Question: why is it bad for your eyes to look into the sun?

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  1. @boron: Basically, the moment you begin looking at the sun, you start to develop a sunburn on your eyeball. Of the three types of light that the sun produces—visible, infrared, and ultraviolet—UV is the most damaging to structures within the eye, especially when reflected off sand, snow or water. The cells of the cornea, the transparent outer layer of the eye, will blister and crack when overexposed to UV light. It’s a lot like a normal sunburn. Symptoms of this condition, known as photokeratitis, dobn’t happen immediately, so you might not realise what’s happened until a few hours after the damage has occurred. The response to the damage is shown by excessive tearing, tissue inflammation, and the feeling that you’ve rubbed your eyes with fine grit sandpaper. Luckily, the effect is almost always temporary, dissipating within 36 hours, and can be prevented by wearing UV-rated eye wear.

    Look steadily at the sun for a little longer—like for a full half hour—and you can cause damage to the retina. This collection of light-sensitive cells located at the back of the eye transmits images to your brain. Solar retinopathy, as the damage is known, may not be painful like photokeratitis—but the results can be permanent. With enough damage to the retina, staring at the sun can leave you partially blind.

    Permanent, complete blindness can also occur from staring at the sun over a long term. The eye’s lens can be damaged from too much UV light, resulting in cataracts and invasive tissue growth . As UV-induced cataracts advance, they can obscure a patient’s vision. If left untreated, they can eventually cause blindness.

    So, staring at the sun without proper eye protection is a clearly bad idea, but doing the same through a telescope or binoculars is just plain dumb. As a magnifying glasses fries an ant, these devices concentrate the suns rays into destructive points, causing immediate photochemical and thermal damage. The UV can literally cook your eyes out of your head, destroying rod-and-cone structures and potentially resulting in permanent blindness.

    More info:


  2. Hmmm, what she said.