WO2006118560A2

WO2006118560A2 - Imaging apparatus and related methods

Info

Publication number: WO2006118560A2
Application number: PCT/US2005/014678
Authority: WO
Inventors: Shizuo Mukai; Paul Yates
Original assignee: Massachusetts Eye And Ear Infirmary
Priority date: 2005-04-29
Filing date: 2005-04-29
Publication date: 2006-11-09
Also published as: WO2006118560A3

Abstract

An imaging apparatus including an arrangement of two lenses and a light source for attachment to a camera or other similar device. The imaging apparatus enables a user to utilize a camera to obtain images of an eye.

Description

IMAGING APPARATUS AND RELATED METHODS

FIELD OF THEINVENTION

[0001] The present invention relates generally to the field of eye imaging, and, more particularly, the invention relates to imaging devices and related methods for imaging an anterior and/or posterior segment of an eye.

BACKGROUND OF THEINVENTION

[0002] Traditional methods of ophthalmic photography require a specially adapted apparatus when studying the interior of an eye. hi contrast to studying the exterior of an eye, a complex illumination system that can illuminate a region of the retina of an eye and allow imaging of this region through the eye is needed for posterior segment photography.

[0003] Typical mydriatic fundus cameras, which are used by ophthalmologists and optometrists, are a single, large piece of apparatus that produce the required illumination, guide and focus the light to the required position, focus the reflected light into a viewing and/or recording apparatus, and store recorded images from the region of the eye being studied, hi these ophthalmoscopes, the light is focused on the region of interest using a number of lenses and mirrors, rather than pointing the light linearly towards the region to be studied.

[0004] hi these devices, illumination of the eye typically is provided by a single bulb, with the light focused through a complex series of lenses, mirrors and light intercepting plates before being coupled into the main optical path and focused into an eye. For example, the light source from a bulb is focused though a series of lenses and mirrors before passing through a light intercepting plate, which allows only a ring of light to pass. This ring of light is then directed through more lenses towards a final mirror. This final mirror changes the direction of the incident light before passing it through a final set of lenses and into the eye. The reflected light from the illuminated portion of the eye is then passed back through the final set of lenses, through a hole in the center of the final mirror, and through further lenses (and possibly further mirrors) towards an attached viewing apparatus.

[0005] This typical configuration occupies a large volume and is therefore of limited portability. Additionally, in this configuration, the electronics generally must be coupled to a main power source. These electronics can include the light source, viewing apparatus, and other electro-mechanical devices associated with the focusing and positioning of the equipment and focal region. The system also requires a complex and delicate optics system, which limits any maintenance and adjustments that can be carried out by an end user. As a result, these devices can be expensive and are generally only of use to professional ophthalmologists and optometrists in a laboratory or examination room environment.

[0006] A number of devices have been designed to try to provide a less expensive, portable mydriatic fundus camera. These devices typically include the imaging and recording apparatus as a unitary structure. Many of these devices use a single light source, or a number of light sources, that are off-axis from the optical view of the patient's eye and require an arrangement of lenses and mirrors to direct and focus the light into the required configuration and direction. Other devices use fiber-optics to provide light from a source remote from the eye.

[0007] Generally, these devices still need a remote power source to provide the power for the systems. Also, the devices generally still require a complex system of lenses, which increase the size and complexity of the device while limiting its portability. These devices also typically have the imaging and recording apparatus built into the system, resulting in a more complex and expensive device.

[0008] As seen from the foregoing, there is a need for a portable, low-cost, easy to use apparatus that can be used in ophthalmic imaging, thus allowing anterior and/or posterior segment imaging in situations where typical ophthalmic photography is unavailable, impractical, or undesirable. It is desirable to provide a simple apparatus that can be used with a standard film or digital camera to illuminate a region of the interior of an eye and produce quality images without the need for additional specialist equipment. It is also desirable for this device to be compatible with existing optical equipment and lenses, allowing the device to be adapted by a user to a specific task with minimal cost, training and effort. SUMMARY OF THE INVENTION

[0009] The invention provides apparati and related methods for imaging an eye, and particularly the anterior and/or posterior of an eye. These apparati are portable and can attach to a hand-held camera, video camera, or other imaging device. They include a light source sufficient to provide illumination to the area of interest, and an arrangement of lenses that allow the reflected light from the area of interest to be focused into the lens of the camera. As a result, the apparati can be used with standard, readily available photography equipment, such as a film or digital camera, or video camera, to provide a truly portable and easy to use device to image anterior and/or posterior segments of the eyes.

[0010] In one aspect of the invention, an imaging apparatus includes a first lens located along an optical axis and a second lens located along the optical axis. The apparatus also includes a light source positioned between the first lens and the second lens. The light source is contained within a housing, and the first lens and second lens are coupled to the housing.

[0011] This aspect of the invention can have any of the following features. At least one of the first and second lenses can be contained within the housing. The light source can include at least one light emitting diode. The light source can include two or more light emitting diodes arranged along an annular path about the optical axis. The light source can include a single light emitting diode. The light source can be offset from the optical axis.

[0012] In another aspect of the invention, an imaging apparatus includes a first lens located along an optical axis and a second lens located along the optical axis. The apparatus also includes a light source including a plurality of light emitting diodes arranged annularly about the optical axis. The first lens is located between the second lens and the light source.

[0013] In another aspect of the invention, an imaging apparatus includes an optical path and a housing. The optical path consists essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source positioned between the first lens and the second lens. The light source is contained within the housing, and the first lens and second lens are coupled to the housing.

[0014] In another aspect of the invention, an imaging apparatus includes an optical path. The optical path consists essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source including a plurality of light emitting diodes. The light emitting diodes are arranged annularly about the optical axis, and the first lens is located between the second lens and the light source.

[0015] In another aspect of the invention, an imaging apparatus includes a first lens located along an optical axis, a second lens located along the optical axis, and a light source. The light source is a single light emitting diode and is offset from the optical axis. The first lens is located between the second lens and the light source. [0016] In another aspect of the invention, an imaging apparatus includes an optical path. The optical path consists essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source. The light source is a single light emitting diode offset from the optical axis. The first lens is located between the second lens and the light source.

[0017] Any of the preceding aspects of the invention can have any one or combination of the following features. The apparatus can be configured to view the interior of an eye. The apparatus can be configured to pass light through the pupil of the eye. The apparatus can be configured to attach to a portable camera. Light from an image can pass substantially along the optical axis into the camera. At least one of the first and second lenses can be detachable. At least one of the first and second lenses can be replaceable with a different lens. The distance between at least two of the first lens, the light source, and the second lens can be capable of being changed to alter the focal distance of the apparatus. The light source can be powered by an energy source located within or immediately adjacent to a housing containing and/or coupled to a first lens, a second lens, and/or a light source. The light source can be a white light light emitting diode. The light source can further include a flash. The light source can be a green light light emitting diode.

BRIEFDESCRIPTION OF THEDRA WINGS

[0018] The objects and features of the invention can be better understood with reference to the drawings described below, and the claims. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention, hi the drawings, like numerals are used to indicate like parts throughout the various views.

[0019] FIG. 1 is a schematic view of a lens attachment and a camera, in accordance with one embodiment of the invention. [0020] FIG. 2 is a schematic side view of the lens attachment and camera of FIG. 1.

[0021] FIG. 3 A is a schematic side view of the lens attachment of FIG. 2, with the internal lenses and light source shown in broken lines.

[0022] FIG. 3B is a schematic end view of the lens attachment of FIG. 2. [0023] FIG. 4 is a schematic sectional side view of the lens attachment of FIG. 2. [0024] FIG. 5 is a schematic sectional side view of a second embodiment of a lens attachment with a light source having two light elements between a first and second lens.

[0025] FIG. 6 is a schematic sectional side view of a third embodiment of a lens attachment with a light source having a single light element between a first and second lens. [0026] FIG. 7 is a schematic sectional side view of a fourth embodiment of a lens attachment with a light source forming a ring of light elements located towards the end of the device.

[0027] FIG. 8 is a schematic sectional side view of a fifth embodiment of a lens attachment with a light source having a single light element located towards the end of the device.

[0028] FIG. 9 is a perspective view photograph of a sixth embodiment of a lens attachment with two white LED's, two green LED's, and two flashes, all mounted on a camera.

[0029] FIG. 10 is a perspective view photograph of the embodiment of FIG. 9, with the housing removed from the camera and a second lens uncoupled from the housing and mounted on the camera.

[0030] FIG. 11 is an end view photograph of the lens attachment of FIG. 9, removed from the camera, with the second lens uncoupled from the lens attachment.

DETAILED DESCRIPTION

[0031] Imaging apparati are provided that can attach to a camera, video camera, and/or other imaging device, either by direct coupling or remote attachment thereto. The imaging apparati of the invention provide small, portable, self-contained devices and allow the eye to be imaged. In particular, the design of the devices according to the invention allow the anterior and/or posterior segments of the eye to be examined, and particularly the fundus and other portions of the retina. The apparatus includes a light source and at least two lenses, with the lenses configured to allow a linear optical path along the apparatus. Imaged light typically enters from one end of the device and exits the other end of the device. [0032] FIG. 1 shows one apparatus according to the invention, a lens attachment 10 mounted on the front of a hand-held camera 12. The camera 12, for example a Nikon 4300 digital camera, can hold additional lenses and attachments through a connection mechanism 24 at the end of the camera's 12 built-in lens, and the lens attachment 10 typically is coupled to the camera 12 via an interaction between an attachment mechanism 34 (FIG. 4) on the lens attachment and the connection mechanism 24 on the camera. The coupling can occur, for example, through a threaded connection, a clipped connection, a clasp connection, a bayonet connection, a magnetic connection, a simple sliding connection (such that the lens attachment simply slides on to the camera lens housing and is held in place through contact pressure), or other appropriate connection. [0033] In the embodiment shown in FIG. I₅ the lens attachment 10 includes a first lens 16, a second lens 18, and a light source 20. The lenses 16, 18 and light source 20 are mounted in, or connected to, a housing 14, with the housing 14 connecting the apparatus to the camera 12 via a coupling mechanism. The first lens 16, at the distal end of the lens attachment 10, is coupled to the housing 14 through a mounting 22 (FIG. 4) that holds the lens. The mounting can be coupled to the housing, for example, by a threaded connection, a clipped connection, a clasp connection, a bayonet connection, a magnetic connection, a simple sliding connection, or other appropriate means. Alternatively, the mounting can be fixedly attached to the housing. In alternative embodiments, the first lens is held in place by a threaded locking mechanism, clasp, or other appropriate means of holding the lens in place, and the lens is either permanently affixed or removably coupled to the housing. The first lens also can have an anti-reflective coating.

[0034] The detachable mounting 22 allows the first lens 16 to be replaced by another lens with different properties, such as, but not limited to, a different focal length, different treatments (such as an anti-reflective coating or polarization), or a different optical design. As a result, the focal distance and optical characteristics of the camera 12 and lens attachment 10 can be adjusted by mounting a first lens with suitable properties. This allows a user to adjust the lens attachment 10 based on the object being imaged or photographed, or on the camera being used. In certain embodiments, the first lens can be a Nikon or VoIk Ophthalmic Lens, such as a VoIk standard 2OD, 25D, 28D, 30D, 4OD, 6OD, 66D, 78D, and 9OD lens, available from VoIk Optical Inc. Mentor, OH. [0035] A second lens 18 is positioned at the proximal end of the lens attachment 10 within the housing 14 and coupled to the housing 14 through a mounting 32 (FIG. 4). The mounting can be coupled to the housing by any of the methods described above. This lens alternatively can be fixed to the housing without the need for a separate lens mounting component, or removably mounted to the housing as described above. [0036] As a result, in certain embodiments, the second lens can be removed and replaced with a lens having different properties, depending upon the requirements of the user, hi alternative embodiments, the second lens can be fixedly held within the housing, for example to simplify the design of the apparatus. The second lens can be a macro lens. For example, the second lens can be a 1OD macro lens with an approximate diameter of 50 mm.

[0037] A light source 20 is located between the first lens 16 and second lens 18, and within housing 14. The light source 20 includes a plurality of individual light elements 21 arranged along an annular path about an optical axis 26 (FIG. 2) running along the length of the center of the lens attachment 10. These light elements can be evenly spaced in a ring surrounding the optical path 26, with the central region 25 of the ring open to allow reflected light from an object to pass along the optical axis 26 towards the proximal end of the lens attachment. Each light element is a light emitting diode (LED). Alternative light sources can have a light intensity similar to a LED, and can include a halogen bulb, a xenon bulb, a cold cathode fluorescent lamp, a maglite (that can include a fiber optic attachment), or an external LED with a fiber optic cable or mirrors and/or prisms. The body on which the LED's are mounted, or the LED's themselves, can be connected to a power source (not shown) to allow power to be provided to each LED. The intensity and placement of the LED's in this and other embodiments of the invention facilitate the simplicity of the designs herein in contrast to typical eye imaging devices in the art.

[0038] The light source 20 directs light from each separate light element 21 in a direction substantially parallel to the optical axis 26. This light is directed towards the first lens 16, such that the light passes through the first lens 16 at the distal end of the lens attachment 10. This light is focused on a region outside the lens attachment 10. In use, the focal point of the first lens 16 is just posterior to a patient's cornea, and the cornea and lens then refract the light and focus it on the retina. As a result, the light source 20 provides lighting for an object placed in the path of light from the lens attachment 10. In alternative embodiments, the light path from one or more of the light source elements is configured to be at an angle to the relative to the optical axis. For example, the light can be directed slightly towards the optical axis as it exits from each light source element, changing the focal point of the light. In certain embodiments, the angle at which the light is directed as it leaves each light source element can be varied through a user enabled manual or electronic adjustment mechanism.

[0039] The light source can be located on a separate mount, such that the mount can be coupled either fixedly or removably to the housing. In alternative embodiments, the light source is fixed directly to the housing of the apparatus without the need for a separate lens mounting component. Also, the power provided to the light source can be varied, such that the light emitted by the light source can be varied to adjust the lighting provided to an object placed within the optical view of the lens attachment. A user can control the provided power through a user interface device, such as a switch, slide, dial, knob or other appropriate mechanism. Alternatively, the light provided by the light source can be a fixed amount.

[0040] Lenses with further optical treatment, such as a non-reflective coating, also can be used. The non-reflective coating can be beneficial in configurations having the light source placed between the two lenses, as the incident light from the light source may result in reflections from the lenses and produce a degradation of the captured image. Appropriate selection of LED's and lenses to minimize light reflection and improve the efficiency of the illumination can be used to address this issue.

[0041] A power source, such as a battery or number of batteries, can be either embedded in a suitable compartment within the housing or attached to an externally mounted battery holder on the housing. In alternative embodiments, a power source for the light source can be provided by a cable connection to a main source or remote battery pack. In further alternative embodiments, power for the light source can be provided by the camera's power source, through a cable or other connection. A user interface, such as a switch, can be provided in certain embodiments to turn power to the light source on and off. This user interface can be mounted on the housing or attached by a cable to the housing. The power can also be controlled by the camera's power switch and/or operating switch.

[0042] In certain embodiments, the housing is made from a number of separate sections that attach together, by threads or other appropriate means, to make up the lens attachment. The lenses and/or light source can be held in place between two sections, either within a separate mounting that attaches to a section of the housing or by fitting into an appropriate mating area built into a section of the housing. In this configuration, access to a lens or the light source can be achieved by separating the appropriate section, allowing adjustment, replacement, or cleaning of a lens or the light source as required by a user or situation. The lenses and light source also can be placed in a moveable holder, such as a track or tilt mechanism, within the housing. In this configuration, the relative positions of the lenses and light source can be adjusted to vary the focal length, or other optical characteristic, of the lens attachment. In certain embodiments the housing can also include a sliding tube mount to change the working distance of the lens attachment.

[0043] In certain embodiments, the housing is a single section, allowing the lenses and light source to be fixedly, removably and/or adjustably mounted within or connected to the housing. Also, the housing can accommodate attachment of additional pieces to the lens attachment. These additional pieces include, but are not limited to, additional optical devices or pieces, additional lighting, and positioning devices to correctly position the lens attachment and camera with respect to an object. Examples of positioning devices include, but are not limited to, a head rest to locate a head and eye at a required position with respect to the lens attachment, or a stand to position the lens attachment and camera with respect to a surface. [0044] In embodiments with a mounting holding a lens, the lens can be replaced with a different lens by removing the mounting from the housing, for example by unscrewing a threaded mounting from the housing, removing the lens from the mounting, inserting a new lens in the mounting, and reattaching the mounting to the housing. In embodiments with a lens fixedly held in a mounting, the lens can be replaced by removing the mounting and lens and inserting a different lens and mounting in its place. In embodiments with a lens mounted directly into a housing, the lens can be replaced by removing or unlocking the mechanism holding the lens in place, removing and replacing the lens, and reattaching the locking mechanism. In embodiments constructed of separate sections, a lens may be removed by separating the sections, for example by unscrewing a threaded connection, and removing a lens held between two sections. A different lens can then be inserted and the sections reconnected.

[0045] FIG. 2 shows a side view of the lens attachment 10 attached to the camera 12. FIGS. 3 A and 3B show a side and end view, respectively, of the lens attachment 10 shown in FIG. 2, but with the internal first 16 and second 18 lenses and the light source 20, shown in broken lines. FIG. 4 shows a section of the lens attachment 10 of FIG. 2, cut along the line A-A in FIG. 3B. This view shows the inner section through the lens attachment 10 in more detail. The optical axis 26 of the apparatus runs along the open central portion of the housing 14. Light can enter at the distal end of the apparatus 10 through the first lens 16, and travel though the inside of the housing 14, including the aperture 25 in the light source 20, and through the second lens 18 at the proximal end of the lens attachment 10. In use, the camera 12 and lens attachment 10 are positioned such that the optical axis 26 is directed towards an eye 28, the rear of the eye positioned in the path of light from the lens attachment 10. An example light path 30 (originating from the light source 20, not shown in FIG. 2), from the end of the lens attachment 10 into the eye 28 and reflected from the retinal region of the eye 28 into the lens attachment 10, is shown in FIG. 2. The light reflected from the object of interest, in this case the retina of an eye 28, passes through the first lens 16, the aperture 25 of the light source 20, and then the second lens 18 of the lens attachment 10. The light image then travels into the front lens of the camera 12, where it can be viewed and/or photographed. In certain embodiments, the light source is configured in an annular shape to take up a minimal amount of cross-sectional area of the housing, minimizing interference with light traveling through the lens attachment from the object to be photographed, such as the eye, to the camera. [0046] The location of one or more of the first lens 16, second lens 18, and light source 20 can be adjusted. In FIG. 4, arrows indicate one possible form of adjustment that can be carried out to vary the locations of the component parts in relation to each other. Arrows 38, 40, and 42 show exemplary movement of the first lens 16, the light source 20, and the second lens 18, respectively. Adjusting one or more of these component parts with respect to another part, or parts, can change the optical characteristics of the system. For example, varying the location of the first lens 16 and the second lens 18 with respect to the camera and the object of interest (e.g., the retina of an eye), can effect the focal distance of the lens attachment 10. By varying the distance between the light source 20 and the first lens 16, properties of the illumination, such as the size of the illuminated area and the light intensity at the location of the object of interest, can be varied.

[0047] Change in the location of the lenses and the light source can be achieved through use of a standard camera lens adjustment mechanism, such as, but not limited to, a focus ring or lever or a sliding mechanism. A focus ring, for example, converts a rotational movement of an outer ring into a linear movement of a lens, allowing a user to accurately change the position of the lens through a rotation of the outer ring. This method also can be mechanized, allowing a user to push a button to enable a mechanical and/or electrical device to move the lens.

[0048] FIG. 5 shows an embodiment of a lens attachment 60 similar to that shown in FIGS. 1-4, and made with similar materials and used similarly, unless otherwise stated, but configured with two LED' s located approximately 180° apart (for example, in the region at approximately 12 o'clock and 6 o'clock) on the annular path about the optical axis 26. The light source 62 consists of two LED's positioned approximately 180° apart at the upper and lower bounds of the annular path traced about the optical axis 26. The luminous intensity of an LED is about 10,000 mcd. This results in a measured light output less than that of a standard indirect ophthalmoscope. The LED's can be located at any distance from the first and second lenses 16, 18. For example, the two LED's can be positioned closer to the second lens than the first lens, giving a longer distance between the light source and the first lens. Also, more powerful LED's or other lights (such as halogen bulbs, xenon bulbs or cold cathode fluorescent lamps) can be used. For example, 20,000 mcd or IW LED's can be used depending on the requirements of the system and the safety requirements of the tests.

[0049] In this embodiment, light is emitted from the LED's in a path substantially parallel to the optical axis 26 of the lens attachment 60 towards the first lens 16 at the distal end of the lens attachment 60. This incident light 64 is focused through the first lens 16 and into the eye 28. The incident light 64 passes through the pupil of the eye 28, although in alternative embodiments the incident light can be configured to pass transclerally. The incident light 64 then illuminates a region of the retina of the eye 28, allowing a posterior segment of the eye to be studied. [0050] Reflected light 66 from the region of the eye illuminated by the incident light 64 passes out through the pupil of the eye 28 and back into the apparatus 60. This reflected light 66 is focused through the first lens 16, passes through the aperture 25 in the light source 62, and is then focused through the second lens 18. Upon exiting the second lens 18, the reflected light 66 can be sent into an attached viewing apparatus, such as a digital camera or other appropriate means of viewing and/or recording the image from the eye 28. The image from the region of interest can then be viewed and/or recorded as required by the user.

[0051] In an alternative embodiment of the design, the incident light is configured to leave the light source at an angle relative to the optical axis of the lens attachment. The angle is chosen depending on the required incident light path into the eye, the required region of the eye to be illuminated, and the illumination required at the posterior segment of the eye to be studied. The angle of the incident light can be varied by configuring a device to change this angle based on a user input. The angle changing device can be a mechanical and/or electrical device with a user input such as, but not limited to, a switch, slide, or knob.

[0052] The distance between the first lens and the second lens along the optical axis can be about 4 cm to about 14 cm in length, and in certain embodiments is about 10 cm in length. The first lens can be a VoIk 6OD (31 mm diameter) , 78D (34 mm diameter), or 9OD (26 mm diameter) ophthalmic lens. In other embodiments, the first lens can be any of a 2OD, 25D, 28D, 30D, 4OD, 6OD, 66D, 78D, and 9OD lens. To obtain quality images after changing the first lens, a change in the distance between the first and second lens also may be necessary. The use of non-reflective coatings and other optical treatments of the lenses also can be applied to improve the quality of the captured images.

[0053] The second lens can utilize lenses similar to, although not necessarily the same as, that of the first lens. In certain embodiments, a 1OD lens, having a diameter of approximately 50 mm, can be used for the second lens. In all these embodiments, the compact design results in a light weight attachment that can easily be mounted on a camera, such as a Panasonic FZ20 digital camera or a Nikon 4300 digital camera, without significantly effecting the ease of use of the camera. This configuration results in a camera and lens attachment that can be easily carried, stored, and used. As a result, posterior segment photography of the eye can be performed easily without the need for a medical facility or for bulky, expensive, non-portable equipment.

[0054] FIG. 6 shows an embodiment of a lens attachment 80 that is similar to FIG. 5, and made with similar materials and used similarly, unless otherwise specified, except that the light source 82 is configured as a single LED rather than two LED's. This embodiment includes all the features of the embodiment described in FIG. 5, with the light source 82 placed between a first lens 16 and a second lens 18. In this embodiment, however, the light source 82 produces a single incident light path 84, which is focused through the first lens 16 and illuminates a region of the eye 28. The reflected light 86 from the illuminated region of the retina of the eye 28 then travels through the first lens 16 and second lens 18, passing into a viewing apparatus, such as a camera. As with the embodiment of FIG. 5, the incident light path can either be substantially parallel to the optical axis of the lens attachment, can be at an angle relative to the optical axis, or can vary based on a user input. [0055] In this configuration, the single light path can allow the incident light 84 to be focused more easily on a smaller region of the eye 28, because the tilt of the lens attachment typically does not have to be finely controlled, although in an alternative embodiment, the incident light 84 can still illuminate the same size region of the eye as that illuminated by a ring or pair of LED's. Also, a larger portion of the reflected light 86 passes through the lens attachment 80 and into the camera relative to the embodiments shown in FIGS. 1-4 and in FIG. 5, because the single light source takes up less space in the interior of the housing as compared with the ring of lights or pair of lights.

[0056] FIG. 7 shows an embodiment of a lens attachment 100 similar to that shown in FIGS. 1-4, and made with similar materials and used similarly, unless otherwise specified, except that the light source 102 is configured as a ring of light elements positioned at the distal end of the lens attachment 100 beyond the first lens 16. As such, the first lens 16 is located between the light source 102 and the second lens 18. hi this configuration, the lens attachment 100 includes all the features described above, but the incident light 104 does not pass through the first lens 16 on its way to the eye 28, and the incident light 104 is directed straight from the light source 102 into the eye 28. The reflected light 106 from the illuminated region of the eye 28 then passes through an aperture 25 in the light source 102, through the first lens 16, and through the second lens 18, before focusing into a viewing device, such as, but not limited to, a camera.

[0057] In this embodiment, the light source 102 is configured such that the light emitted from each light element of the light source 102, for example an LED, is angled inwards towards the optical axis 26 and the pupil of the eye 28. In an alternative embodiment, the incident light path can be configured to pass light transclerally through the region of the eye surrounding the pupil. As described above, in certain embodiments, the angle at which the incident light leaves the light source can be varied. In alternative embodiments, the ring of LED' s tracing an annular path about the optical axis can be replaced by two LED's located 180° apart on the annular path about the optical axis. [0058] FIG. 8 shows another embodiment of a lens attachment 120 similar to that shown in FIG. 7, and made with similar materials and used similarly, unless otherwise specified, except that the light source 122 is a single light element rather than the ring of light elements. As before, this light source 122 can be, for example, an LED. Because the light source 122 is positioned distally beyond the first lens 16, the incident light 124 travels directly from the light source 122 into the pupil of the eye 28, without first passing through the first lens 16. The reflected light 126 from the illuminated region of the retina of the eye 28 then passes out through the pupil of the eye. The light is focused through the first lens 16 and then the second lens 18, and it then passes into the viewing apparatus (e.g., a camera).

[0059] A number of alternative configurations of the above-mentioned embodiments are possible, hi one embodiment, each LED can be replaced by two LED's, each of a different colored light. For example, a green light LED, used to provide a low level light to enable focusing on the retina of an eye without disturbing the patient, can be paired with a bright white LED, used to actually illuminate the eye in order to take a picture. A user interface, such as, but not limited to, a switch can be used to switch between the green light LED(s) and the white light LED(s). Alternatively, this function can be automatically controlled. [0060] In a further alternative embodiment of any of the embodiments mentioned herein, a flash tube also can be used with the lens attachment, in addition to the LED(s), to provide additional lighting when imaging. This allows a lower level of light to be directed to the eye during focusing, with the higher light intensity being used when the flash is fired during the actual imaging procedure. The flash can include a single flash tube, or a number of flash tubes. For example, for the configuration with two LED's located 180° apart on an annular path about the optical axis, the flash can be made from a pair of flash tubes located next to the locations of the two LED's.

[0061] FIGS. 9-11 show another embodiment of a lens attachment 140 similar to that shown in FIG. 5, except that the light source includes two white light LED's 152, two green light LED's 154, and two flashes 156. FIG. 9 shows the lens attachment 140 mounted on a camera 12. The lens attachment 140 includes a first lens 16, and a second lens 18 (shown in FIG. 10), coupled to a housing 14. The length of the lens attachment 140 is approximately 14.5 cm from the first 16 to the second 18 lens.

[0062] The housing 14 is mounted on the camera 12 and attached to electronics to provide and control light to the light source (the light source is shown in FIG. 11). The first lens 16 is, for example, a VoIk 78D digital imaging lens of approximately 34 mm diameter. The camera 12 is a Panasonic FZ20 digital camera, available from Panasonic Corporation, One Panasonic Way, Secaucus, NJ 07094. The camera 12 is set to approximately 2X zoom. In alternative embodiments, different cameras and different settings can be used, based on the requirements of the user.

[0063] The light source includes two sets of three light elements placed approximately 180° apart within the interior of the housing 14 (for example, in the region at approximately 12 o'clock and 6 o'clock). Each set of three light elements includes a white light LED 152, a green light LED 154, and a flash outlet 156. In certain embodiments, the white light LED 152 has a luminous intensity of 20,000 mcd, while the green light LED 154 has a luminous intensity of 5,000 mcd. The flash is produced by a flash unit 142. The electronic circuitry for the flash unit 142 is mounted in an enclosure at the bottom of the camera 12. The light produced by the flash unit 142 is carried through two fiber optic cables 146, that are mounted flush against the flash unit 142, to the interior of the housing 14, where the light is released at an open end 156 (i.e. the flash outlet) of each fiber optic cable 146. The open end 156 is located between a paired white light LED 152 and green light LED 154. The flash unit 142 is controlled by a fire flash adapter 144, such as a Wein Hot Shoe Safe-Sync Adapter, available from Wein Products Inc., 155 W. 25th Street, Los Angeles, CA 90007. The fire flash adapter 144, mounted on top of the camera 12, steps down the voltage from 300V in the fire flash adapter 144 circuitry to the 6V required by the digital camera. The fire flash adapter 144 is also connected to a timing circuit that can turn off the LED's when the flash is fired. The timing circuit can, for example, be a standard 555 integrated circuit timer configured to operate in monostable mode.

[0064] Power to the two white light LED's 152 and two green light LED's 154 can be controlled from a switch mechanism 148 that is mounted to the top of the housing 14. The switch mechanism 148 includes two switches, one that allows the user to switch between the white light LED's 152 and green light LED's 154 and one that can turn off both the white light LED 152 and the green light LED 154 at the 12 o'clock location, so that only the white light LED 152 and the green light LED 154 at the 6 o'clock location are operating. In alternative embodiments, both colors of LED can be switched on or off simultaneously, or be switched on or off independently. In further alternative embodiments, the switch mechanism can be set up such that a single switch controls a single colored LED independently, or can be set up to control another function of the system.

[0065] The green light LED's can be used when taking "Red Free" photographs, that can, for example, accentuate viewing of blood vessels in a retina, and also can allow focusing of the camera under lower light conditions, which are more tolerable to a patient. The white light LED's are useful in situations where more light is required, such as, but not limited to, when an imaging device is configured to take videos or other moving pictures of the retina. Both the white light and green light LED's are powered by four AAA batteries mounted to the bottom of the camera 12. A further switch 150 (as shown in FIG. 10), is connected to the LED's and the 555 timing circuit for the flash and can control whether the LED's are on or off when the flash is fired and a photograph is taken.

[0066] FIG. 10 shows the camera 12 of the embodiment of FIG. 9, with most of the lens attachment 140 removed. The second lens 18 has been uncoupled from the housing 14 and is mounted on the end of the camera 12. The second lens 18 is, for example, a 1OD macro lens. This lens allows the camera 12 to focus at a shorter distance and also provides magnification of an image. [0067] FIG. 11 shows the interior of the lens attachment 140 viewed from the proximal end (end to be attached to a camera) towards the distal end (end pointed away from the body of the camera) of the lens attachment 140. The second lens 18 has been uncoupled from the lens attachment 140. The white light LED's 152 and green light LED's 154 are mounted to the interior of the housing 14 along an annular path about an optical axis, as previously described, of the lens attachment 140. One white light LED 152 and one green light LED 154 are positioned as a pair, each pair approximately 180° apart as more particularly described above. One open end 156 of a fiber optic cable 146 is positioned between the white light LED 152 and the green light LED 154 of each pair of white light and green light LED's. Each of the two white light LED's 152, green light LED's 154, and open fiber ends 156 are mounted to shine light through the lens attachment 140 to the first lens 16 and towards the distal end.

[0068] When taking a photograph with the above system, the camera 12 can be configured with an F-stop of 2.8 and an exposure time of 1/60 of a second. The maximum light exposure is approximately 2000 LUX when using the white light LED's 152, and approximately 1000 LUX when using the green light LED's 154. For comparison purposes, a standard indirect ophthalmoscope produces a maximum light exposure of about 1000 LUX, while a slit lamp used to examine the retina can produce a maximum light exposure up to about 21000 LUX. In alternative embodiments, different F-stops and exposure times can be used depending on the required results and the object being imaged.

[0069] In alternative embodiments of the above lens attachment, a different number of LED's and/or flashes can be included, depending upon the requirements of a user. The lens attachment also can include different colored LED's to produce different luminous intensities. The switches used to control the LED's can be configured to control different or additional functions of the system. Alternatively, the LED's can be automatically controlled, hi alternative embodiments the LED's, flashes, and/or alternative light sources can be located at different locations along the length of the lens attachment. In alternative embodiments, black dots can be placed on the surface of either one or both of the first and second lens, at the point where a reflection occurs, to reduce the reflections visible to the imaging apparatus.

[0070] A number of alternative configurations of the above-mentioned embodiments are possible. In one alternative embodiment, the first and second lenses can be changed, depending upon the type and make of camera or other viewing device to be attached to the lens attachment. For example, a user can switch between digital cameras with different optical specifications by changing one or both of the first and second lens to compensate for the different properties of the camera. In addition, further lenses or other optical equipment also can be coupled to the apparatus to change or enhance the capabilities of the lens attachment. For example, an additional lens can be added between the lens attachment and the camera to change the optical properties of the system.

[0071] In any of the above embodiments, to the extent that the imaging device (e.g. a camera) includes a macro lens, the second lens may be removed insofar as the second lens typically reduces the working distance of the camera and lens attachment combination in a manner similar to a camera's macro lens. In any of the above embodiments, the interior of the housing can be matt black. Any of the above embodiments can further include a single or plurality of blue light LED(s), that can, for example, be of use in fluorescein angioscopy and/or angiography.

[0072] In a further alternative embodiment, the lens attachment can be configured to allow imaging of a different object. For example, a lens attachment, coupled to a camera, can be configured to view a different region of the eye, such as, but not limited to, the pupil.

[0073] It should be understood that alternative embodiments, and/or materials used in the construction of embodiments or alternative embodiments, are applicable to all other embodiments described herein.

INCORPORATIONBYREFERENCE [0074] The entire content of each patent and non-patent document disclosed herein is expressly incorporated herein by reference for all purposes.

EQUIVALENTS

[0075] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments, therefore, are to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

[0076] What is claimed is:

Claims

CLAIMS 1. An imaging apparatus, comprising: a first lens located along an optical axis; a second lens located along the optical axis; and a light source positioned between the first lens and the second lens, wherein the light source is contained within a housing and the first lens and second lens are coupled to the housing.

2. The apparatus of claim 1, wherein at least one of the first and second lenses are contained within the housing.

3. The apparatus of claim 1, wherein the light source comprises at least one light emitting diode.

4. The apparatus of claim 3, wherein the light source comprises a white light light emitting diode.

5. The apparatus of claim 4, wherein the light source further comprises a flash.

6. The apparatus of claim 3, wherein the light source comprises a green light light emitting diode.

7. The apparatus of claim 1, wherein the light source comprises two or more light emitting diodes arranged along an annular path about the optical axis.

8. The apparatus of claim 1, wherein the light source comprises a single light emitting diode.

9. The apparatus of claim 8, wherein the light source is offset from the optical axis.

10. The apparatus of claim 1 , wherein the apparatus is configured to view the interior of an eye.

11. The apparatus of claim 10, wherein the apparatus is configured to pass light through the pupil of the eye.

12. The apparatus of claim 1, wherein the apparatus is configured to attach to a portable camera.

13. The apparatus of claim 12, wherein light from an image passes substantially along the optical axis into the camera.

14. The apparatus of claim 1, wherein at least one of the first and second lenses are detachable.

15. The apparatus of claim 14, wherein at least one of the first and second lenses are replaceable with a different lens.

16. The apparatus of claim 1 , wherein distance between at least two of the first lens, the light source, and the second lens is capable of being changed to alter the focal distance of the apparatus.

17. The apparatus of claim 1 , wherein the light source is powered by an energy source located within or immediately adjacent to the housing.

18. An imaging apparatus, comprising: a first lens located along an optical axis; a second lens located along the optical axis; a light source comprising a plurality of light emitting diodes arranged annularly about the optical axis and wherein the first lens is located between the second lens and the light source.

19. The apparatus of claim 18, wherein the apparatus is configured to view the interior of an eye.

20. The apparatus of claim 19, wherein the apparatus is configured to pass light through the pupil of the eye.

21. The apparatus of claim 18, wherein the apparatus is configured to attach to a portable camera.

22. The apparatus of claim 21, wherein light from an image passes substantially along the optical axis into the camera.

23. The apparatus of claim 18, wherein at least one of the first and second lenses are detachable.

24. The apparatus of claim 23, wherein at least one of the first and second lenses are replaceable with a different lens.

25. The apparatus of claim 18, wherein distance between at least two of the first lens, the second lens, and the light source is capable of being changed to alter the focal distance of the apparatus.

26. An imaging apparatus, comprising: an optical path, the optical path consisting essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source positioned between the first lens and the second lens; and a housing, wherein the light source is contained within the housing and the first lens and second lens are coupled to the housing.

27. An imaging apparatus, comprising: an optical path, the optical path consisting essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source comprising a plurality of light emitting diodes arranged annularly about the optical axis and wherein the first lens is located between the second lens and the light source.

28. An imaging apparatus, comprising: a first lens located along an optical axis; a second lens located along the optical axis; a light source comprising a single light emitting diode offset from the optical axis and wherein the first lens is located between the second lens and the light source.

29. An imaging apparatus, comprising: an optical path, the optical path consisting essentially of a first lens located along an optical axis, a second lens located along the optical axis, and a light source comprising a single light emitting diode offset from the optical axis and wherein the first lens is located between the second lens and the light source.