In the United Kingdom the Department of Health delivers optical benefits for those on a low income. Most opticians participate. The benefits include free sight-testing and vouchers toward the cost of spectacles.
Many in the UK wear spectacles or contact lenses, and the figures are perhaps surprising. About 68% of adults over the age of 16 wear either spectacles or contact lenses; 65% of men and 71% of women.
A large proportion of those who wear spectacles pay for them, in full or in part, with vouchers. Vouchers are used in 31% of all spectacle dispensing in the UK.
In the year to 31 March 2010 there were 11.8 million free eye tests carried out in England for the National Health Service (NHS), and this represents about 23% of the English population. Of this figure, about 40% were for persons over the age of 60 years. Each optometrist in England, on average, conducted about 1200 such tests in the year.
There were also 4.4 million optical vouchers processed for payment at a cost of £192 million pounds. (About $311 millions). It is estimated that vouchers were used by about 8.5 percent of the English population. These and other statistics for such optical services can be found by reference to GOS Activity Statistics 2010
Despite the UK public's involvement with the voucher system, the knowledge needed to determine the amount of voucher benefits lies with the optometrist. It is assumed that the process is considered too complex for the general public. As far as is known, there is no simple brochure for the public that explains how to work out the values.
The page does not intend to describe the full range of general optical services (GOS), for which the optician's practice is the best port of call. Nor is this page intended to replace professional advice in any regard. You should know that your optician and optometrist are the best sources of advice on all optical matters. In particular, only they can advise on the entire range of benefit services, and conduct any eye tests that are needed.
This text explains how to estimate optical voucher values from eye prescriptions.
Health Benefit EntitlementsEdit
The various groups that can receive free NHS optical benefits and the rates for 2012 are listed on the page NHS Eye Care Entitlements 2012 . Information on optical entitlements is also available from opticians' outlets in the UK, and dentists can advise on 'their' benefit products. Information leaflets can also be obtained from benefits offices, and from the Health Benefits section of the Department of Health.
The main entitlement points are these:
- These benefits, and nearly all other benefits in the UK require that a claimant be ordinarily resident. If there is some doubt, a so-called Habitual Residence Test, an interview, can be conducted to determine this.
- At the most general level optical (and dental) benefits are given to those claimants who can show that they have a low income.
- Claimants who already receive a means-tested benefit, or who would have if they applied, (underlying entitlement), will usually get full voucher values.
- Claimants without means-tested benefits may still receive partial assistance, depending on their income and savings. A tapered calculation applies.
- To demonstrate an entitlement to health benefits for a dentist or optician, those with means- tested benefits show a recent entitlement letter, and those without benefits provide a form from the Health Benefits Section of the Department of Health, based on a satisfactory means-testing questionnaire.
Those claimant groups with typical entitlements to optical (and dental) benefits are listed in the drop-box below, though for up-to-date official listings, interested parties should refer to the above-referenced brochures.
This section introduces some of the terms found on eye prescription forms and gives a little information on their meaning. An understanding of this terminology is not strictly necessary, but some may find it of general interest.
|Typical eye prescription extract for Mr. A. Person
in highest spherical power notation.
|Right eye, (O.D)||+6.5||-1.5||95|
|Left eye, (O.S.)||+5.5||-1||85|
|Right eye, (O.D)||+1|
|Left eye, (O.S.)||+1.25|
|Right eye, (O.D)||+1.5|
|Left eye, (O.S.)||+1.75|
Two fictitious prescriptions have been produced in Tables 1 and 2. These make glasses that are identical, though they look quite different in their number content. They are typical of formats used throughout the world, though in the UK the version in Table 1 is by far the most common. Notice that both lenses in the prescription in Table 1 have higher Sphere values that the ones in Table 2. This format with the higher set of sphere powers is the one that is needed for looking up the NHS voucher values, and it is perhaps this factor that has directed the UK's choice of format.
When an optician encounters a prescription that is not in the format of highest spherical power he simply transposes it. The method used is called flat transposition, and it consists of just a few simple sums. Because a person new to these ideas might become confused by an alternative format, the method to check and transpose prescriptions is included in a separate section.
Another task that your optician would take for granted is the modifying of the distance prescription for near or intermediate use. For voucher checking this just involves adding some numbers so it has been included also.
Refer again to the prescription in Table 1. The main data of interest here describe the powers of the correction lenses. In fact powers are expressed in dioptres. Because dioptre values can be added directly, opticians prefer these to the difficulty of adding focal lengths. The focal lengths are the reciprocals of dioptres.
The figures seen in the Sphere, Cylinder, and Add boxes of the prescription are all power values; they are used by the optician to work out the details of lens grinding. Large power values also tell him that more material and more work will be needed to grind the lenses.
- There are shorthand methods to express lens prescriptions. One such method for lenses is shown below. Notice that it is written in the sequence sphere, cylinder, then axis. The example describes the two distance lenses of Table 1. The word prescription itself is often just written as Rx.
+6.5 -1.5 X 95 RIGHT +5.5 -1 X 85 LEFT
|The same eye prescription for Mr. A. Person
in the more unusual notation.
|Right eye, (O.D)||+5||+1.5||5|
|Left eye, (O.S.)||+4.5||+1||175|
|Right eye, (O.D)||+1|
|Left eye, (O.S.)||+1.25|
|Right eye, (O.D)||+1.5|
|Left eye, (O.S.)||+1.75|
- The Sphere column describes the uniform curvature of each lens. It is quite common for the left and right eyes to need different corrections. These curvature components can best be imagined as if they were sliced from the surface of a sphere.
- The Cylinder column is not always used. Only those with astigmatism will have these entries. When this is the case, these figures describe the extent to which the eyes' functions deviate from the true spheres. These too are often different for each eye.
- The signs for the various lens powers can differ. When we refer to lens powers for benefits vouchers we really mean to say the magnitude of the power, that is to say without regard to the signs of the numbers. Although the signs have importance for the lens-maker and for some calculations, the voucher tables do not need them. It may still be of interest to know however, that for the lens-maker, negative and positive powers relate to divergent and convergent lens behaviour respectively.
- The Add values are power increments. These are added to their respective sphere figures for reading glasses (near), or for screen viewing glasses (intermediate). These increments are invariably positive and as such their signs are often missing.
- The Axis entry states the angle for the cylinder function. It tells the optician the angle from the horizontal at which to add the cylindrical compensation, and although it is of importance for lens-making it does not affect the benefit amount. These often differ for each eye.
In making a lens with a given sphere or cylinder power, it would be possible to have the back of the lens flat and all of the spherical or cylindrical functions on the front. However, this would make a thick-looking lens. In fact the lens maker splits his efforts between the back and front of the lens, so that the two surfaces combine to make the prescribed values. His ability to do this makes for thinner lenses.
The section provides an overview of the method to use in choosing the correct voucher value for a new pair of single-vision glasses. The sequence is as follows:
- Inspect the prescription to make sure that both lenses in the distance eye prescription are written in the format of highest spherical power. If they are not, then transpose them so that they both are.
- Add the respective sphere increments if the glasses are for near or intermediate use, to make a new prescription.
- Conduct a trial-lookup of the voucher tables, noting the category for each lens.
- Select the higher of the two category values to be the voucher category for the glasses as a whole.
The sections below explain how to adjust a distance prescription for near or intermediate glasses, how to know whether or not a prescription is in the right format to interpret the voucher table, and if it is not, explains how to transpose it to the format that is. A recent benefits table is included.
Near and IntermediateEdit
If the glasses are for near or intermediate work the respective increments in the add boxes of the prescription must be added to the sphere powers of the distance listing. For example, if glasses for near or intermediate use were needed for the subject in Table 1, their prescriptions could be formed as follows:
NEAR GLASSES LEFT EYE RIGHT EYE To the 'distance' prescription: +5.5 -1 X 85 +6.5 - 1.5 X 95 Add these 'near' values to the sphere: +1.75 +1.5 To give the 'near' prescription: +7.25 -1 X 85 +8 -1.5 X 95
INTERMEDIATE GLASSES LEFT EYE RIGHT EYE To the 'distance' prescription: +5.5 -1 X 85 +6.5 - 1.5 X 95 Add these 'intermediate' values to the sphere: +1.25 +1 To give the 'intermediate' prescription: +6.75 -1 X 85 +7.5 -1.5 X 95
Sometimes glasses for near or intermediate work will fall into a higher voucher category than distance glasses, owing to these increments. Higher voucher categories attract higher benefits.
It may also be of interest to know that because increments are invariably positive, they can be added either before or after transposition, without affecting their use in voucher tables.
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