We offer a wide range of sunglasses, both prescription and non-prescription.
There are three types of sunglasses.
sunglasses that do not give significant protection against the sun
and are worn as fashion accessories.
General purpose sunglasses for reducing glare in bright light or in circumstances such as driving in daylight.
Special purpose sunglasses for activities such as skiing or for people abnormally sensitive to glare.
give comfort in very bright conditions by reducing the total amount of light
reaching the eye and, in particular, protect the eye from the damaging ultra-violet
(UV) part of the spectrum. There are two types of UV - UVB
UVB radiation is substantially absorbed at the surface of the cornea but can reach the retina. Excessive exposure can cause permanent damage to the cornea and conjunctiva, but this may not progress if further exposure is avoided.
UVA radiation penetrates more deeply and can cause damage to the crystalline lens and retina. Permanent effects such as cataract development are seen as accelerations of the ageing process.
Always look for BS 2724. This British Standard sets performance levels for quality, strength, stability, design and manufacture as well as the amount of UV they let through. Purchasing sunglasses that don't conform to this standard is not advised.
Non UV absorbing lenses can do more harm than not wearing anything at all. Behind a tinted lens, the pupil opens wider allowing in more UV light than would happen normally and thus reduces the eyes' natural protection. Sunglasses sold under BS 2724 have a "shade number". Shade numbers relate to the amount of UV allowed through. The higher the number, the better the protection.
Brown and grey are the most popular colours and green is one of the most effective. However, it is the "shade number" that counts not the colour.
For safety, choose plastic, toughened glass or laminated glass lenses. Check sunglasses' lenses by holding them at arm's length and looking through each separately at a vertical line. If the line distorts or wavers when the lens is rotated slightly, the lens is imperfect.
Both sunglasses and contact lenses are available to your normal optical prescription. Your practitioner will be pleased to advise you, but make sure you tell us you wish to have UV protection built in.
If you drive and wear sunglasses don't pick a very dark tint. A medium density is normally sufficient and it is safer as it transmits more light. Tinted lenses are darker at the top than at the bottom and give useful protection from bright overhead light, with a lighter area for map reading or seeing the dashboard.
Photochromic Lenses darken on exposure to sunlight and should react efficiently in changing light conditions. They should not leave much tint present when the lens is not exposed to the sun.
Polarising Lenses reduce reflections from wet or polished road surfaces, but they reveal the stress patterns in older types of toughened windscreens, which can be hazardous.