How Tints & Sunglasses protect your eyes

Buying sunglasses is more than just a fashion statement. Protection from harmful ultraviolet (UV) light is essential to prevent possible damage to the lens or retina of the eye. There is increasing scientific concern at the enlarging size of the North Poles ozone hole and the thinning of the ozone layer over Northern Europe . The suns UV light, without this protective filter now exposes us all to greater risk. The crystalline lens in the eye may become prematurely aged by excessive exposure.

A tint alone on a pair of spectacles will not block UV rays. All it will do is put your eyes in the shade allowing your pupils to dilate more and let in more available light which equals more damaging UV rays. A tint alone only helps in reducing glare and improving visibility.

For best protection, and your peace of mind only choose sunglasses with lenses that block UVA and UVB rays between 290 and 400nm (UV400).

ALL tints supplied by Glasses4Less automatically include FREE UV400 treatment for your protection.

What is UV?

UV can be sub-divided:-

UV light is made of invisible, short wavelength rays from the sun. UV is measured in nanometers (NM) and there are three bands of UV: UVA, UVB, and UVC.

UVC (below 280 nm) is normally absorbed by the upper earth atmosphere before reaching the earth and sunglasses do not need to protect against UVC.

UVB (280-315nm) rays are the most hazardous to eyes and skin. They are responsible for sunburn and snow blindness and can cause eyelid and other skin cancers. UVB is stronger in the summer and also at higher altitudes.

UVA Possibly the most dangerous area, between 315-380nm, causes chronic eye damage, especially low dose exposure over a long period of time. Rays tend to get absorbed by the lenses in your eye and can cause retinal damage and contribute to cataracts. UVA rays are best known, however, for their role in ageing the skin through early wrinkling. UVA rays pass easily through clouds, glass, water, and even clothing.

You will need protection both against direct exposure to UV rays and to reflected rays from snow, sand or water. Ozone depletion in the atmosphere during recent years has increased the likelihood of skin and eye damage by UV rays. UV protection is advised even on overcast and hazy days.

UV protection can be added to any prescription spectacles you don't even need the tint to be fully protected. We offer a protective UV400 coating that is virtually clear, which blocks between 99% and 100% of UV rays.

If you work outdoors or participate in outdoor pursuits, you will benefit greatly from UV protection, for winter snow sports at high altitude full UV protection is an absolute must.

People working under fluorescent lights or at computer VDUs will also benefit from lenses with UV protection.

There is also a possibility that if you take certain types of medication, you may become more sensitive to UV rays than normal. Please check with your doctor for advice on wearing spectacles with UV protection or sunglasses.

Tinted Lenses

This table classifies tint densities by a filter category based on light transmission (LTF) characteristics as defined in BS EN 1836:1997

The end wearer of a tint should note which category their tinted lenses come under and be aware of the restrictions of use that may apply. Drivers beware of wearing tints after lighting up time (night) and ensure that it passes the traffic light recognition test.

Tints helpful in enhancing contrast, reducing glare, reflecting bright light or improving visibility on hazy or overcast days.

Tints work by filtering light and each tint filters light differently. Light to medium shades are good for daily wear. For bright conditions and outdoor sports, darker shades are more appropriate.

Sodium Yellow provides excellent contrast and depth perception in low intensity light. This is a great tint for skiers and shooters on overcast days.

Grey is a neutral, general-purpose tint, popular with golfers, cyclists and runners. Grey does not enhance contrast.

Brown provides good contrast in hazy sunshine. Brown is also suitable for anglers, sailors, skiers and in other sports where there is high-glare.

Green is a neutral, general-purpose tint that provides some contrast in low light and can help reduce eyestrain under bright lights.