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Photic retinopathy. Photic retinopathy is damage to the eye 's retina, particularly the macula, from prolonged exposure to solar radiation or other bright light, e.g., lasers or arc welders. The term includes solar, laser, and welder's retinopathy and is synonymous with retinal phototoxicity. [ 1] It usually occurs due to staring at the Sun ...
Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense direct or reflected sunlight) or artificial (e.g. the electric arc during welding) sources. Photokeratitis is akin to a sunburn of the cornea and conjunctiva.
Underwater vision. Scuba diver with bifocal lenses fitted to a mask. Underwater vision is the ability to see objects underwater, and this is significantly affected by several factors. Underwater, objects are less visible because of lower levels of natural illumination caused by rapid attenuation of light with distance passed through the water.
In people with Cushing syndrome, “too much cortisol leads to a more rounded face, pinkish red cheeks, thinner skin with easy bruises, a puffy neck, and a worsening upper back hump,” Dr. Ghalib ...
Most people in the world depend on the sun to get vitamin D, [31] and elderly populations in low UVB countries experience higher rates of cancer. [32] There are not many foods that naturally have vitamin D. [33] Examples are cod liver oil and oily fish. If people cannot get sunlight, then they will need 1,000 IU of vitamin D per day to stay ...
Backscatter (photography) The backscatter of the camera's flash by motes of dust causes unfocused orb-shaped photographic artifacts. In photography, backscatter (also called near-camera reflection[ 1]) is an optical phenomenon resulting in typically circular artifacts on an image, due to the camera's flash being reflected from unfocused motes ...
We've all grown up thinking that sitting too close to the television is damaging to our eyes ... but that might not be the case. Technology spawns lots of confusion ... and a few affectionately ...
Health threats from cosmic rays are the dangers posed by cosmic rays to astronauts on interplanetary missions or any missions that venture through the Van-Allen Belts or outside the Earth's magnetosphere. [ 1][ 2] They are one of the greatest barriers standing in the way of plans for interplanetary travel by crewed spacecraft, [ 3][ 4][ 5] but ...