The simplest form of spectacle or contact lens is the single-vision lens, made to a single prescription to correct a particular eyesight problem. Concave lenses are used to correct short sight and convex lenses to correct long sight. 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 spectacle frame you choose. Traditionally, spectacle lenses were made of glass but most lenses are now lightweight plastic and there is a wide range of materials available to suit your prescription and lifestyle.
High-Index & Aspheric lenses
If you need high-powered lenses you can improve the weight or appearance of your glasses with special lens materials and designs. High-index materials and aspheric designs mean that lenses can now be made thinner, lighter and better looking than traditional lens types. High-index materials make lenses for short sight thinner, while aspheric designs that minimise the amount of material make lenses for long sight both thinner and lighter.
Bifocals & Varifocals
Bifocal lenses provide a convenient way to combine distance and near vision in one lens. The near vision part of the lens is contained in a small segment visible on the front of the lens and sits level with the top of your lower eyelid so as not to interfere with your distance vision. Although not as cosmetically appealing as a varifocal lens, bifocal lenses are functional and simple to use. If you require clear vision for distance, close-up for reading and for mid or intermediate range (computer use, prices in shops etc) a varifocal lens will be required.
All our lenses at EyewearBrands are supplied by leading UK lens manufacturers, the lenses are made to the highest specification and all conform to British Standard BS2738-3 2004. All our lenses are made from plastic materials.