CBC News · Posted: Oct 02, 2015 4:23 PM EDT | Last Updated: October 3, 2015 ...

Blue-light blocking glasses, widely used to alleviate eye strain and enhance sleep, may not provide the expected benefits, according to a recent comprehensive analysis of 17 studies.

The most effective blue light glasses can filter as much as 35% of blue light. Some designs, particularly those with a sepia-toned print, can block almost all blue light rays (98%).