FIELD OF THE INVENTION

The invention relates to a vision enhancing optical device, and in particular to an optical device for improving a user’s near and/or distance vision.

Directional and orientational terms such as “top”, “bottom” etc. refer to the optical device in its normal orientation of use as represented in Figs. 1 -4. The optical device may, however, be used in other orientations.

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 harder to clearly view nearby objects such as the words in a book for example. Reading glasses which can improve are user’s near vision are therefore in widespread use.

The human eye has an iris forming an aperture through which light can enter the eye. A healthy iris can expand in low-light conditions and contract in bright light so as to optimise 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 word “lens” can be used to describe an element through which light can pass, the lens having opposing surfaces of which at least one is curved and which can focus light from an object to a point. The word “lens” can also be used to describe the optical component of a pair of sunglasses for example, notwithstanding that the glass in most sunglasses is plain and does not focus the light. For ease of understanding, the word “lens” in this specification will be used to describe the optical element of the invention through which light passes, whether or not the optical element acts to focus light, and whether or not the optical element is a part of a pair of spectacles. When differentiating between the different types of optical element in this specification, a lens which acts to focus light will be referred to a focussing lens and a lens which does not act to focus light will be referred to as a plain lens. The term focussing lens will include 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 “lens” when used alone will be used for both a focussing lens and a plain lens.

It will be understood that the light from an object travels as waves. A focussing 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 lens to create an image on the retina or film (for example). 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 lens must reach the same point on the retina or film. If the focussing lens is imperfect or is improperly focussed, light from the same point on the object which pass through different parts of the focussing lens will not reach the same point and the image will be blurred.

A pin hole camera is a device which can create a clear image without a focussing 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. Some spectacles of this type have multiple holes but it is understood that the multiple holes are used individually, i.e. the light passes from an object to the retina through only a single hole and the multiple holes simply make it easier for the user to locate the object. 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. The known spectacles of this type have plain lenses.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vision enhancing optical device which utilises the pin hole effect.

It is another object of the present invention to provide a vision enhancing optical device which does not require specialised fitment as by an optometrist.

It is another object of the present invention to provide a vision enhancing optical device which can be used by different individuals with different imperfections of their eye lens, whereby a single design of optical device is widely usable.

According to a first aspect of the invention there is provided a vision enhancing optical device having a lens with a substantially opaque region and a plurality of apertures in the substantially opaque region, the apertures being of differing dimensions.

Providing multiple apertures of differing dimensions enables a user to vary the degree of vision enhancement by viewing the object through a different-dimension aperture. In particular, it is expected that most users will achieve a clearer image of an object by using a smaller aperture. The user can select an aperture with the most suitable dimension to provide the desired degree of vision enhancement. Desirably, there are apertures of two different dimensions. Preferably, however, there are apertures of three different, or four different, dimensions.

Desirably, the apertures range in dimension from approx. 1 mm to approx. 3 mm. Ideally the smallest aperture(s) have a dimension of precisely 1 mm. Ideally also the largest aperture(s) have a dimension of precisely 3 mm. In embodiments having apertures of three different dimensions the dimensions can be (approx.) 1 mm / 2 mm / 3 mm, or 1 mm / 1 .5 mm / 2 mm, or 1 .5 mm / 2 mm / 2.5 mm, or 2 mm / 2.5 mm / 3 mm, for example. In embodiments having apertures of four different dimensions the dimensions can be (approx.) 1 mm / 1.5 mm / 2 mm / 2.5 mm, or 1.5 mm / 2 mm / 2.5 mm / 3 mm, for example.

Preferably, the relative dimensions of the different-sized apertures differ by 0.5 mm. Such a difference in relative dimensions is expected to provide suitably differentiated degrees of vision enhancement. Smaller or larger differences between the different apertures can nevertheless be provided if desired.

It is understood that an aperture with a dimension less than approx. 1 mm will significantly reduce the amount of light which passes into the eye. 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 light. Accordingly, an aperture dimension of approx. 1 mm is believed to be the minimum in a practical device 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 device for most individuals.

Preferably, multiple apertures of each of the different dimensions are provided. Providing multiple apertures of each of the different dimensions makes it easier for the user to observe an object through an aperture of the chosen dimension. This is particularly beneficial when the optical device is configured as a pair of spectacles in which the position of the lenses is relatively fixed in relation to the user’s eyes. It is therefore not necessary for the spectacles to be fitted by an optometrist or other specialist as would be required to align a single aperture in each lens with each of the user’s eyes. The provision of multiple apertures of each of the different dimensions therefore makes a particular optical device more universal and in particular suitable for different individuals with different spacings between their eyes. The provision of multiple apertures of each of the different dimensions is also expected to make the optical device suitable for sale alongside standard reading glasses for example, and by nonspecialised retailers.

The lens can be a focussing lens. When using such an optical device the user’s vision will be enhanced firstly by the focussing effect of the lens and secondly by the pin hole effect of the apertures. The optical device can be configured similarly to standard reading glasses, for example with a defined focussing power (such as +1 diopter / +1 .5 diopters (for example) as with standard reading glasses). Alternatively, the focussing lens can be a lens with a particular focussing power suited to an eye of a particular individual. Whilst such lenses normally require an optometrist to determine the focussing power required to correct the imperfection of a user’s eye, and the resulting optical device is suited to one particular user, the invention is nevertheless applicable to such use if desired.

Preferably, neighbouring apertures are closely-spaced whereby the opaque region between adjacent apertures is relatively small and it is easy for the user to locate and view an object through an aperture.

Desirably, the multiple apertures of each particular dimension are arranged in a row, i.e. horizontally. The user can therefore move his or her eyes and/or head left and right to view an object through a different aperture without changing the size of the aperture through which an object is viewed and therefore without changing the degree of vision enhancement.

Desirably, the apertures in each row are relatively closely spaced so that the user does not need to move his or her head and/or eyes very far in order to view an object through a different aperture. Also, the close spacing of neighbouring apertures increases the likelihood that a user can comfortably view an object through apertures in both lenses of a pair of spectacles (for example) without requiring the spectacles to be adjusted for his or her particular eye separation. A spacing of approx. 2 mm (edge to edge) between neighbouring apertures is expected to be suitable, but smaller or larger spacings are within the scope of the invention. The spacing between neighbouring apertures in each row can if desired vary according to the dimension of the apertures in that row. Preferably, the spacing between neighbouring apertures will be smaller if the apertures are smaller (and vice versa).

Preferably, the apertures of different dimensions are arranged vertically (i.e. the aperture of a first dimension is above an aperture of a different dimension). The user can therefore move his or her eyes and/or head up and down to change the size of the aperture through which an object is viewed and therefore change the degree of vision enhancement. The aperture of the first dimension can be directly above (i.e. vertically aligned with) the aperture of a different dimension if desired.

Preferably, neighbouring rows of apertures are relatively closely spaced so that the user does not need to move his or her head and/or eyes very far in order to view an object through an aperture in the neighbouring row. A spacing of approx. 2 mm (edge to edge) between neighbouring rows of apertures is expected to be suitable, but smaller or larger spacings are within the scope of the invention. The spacing between neighbouring rows can also vary according to the dimension(s) of the apertures in those rows.

Desirably, the apertures with a smaller dimension are located below the apertures with a larger dimension. This is a particularly beneficial feature when the optical device is used for reading and the like, the user being able to lower his or her line of sight to view a nearby object (such as a book for example). Conversely, the user is able to raise his or her line of sight to view more distant objects.

The opaque region can occupy the whole of the lens apart from the apertures. With such a lens an object can only be viewed through the lens by way of an aperture. Such an embodiment would be suitable for use in sunglasses, ski goggles and the like where it is desired to restrict the amount of light entering the eyes. It can be arranged that the largest apertures are smaller than the user’s iris when contracted and since an object can only be viewed through an aperture the amount of light entering the eye will be reduced. The lens at the apertures can also be polarised and/or tinted to further reduce the amount of light entering into the eye through an aperture. Ski goggles (for example) incorporating the invention can have a reflective coating applied to the outer surface of the whole of the (typically plain) lenses so that the reflective coating covers the opaque region and all of the apertures.

Preferably, however, the lens also has a transparent region, i.e. a region without apertures and through which an object can be viewed without the pin hole effect. With such a lens an object can be viewed through the transparent region (for “normal” vision), or through the apertures (for enhanced vision). For example, if the optical device is configured as a pair of spectacles the user may wish to have normal vision through the lenses for viewing some objects (such as more-distant objects when driving or when viewing a computer screen for example) and enhanced vision for viewing nearby objects (such as when reading for example). Desirably, the transparent region will be above the opaque region, whereby the user can look through the upper transparent region for more distant viewing and through the lower region (with the multiple apertures) for viewing closer objects.

Ideally, the apertures are spaced from the outer edge of the lens by at least approx. 10 mm. This can be particularly beneficial when the device is configured as a pair of spectacles as it is expected that most individuals will find it more difficult to view an object through an aperture which is close to the edge of the lens (and therefore close to the frame surrounding the lens if present). Alternatively, at least the lowermost apertures should preferably be spaced at least approx. 10 mm from the bottom edge of the lens of a pair of spectacles.

It will be understood that locating the apertures away from the edge of the lens restricts the region of the lens in which the apertures can be positioned, and may therefore restrict the number of apertures which can be provided. The opaque region and apertures can, for example, be located substantially centrally within the lens, perhaps with a transparent region above and/or below the opaque region, or alternatively with the opaque region surrounded by a transparent region, as desired. The transparent region of the lens can be a focussing lens or a plain lens as required. References to “normal” vision can therefore include vision which is corrected or improved by a focussing lens. As above stated, the multiple apertures in the opaque region can be formed in a focussing lens or a plain lens as required or desired.

The transparent region can be polarised or tinted, for example when configured as sunglasses for example. In addition, tinting the transparent region can assist users who are colour-blind for example, it being understood that the colour-blindness of some individuals can be reduced by viewing an object through a lens of a certain colour.

The optical device may be wearable, for example the lens may be one or both lenses of a pair of spectacles or a pair of goggles (for example ski goggles, swimming goggles, work goggles/safety glasses etc.). Alternatively, the optical device may be portable, i.e. the lens may be an article (or part of an article) such as a fob or the like, the article being carried by the user and positioned in front of the user’s eye as and when required. The article can suitably be formed into a key fob so as typically to be readily available as and when required.

It will be understood that an optical device which is portable (as opposed to wearable) will benefit less from having multiple apertures of each dimension. Thus, a user will more easily be able to move the portable optical device so as to align a single aperture with his or her eye. It is therefore expected that a portable optical device may have only a single aperture of each differing dimension.

The portable optical device can if desired include a luminous and/or fluorescent and/or brightly coloured element to facilitate its correct orientation and alignment. Because the portable optical device must be correctly aligned with the user’s eye it will be beneficial to provide means to facilitate ease of alignment. For example, the portable optical device (or each of the apertures) can have a luminous or fluorescent or brightly-coloured marker which a user can with practice use to reliably align the chosen aperture with his or her eye. The portable optical device can if desired additionally include a luminous and/or fluorescent and/or brightly-coloured border or edge to enable a user to better locate the optical device when required. The apertures can be circular in which case the references to “dimension” of an aperture will equate to “diameter”. Alternatively, the apertures 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 distance between opposing edges of the particular aperture.

Apertures which are non-circular can have the additional functionality of effectively enabling the user to vary the vision enhancement by viewing an object through a particular part of the aperture. For example, viewing an object through a part of a triangular aperture (for example) close to a corner will effectively provide a smaller aperture than viewing the object through a part of the aperture away from the corner (and similarly for other polygonal apertures).

Preferably, if the apertures are polygonal they are oriented with a corner at the bottom, whereby the user can effectively reduce the dimension of the aperture by looking through a lower part of the aperture.

Polygonal apertures therefore have edges which taper or converge towards a corner - the tapering can be used to vary the effective dimension of the (part of the) aperture through which an object is viewed.

It is not necessary that all of the apertures in a particular optical device are the same shape but that is preferred as it is expected to be more aesthetically pleasing. Two or more different shapes in different rows of apertures, and two or more different shapes in the same row of apertures, are nevertheless within the scope of the invention.

The apertures can be physical apertures, i.e. holes through the material of the lens. Preferably, however, the apertures are spaces in the opaque region with for example the opaque region being printed or otherwise formed on the surface or material of the lens and the apertures being defined by an absence of printing. The opaque region, and therefore the apertures in the opaque region, may be permanent or non-permanent - for example the lens may have an electrochromic or photochromic coating (or be formed as a liquid crystal display (LCD) for example), which darkens to form the opaque region.

If the apertures are physical holes through the material of the lens, it is not necessary that the holes are of consistent dimension through the material. Alternatively stated the apertures can be flared or tapered. Tapering apertures are expected to be beneficial for a portable optical device in particular, with the device being oriented with the larger end of the aperture towards the user’s eye. This is expected to facilitate the correct alignment of the aperture with the eye. The use of an element (such as a luminous, fluorescent or brightly-coloured element) in such a portable optical device has the particular benefit in facilitating the correct orientation of the device relative to the eye, especially with practice.

Desirably, some or all of the opaque region can be patterned. 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 of a flag, logo, emoji or other pattern, as desired, which is visible to others when the device is in use.

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 this region of the 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 an 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”.

According to a second aspect of the invention there is provided a vision enhancing optical device having a lens with a substantially opaque region and at least one aperture in the substantially opaque region, the aperture having edges which converge to a corner.

By virtue of the converging (or tapering) edges, the effective dimension of the aperture reduces towards the corner. A user can vary the effective dimension of the aperture, and thereby change the degree of vision enhancement provided, by altering the line of sight through the aperture towards and away from the corner.

Preferably, the edges are linear and converge consistently towards the corner. The invention can nevertheless be practiced with non-linear edges, albeit edges which are preferably sufficiently linear to converge smoothly towards the corner.

It will be understood that the corner may be a point or vertex where the edges meet, or could instead be rounded. It will also be understood that the aperture could be triangular, square, diamond-shaped or otherwise polygonal (and perhaps an irregular polygon), as desired.

The angle between the edges is preferably no more than 90°, and ideally no more than 60°. It will be understood that an angle of 60° is provided by an equilateral triangle and smaller angles can be provided by an isosceles triangle. Apertures with an obtuse angle between the edges can also be used but are not preferred.

To avoid unnecessary repetition, optional features which are described for any of the aspects of the invention can be utilised with other aspects of the invention with which they are compatible, as desired.

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 shows a pair of spectacles with lenses having a first embodiment of vision enhancing optical device according to the first aspect present invention;

Fig.2 shows a pair of spectacles with lenses having a second embodiment of vision enhancing optical device according to the present invention; Fig.3 shows a pair of spectacles with lenses having a third embodiment of vision enhancing optical device according to the present invention;

Fig.4 shows a pair of spectacles with lenses having a fourth embodiment of vision enhancing optical device according to the present invention;

Fig.5 shows an enlarged view of an array of apertures similar to that of the first embodiment;

Fig.6 represents the view of two objects through a triangular aperture;

Fig.7 shows a portable vision enhancing optical device according to the invention; and

Fig.8 shows a cross-section through part of the optical device of Fig.7.

DETAILED DESCRIPTION

Fig.1 shows a first embodiment of the invention according to the first aspect. This is a wearable optical device, specifically a pair of spectacles 110 with two lenses 1 12. In this embodiment the lenses 1 12 are symmetrical and identical but in alternative designs the lenses are not symmetrical and are ideally mirror-images.

Each lens 112 has a substantially opaque region 114. In this optional embodiment the substantially opaque region 114 is located approximately centrally (in the vertical direction) and each lens 1 12 also has a transparent region 116a at the upper part of the lens and a separate transparent region 1 16b at the lower part of the lens. Borders 1 18a,b lie between the opaque region 114 and the respective transparent regions 1 16a,b.

In an alternative embodiment the opaque region is located approximately centrally in the horizontal direction also, with a transparent region lying to either side of the opaque region and thereby surrounding the opaque region. It is, however, generally preferred to provide the opaque region as a continuous band extending fully across the lens.

A plurality of apertures 120 are located in the substantially opaque region 1 14. The apertures 120 are gaps or spaces in the opaque region through which objects can be viewed. The apertures may be physical apertures (holes) through the material of the opaque region, but in this embodiment the opaque region 114 is printed onto the surface of each lens 112 and the apertures are spaces in the printing.

It is arranged that the region 1 14 is sufficiently opaque so that an object can only be properly viewed through the apertures 120 in the opaque region 114. Whilst it is not necessary that the apertures 120 allow 100% of the incident light to pass through the lens 1 12, nor that the opaque region between the apertures allows 0% of the incident light to pass, the difference in light transmission must be sufficient to ensure that a user’s view of an object is effectively totally determined by the aperture in order to benefit from the pin hole effect.

The apertures 120 are of differing dimensions. In this optional embodiment the apertures 120 are formed in four horizontal rows, each row containing nine apertures. It will be understood that the invention is not limited to this number of rows (and see for example the alternative embodiments of Figs. 2-4 with three rows of apertures), nor to this number of apertures in each row, nor to the same number of apertures in each row.

A similar array of apertures 120 is shown in the enlarged view of Fig.5. Whilst the arrangement of the apertures differs slightly between Figs. 1 and 5 that is incidental and the same reference number is therefore used for the apertures in both of these figures.

As more clearly seen in Fig.5, the apertures 120a in the top row are all of the same dimension, the apertures 120b in the second row are all of the same dimension, the apertures 120c in the third row are all of the same dimension, and the apertures 120d in the bottom row are all of the same dimension.

The apertures 120 in the first embodiment are circular. In this embodiment the apertures 120a are of 3.0 mm diameter, the apertures 120b are of 2.5 mm diameter, the apertures 120c are of 2.0 mm diameter, and the apertures 120d are of 1.5 mm diameter. In an alternative embodiment the apertures are 2.5 mm / 2.0 mm / 1 .5 mm / 1 .0 mm. In both of these embodiments the difference between the diameters of the apertures in all of the neighbouring rows is 0.5 mm but that is not necessarily the case.

In another embodiment there are three rows of apertures; in yet another embodiment there are two rows of apertures. It is expected that in most applications no more than four rows of apertures can be provided in the space available.

In the embodiment of Figs. 1 and 5 the spacing Sv between the edges of neighbouring apertures 120 in each row is 2 mm. The spacing Sh between the edges of neighbouring rows of apertures is also 2 mm. In other embodiments the spacings Sv and Sh are not the same. In yet other embodiments the vertical spacing between neighbouring rows varies depending upon the dimension of the apertures in those rows. Also, the spacing between neighbouring apertures in each row can vary across the row if desired, for example the apertures being more closely-spaced towards the centre of the lens (or vice versa).

As above stated, providing multiple apertures of differing dimensions enables a user to vary the image of an object by viewing the object through a different-dimension aperture. In particular, it is expected that most users will achieve the clearest image of a nearby object by viewing the object through an aperture 120d (i.e. the smallest aperture). However, less light will pass through the smallest apertures and it may be that in particular circumstances an aperture 120c (or 120b, or 120a) may provide a sufficiently clear image (for example to allow the user to read a set of ingredients on a food packet in a supermarket). The user can move the object up or down (or alternatively or additionally can move his or her head and/or eyes up or down), so as to view the object through a chosen row of apertures 120 with the most suitable dimension to provide the desired degree of vision enhancement. It can be, for example, that the user will in practice view a distant object through an aperture in the row 120a or 120b and will view a nearby object through an aperture in the row 120d or 120c.

The user can also move the object left or right (or alternatively or additionally can move his or her head and/or eyes left or right), so as to view the object through one of the apertures in the chosen row. As also stated above, providing multiple apertures in each row makes it easier for the user to align an aperture in each lens with both of the eyes, and also reduces or avoids the requirement for the spectacles 110 to be fitted to the user by an optometrist or other specialist.

It will be seen that the central apertures in each row 120a, b,c and d are vertically aligned whereas the apertures to either side of the centre are offset slightly (which is a consequence of the consistent edge-to-edge spacing and the different aperture dimensions). It can alternatively be arranged that the edge-to-edge spacing varies so that each column of apertures is vertically aligned if desired.

Optionally, the spectacles 1 10 are fitted with focussing lenses (for both the transparent region 1 16 and the opaque region 1 14). In one example the spectacles 1 10 are supplied as reading glasses and the lenses have a focussing power of +1 diopter. A user’s vision for nearby objects will therefore be enhanced firstly by the focussing effect of the lens (in both the transparent region 1 16 and the apertures 120) . The user’s vision for nearby objects will secondly be enhanced by the pin hole effect of the apertures 120.

In an alternative embodiment the spectacles have focussing lenses configured to correct a specific user’s imperfect vision. For example, the whole of the lenses 120 (or at least the transparent regions 116) can be configured to allow a specific user to clearly view distant objects and therefore be suited for driving and the like. As with all such spectacles, it is not necessary that the power of each lens in the pair of spectacles is the same.

Because the opaque region 114 in this embodiment is printed, it is likely to be most cost-effective for the whole of the lens to have the same focussing power. The invention is not, however, limited to that, and it is possible for the transparent region to be a focussing lens and for the opaque region to be a plain lens (and vice versa) as desired. It is also possible to provide a bifocal lens with the focussing power of the transparent region differing from that of the opaque region. It is also possible for all of the lens to be a plain lens. It is not necessary that the apertures 120 in each row are of the same dimension and in an alternative embodiment the size of the apertures differs in one or more of the rows. For example, the size of the apertures may decrease away from the centre of the lens.

It is also not necessary that the apertures are arranged in rows and instead the apertures can be arranged in circles or part-circles. In such embodiments it may be preferred to have a group of the largest apertures at the centre with concentric rings (or part-rings) of apertures around the central apertures progressively decreasing in size away from the centre.

As seen in Figs. 1 and 5, the dimension of the apertures 120 decreases from top to bottom of the opaque region 114. The user must therefore lower his or her line of sight in order to view an object through the smallest apertures. This is expected to be the most comfortable arrangement and matches that of the known bifocal spectacles and contact lenses, with the user raising the line of sight for more-distant objects and lowering the light of sight for nearby objects.

The apertures 120 in Fig .1 are spaced from the top and bottom edges of the lenses 1 14 by approx. 10 mm (in this embodiment with oval-shaped lenses the spacing is measured from the highest and lowest part of the edge of the lens respectively). Some users are expected to find it difficult to view an object through an aperture which is too close to the top or bottom edge of the lens and in this embodiment the apertures are spaced from the top and bottom edges. The apertures can in other embodiments also be spaced further from the side edges of the lens if required. The number of rows of apertures which can be provided, and the number of apertures in each row, are at least partly determined by the overall size of the lenses 114.

Figs. 2-4 show different embodiments of spectacles 210, 310 and 410. In each of these alternative embodiments the opaque region (214 in Fig.2) is located in a lower part of the lens with the consequence that the transparent region (216 in Fig.2) above the border (218 in Fig.2) is larger. In particular, it is expected that the larger transparent regions (216 etc.) of the embodiments of Figs. 2-4 allow the user to have “normal” vision above the border (218 etc.) and enhanced vision below the border. The embodiments of Figs. 2-4 also have three rows of apertures, reflecting the reduced space available as compared to Fig.1 whilst maintaining a desirable spacing from the bottom edge.

The pair of spectacles 210 of Fig.2 further differs from that of Fig.1 in having square apertures 220. With square apertures the term “dimension” most appropriately refers to the length of each edge of the square.

The pair of spectacles 310 of Fig.3 further differs from that of Fig.1 in having diamondshaped apertures 320. With diamond-shaped apertures the term “dimension” could also refer to the length of each edge, but more appropriately refers to the shorter of the two distances between opposing vertices (which in this embodiment is the length of the horizontal line joining opposing vertices).

The pair of spectacles 410 of Fig.4 further differs from that of Fig.1 in having oblong apertures 420 with the longer axis of the oblongs 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).

These other embodiments also demonstrate that the invention is not limited by the shape of the apertures and apertures of other shapes than those shown can also be used. Whilst all of the embodiments have apertures of similar shape, it is within the scope of the invention to have different-shaped apertures on different rows and it is also within the scope of the invention to have different-shaped apertures in one or more of the rows, as desired.

Fig.6 demonstrates a beneficial effect of apertures with edges which converge towards a corner. Fig.6 shows only a single aperture in accordance with the second aspect of the invention. However, a practical device could include multiple apertures of the same size. It will be understood that providing multiple apertures of the same size has the benefit that the optical device can be more universal, especially when configured as a pair of spectacles, in that it is less likely that the apertures will have to be positioned to match a user’s eyes by an optometrist for example. Alternatively or additionally, a practical device could have multiple apertures of different size in accordance with the first aspect of the invention.

Fig.6 shows a triangular aperture 620. The aperture 620 is an equilateral triangle which appears to be an isosceles triangle in the figure because of the perspective (although the aperture could in practice be an isosceles triangle). The aperture has an edge 622 at the top and a corner 624 at the bottom. The aperture 620 is shown artificially enlarged for ease of understanding.

For a triangular aperture the term “dimension” refers to the length of an edge such as the edge 622 (and most appropriately the shortest edge if the triangle is not equilateral).

Fig.6 shows two nearby objects 626a and 626b which are viewed through the aperture 620. This is demonstrated in Fig .6 by a respective ray of light 628a, b passing from each object 626a, b through the aperture 620 to the user's eye 630. It will be seen that the ray of light 628a passes through a relatively wide part of the aperture 620, i.e. close to the edge 622, whereas the ray of light 628b passes through a relatively narrow part of the aperture 620, i.e. close to the corner 624. It will be understood that the pin hole effect is more significant for the ray of light 628b than it is for the ray of light 628a. Alternatively stated, the blurring caused by the user’s defective vision will be smaller for the ray of light 628b than it is for the ray of light 628a so that in practice the user will typically see the nearby object 626b more clearly than the nearby object 626a.

It will be understood that the user can move his or her head and/or eye upwardly and downwardly relative to a single nearby object, whereby the light from that object follows a path similar to that of the ray of light 628a or the ray of light 628b, enabling the user to adjust the degree of vision enhancement provided by a single aperture 620.

It will also be understood that the ability of the user to adjust the vision enhancement by adjusting the line of sight through a tapering aperture is not limited to a triangular aperture and will also be present with the diamond-shaped apertures 320 and the square apertures 220. Whereas the user can simply raise or lower his or her head and/or eyes to adjust the line of sight for the apertures 620 and 320, the user must also adjust the line of sight to the left or right to view an object through a corner of the square apertures 220 which might be more awkward in practice, notwithstanding that the effect is the same.

Whilst the aperture 620 is shown with linear edges which meet at points to define corners of the triangle, it will be understood that the corner 624 could be rounded. It will also be understood that the edge 622 (and also the edges which define the corner 624) need not be linear and could be curved. It is, however, necessary for the aperture to taper, i.e. for the edges to converge towards the corner 624, and it is preferable that the edges converge smoothly towards the corner. Accordingly, any curvature of the edges should preferably be small.

It will be understood that the edges of an equilateral triangle converge to the corner 624 at a relative angle of 60°. For an isosceles triangle the angle of convergence can be smaller and for a square and oblong the angle of convergence is 90°. Pentagonal and hexagonal apertures have a larger angle of convergence and such (obtuse) angles of convergence are not preferred for this aspect of the invention. In particular, smaller angles of convergence will usually enable a user more easily to control the degree of vision enhancement provided.

The triangular aperture 620 is shown with the edge 622 at the top and the corner 624 at the bottom and this is expected to be the most suitable orientation in practice. The triangular aperture could, however, be oriented differently (for example inverted) if desired. In an alternative embodiment with one or more diamond-shaped apertures oriented similarly to Fig.3 a user can raise or lower the light of sight towards a corner.

The optical devices of Figs. 1 -4 are respective pairs of spectacles which are wearable by a user. In the alternative embodiment of Fig.7, the optical device 710 is a portable article, specifically a lens 712 in the form of a fob designed to be carried in a user’s pocket. The lens 712 is a generally diamond-shaped sheet of material and in a practical embodiment would typically have more rounded corners than shown in the drawing. The lens has a physical hole 732 adjacent to one corner, which hole can accommodate a key ring for example. The lens is mostly opaque, either being made of an opaque material or having a surface coated or printed with an opaque material. The opaque surface can be coloured or patterned as desired. Three apertures 720a, 720b and 720c are formed in the opaque material. In this embodiment the apertures are physical holes through the sheet of material but in other embodiments are transparent regions in the opaque region.

It will be understood that the lens 712 may be a focussing lens with a printed opaque surface and with the apertures formed by gaps in the opaque surface. The apertures can therefore provide a pin hole effect which is supplemented by a focussing effect, if desired.

In this embodiment a region 740 of the lens is transparent and the region 740 can be used as a focussing lens independently of the apertures. In an alternative embodiment only the region 740 is a focussing lens and the opaque region is a plain lens. As previously described, the region 740 may be polarised and/or tinted to reduce glare (for example from the sun) and/or to seek to counteract colour-blindness.

Also in this embodiment the apertures 720a, b,c are circular but in other embodiments the apertures can be oval or polygonal as above described and/or as shown in the earlier drawings.

It will be understood that the lens 712 will benefit less from having multiple apertures of each dimension since a user can readily move the lens to align a chosen aperture 720 with his or her eye. The lens 712 therefore has only three apertures 720a, b,c of three different diameters. It is of course possible to provide more than one aperture of one or more of the diameters.

In this embodiment the diameter of the aperture 720a is 2.0 mm, the diameter of the aperture 720b is 1.5 mm and the diameter of the aperture 720c is 1.0 mm. Different embodiments have two, four or more than four apertures, and different embodiments have different specific diameters, as desired to provide the required degrees of vision enhancement. A marker 734a, b,c is located adjacent to each of the apertures 720a, b,c. The markers are brightly coloured and are of different sizes corresponding to the different-sized apertures. The markers can help a user locate the chosen aperture 720a, b,c. In an alternative embodiment the markers can be luminous and/or fluorescent.

Though it is not apparent in the drawing, the edge 736 of the fob is also luminous, fluorescent or brightly-coloured so that the fob is easier to locate when required.

Fig.8 shows a cross-sectional view through a part of the lens 712, in particular through the smallest aperture 720c. It will be seen that the aperture 720c has a flared or tapered upper end 738 so that the hole adjacent to the image 734c is somewhat larger than the required diameter D of the aperture (as above stated in this embodiment the diameter D of the smallest aperture 720c is 1 mm). The other apertures are similarly flared. The flaring of the apertures 720 makes it easier for the user to locate the chosen aperture when the fob is located close to the eye. The marker 734c (along with the images 734a and b) alerts the user to the correct orientation of the fob so that the flared ends face towards the eye.

In one embodiment the fob is approx. 5 mm thick and the unflared length of the aperture is approx. 1 mm.

In an alternative embodiment, the fob has additional functionality, specifically a light or torch is provided on the fob.

Whilst the fob 712 is shown as a diamond shape it could be a different shape, as desired. Whilst many shapes would be suitable it is expected that a diamond-shaped fob with rounded corners, or a circular shape, would be comfortable to use and transport and therefore acceptable to many users.