'Snow blindness (Niphablepsia) is a painful condition, typically a keratitis, caused by exposure of unprotected eyes to the ultraviolet (UV) rays in bright sunlight reflected from snow or ice. This is especially a problem in polar regions and at high altitudes, as with every thousand feet (approximately 305 meters) increase in elevation, the intensity of UV rays goes up five percent.The problem is also related to the condition arc eye sometimes experienced by welders.Snow blindness is akin to a sunburn of the cornea and conjunctiva, and may not be noticed for several hours from exposure. Symptoms can run the gamut from eyes being bloodshot and teary to increased pain, feeling gritty and swelling shut. In very severe cases, snow blindness can cause permanent vision loss.'- wikipediaMattingly was sure the "disappearance" of the stars was due to his gold visor . The doctors had advised him to leave the reflector down, LEST HE BE EXPOSED TO HARMFUL RADIATION, but he couldn’t stand it anymore."" *He blinked the visor open just long enough* for the universe to show a familiar face: There they are! "A Man On The Moon - P.492 A.Chaikin From Dr Phil Plaits very own review of Deep Impact at BadAstronomy dot com."Bad: One of the away team astronauts is blinded by the sunlight . Good: I suspect this may not be totally inaccurate; I am not sure how close The Comet was to the Sun when this happened. I would expect NASA to give them sun visors, however, or build in a UV block to the visor. They were on the dark side of The Comet, after all, so they would not have had their sun visors down, and he was admittedly too panicked to think of snapping it down. Still, a moment's exposure should not have so badly burned his face. That was added for drama." Tribute to Apollo 17's Jack 'Crazy Horse' Schmitt who wasn't the slightest bit concerned about potenial damage to his eyes or burns to his face because he wasn't on the Moon.ALL NASA FOOTAGE USED IN THIS FILM IS PUBLIC DOMAIN.THE...