GB2240405A

GB2240405A - Ophthalmic measures and templates

Info

Publication number: GB2240405A
Application number: GB9101695A
Authority: GB
Inventors: Christopher Forshaw-Whittaker
Original assignee: FORSHAW WHITTAKER CHRISTOPHER
Current assignee: FORSHAW WHITTAKER CHRISTOPHER
Priority date: 1990-01-26
Filing date: 1991-01-25
Publication date: 1991-07-31
Anticipated expiration: 2011-01-25
Also published as: GB2240405B; GB9001887D0; GB9101695D0

Abstract

An ophthalmic measure (10) is made of transparent material and has markings including linear scales, lens outlines and positioning markings on at least one side thereof for use in determining lens positioning or sizing at least. <IMAGE>

Description

Title: Ophthalmic measures and templates DESCRIPTION This invention concerns ophthalmic measures and templates.

In order to produce lenses for a pair of spectacles various measurements have to be taken to enable the lens to be cut to a correct size for a particular spectacle frame, to enable correct positioning of the lens relative to the eye and to enable correct positioning of alternative lens parts within a lens, such as for bifocal lenses.

Presently available ophthalmic measures are limited in their use being opaque. Thus, it is not possible to use them easily with a spectacle frame on a patient, which would be advantageous.

An object of this invention is to provide an ophthalmic measure that may be used in relation to spectacle frames in determining lens positioning or sizing.

According to the invention there is provided an ophthalmic measure that is of transparent material and having markings on at least one side thereof for use in determining lens positioning or sizing at least.

Preferably the measure will be of relatively rigid plastics material and may have markings on both sides thereof. Thus, the markings on the one side of the measure being used may be seen more clearly than the markings on the other side of the measure not being used, whereby reversing the measure different measurements may be taken. Alternatively the ruler may have identical markings visible from both sides of the ruler. Thereby different types of markings may be provided for different areas of the ruler.

The markings on the measure will preferably include one or more of markings for making linear measurements, markings for measuring angles, markings for aiding correct positioning of the ruler relative to the eye and/or to a spectacle frame and markings to indicate lens blank size and positioning. Each type of marking may be in a different colour to the others on the same side of the measure and/or the others of the same type or markings of the same colour may be spaced from each other to avoid confusion.

The preferred shape for the measure of the invention will be generally regularly trapezoidal preferably with the corners thereof between the longer side and the edge sides rounded. Also, corners of the ruler at ends of its longest side may be truncated. The measure of the invention may alternatively be half of such regular trapezoidal figure e.g. having one edge side meeting the longer and shorter sides at right angles. The preferred shaping of the measure of the invention enables it to be positioned snugly against the side of a patients nose for some purposes.

Additionally or alternatively, the ruler may have an indent in its normally lower edge, whereby the ruler may be sited on the bridge of a patient's nose.

Specific markings desirably included on an ophthalmic measure of the invention may include along, preferably the longer side, a linear scale, say marked in millimetres, for measuring head width, i.e. the distance which will be used for determining the setting of spectacle frame arms. Along preferably the shorter parallel side of the ruler is another linear scale, again preferably marked out in millimetres, for use in measuring interpupillary distance (P.D). The scale may be continuous along a substantial length of the ruler or may be provided in two or more discrete lengths preferably one for each end of the ruler. A centre line marking is preferably included on the measure between its side edges so that individual monocular P.D's can be measured using the shorter linear scale. None of these measurements requires a spectacle frame to be in place on the patient.

The measure of the invention preferably also includes a datum line between and parallel to the upper and lower parallel sides of the measure. The datum line is preferably marked out as a linear scale in millimetres. Above and below the datum line are a series of spaced pairs of parallel lines, preferably in a different colour to the datum line, to enable the measure to be positioned on a spectacle frame so that the frame is positioned centrally of the measure relative to its top and bottom edges. Then with the frame centralised and the inner edge of the rim of one lens frame on the centre line, the inner rim edge size can be measured along the datum line. Also from that centre line to the outer edge of the adjacent lens frame can be measured along the datum line to give the distance between lenses.

One or other of the linear scales along the parallel sides of the measure may also be used to measure the required length of a spectacle frame arm and also to measure the bridge projection of a spectacle frame.

Further markings on the measure of the invention may be one or more linear scales normal to and crossing the datum line. Then with a frame positioned centrally relative to the datum line with its bridge overlying one of those linear scales, the height of the frame bridge above the datum line can be measured.

The measure of the invention may further have markings thereon for indicating desired lens size. A marking such as a cross or a circle may be provided for positioning the ruler over the frame on a patient, the marking being to aid alignment with the eye pupil or lid. Then the lens size required is indicated by a series of spaced lines representing different lens sizes. Preferably one pupil position marking and a series of lens markings will be provided for single vision lenses, one for glass varifocal lenses and one for plastics varifocal lenses. In the latter two cases further measurements may be required such as height of progression and fitting height above datum for which the linear scales used for bridge height measurement may be used.

For some lenses particularly bifocal lenses it may be advantageous to have lens templates for use in conjunction with the measure of the invention. Such templates may, indeed, be considered also to be encompassed by the invention. In one preferred embodiment the lens templates will be shaped and sized similarly to the above-mentioned half measure.

Alternatively a lens template of a similar shape and size to a full measure of the invention may be used, such templates actually having two different template markings one set in each half of the template.

Templates according to the invention preferably carry various markings to indicate various lens sizes as well as possibly linear scales for making fitting measurements and other markings for aligning the templates relative to the eye or frame and to a measure of the invention already in position.

The measures of the invention may also have markings for determining angles, such as of a spectacle frame relative to its sides.

The invention will now be further described by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows an ophthalmic measure; Figures 2, 3 and 4 show separately for convenience the various markings on the measure; Figures 5 to 14 show how various measurements are taken using the measure of Figure 1; Figure 15 shows a lens sizer datum aligned; Figure 16 shows a lens template; Figure 17 shows how a lens template is used; Figure 18 shows another ruler according to the invention; Figures 19, 20 and 21 show the ruler of Figure 18 in use; and Figure 22 shows yet another ruler according to the invention.

Referring to Figure 1 of the accompanying drawings, an ophthalmic measure 10 is made of relatively thin transparent plastics material say about 3-4 mm thick and has a generally regular trapezoidal shape having upper and lower parallel sides 12 respectively and angled sides 16. Its corners 18 at the ends of its longer side are rounded. The markings on the measure are shown separately in Figures 2, 3 and 4 for ease of viewing. In practice it is probable that the three sets of markings shown will be in different colours e.g.

those of Figure 2 in blue, Figure 3 red and Figure 4 green. The markings of Figure 2 will probably be on one side of the measure and the markings of Figures 3 and 4 on the other.

Referring to Figure 2 of the accompanying drawings, the markings shown include an upper longer linear scale 20 marked in millimetres, a lower shorter linear scale 22 marked in millimetres, a datum line 24 intermediate and parallel to the linear scales 20, 22 again marked out in millimetres, a centre line 26 normal to the scales 20, 22, two sets of lens outlines 28, two linear scales 30 transverse to the datum line and two linear scales 32 near the lower corners of the measure.

Referring to Figure 3 the markings shown are two sets of parallel lines 34 arranged in pairs equally spaced from the notional position of the datum line, two sets of circles 36, 37, 38 and cross markings 39 for positioning of the measure relative to the eye pupil, angle lines 40 either side of the notional position of the centre line 26 and radiating from the edge of the upper side 12 of the measure and two sets of lens outlines 42.

Referring to Figure 4 there are shown two sets of lens markings 44.

Turning now to the application of the illustrated measure, in Figure 5 the measure is shown being used to measure head width using the upper linear scale 20 and interpupillary distance using the lower linear scale 22.

In Figure 6, the lower linear scale 22. is used to measure right and left monocular pupillary distance.

In Figure 7 spectacle frame side length is measured using the lower linear scale 22.

In Figure 8 height of spectacle frame bridge above the datum line is measured by centering the frame using the lines 34 with the bridge over the linear scale 30 on which the required height is measured.

In Figure 9 spectacle frame bridge projection is measured using the lower linear scale 22.

In Figure 10 inner rim eye size is measured by centering the frame using lines 34, aligning the inner rim edge with centre line 26 and measuring the distance between opposite rim edges on the datum line. The distance between lenses is also measured from the centre line to the outer edge of the other lens rim on the datum line.

In Figures 11, 12 and 13 measuring for particular lenses is illustrated.

In Figure 14 the angle of frame front relative to the frame arms is measured using the angle scale 40.

Figure 15 shows a measure marked out as a lens sizer datum aligner and Figure 16 shows a lens template for use with the measure of Figure 1. That use is illustrated in Figure 17.

Turning to Figure 18 of the accompanying drawings, an ophthalmic measure 50 is made of. relatively thin transparent plastics material say about 3-4mm thick and has a generally regular trapezoidal shape except for its ends 52 of its longer parallel side 54 being slightly truncated, its corners rounded and its other parallel side 56 having an indent 58 in a mid-region thereof. The indent 58 is to enable the measure to be positioned on the bridge of a patient's nose. Various markings are provided on one side of the measure. By using a three pass printing sequence, the markings can be applied in such a way that the same markings are visible from both sides of the measure.Thus, the first lays down markings to be seen from the opposite face of the measure, the second pass lays down a blanking layer, whereby parts of the first layer, such as numbers, that would be confusing if viewed from the side on which the markings are being printed, are no longer visible from the side of the measure which is being printed, and the third pass lays down those marking to be viewed from that side of the measure.

In this way, as can be seen, there is no requirement to repeat markings on the measure ie., in each half 50A and SOB of the measure, but one set of three pairs of markings can be used with the measure either way round.

As shown, the measure 50 has an upper longer linear scale 60 marked in millimetres, two spaced lower shorter linear scales 62 marked in millimetres, a datum line 64 intermediate and parallel to the scales 60 and 62 but in two sections, the first 64A from one edge of the measure substantially to its centre line 66 and the other 64B extending from near the centre line 66 to midway to the other edge of the measure from the centre line, the datum line 64 being again marked out in millimetres, a linear scale 68 transverse to the datum line 64A in millimetres, and a linear scale 70 in millimetres near to a lower corner of the measure in half SOB of the measure.Additional markings include a two sets of parallel lines 72A and B equally spaced from datum line, a set of lens outlines 74 on half 50A of the measure, a second set of lens outlines 76A (continuous) and 76B (broken) on the half 50B of the measure, a pair of cross markings 78 for positioning of the measure relative to an eye pupil, two pairs of semi-circular markings 80 and angle lines 82 radiating from near the longer side into half 50A of the measure.

The markings of the measure 50 are used in more or less the same way as the corresponding markings of the measure of Figure 1 and examples only are given with reference to Figures 19, 20 and 21. In Figure 19, with the intended spectacle frames in position on a patient and the measure half 50A positioned with linear scale 68 centrally of the eye and centrally of the frame using a pair of parallel lines 72A, B, the varifocal datum height can be measured on scale 68 as can the bifocal datum height and the lens blank size determined by reference to the lens outlines 74.

In Figure 20 using the measure half SOB, again with the frame between a corresponding pair of lines 72A, B and the cross 78 over the pupil of the eye, the varifocal rim height can be measured on scale 70, varifocal blank size can be read from lens outlines 76A for a plastics lens and from lens outlines 76B for a glass lens.

In Figure 21 by moving the measure downwards so that the cross 78 is over the lower eyelid, the bifocal rim height can be measured on scale 70.

Finally in Figure 22 of the accompanying drawings a measure 100 is shown that will have the usual markings but will be usable with templates 102 as shown again with the usual markings. The measure includes a locating rib 104 for slot 106 in the template and the rib is slidable in the X and Y directions for adjusting the position of the template for different measurements without having to move the measure itself.

Furthermore, once the template has been moved to a particular position, the measure can be removed from the patient without losing the relative position of the template and any measurement taken thereon.

The lower edge of the measure 100 has a pair of slidable markers 108 for marking a measurement on a scale along that edge. It should be noted that the measure and the template can be of any desired shape including those already described above.

Claims

1. An ophthalmic measure that is of transparent material and having markings on at least one side thereof for use in determining lens positioning or sizing at least.

2. A measure as claimed in claim 1 made of relatively rigid plastics material.

3. A measure as claimed in claim 1 or 2 having markings on both sides thereof.

4. A measure as claimed in claim 1 or 2 having identical markings visible from both sides thereof.

5. A measure as claimed in any one of claims 1 to 4, wherein its markings include one or more of markings for making linear measurements, markings for measuring angles, markings for aiding correct positioning of the ruler relative to the eye and/or to a spectacle frame and markings to indicate lens blank size and positioning.

6. A measure as claimed in claim 5 wherein different types of marking are in a different colour to the others on the same side of the measure and/or the others of the same type or markings of the same colour are spaced from each other to avoid confusion.

7. A measure as claimed in any one of claims 1 to 6, which is generally regularly trapezoidal in shape.

8. A measure as claimed in claim 7, wherein corners thereof between the longer side and the edge sides are rounded.

9. A measure as claimed in claim 7 or 8 having its corners at opposite ends of its longer parallel side truncated.

10. A measure as claimed in any one of claims 1 to 6 which is trapezoidal but having one edge side meeting the longer and shorter sides at right angles.

11. A measure as claimed in any one of claims 1 to 10 having an indent in its shorter parallel side for positioning thereof on a patients nose.

12. A measure as claimed in any one of claims 1 to 11 having along one or both parallel side, a linear scale.

13. A measure as claimed in any one of claims 1 to 12 having a centre line marking between its side edges.

14. A measure as claimed in any one of claims 1 to 13 having a datum line between and parallel to the upper and lower parallel sides of the measure.

15. A measure as claimed in claim 14, wherein the datum line is marked out as a linear scale.

16. A measure as claimed in claim 14 or 15 having above and below the datum line are a series of spaced pairs of parallel lines.

17. A measure as claimed in claim 15 or 16 having one or more linear scales normal to and crossing the datum line.

18. A measure as claimed in any one of claims 1 to 17 having markings thereon for indicating desired lens size.

19. A measure as claimed in any one of claims 1 to 18 having a marking for positioning the rule over the frame on a patient, the marking being to aid alignment with the eye pupil or lid.

20. A measure as claimed in claim 18 or 19, wherein lens size is indicated by a series of spaced lines representing different lens sizes.

21. A measure as claimed in claim 19 or 20, wherein one pupil position marking and series of lens markings will be provided for single vision lenses, one for glass varifocal lenses and one for plastics varifocal lenses.

22. A measure as claimed in any one of claims 1 to 21 having markings for determining angles.

23. An ophthalmic measure or template substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying drawings.