Lenses

Single-vision lenses

The simplest form of spectacles is the single-vision lens, made to a single prescription to correct a particular eyesight problem.

Myopia or short sight is corrected with concave lenses, whilst convex lenses are used to correct for long sight or hypermetropia.

Concave lenses are generally thinner in the centre than they are at the edge and convex lenses are usually thinner at the edge than at the centre.

The curvature of the lens, its thickness and weight will depend on the amount of long or short sight it is designed to correct.

The lens material will also influence the thickness and weight of your lenses, as will the size and shape of the glasses frame you choose. Most lenses are made of lightweight plastic and there is a wide range of materials available to suit your prescription and lifestyle.

Bifocals Lenses

Bifocal lenses contain two optical corrections with a distinct dividing line between the two parts.

Bifocals are for people who need a different prescription for distance close work. The upper part of the lens corrects distance vision and the lower half is for near vision.

Bifocals come in a range of designs depending on your needs. Increasingly, however, varifocal lenses are much more likely to be prescribed.

Varifocal or progressive lenses

Varifocal lenses, also known as progressive lenses, are used for correcting presbyopia (inability to focus on nearby objects) but unlike bifocal lenses have no visible dividing lines between the different corrections.

Instead, they combine distance vision all the way through to your reading vision smoothly from one prescription to the other, allowing the wearer to see clearly at all distances.

Lens technology means that there are many different designs to suit your lifestyle and occupational needs and many materials to choose from.