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Hard Resin (Plastic)
Hard resin lenses are half the weight of glass and are more impact resistant. Current hard coating technology produces a scratch resistant surface that is almost as durable as glass. If safety is especially important polycarbonate offers an alternative that is almost bullet proof!
High density materials allow lenses to be made thinner - reduced edge thickness for short sighted prescriptions, reduced centre thickness for longsighted lenses. The higher the prescription the greater the advantage offered by high index lenses.
Glass lenses are still available in some lens forms but are not often used due to their weight and poor impact resistance if not toughened.
All resin lenses are finished with a hard surface coating to improve scratch resistance. You may also choose to have a reflection free coating which will be finished with a slippery final layer to make these lenses easy to clean.
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What options are there for my lenses?
If you wear prescription spectacles and want an effective pair of sunglasses you have a wide range of tint options. Many of these tints are available as single vision, bifocal, trifocal and progressive lenses. These are available in hard coated plastic and glass and are made from a light sensitive material which is activated by ultra violet light, giving a "reversible" tint which darkens outside in the sunlight and fades indoors. Variable tints are a useful choice for those who want one, general purpose pair of spectacles. However, because variable tint lenses are activated by UV there may be times when the tint is darker than you would like, for example clouds do not block UV and on dull overcast days the tint may be quite dark. There may also be times when the tint is not as dark as you would like, for instance in a car the tint is not activated as effectively because the glass windscreen filters out some UV.
Prescription plastic lenses are lighter, and are more impact resistant than standard glass lenses. Almost all are "hard coated" to make them scratch resistant. There is no difference in optical quality between glass and plastic lenses and in fact the majority of prescription lenses used are plastics of some sort. Some plastic lenses can be tinted by dyeing, which allows a very large range of tint options. These tints will not penetrate some hard, scratch resistant coatings and so must be applied at the time the lens is made before the hard scratch resistant coating is applied. It is also possible to have a UV inhibitor applied to plastic lenses. This is a colourless dye which provides UV protection. A UV absorber should always be applied to prescription sunglasses in addition to the tint itself.
Prescription polarised lenses are available in both hard coated plastic and glass. These are available in single vision, bifocal and progressive lenses.
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Opticlips
We have a local supplier who is able to make a "custom" clip-on to match most frames. This is cut to exactly match the size and shape of the frame and clips around the rim. There are several mount colours (black, antique gold, antique silver and antique copper) with polarising or polycarbonate lenses available in brown, grey and Rayban green.
If you are choosing a new frame consider the "Convertible" range. This is an extensive range including ladies and gents styles; each frame supplied with a clip-on in an identical style and colour as the frame and mounted on magnets. These clip-ons are very easy to put on and off.
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