The most important part of your glasses are the lenses, as it is through these individually crafted pieces of a special plastic material that you will see the world clearly.
Standard and lightweight materials
Most spectacle lenses are made of CR39, which was developed by Columbia Resin. It was their 39th attempt at making a suitable material, hence the name CR39. We can also make your lenses from Trivex, which is the lightest material available. It comes with an anti-breakage warranty and so is ideal for rimless and sports glasses; additionally it gives 100% UV protection, making it the ideal choice for children’s lenses. Trivex bends light slightly more than the standard plastic and will make your lenses fractionally thinner.
If you are concerned about the thickness of your lenses we could consider using an aspheric design or using high refractive index lenses. Aspheric lenses flatten out towards the periphery to enable your lenses to be thinner and high index lenses are made using a denser material which bends light more, allowing the lenses to be less curved and therefore lighter and thinner. Please ask our dispensing staff about the options for your prescription as using an aspheric on a low powered prescription is unnecessary and using a high index lens on a low prescription may make them heavier than a standard material.
As we get older, the eyes become less able to change their focussing and we require different prescriptions for distance and reading. These separate strengths of lens can be incorporated into either a bifocal or a varifocal. Our dispensing staff will help you make the decision about which lens type to choose and will give you advice about which type will suit your lifestyle, occupation and budget.
Varifocals are more complex as there is a blend from the distance to the reading areas and therefore are the more expensive of the two options. Although you may have heard people say that they are difficult to get used to, we find that very few of our patients struggle with them. The key to this success is ensuring that we use a very good quality lens, choose the correct design of varifocal to suit you and making sure that all of the necessary measurements are carried out by qualified staff.
In addition to single vision or multifocal lenses, we can also offer lens types that have been designed to suit your lifestyle.
- occupational lenses, which give a good area for reading and are less powerful at the top of the lens, allowing a computer screen to be clear. This makes them ideally suited to people who work in an office environment.
- an enhanced reading lens. This lens has been developed for those who have a digital lifestyle and includes a near vision boost at the bottom of the lens, to reduce eye fatigue.
- a driving lens, which absorbs short wavelength light and so reduces glare from headlights when driving at night.
Tints / coatings and more.
Standard lens materials reflect 8% of incident light. These reflections can be annoying and so the lenses can have anti-reflection coatings applied during manufacture. These multi-layered coatings eliminate virtually all of the reflections from the lens surfaces.
UV filters can be applied in a similar way.
If you are light-sensitive, you can choose to have either a light tint on your lenses, a dark tint to make them into sunglasses or have photochromic lenses, which change colour according to the light conditions. These options are available with anti-reflection coatings.
If you suffer from glare you can choose to have your prescription sunglasses made with polarised lenses, which eliminate glare from horizontal surfaces, such as a wet road or light reflecting off a river or lake.