What are the Different Types of Spectacle Lenses
We all have unique vision correction needs with varying degrees of near or far sightedness and astigmatism. Today’s lenses are built around your prescription and the way you live to give you a personalised view through your eyeglasses. Here’s the rundown. Single Vision lenses are one power from edge to edge. These lenses are typically prescribed to correct for near sightedness, far sightedness and astigmatism. They're the most common type of prescription lens. They are available in clear lens options, as well as photo-chromatic, permanently tinted, and polarised options.
It is also possible to have lenses made from different kinds of plastic materials to enable stronger lens prescriptions. These are supplied in a thinner and lighter lens option.
Vision is also enhanced by applying an anti reflective treatment to the lens surfaces to reduce glare and distracting reflections.
Lenses can also be made using digital surfacing technology to further enhance edge-to-edge accuracy of prescription and peripheral vision and also further enhance cosmesis by making lenses flatter and thinner. Bifocal Lenses give you two focal points in one lens, to help you see near and far without switching your glasses. There are a number of different variants giving different size and shape areas for the near vision portion for different applications or uses.
Trifocal Lenses give you three focal points in one lens to help you see close-up, mid-range (typically for computer or seeing your car dashboard), and far-away. The lens powers start with close vision at the bottom, mid-vision through the middle, and distance through the top of the lens. Most people find with a little practice, they’re an easy adjustment.
Progressive Power (Varifocal) Lenses are described as ‘three in one’ lenses or ‘bifocals without a line’ although in reality they are far more complex than that. Varifocals are variable power lenses where the power changes progressively from the top (distance portion) down into the bottom (near vision portion).
Modern day varifocals are far more advanced than their earlier predecessors, with the introduction of digital or freeform surfacing technology. This allows for much greater error control across the lens surface, creating wider smoother zones of vision at all distances, leading to better vision and quicker adaptation.
It always advised to seek the advice of a qualified dispensing optician when considering varifocals as they will have the technical training and knowledge to advise of the best design for your individual needs, and to take all the necessary accurate measurements required to ensure good fit and performance of the lenses.
As with all lens types, these are available in clear lens, tinted or photo-chromatic materials and thinner lighter lens options as well the anti reflective treatments previously described.
Occupational lenses are also available for specific visual tasks. This has been made possible by the advances is technology where it is possible to individualise a pair of lenses to use in specific circumstances, such as working in an office where good intermediate and near vision is required and a compromise on the distance vision is not a problem. Often referred to as office varifocals or enhanced readers, they come in a variety of options and can be tailored to the individual. Speak to a good Dispensing Optician for further advice on these.