WO1989007281A1

WO1989007281A1 - Pattern contact lens

Info

Publication number: WO1989007281A1
Application number: PCT/AU1989/000034
Authority: WO
Inventors: Steve Newman; Anthony Phillips
Original assignee: Steve Newman; Anthony Phillips
Priority date: 1988-02-01
Filing date: 1989-02-01
Publication date: 1989-08-10

Abstract

A contact lens (1) comprising at least one pattern (3, 4) and/or opening (4) in the lens and/or groove (2) in or on either the back or front surface of the lens. The pattern (3, 4), opening or groove (2) in combination or individually providing a means to enable proper location of the lens (1) on the eye of a wearer by engagement between the lens, the eye and the eyelid and thereby facilitating the increased transmission of gas through the lens (1).

Description

PATTERN CONTACT LENS The present invention relates to contact lenses and more particularly relates to an improvement in the conventionally known designs of contact lenses which improves lens behaviour on the eye of a wearer.

There are a number of designs presently in existence which are intended to achieve various effects relating to interplay between the cornea, the lens and the eye lids of a wearer. In the past, lenses which usually have a circular appearance from a plan view and a concave outward appearance from a side view and relative to the eye position have had machining performed on them in various ways in an attempt to provide a lens configuration which will enable correct lens orientation on the eye and adequate control of the lens on the eye.

Traditionally the correct lens orientation on the eye has been achieved by providing on the lens surface machined prisms, wedges and truncations.

It is also desirable for a lens to allow transmission of gas between the lens and cornea. Low gas transmission can be a problem.

A contact lens sits in apposition with the cornea or the sclera or both. It is desirable that a lens be able to transmit or allow the passage of oxygen to reach the eye so that natural conditions can be maintained as far as is practicable near the eye and on the eye surface.

Proper orientation of a lens on the eye is necessary for proper correction of astigmatism.

When a lens is oriented in the proper direction the astigmatic error in the lens is closely coincidental with the astigmatic error in the eye. It is essential that this be achieved to prevent visual acuity deteriorating.

The prior art lenses achieve orientation by two main methods. The first relates to prism formation in the lens. This is achieved by machining of the lens surface to allow the eye lids to complement the lens surface configuration thereby assisting in proper location of the lens. In one configuration the lens is thickened towards the bottom.

SUBSTITUTE SHEET j The second method of lens orientation is achieved by zonal thinning. In this case, the top and bottom peripheral areas of the lens are thinned by machining. The eye lid pressure then moves the lens around to find the line of least resistance to thereby hold the lens in the correctly oriented position.

The former method of lens orientation suffers from a number of disadvantages namely; the aforesaid thickened portion or portions of the lens may prevent adequate oxygen transmission through the lens. This can result in oedema or corneal neovascularisation. Another consequence of the lens thickening is wearer discomfort.

The zonal thinning method also has disadvantages. Namely using this method it is difficult to make a lens to the required degree of accuracy and reproducability. The degree of orientation accuracy is not always as good as required and zonal thinning does not work well for high positive powered corrections due to the thinness of the periphery of the lens. The present invention seeks to overcome the aforesaid disadvantages by providing a lens having grooves and/or patterns and/or holes (fenestrations), forming grooves in the front or back surfaces of the lens. The grooves and/or patterns are manufactured into the lens so that they are either proud of or indented into the lens surface according to selected design parameters. The grooves and/or patterns aid in the correct orientation of the lens on the eye and increase gaseous transmission through the lens. Preferably there are a series of grooves, patterns or fenestrations on the lens which are held by the upper eye lid thus aiding lens orientation.

During the blink action the spongy palpebral and/or tarsal bubar conjunctiva grips the indentation in the lens surface and orientates the lens by following the slope of the pattern, grooves or hole fenestrations.

The grooves and/or patterns and/or fenestrations formed on the lens facilitate proper orientation on the eye and without compromise to the relationship between

SUBSTITUTE SHEET | the cornea conjunctiva and lens thereby eliminating discomfort and eye irritation for the contact lens wearer, This type of lens configuration has many advantages over the prior art, for instance, no increase in the lens thickness nor chamferings of the lens surface is necessary for lens orientation as is the case with prior art lens designs; there is almost a limitless number of possible groove, pattern or hole configurations which would achieve the purpose. In addition, it is possible to adapt the grooves to lenses which already have zonal thinning or prism ballast to aid or modify the orientation. Another advantage is that there is an increase in oxygen transmission through the lens resulting from the patterns, holes and/or grooves. In one embodiment the grooving is applied to bifocal contact lenses to improve location of the lens for alternating vision.

In one broad form the invention comprises: a contact lens of the type having a toroidal surface, said lens having either random grooves disposed in a regular or irregular array and of constant or variable length, depth and width, or random patterns formed in the back or front surface of the lens. In another form the invention comprises: a lens having at least one groove in either its front or back or both surfaces, said groove or grooves providing a discontinuity in the thickness in the lens at the location of the grooves, said grooves providing a means for location of the lens on an eye. In a further form the invention comprises a contact lens having formed on either the back or front or both surfaces at least one patterned formation said patterned formation or formations providing a means to enable proper location of the lens on an eye. In its broadest form the present invention comprises an improved contact lens characterised in that the lens comprises at least one pattern and/or opening in the lens and/or at least one groove in or on either the back or front surface of the lens, said at least one pattern and/or opening and/or groove in combination or individually providing a means to enable proper location and orientation of a lens on the eye of a wearer by engagement between said lens, said eye and an eyelid thereby facilitating the increased transmission of gas through said lens.

In the preferred embodiment the grooves, and/or patterns and/or openings are arranged so as to allow the eyelid of a wearer to follow the contours of the said grooves and/or patterns and/or openings to enable the proper orientation of the lens on the eye.

In another embodiment the grooves are parallel and formed in series near the edge of the lens. Alternatively, the grooves can be disposed in a radial array around the periphery of the lens or merely disposed randomly across either the front or back surface of the lens.

In another embodiment patterns are formed at any position on the lens surface either back or front or both according to user requirements.

In one embodiment it is preferable to have the grooves and/or patterns marked on the back surface on the lens to eliminate the potential for Vivo protein deposition. In this case the natural flexibility of the lens will transfer the groove or pattern effect through to the front surface of the lens and thereby interact with the spongy tarsal conjunctiva.

This method or orientation and/or specific modulas can be caused by specific interaction with the upper and/or lower tarsal conjunctiva, the interaction with the palpebral conjunctiva or a combination of various in vivo physiological forces which may or may not include one or both or a combination of the above mentioned forces.

This design is a method or harnessing lid forces and various physiological forces pertaining specifically to the eye and its various movements and actions.

The specific location or movement or physiological improvement in oxygen availability to the cornea is achieved with either a lack of prismatic or wedge or thin

SUBSTITUTE SHEET zone forces or a reduction of these forces from traditional amounts.

The patterns or grooves may be raised proud of the surrounding surfaces or can be indented into these surfaces or can be a combination of both. The patterns may be in any shape or form. The patterns or shapes whether they be raised above the surrounding surfaces or indented below the surfaces can be used to prevent and/or alleviate the "binding" of rigid lenses or silicone (or similar) lenses on the cornea during wear. Binding is a known phenomenon and results in fitting complications in this type of lens wear. It can lead to epithelial denuding of the cornea with consequent risk of infection or ulceration. It can cause ocular problems such as anoxia and/or oedema during wear. The grooves, holes or patterns have the effect of alleviating the binding effect. The fenestrations or holes may be included either in conjunction with the patterns or they may constitute the role method of lens stabilisation. The grooves or patterns can be used to move the lens in a specific fashion to create bifocal effects, for example alternating vision.

The invention will now be described in more detail according to preferred but non-limiting embodiments and with reference to the accompanying illustrations wherein: Figure 1: shows a front elevational view of a contact lens according to one embodiment of the invention. Figure 2: shows a front elevational view of a contact lens according to an alternative embodiment. Figure 3: shows a front elevational view of a contact lens according to an alternative embodiment. Figure 4: shows further possible embodiments of the invention.

Referring to Figure 1, there is shown a contact lens 1 having an array of parallel grooves 2 disposed in an upper half segment of the lens. The array shown is one possible embodiment only and it is envisaged that there is almost no limit to the number of groove permutations and combinations.

UBSTITU To this extent the grooves can be of varying lengths, depths and widths according to particular user requirements.

Figures 2 and 3 show further embodiments of the invention but this time there are patterns 3 and 4 respectively formed on the surface of the lens. Again, as with the grooves, there is virtually a limitless number of possible patterns which can be formed.

Although not shown in the figures, in another embodiment of the invention, the lens can be configured with a combination of grooves, holes and patterns according to user requirements. The grooves and patterns can be formed according to any particular shape, depth configuration or combination. The use of the grooves and patterns essentially has a twofold purpose. Firstly, they provide a facility for increasing (locally, if necessary) the oxygen transmission through the lens. Secondly, they provide means to enable effective and accurate lens location on the eye, also taking into account the physiological response in the eye. To this end the pattern, groove or hole configuration will often be dictated by the physiology of the eye of the wearer.

Oxygen deprivation in the eye can cause long term eye damage and the present invention seeks to alleviate this problem which existed with prior art lens designs.

The physiology of the eye and eyelid interrelation is critical to the operation of the lens of the present invention. Nearly a third of the thickness of the eyelid is made up of the striated orbicularis oculi muscle, which is bordered anteriorly and posteriorly by loose non-adipose connective tissue. The orbicularis is a thin muscle surrounding the palpebral aperture and extending well beyond the orbital margin on to the face.

Structurally and functionally, the muscle is divisible into orbital and palpebral portions. The orbital portion lying beyond the orbital margin with the palpebral portion lying within it.

SUBSTITUTE SHEE In waking hours, the upper eyelid is very active as a result of reflex blinking involving the palpebral portion of the orbicularis muscle. A basic rhythm of blinking occurs at a frequency of at least 12 blinks a minute according to authorities. Alterations of the rate of blinking are produced by many factors such as anxiety, noise or even a stuffy atmosphere. A blink is completed in less than one third of a second. During this period the eye makes a rapid upwards and inwards movement and return. Studies have found this movement to be between 20 and 100 minutes of arc nasally and between 40 to 70 superiorly when the eyes were initially in the primary position. This small displacement is insufficient to account for the movement of a contact lens relative to the eye during a blink. Clearly it is the traction of the eyelid that causes the lens movement.

The force exerted against a contact lens during reflex blinking is considerable. It has been reported that the globe is pressed back approximately 1.25 mm during blinking. In the days of non-flexible (hard) lenses this pressure produced marked corneal distortion over years of wear and with current rigid gas permeable (flexible) lenses the lens itself may become distorted on astigmatic corneas. It is the utilisation of this force or pressure in conjunction with the new lens designs that is proposed to provide the orientation of the lens necessary in the correction of astigmatism and the movement necessary to produce the required lens movement in the bifocal design. Present astigmatic correcting lenses utilise either a single prism (base or "thick" part downwards) or bi-prism (central, "thick" zone and "thin" top and bottom edges) designs. In both designs the upper lid pressure moves the lens to place the line of least resistance in the vertical meridian. The central optic zone of the lens contains the astigmatic correction for the individual eye and the peripheral zone contains the prismatic element(s) for orientation. The disadvantages of the prior art prismatic designs are;

¹. ^Difficulty in accurate manufacture

2. Difficulty in reproducibility

3. Difficulty in modification

4. Poor physiologically because of lens thickness in some designs

5. The principle works less efficiently in positive powered lenses since these are already thin at the upper and lower edges

6. There is slight loss of comfort in some designs compared to spherical lenses.

Almost all present soft bifocal designs currently work on the simultaneous vision principle, i.e. both near the distance foci are directed through the pupil at the same time. ^None have proven particularly successful for the following reasons;

1. Loss of visual quality of both distance and near vision

2. Loss of distance or near vision quality with variations in pupil size ³- Complex manufacture leads to mediocre reproducibility

4. Complex manufacture leads to relative high cost.

In the proposed new astigmatic design lid pressure is utilised to provide a frictional force to orientate the lens. This is achieved by means of either a raised or lowered area at the peripheral, horizontal area of the lens as hereinbefore described. Thus, rather than a prismatic zone decreasing in thickness over a wide lens areas a small raised zone or depressed zone is utilised leaving the average lens thickness similar or close to a non astigmatic lens of similar power. The raised or depressed areas may be lathe cut or even produced as multiple fenestrations. However they are best created by moulding or laser sculpturing.

In the case of a bifocal lens a depression is created in the superior lens area by moulding or laser sculpturing. By utilising narrow but deep grooves, for example in the form of a chain or horizontal figure 8, lid pressure forces the soft conjunctiva into the

{ SUBSTITUTE SHEET grooves. In this way both lens orientation is achieved and also lens movement on blinking (a sufficiently flat fit and suitable lens thickness is assumed) . Thus an alternating bifocal lens design (i.e. a distance top area and lower reading area) can be produced which then allows reading vision or inferior gaze in the same manner as a spectacle bifocal. Multifocal design could also be utilised.

Superior depressions in the lens could also be used to change the axis of an incorrectly locating astigmatic lens.

According to the method aspects of the invention, the grooves and patterns can be formed by any one of a number of processes, including but not limited to: a) Laser Engraving; b) Mechanical Engraving; c) Moulding; and d) Spincasting.

The laser or mechanical engraving techniques can utilise manual or computer controlled facilities according to requirements.

The moulding method employs conventional moulding techniques whereby the lens profile is formed by a minor profile in the mould. Conventional techniques are also employed with the spin casting method.

It will be recognised by persons skilled in the art that numerous variations and modifications can be made to the present invention, such as, but not limited to placing of grooves and/or patterns into a lens whether hard or soft or into the back or front surface or both without departing from the overall spirit and scope of the invention as broadly described herein.

i SUBSTITUTE SHEET j

» I, <

Claims

THE CLAIMS :

1. An improved contact lens characterised in that the lens comprises at least one pattern and/or opening in the lens and/or at least one groove in or on either the back or front surface of the lens, said at least one pattern and/or opening and/or groove in combination or individually providing a means to enable proper location and orientation of a lens on the eye of a wearer by engagement between said lens, said eye and an eyelid and thereby facilitating the increased transmission of gas through said lens.

2. A contact lens according to claim 1, wherein the opening or openings and/or groove or grooves and/or pattern or patterns are fabricated in or on a lens according to prescription requirements of a wearer.

3. A contact lens according to claim 2 wherein the said pattern and/or opening and/or grooves are arranged on or in the lens to enable the eyelid to follow the contours of the openings and/or patterns and/or grooves thereby allowing proper orientation of the lens on the eye.

4. A contact lens according to claim 3 wherein the said groove or grooves are formed by either an indentation or indentations respectively in or reliefs on the lens surfaces such that the grooves are either proud of or recessed into the lens surface.

5. A contact lens according to claim 4 wherein the said grooves are disposed radially about the front and/or back surface of said lens.

6. A contact lens according to claim 5 wherein the said grooves are disposed either vertically, horozontally or diagonally relative to the axes of said lens.

7. A contact lens according to claim 6 wherein the said grooves are disposed randomly across the front and/or back surface of the lens.

8. A contact lens according to claim 7 wherein the said grooves are of irregular shape.

9. A contact lens according to claim 8 wherein the grooves are substantially ovoid.

SUBSTITUTE SH

10. A contact lens according to claim 8 wherein the said grooves have variable depths and widths within each groove and relative to other grooves in the lens surface.

11. A contact lens according to claim 7 wherein the said grooves are of constant cross section.

12. A contact lens according to any one of the foregoing claims wherein the said opening or openings pass through the full thickness of the lens.

13. A contact lens according to claim 12 wherein the pattern or patterns and/or opening or openings and/or grooves are adaptable to bifocal lenses.

14. A contact lens according to claim 13 wherein the patterns and/or openings and/or grooves are adaptable to lenses having zonal thinning.

15. A contact lens according to claim 14 wherein the openings are disposed in close proximity to each other to form at least one group of openings.

16. A contact lens according to claim 15 wherein the openings and/or grooves are configured on the lens according to the physiological characteristics of the eye and eyelid of the wearer.

17. A contact lens according to claim 16 wherein the said pattern or patterns are formed by cuts, etchings or indentations or reliefs on the lens surface.

18. A contact lens according to claim 17 wherein the said patterns, grooves or openings may be disposed in any position on the lens surface.

19. A contact lens according to claim 3 wherein the patterns are formed on either side of the lens shaped in the form of triangles at least one of which is disposed in each of the lower quadrants of said lens.

20. A contact lens according to claim 3 wherein a group of openings substantially defining a diamond shape at or near the periphery of the lens and symmetrical about a horizontal neutral axis of said lens.

21. A contact lens according to claim 3 wherein a patterned S shape is formed at or near the uppermost region of the lens.

22. A contact lens according to claim 3 wherein a grid pattern is formed in each of the lower quadrants of the

SUBSTI lens and near the lens periphery said grid pattern being: triangular and formed by openings in said lens.

23. A contact lens according to claim 3 wherein said pattern or patterns may be in any shape or form on the surfaces of the lens.

24. A contact lens according to any of the foregoing claims wherein the said grooves or patterns can be configured to create a bifocal effect in said lens.

25. A contact lens according to claim 24 wherein the said contact lens is any one or a combination of spherical, toric or bifocal lenses.

26. A method of manufacturing a lens according to any one of the foregoing claims using one or more of the techniques of laser engraving, mechanical engraving, moulding and spincasting.

27. A contact lens as hereinbefore described and with reference to the accompanying illustrations.

SUBSTITUTE SH IEEEETT