Why is UV protection needed and what are the different sunglasses categories?
Why is UV protection needed?
The sun emits ultraviolet radiation containing harmful rays called UVA and UVB. If you spend a lot of time being exposed to UV rays, you may be causing damage to your eyes, and speed up the onset of several ocular pathologies.
We know the suns rays can damage our skin, and in a similar way, it can cause damage to the tissues of our eyes. These rays are invisible, but can cause significant damage.
UVA rays are responsible for the majority of radiation from the sun, and can cause the development of ocular pathology such as macular degeneration and cataract. Macular degeneration is a condition whereby the retina (the light sensitive layer at the back of the eye) is damaged and this can lead to reduced vision. Cataracts cause the lens in the eye to become cloudy and hard to see through, causing reduced vision and glare.
UVB rays can cause the onset of certain ocular tumours.
To reduce the risk of this exposure, it is imperative you wear a pair of good quality sunglasses which have UV protection.
All of our sunglasses are uv400 rated and filter out 99% of UVA and UVB rays. These are slightly higher than the British standard requirement which is why they are the best option to protect your eyes.
Sunglasses categories
How much light that passes through the lens, determines the category number of the sunglasses lens. The more light that passes through the lens, the lighter the lens will be, and vice versa, a lens which lets through less light will be darker and block more light from getting through to your eye.
The darker the glasses, does not mean they will offer higher UV protection. The lens colour is simply how much light can pass through the lens, whereas the UV protection filter stops UV light from passing through.
- Category 0 lenses tend to be very lightly tinted and are fashion glasses or for indoor use.
- Category 1 lenses are often yellow or a very pale colour. These are fashionable, and only provide mild protection on overcast days.
- Category 2 lenses tend to be orange, red or blue. These are suitable for overcast weather or slightly bright days.
- Category 3 lenses are the most common, and are often brown, grey or green. These are great for everyday wear.
- Category 4 lenses are often a very dark brown or grey. These are not suitable for driving and are generally used for speciality sports such as skiing or mountaineering.
References:
- British Standards Institution (2015), Eye and face protection. Sunglasses and related eyewear. Sunglasses for general use. BS EN ISO 12312-1:2013+A1:2015.