Though closing your eyes during UV exposure does block out some visible light, the human eyelid fi lters less than 25 percent of damaging
UV rays. The very thin skin and underlying membrane of the eyelid do not keep
UV rays from penetrating the eye, potentially burning the cornea and doing more severe damage to the lens and retina. In addition to night vision loss, excessive unprotected UV light exposure will also damage color vision and can even result in cancer of the eyelids.