Is it only the bright light that is dangerous when viewing the sun?

Actually, although filters and glasses do safely block the intense sunlight that is known to damage retinas, the infrared ‘heat’ from the sun can also make viewing uncomfortable as it literally warms the eye.  This is why staring at the sun for minutes at a time even with proper filters can still over-heat the tissues and fluids in the eye, and the consequences of this heating can be dangerous as well. To avoid this problem before totality takes place, try not to use your filters without frequently looking-away to cool your eyes. During totality, there is no adverse heating of the eyeball since the solar disk is not visible.