AU2005253648B2 - Opthalmic camera and opthalmic camera adaptor - Google Patents

Abstract

An ophthalmic camera (10) comprising a camera (12) having a lens (18) aligned with a second lens (16) and at least one illumination means (14).The illumination means (14) is capable of movement relative to the camera lens (18) so that the beam of light emitted by the illumination means (14) is able to be focused by the second lens (16) through the pupil onto the fundus. In another embodiment, the ophthalmic camera comprises a camera (52), an illumination means (54) and a beamsplitter (58). The camera (52) and the beamsplitter (58) form an alignment axis X and the illumination means (54) together with the beamsplitter (58) form an illumination axis Y perpendicular to the alignment axis X. The illumination means (54) is capable of movement relative to the illumination axis Y so that the beam of light reflected by the beamsplitter (58) towards the pupil (70) is substantially the same size as the pupil (70) to maximise the amount of light entering the pupil without impinging upon the iris to avoid contracting of the pupil (70).

Description

- 1 "Ophthalmic Camera and Ophthalmic Camera Adaptor" Field of the Invention The present invention relates to an ophthalmic camera and an ophthalmic camera adaptor. In particular, the invention relates to the optical arrangement that forms 5 the basis for the ophthalmic camera and ophthalmic camera adaptor. Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 10 Furthermore, throughout the specification, unless the context requires otherwise, the word "include" or variations such as "includes" or "including", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Background Art 15 Each document, reference, patent application or patent cited in this text is expressly incorporated herein in their entirety by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application or patent cited in this text is not repeated in this text is merely for reasons of conciseness. 20 The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the 25 person skilled in the art in any jurisdiction as at the priority date of the invention. Images of the fundus of a patient's eye can degrade due to many factors. Such factors include: reflection of light from the cornea or iris; 30 e reflection of light from the walls of the ophthalmic lens; and -2 e use of an incorrect level of illumination for the pupil colour of the patient's eye. One method of overcoming some of the above problems is to use low level illumination devices. However, using such illumination devices, typically, reduces 5 the field of view of the image and may not be appropriate for the fundus being examined. Embodiments of the present invention seek to provide an optical arrangement that reduces the level of reflection by one or more of the cornea, iris, or walls of the ophthalmic lens, or to provide the consumer with a useful or commercial choice. 10 Disclosure of the Invention In accordance with a first broad aspect of the present invention, there is provided an ophthalmic camera for taking an image of a fundus of an eye, the camera comprising: a camera having a camera lens; 15 at least one illumination means; a second lens, centres of the second lens and the camera lens being aligned to form an alignment axis, wherein a beam of light emitted by the illumination means is able to be focused by the second lens through a pupil of the eye onto the fundus, wherein the illumination means comprises a plurality of light sources, 20 each light source having a respective radial axis and a respective axial plane, the plurality of light sources being disposed around a circumference of the camera lens, and wherein the illumination means is set to a setting representative of the pupil, the setting specifying a position of at least one light source of the illumination means linearly along its respective radial axis and pivoted about the 25 axial plane such that the beam of light emitted by the illumination means is focused relative to the centre of the second lens; a first polariser located within the alignment axis and positioned in front of the second lens; and -3 a second polariser attached to at least one light source of the illumination means such that light emitted by the illumination means passes through the second polariser, the first polariser being oppositely polarised to the second polariser to thereby filter the light. Preferably, the plurality of light sources comprise a plurality of Light Emitting Diodes (LEDs) configured to provide, in use, a light beam emitted directly towards the second lens to be focused by the second lens through the pupil of the eye onto the fundus. Preferably, the plurality of LEDs are mounted so as to be movable relative to the camera lens. Preferably, the plurality of LEDs are mounted proximate or as close as possible to the camera lens, disposed to surround the circumference of the camera lens and are spaced equidistant from adjacent LEDs. Preferably, the ophthalmic camera further comprises control means, the control means having a plurality of settings such that, when the setting of the control means is changed, at least one light source of said illumination means moves linearly along its respective radial axis to the position specified by the new setting; and pivots about the axial plane until the circle of light emitted by said illumination means is focused relative to the centre of the second lens. Preferably, the ophthalmic camera includes automated measuring means, the automated measuring means operable to analyse a pupil being examined and change the setting of the control means to the most appropriate setting on the basis of the analysis of the pupil. Preferably, the ophthalmic camera comprises focusing means for focusing the second lens. Preferably, the focusing means comprises means for allowing linear movement of the second lens along the alignment axis. Preferably, the field of view of the camera lens is adjustable. Preferably, the illumination means comprises a solid state light emitting diode.

- 3a In accordance with a second broad aspect of the present invention, there is provided an ophthalmic camera comprising: a camera having a camera lens; an illumination means; a second lens; a beam splitter; and a light focusing lens; centres of the second lens, the camera lens and the beam splitter being aligned to form an alignment axis, and centres of the beam splitter, light focusing lens and the illumination means being aligned to form an illumination axis perpendicular to the alignment axis, the illumination means being movable relative to the illumination axis and the light focusing lens so that a beam of light from the illumination means is focused by the light focusing lens towards the beam splitter, -4 and reflected by the beam splitter along the alignment axis towards and through a pupil of an eye being examined, the illumination means thereby being movable relative to the alignment axis and the second lens, wherein the position of the illumination means is adjustable to be set to a setting, the setting specifying the 5 position of the illumination means linearly along the illumination axis and pivoted about a plane that includes the alignment axis and the illumination axis to focus the beam of reflected light so that it is substantially the same size as the pupil to maximise the amount of light entering the pupil without impinging upon an iris of the eye to thereby avoid contraction of the pupil. 10 Preferably, the illumination means is able to move linearly along the illumination axis such that the light reflected by the beam splitter towards a retina of the eye is substantially aligned with the centre of a first surface of the second lens, and/or wherein the illumination means is able to pivot about a pivot point to permit the illumination axis to be moved and adjusted relative to said alignment axis. 15 Preferably, the ophthalmic camera comprises control means, the control means having a plurality of settings such that, when the setting of the control means is changed, said illumination means moves linearly along the illumination axis to a predetermined position associated with the new setting. Preferably, the ophthalmic camera includes automated measuring means, the 20 automated measuring means operable to analyse the pupil being examined and change the setting of the control means to the most appropriate setting on the basis of the analysis of the pupil. Preferably, the setting represents pupil sizes selected from the group comprising: pupils of size less than 3mm; pupils having a size between 3 - 4mm; and dilated 25 pupils. In accordance with a third broad aspect of the present invention, there is provided an adaptor for an ophthalmic camera having a body and a camera housed within the body, the adaptor comprising: optics for illuminating a subject within an optical axis of the camera in 30 accordance with the first and second broad aspects of the present invention as hereinbefore described; -5 means for releasably engaging the body; and an aperture extending therethrough; wherein, when releasably engaged with the body, the aperture aligns with the optical axis such that least a portion of the optical axis of the camera is not 5 obscured. In accordance with a fourth broad aspect of the present invention, there is provided a method of imaging a fundus of an eye with an ophthalmic camera, the method comprising the steps of: aligning a centre of a camera lens of the ophthalmic camera and a centre 10 of a second lens to form an alignment axis; disposing a plurality of light sources of an illumination means around a circumference of the camera lens, each light source having a respective radial axis and a respective axial plane, wherein the beam of light emitted by the illumination means is able to be focused by the second lens through 15 a pupil of the eye onto the fundus; setting the illumination means to a setting representative of the pupil, the setting specifying a position of at least one light source of the illumination means linearly along its respective radial axis and pivoted about the axial plane such that the beam of light emitted by the illumination means is 20 focused relative to the centre of the second lens; locating a first polariser within the alignment axis such that the first polariser is positioned in front of the second lens; and attaching a second polariser to at least one light source of the illumination means such that light emitted by the illumination means passes through the 25 second polariser, the first polariser being oppositely polarised to the second polariser to thereby filter the light. Preferably, the method further comprises the step of: -6 moving at least one light source of the illumination means along its respective radial axis to a predetermined position associated with a setting of a control means when the control means is set to the associated setting. Preferably, the method further comprises the steps of: 5 analysing the pupil being examined; determining the most appropriate associated setting on the basis of the analysis of the pupil; and changing the setting of the control means to the most appropriate associated setting. 10 Preferably, the method comprises the steps of: directing the beam of light through a first polariser; and taking an image of the beam of light through a second polariser of opposite polarisation to the first polariser. In accordance with a fifth broad aspect of the present invention, there is provided 15 a method of imaging a fundus of an eye with an ophthalmic camera, the method comprising the steps of: directing light emitted by an illumination means to a light focusing lens; and focusing the light towards a beam splitter to be reflected by the beam splitter towards the fundus so that a size of beam of light can be 20 commensurate to a size of a pupil of the eye; wherein centres of the beam splitter, light focusing lens and illumination means are aligned to form an illumination axis and centres of a camera lens of the ophthalmic camera, second lens and the beam splitter are aligned to form an alignment axis perpendicular to the illumination axis; and 25 adjusting the illumination means to a setting, the setting specifying a position of the illumination means linearly along the illumination axis and pivoted about a plane that includes the alignment axis and the illumination axis such that a centre of the beam of light reflected by the beam splitter -7 towards the pupil is substantially aligned relative to a centre of a first surface of the second lens. Preferably, the method further comprises the step of pivoting the illumination means about the plane that includes the alignment axis and the illumination 5 axis. Preferably, the method further comprises the step of: moving the illumination means along the illumination axis to a predetermined position associated with a setting of a control means when the control means is set to the associated setting. 10 Preferably, the method further comprises the step of: analysing the pupil being examined; determining the most appropriate associated setting on the basis of the analysis of the pupil; and changing the setting of the control means to the most appropriate 15 associated setting. Preferably, the setting represents pupil sizes selected from the group comprising: pupils of size less than 3mm; pupils having a size between 3 - 4mm; and dilated pupils. The invention will now be more fully understood in light of the following description 20 of several specific embodiments. Brief Description of the Drawings The invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure la is a schematic of the optics of an ophthalmic camera and ophthalmic 25 camera adaptor of a first embodiment of the present invention showing linear movement of the LED's.

-8 Figure lb is a schematic of the optics of the ophthalmic camera and ophthalmic camera adaptor of the first embodiment, similar to Figure lb but showing angular movement of the LED's. Figure 2 is an isometric view of the schematics of the optics of the ophthalmic 5 camera and ophthalmic camera adaptor of the first embodiment of the present invention. Figure 3 is a schematic of the optics of an ophthalmic camera and ophthalmic camera adaptor of a second embodiment of the present invention. Figure 4 is a schematic of the optics of an ophthalmic camera and ophthalmic 10 camera adaptor of a third embodiment of the present invention. Figures 5a and 5b are perspective views of an ophthalmic camera adaptor of an embodiment of the present invention. Best Mode(s) for Carrying Out the Invention The first embodiment of the best mode invention for carrying out the invention is 15 directed towards an ophthalmic camera apparatus 10, generally comprising a camera 12 highly sensitive to low light (ie. somewhere in the range of <0.05 lux), an illumination means in the form of a plurality of solid-state LEDs 14, and an ophthalmic lens 16 all contained within a housing (not shown). This arrangement is shown graphically in Figure 1. 20 The camera 12 has a camera lens 18 and so the ophthalmic lens constitutes a second lens of the apparatus 10. Ideally, the camera lens 18 has a diameter of 5 8mm. The camera lens 18 provides for an adjustable field of view. The plurality of LEDs 14 surround the circumference of the camera lens 18 and are linked to a control unit 20. The intensity of the light generated by LEDs 14 can 25 be varied by way of the control unit 20. Each LED 14 is equidistant to its adjacent LEDs 14. Each LED 14 also has an adjustable illumination angle. As shown in Figures la and 2, LEDs 14 are able to move linearly along their respective radial axes (marked A through E), relative to the main optical axis X.

-9 As shown in Figures lb and 2, each LED 14 is also able to pivot about a pivot point thereof (A' to E'), towards, or away from the camera lens 18, so that the illumination axis Y thereof can move either towards or away the point of intersection of the optical axis X with the ophthalmic lens 16, in order to 5 compensate for linear movement of the LED along its respective radial axis A-E and corresponding displacement of the illumination axis Y relative to the optical axis X. The ophthalmic lens 16 has an inner convex surface 22 that opposes the camera lens 18. The central axis of the camera lens 18 aligns with the central axis of the 10 inner convex surface 22 to form an alignment axis, which constitutes the main optical axis X. Ideally, the ophthalmic lens 16 is of the same size as, or smaller than, the camera lens 18. An anti-reflective coating may be applied to the ophthalmic lens 16. The ophthalmic lens is typically in the range of 20 to 90 dioptres, with 40 dioptres 15 considered optimum. To allow for focusing of the ophthalmic lens 16, the ophthalmic lens 16 is capable of linear movement along optical axis X of the monochromatic camera 12. The position of the LEDs 14, as well as the illumination angle of LEDs 14 and field of view of the camera lens 18, are all a function of the current setting of the 20 ophthalmic camera apparatus 10. Each setting of the ophthalmic camera apparatus 10 represents a range of sizes of a pupil 24 of a patient with being examined with the apparatus. To elaborate, e setting 1 is used for pupils of size less than 3mm; e setting 2 is used for pupils having a size between 3-4mm; and 25 e setting 3 is used for dilated pupils. Upon choosing a setting: * The illumination angle of a beam of light 26 generated by each LED 14 along its illumination axis Y is restricted or enlarged, as appropriate, such that the circle generated by the beam of light 26 at 30 the point of intersection with the ophthalmic lens 16 is of a size that, -10 when the light is focused by the ophthalmic lens 16 onto the pupil 24, the angle of the focused light 0 provides a wide field of view for the appropriate pupil 24 size. . LEDs 14 move linearly along their respective radial axes (marked A 5 through E) and pivot about their respective pivot point (marked A' through E') such that the centre of the circle generated by the beam of light 26 at the point of intersection with the ophthalmic lens 16 can be precisely adjusted with respect to the centre of the ophthalmic lens 16. 10 e The field of view of camera lens 18 is restricted to substantially the same size as the pupil 24 size associated with the setting. This allows the same LEDs 14 to be used for pupils 24 of all sizes while negating the need to unnecessarily restrict the field of view of the camera lens 18 to avoid reflection from the cornea or iris. This also means that for larger size pupils 24, 15 the angle of the focused light 0 along the illumination axis Y is greater than the angle of the focused light 0 generated in respect of smaller size pupils 24. The second embodiment of the best mode is substantially similar to the first embodiment, where like numerals reference like parts, but involves the use of optical filters. As shown in Figure 3, a first filter 28 is located along the optical axis 20 X of the camera 12 at a position in front of camera lens 18. A second filter 30 is attached to each LED 14, such that the beam of light 26 emitted thereby passes through the second filter 30. The first filter 28 is oppositely polarised to second filter 30. As the beam of light 26 reflects off the fundus 24 it enters the ophthalmic lens 18. 25 On entering the ophthalmic lens 18, the polarisation of the beam of light 26 is reversed. However, as the beam of light 26 enters the ophthalmic lens 18, light that reflects off the two walls of the ophthalmic lens 18 will not be captured by the camera 12 due to the cross-polarisation effect of first and second filters 28, 30. The third embodiment of the best mode is shown in Figure 4, and is directed 30 towards an ophthalmic camera apparatus 50 comprising a digital camera 52 - 11 highly sensitive to low light (ie. somewhere in the range of <0.05 lux), a solid state LED 54, an ophthalmic lens 56, a beamsplitter 58 and a light focusing lens 60, all contained within a housing (not shown). The digital camera 52 has a camera lens 62. Ideally, the camera lens 62 has a 5 diameter of 5-8mm. The camera lens 62 provides for an adjustable field of view. The ophthalmic lens 56 has an inner convex surface 64 that opposes the camera lens 62. The centre of the camera lens 62 aligns with the centre of the inner surface 64. Ideally, the ophthalmic lens 56 is of the same size as, or smaller than, the camera lens 62. 10 The ophthalmic lens 56 is typically in the range of 20 to 90 dioptres, with 40 dioptres considered optimum. To allow for focusing of the ophthalmic lens 56, the ophthalmic lens 56 is capable of linear movement along optical axis X of the digital camera 52. Opposite the outer convex surface 66 of the ophthalmic lens 56, but still within the 15 optical axis X of the digital camera 52, is beamsplitter 58. In this embodiment, beamsplitter 58 is a 50/50 beamsplitter, but beamsplitters of other proportions may be used. Located substantially at a right angle to the optical axis X of the digital camera 52, as taken at the point of intersection with beamsplitter 58, is illumination axis Y. 20 Located on illumination axis Y are light focusing lens 60 and solid state LED 54. Solid state LED 54 is capable of linear movement along illumination axis Y. Solid state LED 54 is also capable of pivotal movement about a pivot point that permits the illumination axis to be moved and adjusted relative to the optical axis X. Solid state LED 54 has an adjustable illumination angle. The intensity of the light 25 generated by the solid state LED 54 is also adjustable. As with previous embodiments of the invention, the position of the solid state LED 54, the illumination angle of LED 54 and the field of view of the camera lens 62, are all a function of the current setting of the ophthalmic camera apparatus 50. Each setting of the ophthalmic camera 50 apparatus represents a range of sizes 30 for the pupil 70 of a patient being examined with the apparatus. To elaborate, - 12 e setting 1 is used for pupils 70 of size less than 3mm; e setting 2 is used for pupils 70 having a size between 3-4mm; and a setting 3 is used for dilated pupils 70. Upon choosing a setting: 5 * The illumination angle of light emitted by solid state LED 54 is restricted or enlarged, as appropriate, such that the circle of light reflected by the beamsplitter 58 towards pupil 70 is of a size that the angle of the focused light 0 provides a wide field of view for the appropriate pupil 24 size. 10 e Solid state LED 54 moves linearly along illumination axis Y and pivots about the plane that includes illumination axis Y and optical axis X such that the centre of the circle of light reflected by the beamsplitter 58 towards pupil 70 is substantially aligned with or relative to the centre of the outer surface 66 of the ophthalmic lens 15 56. * The field of view of camera lens 62 is restricted to substantially the same size as the pupil 70 size associated with the setting. This also means that for larger size pupils 70, the angle of the focused light 0 is greater than the angle of the focused light 0 generated in respect of smaller size 20 pupils 70. The fourth embodiment of the best mode is directed towards an ophthalmic camera adaptor 100. The ophthalmic camera adaptor 100 is shown in Figures 5a and 5b. The ophthalmic camera adaptor 100 consists of a body 102. In the embodiment 25 being described, body 102 is substantially rectangular in shape and has a rear face 104, two sides 106a, 106b and a front face 108. Located centrally about rear face 104 is an aperture 110. Aperture 110 extends through the ophthalmic adaptor 100 such that the aperture 110 is also located -13 centrally about front face 108. Situated adjacent aperture 110 is an interface contact 112. Adjacent face 104 are two snap clips 114a, 114b. Snap clip 114a extends from side 106a, while snap clip 114b extends from side 106b. Each snap clip 114 has 5 an internal recess 116a, 116b positioned such that, when appropriate pressure is applied, the snap clips 114 can flex towards aperture 110. Snap clips 1 14a, 1 14b are adapted to be releasably retained within grooves on the body of a camera (not shown) to which it is ultimately attached. Surrounding front face 108, and extending along a portion of sides 106 towards 10 rear face 104, is a rubber overmoulding 118. Rubber overmoulding 118 covers a portion 120 of each snap clip 114. Finger grips 122 are formed within the external surface 124 of rubber overmoulding 118 at a position substantially adjacent portion 120. The optics as described in any of the previous embodiments of the invention can 15 be implemented in this ophthalmic adaptor 100 arrangement. The optics are connected to the interface contact 112 such that control of the optics is facilitated through the interface contact 112. It should be appreciated by the person skilled in the art that the present invention is not limited to the above embodiments and that variations and modifications 20 thereof are considered to be within the scope of the invention. In particular, the following modifications and variations fall within the scope of the invention: e LEDs 14 may have a fixed illumination angle. In this arrangement, a collimator, or other like device, may be positioned in front of each LED 14. On choosing a setting, the collimator, or other like device, 25 will operate to restrict or enlarge, as appropriate, the beam of light 26 generated by the LED 14 such that the circle generated by the beam of light 26 at the point of intersection with the ophthalmic lens 16 is of substantially the same size as the pupil 24 size associated with the setting. A similar collimator arrangement can be implemented in 30 respect of the third embodiment of the invention.

- 14 * The ophthalmic camera 10, 50 and ophthalmic camera adaptor 100 may include magnification lenses. Each magnification lens is associated with at least one setting, such that, on choosing the setting, the magnification lens is positioned within the optical axis X 5 of the monochromatic camera 12 and in-between the ophthalmic lens 16 and the camera lens 18. * Camera 12 may be a monochromatic camera. Additionally, camera 12 may be a digital camera. " LEDs 14, 54 can be replaced by a light focusing means and light bulb 10 arrangement. " Beamsplitter 58 may be replaced with a prism arrangement. " The ophthalmic lens 16 may be replaced with any other type of lens. e The plurality of LEDs 14 may be replaced with a single LED 14 disposed about the circumference of the camera lens 18. 15 Alternatively, more or less LEDs 14 may be used than have been described herein. " An alternate number of settings may be used than has been described herein. Alternatively, rather than having settings that move the LEDs 14 to predefined positions, the linear and pivotal movement 20 of LEDs 14 may be facilitated through separate manual controls. Similarly, the illumination angle of beam of light 26 and the field of view of camera lens 18 may be facilitated through separate manual controls. e The linear and pivotal movement of LEDs 14, the illumination angle 25 of beam of light 26 and the field of view of camera lens 18 may be facilitated through a single manual control. " The intensity of the LEDs 14, 54 may be controlled by means of settings representing the various pupil colours. Alternatively, the intensity of the LEDs 14, 54 may be controlled by manual adjustment 30 across the spectrum of intensities.

- 15 * An iris structure may be used to assist in limiting the field of view of the camera lens 18. The iris may be manually or automatically controlled. * Control unit 20 may be adapted to control the linear and pivotal 5 movement of LEDs 14, the illumination angle of beam of light 26 and the field of view of camera lens 18 based on the determined size of the pupil 24 to be examined. e The linear movement of the ophthalmic lens 18 as a means of focusing the image to be captured can be replaced by other focusing 10 structures. * The adaptor structure mentioned above can be replaced with any other structure incorporating the optical arrangement mentioned. e The interface contact 112 may be omitted and in its place control unit 20 may be in-built into the adaptor. 15 It should be further appreciated by the person skilled in the art that features and modifications discussed above, not being alternatives or substitutes, can be combined to form yet other embodiments that fall within the scope of the invention described.

Claims (20)

1. An ophthalmic camera for taking an image of a fundus of an eye, the camera comprising: a camera having a camera lens; 5 at least one illumination means; a second lens, centres of the second lens and the camera lens being aligned to form an alignment axis, wherein a beam of light emitted by the illumination means is able to be focused by the second lens through a pupil of the eye onto the fundus, wherein the illumination means comprises a plurality of light sources, 10 each light source having a respective radial axis and a respective axial plane, the plurality of light sources being disposed around a circumference of the camera lens, and wherein the illumination means is set to a setting representative of the pupil, the setting specifying a position of at least one light source of the illumination means linearly along its respective radial axis and pivoted about the 15 axial plane such that the beam of light emitted by the illumination means is focused relative to the centre of the second lens; a first polariser located within the alignment axis and positioned in front of the second lens; and a second polariser attached to at least one light source of the illumination means 20 such that light emitted by the illumination means passes through the second polariser, the first polariser being oppositely polarised to the second polariser to thereby filter the light.

2. An ophthalmic camera as claimed in claim 1, wherein the plurality of light sources comprise a plurality of Light Emitting Diodes (LEDs) configured to 25 provide, in use, a light beam emitted directly towards the second lens to be focused by the second lens through the pupil of the eye onto the fundus.

3. An ophthalmic camera as claimed in claim 2, wherein the plurality of LEDs are mounted so as to be movable relative to the camera lens. - 17

4. An ophthalmic camera as claimed in claim 3, wherein the plurality of LEDs are mounted proximate or as close as possible to the camera lens, disposed to surround the circumference of the camera lens and are spaced equidistant from adjacent LEDs.

5 5. An ophthalmic camera as claimed in any one of the preceding claims, further comprising control means, the control means having a plurality of settings such that, when the setting of the control means is changed, at least one light source of said illumination means moves linearly along its respective radial axis to the position specified by the new setting; and pivots about the axial plane until 10 the circle of light emitted by said illumination means is focused relative to the centre of the second lens.

6. An ophthalmic camera as claimed in claim 5, including automated measuring means, the automated measuring means operable to analyse a pupil being examined and change the setting of the control means to the most 15 appropriate setting on the basis of the analysis of the pupil.

7. An ophthalmic camera as claimed in any preceding claim comprising focusing means for focusing the second lens.

8. An ophthalmic camera as claimed in claim 7, wherein the focusing means comprises means for allowing linear movement of the second lens along the 20 alignment axis.

9. An ophthalmic camera as claimed in any preceding claim, wherein the field of view of the camera lens is adjustable.

10. An ophthalmic camera as claimed in any preceding claim, wherein the illumination means comprises a solid state light emitting diode. 25

11. An adaptor for an ophthalmic camera having a body and a camera housed within the body, the adaptor comprising: optics for illuminating a subject within an optical axis of the camera in accordance with any one of the preceding claims; means for releasably engaging the body; and - 18 an aperture extending therethrough; wherein, when releasably engaged with the body, the aperture aligns with the optical axis such that least a portion of the optical axis of the camera is not obscured. 5

12. A method of imaging a fundus of an eye with an ophthalmic camera, the method comprising the steps of: aligning a centre of a camera lens of the ophthalmic camera and a centre of a second lens to form an alignment axis; disposing a plurality of light sources of an illumination means around a 10 circumference of the camera lens, each light source having a respective radial axis and a respective axial plane, wherein the beam of light emitted by the illumination means is able to be focused by the second lens through a pupil of the eye onto the fundus; setting the illumination means to a setting representative of the pupil, the 15 setting specifying a position of at least one light source of the illumination means linearly along its respective radial axis and pivoted about the axial plane such that the beam of light emitted by the illumination means is focused relative to the centre of the second lens; locating a first polariser within the alignment axis such that the first polariser is positioned in front 20 of the second lens; and attaching a second polariser to at least one light source of the illumination means such that light emitted by the illumination means passes through the second polariser, the first polariser being oppositely polarised to the second polariser to thereby filter the light. 25

13. A method of imaging a fundus of an eye with an ophthalmic camera, the method being as claimed in claim 12, the method further comprising the step of: moving at least one light source of the illumination means along its respective radial axis to a predetermined position associated with a setting of a control means when the control means is set to the associated setting. -19

14. A method of imaging a fundus of an eye with an ophthalmic camera, the method being as claimed in claim 13, the method further comprising the steps of: analysing the pupil being examined; determining the most appropriate associated setting on the basis of the 5 analysis of the pupil; and changing the setting of the control means to the most appropriate associated setting.

15. A method of imaging a fundus of an eye with an ophthalmic camera, the method being as claimed in any one of claims 12 to 14, the method further 10 comprising the steps of: directing the beam of light through a first polariser; and taking an image of the beam of light through a second polariser of opposite polarisation to the first polariser.

16. A method of imaging a fundus of an eye with an ophthalmic camera as 15 claimed in any one of claims 12 to 15, wherein the setting represents pupil sizes selected from the group comprising: pupils of size less than 3mm; pupils having a size between 3 - 4mm; and dilated pupils.

17. An ophthalmic camera as claimed in any one of claims 1 to 10, wherein the setting represents pupil sizes selected from the group comprising: pupils of 20 size less than 3mm; pupils having a size between 3 - 4mm; and dilated pupils.

18. An ophthalmic camera as claimed in any one of claims 1 to 10 or 17 substantially as hereinbefore described with reference to the accompanying drawings.

19. An adaptor for an ophthalmic camera as claimed in claim 11 substantially 25 as hereinbefore described with reference to the accompanying drawings.

20. A method of imaging a fundus of an eye with an ophthalmic camera as claimed in any one of claims 12 to 16 substantially as hereinbefore described with reference to the accompanying drawings.