Vitamin D produced by ultraviolet stimulus from the sun, it helps skin to produce vitamin D up to 1000 IUs per minute, not juts skin Vitamin D give more positif health effects for human body. This vitamin has regulatory roles in calcium metabolism, positif effects for nervous system function, bone growth and maintain for bone density. Vitamin D gives cell proliferation, insulin secretion, blood pressure and immunity. Lack of Ultraviolet radiation may caused little production for Vitamin D, but too much Ultraviolet radiation can cause a direct DNA damage, sunburn and skin cancer. Apropriate amount of Ultraviolet depend on skin color that leads to a limited amount on direct DNA damage. Its recognizing and repairing by the body, and more its increased by melanin production.
Ultraviolet is invisible, but it can feel by the direct effects on sunburn or undirect by the painful condition, so it has influence on human health. Ultraviolet found in sunlight and classified as an non-ionizing radiation. But high intensive of Ultraviolet light are danger for the eyes, its driven to catracts, pterygium, and pinguecula formation. Some people do something for that, many has suggest to use sunglasses or eyeglasses to have some protection. Because some plastic lenses give more protection than glass lenses, it understanding by glass is more transparent but the plastic lenses has not. In many cases you should have another option such as interchangeable lenses.
In this problem on global warming, may not such as wasted ion, or dust, on micro type, but also lights has direct effects for the eyes. You should use mask or something to protect eyes from being dry with many sunglasses which can buy or find on the store. Not juts for health to keep, but any style can give you more and more beneficial for your days. If unsure to buy, may look at this sunglasses store on the internet, which will you guide to find the apropriate sunglasses for you at the assured and secure transaction. For daily lifestyles may take a look for Boys' Sunglasses, or Girls' Sunglasses, in term of Sun Protection.