Glare and eye strain

This office area with large panes shows how much glare there could potentially have been if the glass had not been treated to reduce the glare and heat allowing occupants to comfortably work without eye strain or overheating.

Bright sunlight can make it difficult to focus or see, and this can cause visibility issues like eye-strain, migraines, general discomfort and other problems. And the older you get, the more sensitive your eyes become to the potential glare associated with sunlight.