
A tourist watches a solar eclipse through eclipse-viewing glasses in 2009 in Varanasi, India.
The condition is called solar retinopathy, and it occurs when bright light from the sun floods the retina on the back of the eyeball. The retina is home to the light-sensing cells that make vision possible. When they're over-stimulated by sunlight, they release a flood of communication chemicals that can damage the retina. This damage is often painless, so people don't realize what they're doing to their vision.
Solar retinopathy can be caused by staring at the sun (regardless of its phase), but few people can stand to look directly at our nearest star for very long without pain. It does happen occasionally - medical journals record cases in which people high on drugs have stared at the sun for long periods of time, causing serious damage. Adherents of sun-worshipping religious sects are also victims. In 1988, for example, Italian ophthalmologists treated 66 people for solar retinopathy after a sun-staring ritual.














Comment: The perfect marriage, Big Pharma and DARPA: