Which sunglasses to choose?
There's a lot to consider when picking new sunglasses. Do you want to go for designer shades, opt for the latest fashion in frames, or choose a shape that best suits your features?
Although all relevant considerations, the most important question to ask is: do they properly protect your eyes from the sun?
We've spoken to two experts about the need to choose wisely when it comes to sunglasses for your long term eye health.
Firstly, Dr Susan Blakeney, clinical adviser to the College of Optometrists:
What damage can the sun do?
Protecting your eyes from the sun is really important, not doing so may lead to a number of problems. The deeper structures of our eyes do have some built-in protection. However, ultraviolet rays may still damage the lens and the retina, which is the light-sensing tissue that forms the inner lining at the back of the eyeball.
Sun damage has been linked to the formation of cataracts, and may be linked to age-related macular degeneration (AMD), which is a major cause of blindness in the UK.
People who are outdoors a lot, or who live in sunny climates, are also more at risk of developing pterygia. These are benign growths on the surface of the eyeball. They are not cancerous, but they can be uncomfortable, and might affect your vision.
Does the shape, fit and size of the sunglasses matter when it comes to protecting eyes?
It is important to ensure that whatever sunglasses you choose fit your face well and relatively snugly so that light doesn't enter your eye from around the lens.
They should also be adjusted so that they are comfortable and don't fall down.
What are polarised lenses?
Polarised lenses absorb light where the vibrations travel in one particular direction. Most light is unpolarised, meaning that the vibrations are random. However, when this light is reflected off certain surfaces, such as water, the light becomes partially polarised. Polarised lenses absorb this partially polarised light, reducing the glare from the reflected surfaces.
We also spoke to Kelly Plahay, chairman of the Eyecare Trust:
What's the difference between UVA and UVB light?
UVA is longwave UV radiation. UVA accounts for around 95% of UV radiation that reaches the Earth. It is present all year and can penetrate layers of the eye right through to the retina.
UVB is a medium wave radiation that isn't usually present during the winter months. UVB rarely reaches the retina as the cornea absorbs it as the light enters the eye.
How do you know your glasses have the correct level of UVA/UVB protection?
Always check that your sunglasses or UV lenses have a CE, UV 400 or British Standard Mark. This will ensure they provide adequate protection from both UVA and UVB.