Some of the optical terms used on the promotional leaflets can be quite technical. We’ve put together some information, which might come in handy when you’re deciding what’s best for you.

Lens Types

SINGLE VISION

BIFOCAL

VARIFOCAL

TRIFOCAL

Materials

The majority of lenses we use now are made from plastic, which is in general, lighter and safer than glass. It is usually combined with a scratch resistant coating to protect the lens surface from everyday wear and tear.

Originally all spectacle lenses were made from glass and although not so commonly used now it still plays a very important role. The very thinnest materials available are still made from glass so for those with a high prescription can give excellent cosmetic results.

Polycarbonate is a very light, tough plastic and is used for both occupational safety specs and sports protection. It is also one of the recommended materials for rimless frames to provide extra strength.

Tints & Coating

There is a large range of tints available to both cosmetically enhance and improve the performance of the lenses. Tints can be either fixed or photochromatic, which is activated by the UV in the suns rays causing the tint to darken in bright sunlight. A UV inhibitor can also be added to both glass and plastic lenses to give additional protection to the eyes from ultra violet radiation which is a known cause of cataract and macular degeneration.

Most lenses now can be supplied with an antireflection coating which reduces the surface reflection on the lens, this improves the lens performance by reducing glare from oncoming traffic whilst driving and using VDU screens. The cosmetic appearance of the spectacles is more natural so reduces unsightly reflections in photographs and optimizes the appearance of the frame.