Sunlight stimulates the release of dopamine from the retina, which in turn appears to prevent the eyeball from growing too oblong. Indoor and outdoor light are totally different beasts. Even on overcast days, outdoor light is ten times brighter and covers vastly more of the light spectrum. Educators are scrambling to come up with solutions, including installing full-spectrum indoor lights and glass ceilings over classrooms. There’s a better solution: go outside.