Spectacle Lens Information
Up until now you might not have given much thought to your lenses. After all, at first glance they may appear rather ordinary but this first impression is deceptive. In simple terms, lenses come in three types, single vision, bifocal and varifocal all of which offer very different functions to the wearer.
Single vision lenses
In the majority of cases, this is what the first time spectacle wearer will require. As the phrase suggests, single vision lenses offer a single focal power and correct close-up or distance vision. Single vision lenses are worn for reading if you are long sighted and for distance if you are short sighted. The lens has one overall power, No lines.
Bifocal lenses
There will come a time in your life, usually in your forties, when you will need glasses to improve both close-up and distance vision. One option is to have two pairs of spectacles but this can be both inconvenient and frustrating. Bifocals are two lenses in one, enabling the wearer to see clearly at two points only, close-up and distance. However they cannot cater for the intermediate distances.
Progressive (Varifocal) lenses
If you prefer not to wear different spectacles for distance and near and want to avoid the restriction of bifocals, a solution is progressive lenses. Not only will these lenses look better cosmetically because they have no dividing lines or segments, but they will also offer complete vision at all distances. Varifocals have an infinite (varies) number of working distances which can be found by looking further down/up. With no visible line, stronger power towards the lower portion for closer work.
Why do Premium varifocal lenses take longer to manufacture?
Lenses made specifically for the patients prescription, not kept in stock. All surfaced specially for shape of patients frame.made in specialist laboratories.
Intermediate / Near tasks
Occupational lenses specifically designed for the individuals specific visual needs at work or at home, this lens is for near work and intermediate with NO DISTANCE PORTION.
Stock and Surfaced Lenses
A Stock lens is off the shelf and cut down to fit the frame. A Surfaced lens is a specially made lens taking the actual size and shape of the frame into account before manufacturing. This will make most prescription lenses thinner and lighter. A Surfaced lens which takes the shape of the specific frame into account so that the lens is thinnest at all points around the lens, essential on mid to high powered plus lenses.
Aspheric and Bi-Aspheric
A lens which makes most prescription lenses thinner and lighter by design. Cosmetically they look better by not magnifying or minifying the patients eyes as much. Reduces peripheral distortions to improve field of view.
Refractive Index
How dense the plastic or glass lens is, the denser the lens the more power can be created with a smaller amount of the material (higher index). This gives the patient the ability to have a thinner lens which does the same job as a fatter (lesser index) lens. Especially useful for mid to higher prescriptions. High Index technology has enabled us to produce lenses that are up to 50% lighter and thinner than standard lenses. Even high powered prescriptions can be manufactured to result in significantly thinner, lighter and more aesthetically appealing spectacles.
Polycarbonate Lenses
More impact resistant than standard plastic materials especially for sports etc…
Photochromic
A Lens which reacts with UV changing to a darker tint normally available in brown and grey.
Hard Coat
A coating on the lens which enhances the working life time by reducing scratches on the lens which in time would otherwise interfere with the vision.
Anti-Reflective Coatings
Multi Anti-Reflective coatings reduce dazzle/glare from artificial lights such as VDU screen, traffic lights when driving or simply reading in evenings. Cosmetically enhances lenses as lets more light through and less white reflections and improving performance. The lens does have to be kept cleaner to fully appreciate the effect of the coating. For example a camera lens and good quality binoculars.
Call J Oliver Radley Opticians on 01763 273300 to make an appointment now.