Although ultraviolet radiation is invisible to the human eye, most people are aware of the effects of UV through sunburn and tanning beds. A great deal (>97%) of mid-range ultraviolet (almost all UV above 280nm and most above 315nm) is thankfully blocked by the ozone layer, because it would cause much damage to living organisms if it penetrated the atmosphere. A small fraction of the overall UV light does penetrate and this is responsible for sunburn and the formation of vitamin D in all organisms that produce this (including humans). The UV spectrum thus has many effects, both beneficial and damaging to human health including the eyes.
http://www.hammondopticians.co.uk/wp-content/uploads/2015/09/hammond-opticians-enfield.png 0 0 hammondopticians http://www.hammondopticians.co.uk/wp-content/uploads/2015/09/hammond-opticians-enfield.png hammondopticians2013-04-24 10:17:072013-04-22 13:30:53Dangers of Ultraviolet Radiation to Children's Eyes
High intensities of UV light are hazardous to the eyes, and exposure can cause a painful acute condition known as Welders Flash (arc eye) and has been linked to longer term eye damage including cataracts, macular degeneration, pingueculae and pterygia as well as photo keratitis that can cause temporary vision loss.
UV light is absorbed by molecules known as chromophores, which are present in eye cells and tissues. Chromophores absorb light energy from the various wavelengths at different rates – a pattern known as the absorption spectrum. If too much UV light is absorbed, eye structures such as the cornea, the crystalline lens and the retina can be damaged.
To protect your eyes from harmful solar radiation, sunglasses with 100% UV blocking should be used. Frames with a close-fitting wraparound style provide the best overall protection because they limit how much incident (stray) sunlight reaches your eyes from above, below (reflected) and from around the side of your sunglass lenses.
For even greater protection, polarised lenses help reduce the ill effects of glare caused by polarised light. This happens when light is reflected off shiny surfaces like snow, water and sand.
Our eyes are ten times more sensitive to UV light than our skin and children’s eyes are at the greatest risk of suffering from UV damage. Large pupils and clearer crystalline lenses result in up to 70% more UV light reaching the child’s retina compared to an adult. Therefore, it is especially important for kids to protect their eyes from the sun rays.
Experts say that nearly 50% of our lifetime exposure to UV rays may occur by the age of 18, particularly as many children spend significantly more time outdoors than the average adult.
According to the Eyecare Trust, "Ideally all children – and adults – should wear good quality sunglasses and a peaked hat when spending time outdoors. It is especially important for parents to safeguard their children’s eyes when they are playing on the beach or by water, where the effect of the reflected light is much greater."
Children’s sunglasses should always carry the European Standard CE mark or the British Standard BSEN 1836:1997 as this guarantees that the sunglasses offer a safe level of UV protection. ‘Toy‘ sunglasses which may look very cute, generally do not provide such comprehensive cover from UVA & UVB radiation and can actually cause even more damage because the tinted lenses dilate (increase in size) the pupils, thereby allowing more UV light to enter the eye.