WO2014128466A1 - Ocular prosthesis - Google Patents

Ocular prosthesis Download PDF

Info

Publication number
WO2014128466A1
WO2014128466A1 PCT/GB2014/050492 GB2014050492W WO2014128466A1 WO 2014128466 A1 WO2014128466 A1 WO 2014128466A1 GB 2014050492 W GB2014050492 W GB 2014050492W WO 2014128466 A1 WO2014128466 A1 WO 2014128466A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
prosthesis
pupil
voltage
electrodes
pair
Prior art date
Application number
PCT/GB2014/050492
Other languages
French (fr)
Inventor
Thomas STEAD
Fergal COULTER
John PACEY-LOWRIE
Philip BREEDON
Original Assignee
The Nottingham Trent University
John Pacey-Lowrie Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02Prostheses implantable into the body
    • A61F2/14Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
    • A61F2/141Artificial eyes
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/02Details
    • A61N1/04Electrodes
    • A61N1/05Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0526Head electrodes
    • A61N1/0543Retinal electrodes
    • AHUMAN NECESSITIES
    • A63SPORTS; GAMES; AMUSEMENTS
    • A63HTOYS, e.g. TOPS, DOLLS, HOOPS, BUILDING BLOCKS
    • A63H3/00Dolls
    • A63H3/36Details; Accessories
    • A63H3/38Dolls' eyes
    • A63H3/40Dolls' eyes movable

Abstract

The invention relates to light-reactive ocular prosthetics. Embodiments include an ocular prosthesis (300) comprising an adjustable pupil (106), wherein the prosthesis is configured to apply a voltage across a pair of electrodes defining a lateral extent of the pupil to change the lateral extent of the electrodes.

Description

OCULAR PROSTHESIS

Field of the Invention

The invention relates to light-reactive ocular prosthetics. Background

Ocular prosthetics, or artificial eyes, are designed to aesthetically replace missing, damaged or underdeveloped eyes. Realism is a key consideration in the design of ocular prosthetics, as this benefits the confidence and comfort of the wearer. Ocular prosthetics are generally handmade and bespoke, a necessity brought about by the variation in form as a result of the varying needs of the wearer. Ocular prosthetics can however range in style from standard manufactured pieces that may be ordered remotely to pieces designed and handmade over the course of a number of consultations between the maker and the wearer. The resulting prosthetic can be extremely realistic, but problems remain in relation to how the prosthetic is used in practice. One such problem is that the prosthetic is inevitably fixed both in position and appearance. In varying light conditions a real eye will vary by its pupil varying in size. This can result in a user's real eye having a differently sized pupil to that of the prosthetic, which reduces the realism of the prosthesis. Light-reactive ocular prosthetic eyes have been proposed, for example by

Leuschner and Lapointe et al (see references 4 and 5), in which a liquid crystal display or light valve is used to simulate a varying pupil. These proposals may, however, result in additional problems such as a lack of contrast between the pupil and a surrounding iris, which can affect the realism of the resulting prosthetic, as well as the need to provide a complex array of addressable patterns to reproduce a pupil of appropriate size and shape, which may conflict with the need for a customised solution in each individual case. Other forms of light reactive ocular prostheses have been proposed, such as in US4332039 (reference 6) disclosing a magnetically-actuated pupil, in US6139577 and US6576013 (references 7 and 8), both of which disclose the use of a liquid crystal display, and in US5061279 (reference 9), disclosing the use of a photochromic pigment for simulating a dilating pupil.

It is an object of the invention to address one or more of the above problems. Summary of the Invention

In accordance with the invention there is provided an ocular prosthesis comprising an adjustable pupil, wherein the prosthesis is configured to apply a voltage across a pair of electrodes defining a lateral extent of the pupil to change the lateral extent of the electrodes, for example in response to a change in incident light intensity.

An advantage of the ocular prosthesis according to the invention is that a realistic pupil can be created that can be easily incorporated into a prosthesis that may be custom made for an individual.

The pupil may be configured such that an increased voltage applied across the pair of electrodes causes the lateral extent of the pupil to expand. The prosthesis thereby requires no applied signal when the pupil is to be in a contracted state, which would be a typical normal state in bright light, thereby saving on power requirements.

The electrodes are preferably disposed on opposing faces of an electroactive polymer film. The electroactive polymer film may be affixed to, and held in planar tension by, a surrounding support structure. The support structure may comprise a pair of rings affixed to opposing faces of an outer edge of the electroactive polymer film. The support structure may comprise a transparent, preferably curved, plate extending across a first face of the polymer film and pupil, and may comprise an iris image extending across a second opposing face of the polymer film and pupil, i.e. behind the pupil with the ocular prosthesis configured in use. The iris image may be applied to a face of a plate (preferably curved) extending across the second face of the polymer film. An advantage of using an electroactive polymer film is that a more realistic pupil and iris combination is made possible, since a realistic painted iris can be provided behind the film, which is typically transparent. Although the iris image will be fixed, the variable pupil created by the changing shape of the electrode on the polymer film creates a convincing illusion of a real varying pupil.

The prosthesis preferably comprises a controller and a light sensor connected to the controller, the controller configured to provide a voltage signal to apply the voltage across the pair of electrodes, the voltage signal being dependent upon incident light intensity falling on the light sensor. In preferred embodiments the prosthesis is self-contained, i.e. comprises all of the required components to respond to changes in light intensity without the need for external connections.

The prosthesis may further comprise a voltage transformer configured to transform the voltage signal from the controller and apply the voltage across the pair of electrodes. The transformer may be configured to apply a voltage of up to over 500V, and optionally up to 1.5 kV, across the pair of electrodes. The transformer may for example be a dc-dc transformer. Detailed Description

The invention is described in further detail below by way of example and with reference to the accompanying drawings, in which:

figure la is a schematic cross-sectional view of an artificial pupil for an ocular prosthesis according to an embodiment of the invention;

figure lb is a schematic cross-sectional view of the artificial pupil of figure la with a voltage applied;

figure 2a is a schematic plan view of the artificial pupil of figure la;

figure 2b is a schematic plan view of the artificial pupil of figure la with a voltage applied;

figure 3 is a schematic block diagram of the functional components making up an ocular prosthesis according to an embodiment of the invention;

figures 4a and 4b are an exploded schematic view and a side view of an exemplary embodiment of an artificial pupil and iris for an ocular prosthesis according to the invention;

figures 5a and 5b are photographs of an exemplary embodiment of an artificial pupil and iris constructed according to the illustrated embodiment of figure 4, with the pupil in a contracted state (figure 5a) and in a dilated state (figure 5b); and

figure 6 is an exploded view of an exemplary prototype ocular prosthesis. Exemplary embodiments of a light reactive ocular prosthesis according to the invention may use electroactive polymer technology to create the impression of a dilating and contracting pupil. Electroactive polymer (EAP) technology has applications in various fields, most notably in artificial muscle technology for use in force feedback applications such as 'soft' robotics [see reference 1 , and in particular chapter IV, in which various EAP materials and their applications are discussed] . As applied to ocular prostheses, the visual impression of dilation of a pupil can be achieved using this technology, using a technique similar to that of Rossiter et al [reference 2, which discloses the use of a 500 μιη thick circular biaxially prestrained polyacrylate film as a dielectric medium for mimicking a pigmented chromatophore sacculus] .

In applying EAP technology to the visual representation of a dilating or contracting pupil, a stretched, transparent elastomer film can be encapsulated under tension. The elastomer film may be encapsulated between two rings, which may be of the same size and thickness to avoid any distortion under tension. Once encapsulated, a circular film of a conductive paste is painted onto the transparent stretched elastomer, the paste representing the artificial pupil. When a high voltage (typically up to around 1.5 kV) is applied to the conductive paste across the elastomer film, the pupil will appear to dilate, as a result of the film being acted upon by Maxwell pressure [reference 3, which discloses fabrication and characteristics of spin coated dielectric films for use in stacked dielectric elastomer actuators] due to the application of an electric field. Altering the applied voltage, and therefore the applied electric field, allows the electrode to visually represent dilation and contraction of a pupil. A light sensor can be used in the prosthesis to detect ambient light conditions.

In exemplary embodiments the light sensor may be a light dependent resistor (LDR), or photoresistor. Other types of light sensors may alternatively be used such as a light sensitive diode (photodiode) or light sensitive transistor (phototransistor). A signal from the light sensor can be interpreted by a programmable micro-controller, which determines the voltage to be applied across the EAP film.

Figures la and lb, and figures 2a and 2b, illustrate schematically in cross- sectional view and plan view respectively various components of an exemplary ocular prosthesis making up a pupil assembly 100 for forming an artificial adjustable pupil 106. An elastomeric electroactive polymer film 101 is held in tension across a supporting structure in the form of a pair of rings 102a, 102b between which the film 101 is clamped. First and second electrodes 103a, 103b forming the pupil 106 are applied across opposing faces of the film 101. At least one of the electrodes 103a, 103b comprises a dark, preferably black, pigment (such as carbon black) for simulating the appearance of a pupil, and both electrodes 103a, 103b are sufficiently elastic or otherwise compliant to stretch and contract along with the underlying film 101. The electrodes 103a, 103b may for example comprise carbon grease, as disclosed by Rossiter et al. [reference 2] . Electrode traces 104a, 104b are applied across the opposing faces of the film 101 to connect the electrodes 103a, 103b to leads 105a, 105b across which a voltage may be applied. The electrode traces 104a, 104b may be pigmented differently to the electrodes 103a, 103b forming the pupil 106 so as to minimise their appearance in the prosthesis. The electrode traces 104a, 104b may for example be coloured to be similar to the surrounding iris, or may be made transparent. On application of a voltage across the leads 105a, 105b, the electroactive film

101 expands in the plane of the film, resulting in the electrodes 103a, 103b expanding along with the film and creating the appearance of the pupil 106 becoming dilated, as shown in the differences between figures la and lb and figures 2a and 2b. When the voltage is removed, the film returns to the unexpanded state and the pupil 106 contracts. A dilation/contraction of the pupil 106 can thereby be created that is controllable by the applied voltage.

Figure 3 illustrates in schematic block diagram form the functional components of an ocular prosthesis 300 comprising the pupil assembly 100 of figures 1 and 2. A microcontroller 301 , powered by a battery 302, receives a signal from a light sensor 303 and, in response to a detected amount of light, provides a signal to the leads of the pupil assembly 100. As the voltages required to cause the electroactive film will typically be very high, a transformer 304 is preferably provided to increase the voltage signal produced by the microcontroller 301 to a level that is sufficient to cause a response. If the detected amount of light is above a certain level, no signal will need to be applied to the pupil, which will be in contracted in its unactivated state. The prosthesis may therefore be configured to save on battery power by disabling the output signal to the pupil assembly when the detected amount of light exceeds a preset amount.

As an illustrative example, the input voltage to the micro-controller 301 provided by the battery 302 may be 5V, and the output voltage from the controller 301 may be increased by the transformer 304 to supply a voltage of up to 1.5 kV to the pupil assembly 100, with the maximum voltage corresponding to a maximum degree of dilation of the pupil 106. Figures 4a and 4b illustrate schematically an exploded view and side view of components making up an exemplary pupil assembly 400, in which the supporting structure for the elastomeric electroactive film 401 is provided by a pair of curved transparent plates or lenses 402a, 402b, which may be made of glass. An image representing the iris may be provided on one of the plates 402a, 402b, preferably the plate that is positioned behind the pupil 406 when assembled into the prosthesis. The artificial pupil and iris image is encapsulated between the two lenses 402a, 402b, which provides some refraction adding realism to the appearance of the pupil. The concave shape of the inside of the glass lenses allows the elastomer to flex when the pupil is dilated. The iris image may be painted on the concave surface of the lower lens, i. e. behind the pupil, thus preserving an important element of the hand-making process of ocular prosthetics. An exemplary embodiment of a pupil assembly 500 made according to that shown in figures 4a and 4b is shown in figures 5a and 5b, with figure 5a showing the pupil 506 in a contracted state and figure 5b with the pupil 506 in a dilated state. An iris image 508 is painted on to a plate behind the pupil 506, and a curved transparent plate or lens is provided in front of the pupil, serving to protect the electroactive polymer film as well as to prevent contact with the high voltage applied to the film and to provide a desired aesthetic appearance.

Figure 6 shows an exploded view of an exemplary prototype ocular prosthesis 600, showing the various components making up the device. The prosthesis 600 comprises a removable front casing 605 imitating the appearance of the sclera, and a rear casing 608 for housing the electronic components 607 including the controller, transformer and battery. A frontal encapsulating lens 601 covers the front of the prosthesis, behind which is provided a frontal lens 602 providing a refraction effect that adds to the realistic appearance of the artificial pupil. The artificial pupil assembly 603 is provided behind the frontal lenses 601 , 602, behind which is provided a rear encapsulating lens 604 having a curved lens carrying a painted image of the iris. A light dependent resistor 606 is provided for measuring ambient light conditions, from which the controller determines the voltage to be applied to the artificial pupil. Other embodiments are intentionally within the scope of the invention, which is defined by the appended claims.

References

1. Zhang R., "Development of Dielectric Elastomer Actuators and their Implementation in a Novel Force Feedback Interface" Doctor of Technical Sciences dissertation, Swiss Federal Institute Of Technology Zurich, 2007.

2. Rossiter J. et al., "Biomimetic chromatophores for camouflage and soft active surfaces", Bioinspiration & Biomimetics 7 (2012) 036009.

3. Lotz P. et al., "Dielectric Elastomer Actuators using improved Thin Film Processing and nanosized Particles" Electroactive Polymer Actuators and Devices (EAPAD) 2008, Proc. of SPIE Vol. 6927, 692723 (2008).

4. J. Lapointe et al., "An ocular prosthesis which reacts to light", Proc. SPIE 7885, Opthalmic Technologies XXI, 7885 12 (February 1 1 , 201 1); doi: 10. 1 17/12.874078

5. F.W. Leuschner, "Light-controlled pupil size for ocular prosthesis", Proc. SPIE 1644, Opthalmic Technologies II, 320 (August 14, 1992); doi: 10. 1 1 17/12. 137438

6. LaFuente, H., US Patent 4332039 ( 1982).

7. Schliepman, F. et al , US Patent 6139577 (2000).

8. Budman, F. et al., US Patent 6576013 (2003).

9. Friel, T., US Patent 5061279 ( 1991).

Claims

1. An ocular prosthesis comprising an adjustable pupil, wherein the prosthesis is configured to apply a voltage across a pair of electrodes defining a lateral extent of the pupil to change the lateral extent of the electrodes.
2. The ocular prosthesis of claim 1 wherein the prosthesis is configured to change the applied voltage in response to a change in detected incident light intensity.
3. The prosthesis of claim 1 or claim 2 wherein the pupil is configured such that an increased voltage applied across the pair of electrodes causes the lateral extent of the pupil to expand.
4. The prosthesis of any preceding claim wherein the pair of electrodes are disposed on opposing faces of an electroactive polymer film.
5. The prosthesis of claim 4 wherein the electroactive polymer film is affixed to, and held in planar tension by, a surrounding support structure.
6. The prosthesis of claim 5 wherein the support structure comprises a pair of rings affixed to opposing faces of an outer edge of the electroactive polymer film.
7. The prosthesis of claim 5 or claim 6 wherein the support structure comprises a transparent curved plate extending across a first face of the polymer film and pupil.
8. The prosthesis of claim 7 comprising an iris image extending across a second opposing face of the polymer film and pupil.
9. The prosthesis of claim 8 wherein the iris image is applied to a face of a curved plate extending across the second face of the polymer film.
10. The prosthesis of any one of claims 2 to 9 comprising a controller and a light sensor connected to the controller, the controller configured to provide a voltage signal to apply the voltage across the pair of electrodes, the voltage signal being dependent upon incident light intensity falling on the light sensor.
1 1. The prosthesis of claim 10 comprising a voltage transformer configured to transform the voltage signal from the controller and apply the voltage across the pair of electrodes.
12. The prosthesis of claim 1 1 wherein the transformer is configured to apply a voltage of up to over 500V, and optionally up to 1.5 kV, across the pair of electrodes.
PCT/GB2014/050492 2013-02-22 2014-02-20 Ocular prosthesis WO2014128466A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB201303131A GB201303131D0 (en) 2013-02-22 2013-02-22 Ocular prosthesis
GB1303131.5 2013-02-22

Publications (1)

Publication Number Publication Date
WO2014128466A1 true true WO2014128466A1 (en) 2014-08-28

Family

ID=48091909

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2014/050492 WO2014128466A1 (en) 2013-02-22 2014-02-20 Ocular prosthesis

Country Status (2)

Country Link
GB (1) GB201303131D0 (en)
WO (1) WO2014128466A1 (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4332039A (en) 1980-10-31 1982-06-01 Lafuente Henry Ocular prosthesis which simulates change in pupil diameter
SU1113117A1 *
US5061279A (en) 1990-11-15 1991-10-29 Friel Timothy P Photochromic dilating pupil for ocular prosthetics
US6139577A (en) 1998-03-06 2000-10-31 Schleipman; Fredrick Dilating ocular prosthesis
US6576013B1 (en) 2002-01-08 2003-06-10 International Business Machines Corporation Eye prosthesis
US20080032593A1 (en) * 2006-08-02 2008-02-07 Benq Corporation Eye module and facial expression module and display method thereof
US20100010626A1 (en) * 2008-07-08 2010-01-14 Hon Hai Precision Industry Co., Ltd. Artificial eye
WO2011134081A1 (en) * 2010-04-26 2011-11-03 Corporation De L ' Ecole Polytechnique De Montreal B.R.C.D.T. Prosthetic eye with a dynamic liquid crystal pupil

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU1113117A1 *
US4332039A (en) 1980-10-31 1982-06-01 Lafuente Henry Ocular prosthesis which simulates change in pupil diameter
US5061279A (en) 1990-11-15 1991-10-29 Friel Timothy P Photochromic dilating pupil for ocular prosthetics
US6139577A (en) 1998-03-06 2000-10-31 Schleipman; Fredrick Dilating ocular prosthesis
US6576013B1 (en) 2002-01-08 2003-06-10 International Business Machines Corporation Eye prosthesis
US20080032593A1 (en) * 2006-08-02 2008-02-07 Benq Corporation Eye module and facial expression module and display method thereof
US20100010626A1 (en) * 2008-07-08 2010-01-14 Hon Hai Precision Industry Co., Ltd. Artificial eye
WO2011134081A1 (en) * 2010-04-26 2011-11-03 Corporation De L ' Ecole Polytechnique De Montreal B.R.C.D.T. Prosthetic eye with a dynamic liquid crystal pupil

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
F.W. LEUSCHNER: "Light-controlled pupil size for ocular prosthesis", PROC. SPIE 1644, OPTHALMIC TECHNOLOGIES, vol. II, 14 August 1992 (1992-08-14), pages 320
J. LAPOINTE ET AL.: "An ocular prosthesis which reacts to light", PROC. SPIE 7885, OPTHALMIC TECHNOLOGIES, vol. XXI, 11 February 2011 (2011-02-11), pages 788512, XP060005761, DOI: doi:10.1117/12.874078
LOTZ P. ET AL.: "Dielectric Elastomer Actuators using improved Thin Film Processing and nanosized Particles", ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) 2008, PROC. OF SPIE, vol. 6927, 2008, pages 692723
ROSSITER J. ET AL.: "Biomimetic chromatophores for camouflage and soft active surfaces", BIOINSPIRATION & BIOMIMETICS, vol. 7, 2012, pages 036009, XP020229316, DOI: doi:10.1088/1748-3182/7/3/036009
ZHANG R.: "Development of Dielectric Elastomer Actuators and their Implementation in a Novel Force Feedback Interface", DOCTOR OF TECHNICAL SCIENCES DISSERTATION, SWISS FEDERAL INSTITUTE OF TECHNOLOGY ZURICH, 2007

Also Published As

Publication number Publication date Type
GB201303131D0 (en) 2013-04-10 application

Similar Documents

Publication Publication Date Title
US7369321B1 (en) Variable-focus liquid lens
US20090279050A1 (en) Electro-optic lenses for correction of higher order aberrations
US20050036109A1 (en) Enhanced electro-active lens system
US3904281A (en) Flexible refracting membrane adhered to spectacle lens
US5108429A (en) Micromotor actuated adjustable focus lens
US7220279B2 (en) Accommodating lens assembly
US7142369B2 (en) Variable focus liquid lens
US7753953B1 (en) Accommodating intraocular lens system
US20130245754A1 (en) Adaptive intraocular lens
US6069742A (en) Optical apparatus and method
US20120268712A1 (en) Fluid Filled Adjustable Contact Lenses
US6638304B2 (en) Vision prosthesis
US20100053549A1 (en) Method and apparatus for constructing a contact lens with optics
US7229476B2 (en) Intraocular lens positioning
WO2012051223A2 (en) Telescopic contact lens
US7261736B1 (en) Vision prosthesis with artificial muscle actuator
US20120140167A1 (en) Dynamic Changeable Focus Contact And Intraocular Lens
US20120120365A1 (en) Molded lens with nanofilaments and related methods
US6576013B1 (en) Eye prosthesis
US6391057B1 (en) Dilating ocular prosthesis
US6139577A (en) Dilating ocular prosthesis
WO2010133317A9 (en) Lens with variable refraction power for the human eye
US20110157541A1 (en) Transition lenses with virtual pupil
JP2007526517A (en) Variable focus lens
US3603305A (en) Sensory development apparatus

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14712704

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14712704

Country of ref document: EP

Kind code of ref document: A1