Field of the Invention

The present invention relates to prosthetic eyes and, in particular, to a dilating pupil mechanism, and a prosthetic eye iris button and/or prosthetic eye having the dilating pupil mechanism.

The invention has been developed primarily for use in prosthetic eyes for use by people and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use and is applicable to other fields such as providing a dilating pupil mechanism in prosthetic eyes for puppets, dolls or robots, or animals, for example.

Background Art

The use of prosthetic eyes is well known. Typically, a person who loses an eye through an accident or disease or other reason has an impression of their eye socket taken once the eye has been surgically removed and a packing material known as a coral ball, or orbital or ocular implant, is added in place of the removed eyeball. The coral or orbital ball is preferably composed of a hydroxyapatite material and the muscles are knitted to it so that the coral ball is caused to move by movement of the eye socket muscles. A model of the eye socket is then constructed from a wax or polymeric material.

A prosthetic eye iris button, similar to a pupil, iris and cornea and typically about 12.5mm wide and 5mm high, is selected and built into the polymeric mould pattern. The iris button is adjusted to give proper direction of gaze as well as allowing for the proper opening and contour of eyelids of the person intended to wear the prosthetic eye. A final mould of the eye socket is taken and the iris button is inserted into a mould. A thin layer of plastic is ground from the front surface of the prosthetic and a painted shell is made by placing a transparent sheet between the artificial eye and a new layer of clear plastic. The artificial eye is then coloured, most typically by hand painting the iris, blood vessels, etc. on a rear surface of the iris button. Once the colour of the iris and scleral regions are satisfactorily matched to the remaining eye of the wearer, an acrylic (PMMA) resin is cured to the front surface to protect the colour of the eye during polishing and wearing.

It will be appreciated that the prosthetic eyes are fitted to a user when they have lost one eye to provide a normal appearance of having a pair of healthy eyes. This is in addition to the surgical packing of the eye socket with the coral ball or orbital implant which prevents any deformation, sagging or shape distortions due to the absence of one eyeball. The prosthetic eyes can be configured to be attached to a post extending from the coral ball or orbital implant and through the eye socket. Alternatively, a magnet is disposed in the eye socket behind the skin layer of the socket such that the prosthetic eye is magnetically attracted thereto. A common option is to simply retain the prosthetic eye under the eyelids and against the eye socket behind which is the coral ball or orbital implant.

It will be appreciated that as the wearer's remaining eye moves or responds to environmental conditions, the coral ball or ocular implant will be caused to move in correspondence with the wearer's remaining eye. This, of course, will cause not only the coral ball to move accordingly, but also for the prosthetic to move. In practice, mounting a prosthetic eye to a post extending from an eye socket provides the greatest range of movement, however, it is undesirable having material protruding from the eye socket as this is in effect an open wound and a potentially dangerous source of infection. The use of magnetic coupling between the prosthetic eye and the eye socket removes the risk of infection by having a post protruding through the eye socket but use of the magnets does not provide for the same degree or extent of movement of the prosthetic eye as compared with use of a post. However, it is still not desirable to surgically deposit magnets intermediate the coral ball or ocular implant and the eye socket as there is no certainty that the magnetic material will remain inert in the human body. It is known that a pupil dilates from a diameter of between 3mm to 4mm to 5mm to 6mm in response to a diminution of incident light intensity. The pupil size must be relatively accurately reproduced in the prosthetic eye to avoid obvious and noticeable differences with the size of the pupil of the other eye.

It will be appreciated that because of this it is desirable for users to typically have two prosthetic eyes, one for daytime or bright environment use and one for low light or night-time situations. Unfortunately, this requires prosthetic eye wearers to purchase a second prosthetic eye or to arrange for a health insurance company to fund same.

In order to address the need for two different prosthetic eyes having two different pupil sizes, US Patent No. 7,31 1,397 (Young) discloses a prosthetic eye having a simulated iris and a horizontal polarised disc at the centre of the iris. The centre of the polarised disc is painted black to simulate a pupil having a relatively small diameter. A rear of the polarised disc is painted to blend with the iris or to simulate the colouring of the eye around the ciliary muscle.

In the disclosure of Young, the prosthetic eye is used in conjunction with a pair of eyeglasses having a linearly polarising lens with the transmission axis in the vertical plane. In use, disposing the eyeglasses over the pupil causes the pupil to appear dilated as the entire disc is blackened due to the polarising nature of the disc and the eyeglass polarising lens. Unfortunately, this solution requires a user to wear glasses which is generally inconvenient for those users who do not ordinarily require glasses to correct their vision in the remaining eye. In any event, the polarising glasses obscure the eyes thus reducing the impact.

Another attempt at providing a dilating pupil mechanism is disclosed in US Patent No. 6,576,013 (Budman et al). Budman provides an eye prosthesis having an LCD display to simulate an iris and a pupil image. Ambient light is measured by a light sensor disposed in the prosthetic and an image is selected from a memory of images based on that level of light to provide an appropriately dilated pupil and corresponding iris size. A significant degree of miniaturisation of high resolution liquid crystal displays is required to be able to be positioned within an artificial eye, as well as the inclusion of the memory chip and the light sensor. A solar panel or other solar array is disposed in the prosthetic eye or otherwise attached to the LCD mechanism therein.

Unfortunately, the use of an LCD screen to simulate both the iris and the pupil is impractical. The space available in a typical prosthetic eye is relatively small, especially when considering requirements to produce a relatively high quality LCD based display mechanism in the prosthetic eye. Furthermore, artificial irises are painted in a plurality of layers, 40 layers not being uncommon. The layered irises provided by hand painting give a real depth to the iris. Unfortunately, printing or displaying on an LCD-type screen simulated iris does not project the same depth and is relatively easily noticeable when comparing the iris of a prosthetic eye with the natural remaining eye. Furthermore, the power consumption of the LCD-based system and its reliability over time are questionable. For example, physical shock or the presence of excessive electromagnetic fields may disable or cause the LCD-based prosthetic eye to malfunction or cease operation.

Genesis of the Invention

It is the genesis of the present invention to provide a dilating pupil mechanism for use in prosthetic eyes or prosthetic eye buttons that will overcome or substantially ameliorate one or more of the disadvantages of the prior art, or to provide a useful alternative.

Summary of the Invention

According to a first aspect of the invention there is provided a dilating pupil mechanism comprising a magnifying lens disposed at or adjacent a mechanism front surface, and a pupil configured for linear movement toward or away from the magnifying lens.

According to a second aspect of the invention there is provided a prosthetic eye button configured for use in forming a prosthetic eye, the prosthetic eye button comprising a pupil mechanism according to the first aspect of the invention. According to a third aspect of the invention there is provided a prosthetic eye having a dilating pupil mechanism according to the first aspect of the invention.

According to a fourth aspect of the invention there is provided a prosthetic eye configured for receiving a prosthetic eye button according to the second aspect of the invention.

According to another aspect of the invention there is provided a method of providing a dilating pupil mechanism, the method comprising the steps of providing a magnifying lens at or adjacent a mechanism front surface and a pupil, and configuring the pupil for linear movement towards or away from said magnifying lens.

It can therefore be seen that there is advantageously provided a dilating pupil mechanism having a movable pupil. The pupil is preferably moved by magnetic interaction of the pupil with an external actuator or by use of a linear actuator with the pupil disposed on the end. It will be appreciated that no surgical means are required to provide a dilating pupil mechanism and significant miniaturisation of display devices is not required. Yet further, it will be appreciated that the present invention does not require the use of complementary polarising or other type of glasses to achieve the dilating pupil effect.

Brief Description of the Drawings:

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is a schematic cut-away side view of a prosthetic eye having a dilating pupil mechanism according to a first preferred embodiment;

Fig. 2 is a schematic cut-away side view of a prosthetic eye having a dilating pupil mechanism according to a second preferred embodiment;

Fig. 3 is a schematic cut-away side view of a prosthetic eye having a dilating pupil mechanism according to another preferred embodiment; and

Fig. 4 is a schematic cut-away side view of a prosthetic eye having a dilating pupil mechanism according to another preferred embodiment. Detailed Description

Referring to the drawings generally, throughout the description of the preferred embodiments like reference numerals have been used to denote like components or components having like functions unless stated otherwise. In Fig. 1 , there is shown a schematic cut-away side view of a prosthetic eye 1 having a prosthetic eye button 3 and a scleral region 5.

The prosthetic eye 1 further includes a dilating pupil mechanism 7 which includes a pupil 9 disposed in a pupil cavity 11 in which the pupil 9 is able to be moved linearly a predetermined distance. The pupil 9 includes a pupil front face 13 and a pupil rear face 15. A pupil stem 17 extends outwardly from a centre of the pupil rear face 15. The stem is configured to linearly move within a pupil stem bore 19.

A magnifying lens 21 is disposed at or adjacent a prosthetic eye front surface 23 and in the preferred embodiment of Fig. 1 forms part of a front surface 25 of the prosthetic eye button 3. The dilating pupil mechanism 7 includes a mechanism rear surface 27 spaced apart from the prosthetic eye front surface 23. The mechanism rear surface 27 is the rear surface of the prosthetic eye button 3. The mechanism rear surface 27 is disposed intermediate the prosthetic eye front surface 23 and a prosthetic eye rear surface 29.

The mechanism rear surface 27 typically has an iris painted on a face 31 facing away from the prosthetic eye front surface 23. The iris 31 is most preferably hand painted and formed from a plurality of painted layers.

The pupil 9 is configured for linear movement within the pupil cavity 1 1. In a first position, the pupil 9 is disposed adjacent the magnifying lens 21 to provide the appearance of a pupil of a predetermined size. The pupil 9 is moved linearly away from the magnifying lens 21 a predetermined distance which magnifies the pupil 9 thereby increasing its size when viewed from the prosthetic eye front surface 23. The pupil cavity 1 1 includes a flat magnifying lens rear surface 33 and a substantially spherically curved magnifying lens front surface 35. Substantially in a centre of the magnifying lens front surface 35 is a button projection 37 extending outwardly and away from the curved front surface 35. The button projection 37 is shown dotted as this element is used to hold the prosthetic eye button 3 to allow the iris to be painted on the rear face 31. Once the prosthetic eye button 3 is formed with the prosthetic eye 1, the button projection becomes substantially invisible and is integrally formed with the prosthetic eye front surface 23.

As noted, the pupil 9 is disc shaped and at least the disc of the pupil 9 is formed from a magnet. The pupil front face 13 facing the magnifying lens 21 is formed from a north face of a magnet and the pupil rear face 15 facing away from the magnifying lens 21 is formed from the south pole of the magnet. Of course, the pupil front face 13 could be formed from a south pole of a magnet and the pupil rear face 15 formed from the north pole, or the stem 17 formed from a magnet having longitudinally spaced apart poles.

In use, the wearer of the prosthetic eye 1 simply brings a magnet (not illustrated) into proximity to the prosthetic eye front surface 23. With the pupil front face 13 being formed from the north pole of a magnet, when a south pole of a magnet is moved to or adjacent to the prosthetic eye front surface 23, the opposite magnetic pole on the pupil front face 13 causes it to be attracted toward the prosthetic eye front surface 23. In the embodiment of Fig. 1 , this produces a small or undilated pupil appearance. When the north pole of the magnet is moved adjacent the magnifying lens 21, the pupil front surface 13 is repelled therefrom and moved linearly away from the magnifying lens 21 to thereby give the impression of an enlarged or dilated pupil. During linear movement of the pupil 9 toward or away from the magnifying lens 21 , the pupil stem 17 is engaged with the pupil stem bore 29 which acts as a guide and retainer for the pupil stem 17.

It will be appreciated that the magnet used to move the pupil 9 can be embodied in any object or be in any shape, as desired. For example, a magnet may be embedded in a finger ring or in a make up applicator device or hair brush. In this way, the pupil 9 can be moved by magnetic repulsion or attraction without a user needing to draw attention to themselves. Further, a mirror (not illustrated) can be mounted to or be integral with the finger ring or applicator to allow a user to confirm correct movement of the pupil 9 and hence correct level of dilation.

The pupil 9 is linearly moveable a distance of about lmm, however, it will be appreciated that any preferred distance of linear movement can be provided depending, for example, on the dimensions of the prosthetic eye button 3 and this is most preferably in the range of 0.5mm to 4mm. The pupil 9 has a disc diameter of 3 mm to 4mm so that when moved closest to the magnifying lens 21 the pupil appears to be substantially 3mm to 4 mm in diameter. As the pupil moves away from the magnifying lens 21, the pupil diameter is magnified to appear to have a diameter of 6mm to 7mm, however, this can be any preferred.

In the embodiment of Fig 1 the distance between the spherically curved front surface 35 of the magnifying lens 21 to the flat magnifying lens rear surface 33 is approximately 2 mm. The pupil cavity 11 extends approximately lmm thereby providing the pupil 9 a distance of lmm travel. The distance between the mechanism rear surface 31 and the start of the pupil cavity 11 is about 2mm. The iris painted on the rear surface 31 is about 1 lmm to 12mm in diameter and is substantially circular or disc shaped. It will be appreciated that the iris diameter is preferably in the range of 8mm to 14mm wide.

The prosthetic eye scleral region 5 is also preferably hand-painted to include the features of the scleral region of a remaining eye of a wearer such as blood vessels or slight colouration. The prosthetic eye button 3 and the prosthetic eye 1 are each preferably formed from a PMMA (polymethylmethacrylate) resin so that when the prosthetic eye front surface 23 is disposed over the spherically curved front surface 35 of the magnifying lens 21, optical distortions or aberrations through interfacing different materials are minimised. It will be appreciated, however, that any preferred materials can be used to form the prosthetic eye, prosthetic eye button and components of the dilating pupil mechanism. Similarly, any preferred shape of magnifying lens 21 can be provided. For example, the pupil cavity 11 is preferably filled with an optically clear silicon liquid or other viscous liquid but can be a vacuum or air-filled. The viscous liquid provides a mechanical stability to the pupil 9 and a resistance to linear movement in the absence of a magnet being proximal. The viscous liquid also provides the added advantage of minimising undesirable optical effects that may be present from the interface between magnifying lens 21 and pupil cavity 9.

In other embodiments of the invention (not illustrated) the pupil 9 can be any magnetisable or magnetically permeable material that acts as a magnet responsive to the north and/or south pole of a magnet brought adjacent thereto. Furthermore it will be appreciated that the magnifying lens 21 can have integrally formed therewith a compounding lens formed from a similar or dissimilar material, or the dilating pupil mechanism 7 can include a compounding lens disposed intermediate the flat rear surface 33 of the magnifying lens and the pupil front face 13. Further, it will be appreciated that the prosthetic eye button 3 can be formed so that the rear surface 31 is integral with the magnifying lens 21 if desired.

Referring now to Fig. 2, there is shown a second preferred embodiment of the dilating pupil mechanism 7 in a schematic cut-away of a prosthetic eye 1.

In this embodiment, the pupil cavity 11 is substantially the same diameter as the pupil 9 and no pupil stem 17 or bore 19 is provided. The movement of the pupil 9 is guided by the pupil cavity 1 1 rather than the pupil stem 17 in the embodiment of Fig. 1. The dilating pupil mechanism 7 of the second preferred embodiment of Fig. 2 operates otherwise in the same manner as the dilating pupil mechanism 7 of the first preferred embodiment of Fig. 1.

Referring now to Fig 3, there is shown a schematic cut-away side view of a prosthetic eye having a dilating pupil mechanism 7 according to the third preferred embodiment. In this embodiment, a linear actuator 41 is disposed in a linear actuator cavity 43 in the mechanism rear surface 27. The linear actuator is connected to the stem 17 of the pupil 9 so that movement of the linear actuator 41 moves the pupil stem 17 linearly a predetermined distance toward or away from the magnifying lens 21. This provides the appearance of a dilating pupil 9, however, the case of an undilated pupil 9 is shown in Fig. 3 where the pupil 9 is disposed at or adjacent the magnifying lens 21.

The pupil front face 13 includes a solar array 45 or other solar power source disposed over part or all thereof. The solar array 45 is in electrical communication with the linear actuator 41 by means of electrical wires (not illustrated) disposed through the stem 17. The linear actuator 41 is biased away from the magnifying lens 21 in the second position so that the pupil has the appearance of having a maximum diameter when viewed through the magnifying lens 21 from the front. When light falls on the solar array 45, the linear actuator 41 is caused to linearly move the pupil 9 toward the magnifying lens 21 and thereby appear to diminish the size of the pupil 9. Up to some predetermined maximum incident light on the solar array 45, the linear actuator 41 will move a maximum distance so that the pupil 9 is moved to the first position adjacent the magnifying lens 21 as would be expected in bright light conditions.

Once the incident light is removed from the solar array 45, the linear actuator 41 moves back to the second position away from the magnifying lens 21 to appear larger or dilated in correspondence with lower light levels falling on the solar array 45 which corresponds to low ambient light. The linear actuator 41 is most preferably powered by as low a voltage as possible. Low voltage miniaturised linear actuators can be obtained to specification, for example, voltages wherein the linear actuator power cables are disposed within the pupil stem 17, can be custom sourced from Firgelli Technologies Inc. of Canada, for example.

It will be appreciated, that the solar array 45 may be disposed anywhere in or on the prosthetic eye 1 , or remotely thereto. In the embodiment of Fig. 4, there is shown a schematic cut-away side view of a prosthetic eye 1 having a dilating pupil mechanism 7 according to the fourth preferred embodiment. This embodiment is similar to the embodiment of Fig. 3 except that the solar array 45 is removed and electrical wires to provide power to the linear actuator 41 are disposed through the mechanism rear surface 27 and prosthetic eye rear surface 29. The electrical wires 47 terminate at the linear actuator 41 at one end and at contacts 49 at a surface of the prosthetic eye 1 or proud thereof. The surface of the prosthetic eye 1 can be any surface that is in contact with the eye socket or eyelids or to a corresponding electric connection provided by a prosthetic eye post extending from the eye socket, and need not necessarily be prosthetic eye rear surface 29.

The electrical power provided to the contacts 49 can be provided by electrical connection to the optic nerve or other residual eye component that provides electrical stimulus provided by a corresponding or non-corresponding nerve or component of the wearer's remaining eye. That is, elements remaining in the eye requiring the prosthetic such as muscles or nerves can be used to provide electrical power to contacts 49.

For example, the contacts 49 may be in electrical communication with the optical nerve of the missing eye via a post (not illustrated) and when the optic nerve of the wearer's remaining eye is stimulated by incident light which dilates the pupil of the remaining eye, a corresponding and involuntary signal generated in the optic nerve of the missing eye provides power to the contacts 49. The power can be amplified or not, as desired. Such amplification may be provided by the human body or by a miniature amplifier device disposed electrically intermediate the contacts 49 and the electrical contact with the human body. Although not illustrated, such an amplifier may be disposed in the prosthetic eye 1 behind the painted iris or be disposed behind the rear surface 29 of the prosthetic 1 or in a space behind it.

The foregoing describes only preferred embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, the pupil 9 can be moved by any preferred means. In respect of the second preferred embodiment employing no pupil stem 17 where the pupil cavity 1 1 and pupil bore 19 are the same, the iris can be slightly magnified to appear wider than the pupil cavity 1 1 so that any undesirable optical effects at the interface between the pupil cavity 1 1 and the surrounding eye button are minimised. Furthermore, any preferred materials can be used as desired, for example, glass or plastics other than PMMA, and any preferred shapes of the components of the dilating pupil mechanism 7 or the prosthetic eye button 3 or the prosthetic eye 1 can be provided as desired. The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "including" or "having" and not in the exclusive sense of "consisting only of.