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Prolonged optical exposure to sunlight, especially intense ultraviolet light, may be linked to cortical cataracts, [50] [15] and high levels of visible light is maybe linked to macular degeneration. However, significant daily exposure to bright light may be necessary for children to avoid myopia (nearsightedness). [51]
In the average human adult it is estimated that 50 to 70 billion cells die each day from apoptosis. One of the largest promoters of apoptosis is exposure to ultraviolet (UV) light. While UV light is essential to human life it can also cause harm by inducing cancer, immunosuppression, photoaging, inflammation, and cell death. [1]
Does the sun cause skin cancer: up 170%. What causes cancer in sunscreen: up 160%. ... Wearing high quality sunglasses that offer 100 percent UV protection from all UV light.
Fluorescent light bulbs and tubes internally produce ultraviolet light. Normally this is converted to visible light by the phosphor film inside a protective coating. When the film is cracked by mishandling or faulty manufacturing then UV may escape at levels that could cause sunburn or even skin cancer. [53] [54]
Less energetic radiation, such as visible light, only causes excitation, not ionization, which is usually dissipated as heat with relatively little chemical damage. Ultraviolet light is usually categorized as non-ionizing, but it is actually in an intermediate range that produces some ionization and chemical damage.
Exposure to non-ionizing ultraviolet light is a risk factor for developing skin cancer (especially non-melanoma skin cancers), sunburn, premature aging of skin, and other effects. Despite the possible hazards it is beneficial to humans in the right dosage, since Vitamin D is produced due to the biochemical effects of ultraviolet light.
The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. [2] [10] The UV light may be from the sun or other sources, such as tanning devices. [2] Those with many moles, a history of affected family members, and poor immune function are at greater risk. [1]
UV-B treatments for skin conditions such as psoriasis, vitiligo, and atopic dermatitis are administered in very low doses, often lasting only a few minutes or less than a minute when using lamps emitting 290-300 nanometer light. This low dosage does not significantly increase the risk of skin cancer, making UV-B phototherapy a safe treatment ...