More specifically bright lights and sharp gradients on the retina stimulate the release of dopamine in the retina which blocks the elongation of the eye. http:

More specifically bright lights and sharp gradients on the retina stimulate the release of dopamine in the retina which blocks the elongation of the eye. http://www.nature.com/news/the-myopia-boom-1.17120 http://www.nature.com/news/the-myopia-boom-1.17120