A 20-second look at the sun cost Lou Tomososki much of the sight in his right eye. So he has some words of advice for people tempted to look at the upcoming solar eclipse: "You'll be sorry!"
He was a teenager when his science teacher told the class about a solar eclipse happening that afternoon. He thought nothing of it at the time, he said. But it left him with a pea-sized blank spot in his right eye.
On Monday, August 21, 2017, a total solar eclipse will be visible in totality within a band across the entire contiguous United States; it will only be visible in other countries as a partial eclipse. The last time a total solar eclipse was visible across the entire contiguous United States was during the June 8, 1918 eclipse.