What to look for in solar eclipse glasses

Workers at American Paper Optics in Bartlett, Tenn., work amid stacks of thousands of pairs of paper eclipse viewing glasses. APO is the world’s leading manufacturer of the glasses, which millions of people will use to view the April 8 eclipse.

A crowd reacts to the view of a partial solar eclipse as it peaks at over 70% percent coverage on Aug. 21, 2017, in New York.

A solar eclipse rolls through the Pittsburgh area on Aug. 21, 2017.