is all it takes to cause eye damage: People are now reporting pain in their eyes.
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Just after the eclipse concluded in the United States, searches for "eyes hurt" soared, as you can see in the graph below. "When you look directly at the sun, the intensity of the light and the focus of the light is so great on the retina that it can cook it", Dr. Christopher Quinn, president of the American Optometric Association, told CNN.
If you didn't use the glasses, that could be another story.
Missy Guyer, office manager at Midwest Eye Consultants, said that while the office received a flood of phone calls Tuesday from people looking for eclipse-proof glasses, she hasn't talked with anyone anxious about eye damage. The symptoms largely depend on the type of injury at the back of the eye. However for some watchers, questions over eclipse glasses, and their own vision remain.
"Staring at the sun normally is bad whether an eclipse is going on or not", Orge said.
Vision can be restored over several months to a year, but in 50% of cases, vision loss is permanent.
These symptoms can include blurry vision, a central blind spot in one or both eyes, increased sensitivity to light, distored vision or changes in teh way you see color.