Sunlight onbthe retina helps form Serotonin. Has to be direct or through eyelids, not through any glass. A doctor told me a leading theory about how outside ti

Sunlight onbthe retina helps form Serotonin. Has to be direct or through eyelids, not through any glass. A doctor told me a leading theory about how outside time helps is by shifting focus from faraway to close and back. So look at things up at top of buildings or upper canopy of trees then into some nearby detail back and forth my. It's a kind of excersize for eye focus. My son's eyes have held close to 20/20 into High School. We have good views for this from our apartment. I've taught him to check cornices and close details as he walks to and from school.