FIELD OF THE INVENTION

The invention relates to a contact lens, and in particular to a contact lens for further improving a user’s near and/or distance vision.

BACKGROUND TO THE INVENTION

A human eye has a lens which is provided to focus light from an object being viewed onto the retina. The lens is somewhat flexible and its curvature can change to enable the viewing of distant objects or nearby objects, as desired. Many individuals, however, have imperfect vision and need assistance to clearly view distant objects or to clearly view nearby objects (or in some cases both). Optometrists can measure the degree and type of imperfection of an individual’s eyes and provide a physical lens to correct or at least reduce the effect of the imperfection. The physical lens is typically provided as part of a pair of spectacles or as a contact lens.

The near vision of many individuals worsens with age, in that it often becomes more difficult to clearly view nearby objects such as the words in a book for example. Reading glasses which can improve a user’s near vision are therefore in widespread use.

The human eye has an iris forming an aperture (the pupil) through which light can enter the eye. A healthy iris can dilate in low-light conditions and contract in bright light so as to adjust the amount of light passing to the retina.

A camera also uses a lens (or in most cases multiple lenses) to focus the light from an object onto a film or a charged-coupled device (CCD). Most cameras also have an adjustable aperture to control the amount of light passing to the film or CCD.

It will be understood that the term “contact lens” describes a component which in use directly contacts a user’s eye and through which light can pass to the user’s pupil and retina. Some contact lenses are clear and permit almost 100% of the incident light to pass through. Other contact lenses are tinted and allow a slightly reduced proportion of the incident light to pass through. Some contact lenses are tinted specifically to reduce or avoid a user’s colour-blindness. Other contact lenses are coloured and/or patterned to change the appearance of the user’s eye.

Most contact lenses can focus light from an object to a point. However, some contact lenses do not focus light, for example changing the appearance of a user’s eye is the sole function of some contact lenses. For ease of understanding, the term “contact lens” in this specification will embrace those contact lenses which act to focus light and also those contact lenses which do not act to focus light. To differentiate between these different types of contact lenses in this specification, a contact lens which acts to focus light will be referred to a focussing contact lens and a contact lens which does not act to focus light will be referred to as a plain contact lens. The term focussing contact lens will include contact lenses which cause light to converge to a point or to diverge from a point, lenses of both types being used to correct imperfect vision. Unless the context requires otherwise, the more general term “contact lens” will be used for both a focussing contact lens and a plain contact lens.

It will be understood that the light from an object travels as waves. A focussing contact lens causes the wavefronts to bend so that they may be focussed at a desired point. Multiple waves pass from each point of the object through the focussing contact lens to create an image on the retina. To create a clear or sharp image the different waves from the same point on an object which pass through different parts of the focussing contact lens must reach the same point on the retina. If the focussing contact lens is imperfect or is not properly suited to the user, light from the same point on the object which pass through different parts of the focussing contact lens will not reach the same point on the retina and the image will be blurred.

A pin hole camera is a device which can create a clear image without a lens. The camera has a substantially opaque surface with a very small hole through which light can pass to a film or screen. The device operates by restricting the aperture through which light can pass and thereby reducing the range of different paths for the light to pass from each point on the object to the film or screen. Reducing the range of different paths which the light can take has the effect of reducing the blurring and thereby creating a clearer image.

It is known to use the principle of a pin hole camera (or the pin hole effect) also in spectacles, whereby the spectacle lens is generally opaque and has a small hole through which the light can pass to the user’s eye. The user’s iris is therefore effectively bypassed with the size of the aperture through which light can pass to the retina being determined by the small hole rather than by the user’s iris. The focussing effect of the eye lens is therefore limited and the blurring caused by imperfections in that focussing effect is reduced.

SUMMARY OF THE INVENTION

According to the invention there is provided a contact lens with a substantially opaque region surrounding an aperture.

It is intended that the aperture will lie over the user’s pupil in use and at least some of the user’s pupil will be obscured by the opaque region. The opaque region therefore restricts the area through which light can pass to the user’s retina and therefore reproduces the pin hole effect to enhance the user’s vision.

It will be understood that references to “opaque” in this specification will include almost opaque, i.e. it is not necessary that 0% of the incident light can pass through the opaque region of the contact lens. For the pin hole effect to operate effectively it is necessary that almost no light passes through the opaque region and almost all of the light passing to the user’s retina passes through the aperture. However, a material which allows a small proportion of the incident light to pass through to the user’s retina can be effective and will therefore fall within the term “opaque”.

Desirably, the aperture has a dimension in the range from approx. 1 mm to approx. 3 mm. Ideally the minimum dimension for the aperture is precisely 1 mm. Ideally also the largest dimension for the aperture is precisely 3 mm. It is understood that an aperture with a dimension less than approx. 1 mm will significantly reduce the amount of light which passes to the retina. The enhancement in the vision produced by such a small aperture is expected in many circumstances to be more than offset by the reduction in clarity caused by the reduced amount of transmitted light. Accordingly, an aperture dimension of approx. 1 mm is believed to be the minimum in a practical contact lens for most individuals.

It is also understood that the iris of some individuals can contract to a diameter of approx. 3 mm. Providing a maximum dimension for the aperture which is larger than 3 mm might therefore provide no restriction over the user’s iris and have little if any benefit in practice. Accordingly, a dimension of approx. 3 mm is believed to be the maximum in a practical contact lens for most individuals.

Contact lenses according to the invention can be provided with an aperture dimension of 1 .0 mm, or 1 .5 mm, or 2.0 mm, or 2.5 mm, or 3.0 mm (all approx.). Contact lenses with apertures having intermediate dimensions (e.g. 2.3 mm) can be provided if desired, but it is expected that the degree of vision enhancement provided by smaller differences in aperture dimension (for example between an aperture dimension of 2.3 mm and an aperture dimension of 2.5 mm) will not be discernible to most users.

The contact lens can be a focussing contact lens. When using such a contact lens the user’s vision will be enhanced firstly by the focussing effect of the contact lens and secondly by the pin hole effect of the aperture. The focussing contact lens can have a particular focussing power suited to an eye of a particular individual, or the focussing lens can have a standard focussing power suited to the eyes of many individuals. The latter can if desired be suited to reading, having a focussing power of +1 diopter for example.

The opaque region can occupy the whole of the contact lens apart from the aperture, i.e. the opaque region can extend to the outer edge of the contact lens. Alternatively, the contact lens can have a transparent region outside all or part of the opaque region. For example, the opaque region can be a ring surrounding the aperture, which ring is itself surrounded by a transparent region. Provided that the opaque region covers the outer part of the user’s pupil no light will pass through the surrounding transparent region to the user’s retina. The contact lens at the aperture can be polarised and/or tinted/coloured to further reduce the amount of light entering into the eye. Such a contact lens can be suited to use in bright conditions (for example to replace or supplement sunglasses), or for users who are colour blind and are assisted by viewing objects through a particular colour filter. The opaque region can be polarised and/or tinted similarly to the aperture. The aperture (and the opaque region as desired) can be made photochromic and become more tinted in brighter conditions.

The aperture can be circular in which case the references to “dimension” of an aperture will equate to “diameter”. Alternatively, the aperture can be non-circular such as oval, or polygonal such as square, diamond-shaped, oblong or triangular for example. In these alternative-shaped apertures the references to “dimension” will generally equate to the length of the shorter sides, or to the distance between opposing edges of the particular aperture.

Preferably the aperture is transparent. In other words the aperture is a space in the opaque region with for example the opaque region being printed or otherwise formed on the surface or into the material of the contact lens and the aperture being defined by an absence of printing. Providing a transparent aperture in the opaque region allows the material of the contact lens to be continuous which is expected to be the most comfortable arrangement for most users. Alternatively, the aperture can be a physical hole through the material of the contact lens (although a physical hole in the contact lens may be uncomfortable for some users).

Desirably, some or all of the opaque region can be patterned and/or coloured. Since this region of the lens is opaque it is possible to apply a chosen pattern without impairing the user’s view. For example, the opaque region can carry an image to change the appearance of the user’s eye, perhaps to a different eye colour, or otherwise patterned for example with a flag, logo, emoji or other pattern, as desired, and which is visible to observers when the contact lens is being worn. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:

Fig .1 represents a user’s eye and a contact lens according to the present invention;

Fig.2 shows a front view of the contact lens of Fig.1 ;

Fig.3 shows a front view of an alternative design of contact lens;

Fig .4 shows a front view of another alternative design of contact lens;

Fig.5 shows a front view of yet another alternative design of contact lens;

Fig.6 shows a front view of a further alternative design of contact lens;

Fig.7 shows a front view of another further alternative design of contact lens; and

Fig.8 shows a front view of yet another further alternative design of contact lens.

DETAILED DESCRIPTION

Fig.1 represents a human eye 10 and a contact lens 112. A front view of the contact lens 112 is shown in Fig.2. Whilst a small gap is shown between the surface of the eye 10 and the contact lens 112 in Fig.1 that is solely for the purposes of clarity and in practice the contact lens 1 12 will directly engage the eye 10.

The contact lens 112 is a plain contact lens having a uniform thickness. In an alternative embodiment the contact lens is a focussing contact lens, in which typically its inner and outer surfaces (i.e. the curved surfaces which face towards and away from the eye respectively) are not parallel. In addition, it will be understood that in practice the contact lens 112 will taper towards its outer edge so that when the user closes the eye 10 the eyelids ride smoothly over the edge of the contact lens 112.

The contact lens 1 12 has a substantially opaque region 114 surrounding an aperture 1 16. A border 118 defines the edge of the aperture.

The user’s pupil 20 is also represented in Fig.1 . The pupil 20 has a diameter P and it will be understood that the diameter of the pupil will typically vary dependent upon the light conditions, the iris surrounding the pupil dilating or contracting to adjust the amount of light passing through the pupil 20. The diameter P represents the smallest diameter for the user’s pupil 20, i.e. as will typically occur in bright light.

As shown in Fig.2, the aperture 1 16 is circular and has a diameter A. It is arranged that the diameter A is smaller than the diameter P so that the contact lens 1 12 artificially restricts the area of the pupil 20 (and thereby the eye lens (not shown)) through which light can pass to the retina, and thereby provides a pin hole effect.

In this embodiment the opaque region 1 14 is totally opaque, i.e. it allows 0% of light to pass through, but that is not essential and an opaque region which allows a small proportion of incident light to pass through is within the scope of the invention. Accordingly, an object can only be properly viewed through the aperture 116.

In this embodiment also the aperture 1 16 allows 100% (or substantially 100%) of incident light to pass through to the pupil 20, but that is also not essential and in other embodiments the aperture 116 can be polarised and/or tinted as described below. The difference in light transmission between the aperture 116 and the opaque region 114 is sufficient to ensure that a user’s view of an object is effectively totally determined by the aperture 116 so as to benefit from the pin hole effect.

It will be understood that, in common with known contact lenses, the contact lens 1 12 generally moves with the user’s eyeball so that the aperture 1 16 remains approximately centred over the pupil 20 as the eyeball moves within its socket. In an alternative embodiment in which the contact lens is a focussing contact lens, the focussing contact lens can be provided to assist with reading for example, with the focussing contact lens having a focussing power of +1 diopter for example. A user’s vision for nearby objects will therefore be enhanced firstly by the focussing effect of the contact lens. The user’s vision for nearby objects will secondly be enhanced by the pin hole effect of the aperture 116. The focussing part of the contact lens can be restricted to the aperture 1 16, or it can also extend across some or all of the opaque region 1 14, as desired.

In another alternative embodiment the focussing contact lens is configured to correct a specific user’s imperfect vision in one eye (or both eyes if the same correction is required for both of the user’s eyes). For example, the focussing contact lens can be configured to allow a specific (short sighted) user to clearly view distant objects and therefore be suited for driving and the like.

The opaque region 1 14 is printed onto at least one of the inner and outer surfaces of the contact lens 1 12 (i.e. the curved surfaces which face towards and away from the eye 10 respectively) and the aperture 116 is a gap or space in that printing. In an alternative embodiment the opaque region is formed by impregnating an opaque material into the material of the contact lens.

It is expected to be most cost-effective for the whole of the contact lens to have the same focussing power. The invention is not, however, limited to that, and it is possible for the aperture to be a focussing lens and for the opaque region to be a plain lens as desired. It is also possible to provide a bifocal contact lens having two different focussing powers within the aperture.

The opaque region 114 can be coloured or tinted (which words are used interchangeably in this description and describe a uniform colouration across the contact lens). Alternatively, the opaque region 1 14 can be multicoloured and/or patterned, i.e. having a non-uniform arrangement of colours to produce an image which is visible to an observer. The image can be a picture of an object such as an emoji or flag for example, or can be an abstract image and/or a multi-coloured image. The image can change the appearance of the eye 10 as desired. Figs. 3-8 show different embodiments of contact lenses 212, 312, 412, 512, 612 and 712. These contact lenses are shown to be larger than the contact lens of Fig.2 but that is for the purposes of clarity only and in practice the contact lenses are all (substantially) the same size (and preferably the same size as known contact lenses).

The contact lens 212 has a tinted (and/or polarised and/or photochromic as desired) aperture 216. The aperture 216 is nevertheless transparent and thereby distinguished from the opaque region 214. It is ideally arranged that the colouring of the aperture 216 matches that of the opaque region 214 so that the contact lens 212 appears to an observer to be the same colour throughout. Alternatively, the colouring of the aperture 216 can differ from the colouring of the opaque region 214.

The border 218 between the aperture 216 and the opaque region 214 is shown in Fig.3 but may not be visible in practice (and similarly for the other embodiments).

The contact lens 312 of Fig.4 has a tinted (and/or polarised and/or photochromic as desired) aperture 316. In this contact lens the opaque region 314 does not extend to the outer edge of the contact lens and comprises a discrete ring around the aperture 316. The opaque region therefore effectively resembles a thick border around the aperture. A transparent region 322 surrounds the opaque region 314. It should be arranged that the outer edge of the opaque region 314 is at least as large as the user’s pupil when the iris is fully dilated so that all of the light passing to the retina passes through the aperture 316 regardless of the light conditions. The diameter of the outer edge which separates the opaque region 314 from the transparent region 322 may be 8-10 mm for example.

In the embodiments of Figs. 1 -4 the diameter A of the aperture 116, 216, 316 is 3.0 mm. In the alternative embodiment of Fig.5 the diameter of the aperture 416 is 1.5 mm. Contact lenses with other aperture diameters can be provided, preferably between approx. 1.0 mm and approx. 3.0 mm. The contact lens 512 of Fig.6 differs from those of Figs.1 -5 in having a square aperture 516. With a square aperture the term “dimension” most appropriately refers to the length of each edge of the square.

The contact lens 612 of Fig.7 differs from those of Figs.1 -5 in having a triangular aperture 616. The triangular aperture 616 is an equilateral triangle but it could alternatively be an isosceles or scalene triangle. With triangular apertures the term “dimension” most appropriately refers to the length of the shortest edge.

The contact lens 712 of Fig .8 differs from those of Figs.1 -5 in having an oblong aperture 716 with the longer axis of the oblong being horizontal. With oblong apertures the term “dimension” most appropriately refers to the length of the shorter edges (which are the vertical edges in this embodiment).

The embodiments of Figs. 6-8 demonstrate that the invention is not limited by the shape of the aperture and apertures of shapes other than those shown can also be used (including oval, diamond-shaped, pentagonal or hexagonal, for example).

The apertures 416, 516, 616 and 716 are shown without any tint or colour but the contact lens could be tinted and/or polarised and/or photochromic as desired similarly to that described above. These contact lenses could also include a transparent region outside the opaque region similar to that of Fig .4, as desired. In these latter embodiments the outer edge which separates the opaque region from the transparent region could be circular or could be square, triangular or oblong respectively to match the shape of the aperture, as desired.

Whilst the border 118 etc. may not be visible in some practical embodiments, it is likely that the opaque region 114 etc. will be visible. In particular, in embodiments with a transparent region outside the opaque region, it is expected that the outer edge which separates the opaque region from the transparent region would be visible to an observer. The opaque region could therefore be used to create an image or part of an image. For example, the outer edge of the opaque region could be made into the shape of a chosen image (such as the shape of a country or continent for example). Accordingly, the contrast between the opaque region (e.g. 314) and the transparent region (e.g. 322) could be used to create a chosen image (or part of an image) upon the contact lens.