UV Radiation

What you should know about UV radiation...

baby sunUltraviolet (UV) radiation is part of the electromagnetic spectrum emitted by the sun. UV radiation is categorised as UVA, UVB and UVC rays. Whereas UVC rays (wavelengths of 100-280 nm) are absorbed by the atmospheric ozone, most radiation in the UVA range (315-400 nm) and about 10 % of the UVB rays (280-315 nm) reach the Earth’s surface. Both UVA and UVB contribute benefits as well as threats to human health.

Both UVA and UVB cause damage to the skin, age it prematurely, and increase the risk of skin cancer. UVB is the chief culprit behind sunburn, while UVA rays, which penetrate the skin more deeply, are associated with wrinkling, leathering, sagging, and photoaging. They also exacerbate the carcinogenic effects of UVB rays, and increasingly are being seen as a cause of skin cancer on their own.

uv rays

Small amounts of UV are essential for the production of vitamin D in people, yet prolonged and overexposure may result in acute and chronic health effects on the skin, eye and immune system.  Sunburn is the best-known acute effect of excessive UV radiation exposure. Over the longer term, UV radiation induces inflammatory reaction of the eye, degenerative changes in cells of the skin, fibrous tissue and blood vessels leading to premature skin aging, photodermatoses and actinic keratoses.  In the most serious cases, skin cancer and cataracts can occur.

UV and Skin/Skin Colour

It is a popular misconception that only fair-skinned people need to be concerned about overexposure to the sun. While it is true that darker skin has indeed more protective melanin pigment and therefore lower incidence of skin cancer, skin cancers do occur with this group as well. This misconception is one reason darker-skinned people are usually diagnosed at a later, more potentially fatal stage, whereas most skin cancers are curable if caught and treated in a timely manner.

It is also important to note that the risks of UV radiation-related health effects on the eye and immune system, are independent of skin type.

Babies and children especially require special protection as they are at a higher risk of suffering damage from exposure to UV radiation than adults. A child's skin is thinner and more sensitive and even a short time outdoors in the midday sun can result in serious burns. Epidemiological studies have also shown that frequent sun exposure and sunburn in childhood set the stage for high rates of melanoma later in life. 

UV and Eyes

Without realizing it, we may expose our eyes to danger every day, simply by going outside. Over time, the sun’s rays can seriously damage the eyes and surrounding skin, leading to vision loss and conditions from cataracts and macular degeneration to eye and eyelid cancers.

Although the eyelid is designed to protect the eye, its skin is exceedingly thin and contains many fragile tissues that may be injured by UV light. Inside the eye, the lens and the cornea, both transparent, filter UV rays, but by doing so for many years, they may become damaged. This is especially true for the lens, which through years of UV absorption, turns yellowish and cataractous.

Children’s eyes differ from adults’ in that children’s ocular lenses cannot filter UV light and prevent it from reaching their retinas as effectively as adults’ ocular lenses. In simple terms, the lens inside a child's eye is clearer than an adult's lens, therefore enabling more UV to penetrate deep into the eye. This results in children’s retinas being exposed to more UV light and susceptible to retinal damage if they are not adequately protected. As UV exposure is cumulative, it is important to begin protection at an early age. Over a lifetime, damage from unprotected exposure to UV rays can lead to eye diseases and conditions that will affect the health of the eyes and vision.

UV and Eyes

Singapore's UV Index...

UV radiation levels vary substantially with time and place. Singapore, situated at the equator, is consistently in the highest UV Index band. 

Month J F M A M J J A S O N D
Singapore (1°N) 11 12 13 13 11 11 11 11 12 12 11 10

Presenting the UV International colour codes Baby Beachbums

Sources: http://www.who.int/uv/en/, http://www.skincancer.org/prevention/sun-protectionhttps://www.thevisioncouncil.org/content/uv-protection/kids