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Choosing your Lenses

So you have had your eyes tested and have an up to date prescription. We suggest having a look at our Understanding your Prescription section first.

Lens Type

There are six basic types of lenses that are suitable for different purposes.
Single Vision Lenses have a single focal length and may be set for distance, reading or intermediate use.
Multifocal lenses have more than one focal length and may be subdivided into bifocal, varifocal and office type lenses.

Distance

A general purpose prescription that unless you are over forty(ish) and have been prescribed a reading add your only prescription. For anyone with just a distance prescription these spectacles will do everything including reading.

Reading

Your prescription will have a near vision/reading addition. Please ensure you enter this correctly when you order your spectacles. These spectacles are designed to work at close distances and are normally set with a working distance of 35-50 cm. They are not suitable for driving but unless you have an intermediate addition as well will normally work well with a computer.

Intermediate

Your prescription will have an intermediate addition which may have been written by optician as a computer add or music add depending on what you discussed in the sight test. It will be a lower power than your reading glasses and will allow you see at a longer working distance than your readers but is not suitable for driving. You may also struggle with very small print but they will allow you to see normal sized print and your computer/laptop/tablet/music stand etc with ease.

Bifocals
As the name suggests bifocals have two distinct areas with two different focal lengths, generally distance and reading but if you want distance and intermediate enter the intermediate add when prompted during the order process.
You will need a frame that is deep enough to get the lenses into but most frames are deep enough, we have tried to limit the lens choices on frames that are unsuitable so if you cannot select a bifocal lens the frame is too shallow.

Standard Bifocals

D28 - A D-segment bifocal with a 28mm wide reading section. This is by far the most common type and if you are unsure or this is your first pair of bifocals choose these. They offer a great blend of performance and price and as the centre of the reading section is at the top of the reading segment they are easy to use. An anti-reflection coating will help to disguise the line. They are available as thinner lenses and as photochromic lenses too.

D28

R24 - A round segment bifocal with a 24mm wide reading section. These are used mainly for plus prescriptions as the segment is less obvious than a D segment lens. We recommend only choosing these if this is what you are already wearing as the centre of the reading segment is at the centre of the circle. This means you have to move you eyes further to access the full reading power.

R24

Wider Bifocals
D35 - A D segment lens with a wider near vision area, preferred by some people especially if you do a lot of close work.

D35

R38 - A round segment lens with a wider near vision area, again we would generally only recommend these if you are already wearing them.

R38

Executive Bifocals - These have a line all the way across the lens and consequently give a huge reading area which is ideal for certain specialist uses such as draughtsmen who use a wide drawing board. However there are drawbacks, the lens will be thicker than normal, often a lot thicker, the line is very obvious and they only come in standard plastic as a clear lens. They can only be fitted into a full frame not a supra or rimless mount.

Exec

Varifocals

For simplicity and to give the best possible value we offer three grades of varifocal lens, Standard, Better and Best.
All varifocals work in much the same way in that the distance portion of the lens is at the top, this is so you can see to drive, watch the TV and generally walk around in comfort. Where they differ from distance or reading lenses is that they have a specially worked corridor which gradually increases the plus power of the lens from top to bottom so that towards the bottom of the lens you are looking through your reading prescription. As this is a blend of power you will pass through all focal lengths from distance to intermediate to near along the way.

Standard VF

However all varifocals are not the same, there are literally hundreds of designs out there all offering slightly different things. In general though two principles hold true. The newer the design the wider the intermediate and reading sections will be. As you might expect this also means that the more expensive the lens the better it will be and consequently the easier it will be to use.
Our standard varifocals have been specially selected to give you the best performance possible for the best possible price, in most cases they will work perfectly well and from previous experience we had great results with these lenses. I am currently wearing a standard pair of varifocals with an anti-reflection coating. These are my first pair of varifocals and they work so well that I am almost completely unaware I am wearing them.
Our better lenses use a newer slightly softer design that gives a wider field of view for reading, these are what are generally referred to as Digital Freeform Varifocal lenses.

Better VF

Our Best lenses are the latest designs from some of the biggest lens companies in the world. These are also Digital Freeform Varifocal lenses but offer the widest field of view for near vision and also have less distortion in the corners than standard lenses. Essentially other than the price there should be nothing to put you off these lenses as they offer the highest levels of visual comfort at a great price.

Best VF

We do not offer personalised varifocal lenses currently as we feel that we cannot undertake the extra level of fitting and measurements that these lenses require without seeing the frame on you. From personal experience we can also say that the extra benefits are currently small compared to the best freeform lenses on the market but that the price is significantly higher.
Office Lenses

These are lenses designed primarily for office/desk work. They work in a similar way to varifocals but do not have a distance portion. They have a wide intermediate section at the top and a wide near section at the bottom. If you spend a lot of time using a computer these are ideal. They are not suitable for driving.

Office

Lens Coatings

All our frames come as standard with CR39 plastic lenses. This is the basic material that the vast majority of modern spectacle lenses are made. We no longer use glass lenses unless you specially request them.
Standard plastic lenses are reasonably robust and are unlikely to break if dropped however they can be scratched if you aren't careful with them.

Scratch Resistant Coating

This is a thin layer of clear plastic made from a tougher material that coats both sides of the lens and makes it more difficult to scratch the lens. Please be aware that these lenses are scratch resistant and not scratch proof. Sadly there is no such thing.

Anti-Reflection Coating

When light strikes a refracting surface such as a spectacle lens most of the light passes through the lens but a small amount is reflected back. This reduces the amount of light getting to the eye. An anti-reflection coating allows nearly all of the incident light to pass through the lens. Typically a standard lens reflects 10-12% of the incident light and with an anti-reflection coating less than 1% is reflected.
It works by using destructive interference with the light wave, the coating is 1/4 of the thickness of the wavelength on which it works. There are many layers of coating which work on different wavelengths. Sounds complicated doesn't it? Actually it's very clever science and what it means is that your lenses are clearer which allows them to work better in low light conditions. They are particularly good at cutting down glare from car headlights, computer screens etc. They look better too as everyone else can see through the lens to your eyes. Includes a scratch resistant coating as standard.
This coating is standard on all thinner lenses.

Premium Anti-Reflection Coating

All the benefits of a scratch resistant coating, an anti-reflection coating but with a super slippery hydro/oleophobic coating too. Water and oil repellent so that rain tends to bead and run off the lenses. Also as they are slippery they are more difficult to scratch. Simply the best.

NOT ALL COATINGS ARE AVAILABLE ON ALL LENSES - We will advise you if you have chosen an incompatible combination.
Executive Bifocals are only available with standard or scratch resistant lenses.

Lens Colour Options

Clear lenses are supplied as standard but most tints are available on standard lenses.
Please note we cannot supply other tints than those specified on thinner lenses. 1.74 index lenses are not available with tints or Photochromic lenses. Polarised Lenses are only available on standard or 1.6 index lenses and are not available on Bifocals or Office Lenses.

WE WILL ADVISE YOU IF YOU HAVE CHOSEN AN INCOMPATIBLE COMBINATION.

Photochromic Lenses

Commonly referred to by the defunct brand name of reactolite or as transitions lenses. Transitions is also a brand name but the generic term is photochromic. They react to the UV light level and go dark in the sun. Almost clear indoors they are a great all round lens. As good as sunglasses outside and fading gradually back to clear when you come indoors. However they do not really work in the car as the windscreen cuts out most of the UV light hitting the lens. If you want dark lenses for driving you would be better off with sunglasses (or a convertible). By default they are 100% UV protected.

pc

Tint Colours

Our three standard tint colours are the ones most in use by sunglass manufacturers across the world. All are UV protected and are great options for your new sunglasses. They are tinted to absorb 85% of the incident light so that only 15% reaches your eyes. In general it is best to choose a tint that matches the frame however brown makes things look redder and therefore warmer, grey makes things look bluer and therefore cooler, G15 is the most neutral tint as used originally by Rayban in its legendary aviator sunglasses.

Tint Colours

If you do not want dark sunglass lenses then in the comments box on the order screen please specify how dark you would like the tint.

Grade 1 = Pale Tint, cuts out 10-15% of the light. (This is the only tint suitable for night driving.)
Grade 2 = Fashion Tint, cuts out 25-30% of the light. (Not suitable for night driving)
Grade 3 = Medium Tint, cuts out 50% of the light. (Not suitable for night driving)
Grade 4 = Sunglass Tint, cuts out 85% of the light. (Not suitable for night driving)

We will not supply lenses darker than this as they are too dark for driving and only suitable for mountain conditions.
All tints from Grade 2 and darker are supplied with a 100% UV coating.

Graduated Tints

These lenses are darker at the top than at the bottom. Designed to mirror the natural shade you get from your eyebrows and help you read by looking through the clearer part at the bottom of the lens.

Choose a colour and specify how dark you would like the lens at the top using the grade system above. (If no grade is specified we will supply a dark tint at the top as you would find in a sunglass.)

Please note
A grade 1 graduated tint is not worthwhile.
Specifying a graduated tint with an anti-reflection coating will take an extra 5-7 working days as the anti-reflection coating can only be applied after the lens has been tinted.

Grad Tints

Other Tint Colours

We can do Pink, Blue, Yellow or Green and we can achieve other colours by mixing the above. Please specify what colour tint you would like in the comments box on the order screen.
Use the grade system as above but most other tints will not go as dark as our standard tints. Usually we can only achieve a Medium Grade 3 at the darkest point.
Graduated tints are also available.

PLEASE NOTE WE CAN ONLY DO OTHER TINT COLOURS ON STANDARD THICKNESS LENSES.
We will inform you if you have chosen an incompatible combination.

Polarised Lenses

Polarised lenses help to reduce glare as well as the amount of incident light. They are brilliant at taking the glare off a wet road or the sea. Recommended for watersports or any outdoor activity such as running, cycling or driving. (One note of caution, polarised lenses can make some led displays difficult to read.) Much nicer to wear than a standard tint.
Only available in a sunglass tint in Grey or Brown and on most but not all lens types. They are not suitable for night driving.

Lens Thickness

Standard Thickness n=1.50

All our lenses are plastic, glass lenses are very rare nowadays. Plastic lenses are shatter resistant which makes them safer and are about half the weight of the equivalent glass lens. If you would like glass lenses please contact us at sales@favershamoptical.com

Standard plastic lenses are made of a material called CR39 and are generally lightweight and optically free from distortion. They do however scratch fairly easily if you aren't careful with them so a scratch resistant coating may be of benefit.
We will supply standard lenses unless you specify another option.

In general if the Sphere value of your prescription is lower than +/-4.00D standard lenses will be fine. For higher prescriptions we would recommend a thinner material to improve the cosmetic appearance and to reduce the weight.
See the table below.

Mid Index n=1.60

"n" refers to the refractive index of the lens material, the bigger the number the more the light is refracted at each surface and the thinner the lens can be.
Most lenses of this thickness and thinner are supplied as standard with an anti-reflection coating as the surface is naturally more reflective which makes the lenses appear unattractive.
These lenses are approximately 25-30% thinner and lighter than standard lenses.

In general if the sphere value of your prescription is between +/-2.50D and +/-6.00D these are good lenses to choose.

High Index n=1.67

These lenses are thinner than 1.60 and not quite as thin as 1.74. A good option for prescriptions from +/-4.00D to +/-8.00D.
Some lens types are not available in this thickness lens, including some bifocal types and most tints are not available.

Very High Index n=1.74

The thinnest lenses available in plastic. Recommended for prescriptions higher than +/-5.00D
Photochromic lenses or tints are not available in this material and other lens options are limited. Standard varifocals, and all bifocals and office lenses are not available in this material.

Sphere Value (D) Standard Index n=1.50 Mid Index n=1.60 High Index n=1.67 Very High Index n=1.74
+/-1.00 Recommended
+/-2.00 Recommended
+/-3.00 RecommendedOption Option
+/-4.00 OptionRecommended Option Option
+/-5.00 OptionOption Recommended Option
+/-6.00 Option Recommended Option
+/-7.00 Option Recommended
+/-8.00 OptionRecommended
+/-9.00 Recommended
+/-10.00 Recommended

Most lenses are actually available in all prescriptions up to +/-10.00D but a +/-10.00 lens in standard plastic will be very thick and heavy so is not recommended.

Prescriptions over +/-10.00D are available but due to the more complicated nature of these complex prescriptions please contact us for advice first.

In all cases if you select an incompatible combination we will contact you and offer some alternatives. We are unable to restrict the options other than lens type due to the way the website architecture works.
Sorry for any inconvenience this may cause.