Portable eye viewing device enabled for enhanced field of view

An ophthalmoscope includes an illumination assembly having a light source disposed along an illumination axis and an imaging assembly configured for delivering an image to an imaging device. Each of the imaging and illumination assemblies are disposed in an instrument housing, the ophthalmoscope being configured for attachment to an electronic imaging device and in which the imaging assembly produces a field of view of about 40 degrees to permit more comprehensive eye examinations to be reliably conducted. In at least one version, a portable electronic device, such as a smart device, can be coupled to the instrument or configured to wirelessly receive images therefrom.

TECHNICAL FIELD

The application is generally related to the field of diagnostic medicine. More specifically, the application is directed to a hand-held or bench top ophthalmic device having an optical assembly that provides an enhanced field of view of the eye of a patient and enables enhanced diagnostic eye examinations, such as diabetic retinopathy, to be reliably performed. Real time images that are captured by the ophthalmic device can be directed to a portable electronic device, such as a smartphone, which can be integrated with the instrument to receive images or be remotely connected therewith.

BACKGROUND OF THE PRIOR ART

Ophthalmoscopes are commonly known medical diagnostic instruments used to perform routine examinations of the eye of a patient during a primary physician's visit. Due to their relatively low cost, these instruments are commonly found in the physician's office, hospitals and urgent care medical facilities. A typical ophthalmoscope is defined by an instrument head that is attached to the upper end of a handle portion, enabling the instrument to be relatively compact and capable of being held for use in a single hand of the caregiver. The handle portion retains a source of power (e.g., a plurality of rechargeable batteries) for energizing a contained light source, such as an incandescent lamp or at least one LED, in order to provide sufficient light to the intended target (i.e., the eye), through a distal end of the instrument head. An optical or imaging system contained within the instrument head images the illuminated retina of the eye and directs that image to either an eyepiece or an electronic imaging element, which is disposed at the proximal end of the instrument head.

Fundus cameras, such as described by EP 1 138 255 A1, are a much more sophisticated diagnostic apparatus, as compared to ophthalmoscopes, that are also used for measuring and determining various conditions involving the eye. These latter devices are quite prohibitive in cost, as compared to typical ophthalmoscopes, and can often easily exceed $25,000. The optical systems incorporated in fundus cameras are considerably more intricate and complex than those used in ophthalmoscopes and are also much larger, typically requiring a patient to utilize a chin rest or similar configuration for purposes of stability when conducting an examination. Advantageously, these instruments are configured to provide a field of view of at least 30 to 40 degrees relative to a target of interest (i.e., the eye), which adds significant functionality and capability as compared to direct ophthalmoscopes, the latter usually having a more restricted field of view of only about 5 degrees. Having a larger field of view is essential for enabling more comprehensive diagnoses, such as diabetic retinopathy, to be reliably conducted. Diabetic retinopathy often has no early warning signs, but first stages can be detected by fundus photography in which microaneurysms (microscopic blood-filled bulges in the artery walls), as well as retinal ischemia (blocked or narrowing retinal blood vessels) indicative of the lack of blood flow can be readily and proactively detected.

Given the present state of healthcare reform, a general need exists to provide an eye viewing device, such as an ophthalmoscope, that can reliably provide a larger field of view in order to permit more comprehensive eye examinations to be conducted, but in lieu of a fundus camera.

To that end, there have been numerous attempts to design diagnostic instruments that enable a caregiver to view more of the fundus of the eye. The majority of these attempts has been realized, but by means of scanning the area of interest and not directly viewing the desired area all at once and/or requiring medication to also dilate the pupil of the eye. Pupil dilation creates a level of inconvenience and discomfort for the patient.

More recently, Applicants have developed a digital ophthalmoscope with a contained imaging system that is capable of producing about a 25 degree field of view, using panoramic imaging of the retina. In one version, a smartphone is mechanically supported to the rear of an instrument housing with the imager of the smartphone being positioned in alignment with the contained optical assembly of the instrument or in which the optical assembly is augmented to divert an image to the portable electronic device in order to directly receive captured images.

Still further, it would be advantageous to provide an ophthalmic instrument that provides greater versatility in regard to operation when used in conjunction with a portable electronic device, such as a smartphone or a tablet PC.

BRIEF DESCRIPTION

Therefore and according to a first aspect, there is provided an ophthalmic instrument comprising an imaging assembly having a defined imaging axis and an illumination assembly comprising a source of illumination and having a defined illumination axis, each of the illumination and optical assemblies being disposed within an instrument housing. The instrument including a imaging device wherein the source of illumination creates a focused illumination spot through the pupil that is off axis relative to the optical axis of the instrument and in which the imaging assembly is configured to enable a field of view of at least 40 degrees of the retina of a subject that is directed to the imaging device.

According to at least one version, the imaging system comprises an objective lens and a projection lens, each being disposed along the optical axis and in which the objective lens is sized in order to enable about a 40 degree field of view of the intended target.

According to one version, an imaging device is attachable to the instrument. In at least one embodiment a portable electronic device, such as a smartphone, having a contained electronic imaging element is directly aligned with the imaging assembly along the imaging axis of the instrument when the portable electronic device is attached thereto. According to another embodiment, an electronic imager is disposed within the ophthalmic instrument wherein the images received by the imager can be wirelessly transmitted to a portable electronic device, such as a smartphone or tablet PC, the latter being further configured to control the operation of the ophthalmic instrument. Through this latter form of connection, there is no requirement having to specifically align the imaging element of the portable electronic device with the imaging assembly of the instrument.

According to another version, there is provided a method for enabling increased capability in an ophthalmoscope, the method comprising the steps of:

providing an imaging assembly including an objective lens and a projection lens each disposed commonly along an imaging axis;

providing an illumination assembly having a source of illumination disposed along an illumination axis of the instrument and at least one optical element for causing illumination to be directed through the pupil of a patient's eye and off axis relative to the imaging axis of the instrument and in which a field of view of at least 40 degrees is produced by the imaging assembly and in which an imaging device is configured to receive images from the imaging assembly.

The objective lens is sized to enable the increased field of view wherein the off-axis alignment of the illumination assembly provides sufficient light as a point source to the target while reducing glare-related effects.

According to at least one version a portable electronic device, such as a smartphone, a tablet PC or other device having a contained electronic imager, can be disposed such that the contained imager is aligned along the imaging axis to receive a resulting image. Additional optical elements can be added to adapt to the imaging device, such as to increase magnification and resolution. In another version, an electronic imager can be disposed along the imaging axis to receive an image that can be transmitted wirelessly to a portable electronic device, such as smartphone or a tablet PC, which is either attached to the instrument or located in close proximity thereto.

One advantage provided is that of increased capability in which an ophthalmoscope, configured in the manner described herein, produces a significantly wider field of view to enable similar capabilities of prohibitively more expensive fundus cameras, such as diabetic retinopathy.

Another advantage realized is that enhanced examinations can take place in a doctor's office, enabling proactive diagnoses to be made and in which a field of view of at least 40 degrees can be achieved without medication to dilate the pupil of the eye.

Yet another advantage is that the herein described instrument can be connected and controlled by a portable electronic device that is either directly or indirectly attached to the instrument.

Still another advantage is that the resulting data can be streamed to a “Cloud” service, external peripheral devices, or remote clinical sites using custom software applications.

Yet another advantage is the ability to easily configure the solution to work as a portable instrument, or parked in a chin-rest stand (operated by a practitioner) or a binocular stand (operated by the patient).

These and other features and advantages will be readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

This description relates to certain exemplary embodiments of an ophthalmic instrument (i.e., an ophthalmoscope) that is configured to present a suitable (40) degree field of view of a target of interest (i.e., the eye), thereby enabling enhanced examinations to be conducted by a clinician, ophthalmologist, primary physician or other caregiver and as used in conjunction with at least one portable electronic device. It will be apparent that other versions can be created that include the inventive concepts described herein. In addition and throughout the course of this description, various terms are used in order to provide a suitable frame of reference with regard to the accompanying drawings. These terms, such as “distal”, “proximal”, “upper”, “lower”, “above”, “below”, “top”, “bottom”, “forward” and “backward” however, are not intended to specifically limit or otherwise narrow the scope of the invention, unless where expressly so indicated.

Referring toFIG. 1, a schematic system layout of an ophthalmoscope100in accordance with a first exemplary embodiment is depicted. The ophthalmoscope100(also synonymously referred to throughout as the “instrument”) is preferably designed with a housing (not shown in this view) having an interior that is appropriately sized to retain a plurality of components, including an illumination assembly120and an imaging assembly140. According to this embodiment, the illumination assembly120includes at least one light source, such as a white or multicolor LED124, which is fixedly disposed to a circuit board (not shown). According to this embodiment, the LED124emits a white light along a defined illumination axis127. In another version, the LED124can emit an amber light, having a wavelength of about 590 nm. The emitted light is caused to impinge upon a reflective surface of a mirror128which is angled to direct reflected light toward a distal end of the instrument100. According to this embodiment, the mirror128is angled such that the angle between the viewing axis158of the instrument100and the illumination axis127is approximately 4 degrees. Optionally, a linear polarizer (not shown) can be disposed along the illumination axis127between the mirror128and the LED124in order to reduce the effects of glare.

An aperture stop132is disposed distally forward of the mirror128along the defined illumination axis127and through which light reflected from the mirror128is directed toward a target (i.e., the eye, shown herein schematically as160) of interest, and as discussed herein. According to this embodiment, the aperture stop132has a spacing of approximately 1 mm in order to control the amount of reflected light passing therethrough.

According to this exemplary embodiment, the illumination assembly120further includes an objective lens144that is centered and aligned along an optical or imaging axis158,FIG. 2, of the instrument100. The objective lens144is made from an optically clear acrylic according to this version, although other suitable optically materials can be alternatively used, the objective lens144being defined by opposing distal and proximal surfaces145and147, respectively. As discussed herein, light153passing through the aperture stop132is directed for entry through the proximal surface147of the objective lens144wherein the light is focused and passes through the pupil162of the eye (the latter being shown schematically as160) at an angle relative to the imaging axis158,FIG. 2, of the instrument100. A resulting illumination spot, shown schematically as138, is formed on the cornea163and is laterally offset from the imaging axis158. This light is then further directed and reflected as an image of the back (fundus164) of the eye160.

Referring toFIGS. 1 and 2, the imaging assembly140of the instrument100described herein is defined by the objective lens144, as well as a projection lens150, each being disposed along the optical or imaging axis158that is coextensive through respective distal and proximal ends of the instrument100. The objective lens144is disposed at an intermediate position along the imaging axis158and at a sufficient working distance (WD) from the front of the eye160. More specifically, the objective lens144according to this exemplary embodiment is defined by an outer diameter of approximately 26 mm and a thickness of approximately 12 mm, the distal surface145of the objective lens144is disposed at a WD of 25 mm from the pupil162of the eye160, and the distance between the proximal surface147of the objective lens144and a distal surface152of the projection lens150is about 58-59 mm. The distal surface145of the objective lens144includes a radius of curvature of 18 mm with a conic constant (K) of −2.3 and the proximal surface147has a radius of curvature of −18 mm and a conic constant (K) of −2.3.

Still referring toFIGS. 1 and 2, the projection lens150according to this specific embodiment is a section of BK7 crown glass having an outer diameter of approximately 3 mm and an axial length extending along the imaging axis158of approximately 4.9 mm. The distal surface152of the projection lens150is plano and an opposing proximal surface156of the projection lens150is defined by a radius of curvature of approximately −25.84 mm.

A portable electronic imaging device180(shown schematically inFIG. 2), such as smartphone, is disposed at the proximal end of the instrument100and proximal to the projection lens150. The projection lens150is disposed forward (distal) of the portable electronic imaging device180and aligned therewith along the imaging axis158.

In terms of operation and according to this exemplary embodiment, illumination light rays, as shown in dashed lines153, in the form of white light is emitted from the LED124, reflected from the mirror128and directed through the aligned aperture stop132toward the distal end of the instrument100. As noted, the directed light rays153passing through the objective lens144are focused by this lens144and pass through the pupil162, the latter having a spacing of approximately 2 mm, as an illumination spot138that is disposed slightly off axis relative to the imaging axis158of the instrument100. More specifically and according to this embodiment, the formed illumination spot138is approximately 1 mm from the imaging axis158wherein the illumination spot138is focused onto the cornea163of a patient's eye160. Sufficient illumination is provided by the LED124to enable reflection of the light from the fundus (retina) of the eye160.

A set of solid lines154depict imaging light rays wherein the reflected light includes an image of the fundus164of the eye150, which is transmitted by outwardly projecting rays from the pupil162of the eye160as a cone of light through the objective lens144along the imaging axis158of the instrument100. Referring toFIGS. 1 and 2, and based on the design of the illumination and imaging assemblies, this cone of light encompasses a 40 degree field of view that is narrowed and passes through the projection lens150for transmission to the attached portable electronic imaging device180, such as a smartphone having a cover glass184and an integrated electronic imaging element186. Each of the LED124, mirror128and aperture stop132are disposed out of the imaging path of the herein described instrument100. More specifically and according to this embodiment, the center of the aligned aperture stop132is about 4 mm from the imaging axis158of the herein described instrument100.

As shown in the enhanced view at the proximal end of the imaging assembly140according toFIG. 2, the imaging light rays154passing through the projection lens150are narrowed and caused to pass through the cover glass184and are further directed to the retained electronic imaging element186of the portable electronic device180. According to this version, a two lens imaging system is sufficient to create a 40 degree field of view in a compact ophthalmic device. Additionally, at least one linear polarizer (not shown) can be provided along the imaging axis158between the projection lens150and the imaging device180for controlling glare, such as from any of the contained optical elements and eye structures.

While the prior two-lens imaging assembly is highly effective in creating a 40 degree field of view, improvements in resolution and/or magnification can be made. To that end and referring toFIGS. 3 and 4, another exemplary imaging assembly210for an ophthalmoscope200is herein described. The illumination assembly and the housing of this instrument200are each not shown for the sake of clarity. For purposes of this embodiment, however, the illumination assembly can be similar to the version described according toFIGS. 1 and 2and the instrument housing can be typified, such as depicted inFIGS. 8 and 9and discussed infra. According to this specific embodiment, the imaging assembly210is defined by an objective lens244having respective distal and proximal surfaces245,247and a projection lens250, each commonly disposed and aligned along an imaging axis258and in relation to an eye160, shown schematically only inFIG. 3, of a patient. According to this embodiment, the specific design of each of the foregoing optical elements is identical to the two lens imaging assembly140, previously discussed with reference toFIGS. 1 and 2in which reflected light from the eye160,FIG. 3, is produced as a cone of light that is directed to the objective lens244, the latter being appropriately sized and positioned to create a suitable (i.e., 40 degrees) field of view, the light being narrowed and further directed to the projection lens250, in a manner previously described. In addition and according to this exemplary embodiment, a plurality of additional optical elements are provided, each of these elements being disposed in proximal relation to the projection lens250along the defined imaging axis258. These additional optical elements may be assembled integrally as part of the instrument200itself or alternatively can be added as a separate module in order to facilitate modification of an existing eye viewing device.

An enlarged view of the added proximal portion of the exemplary imaging assembly210is shown inFIG. 4. More specifically, this assembly210comprises the projection lens250having a plano distal surface252and a curved proximal surface256, as previously described with regard to the imaging assembly ofFIGS. 1 and 2. An aperture stop280is disposed between the projection lens250and a achromatic doublet284, such as an Edmund Scientific Model No. 45-089 in which the reflected light rays254are further directed along the imaging axis258to a pair of imaging lenses260, including a first lens264and a second lens268. According to this specific embodiment, the imaging lenses260are a pair of plano-convex lenses, such as Edmund Scientific Model No. 45-226. The imaging lenses260are disposed with a distal plano surface265of the first lens264facing the achromatic doublet284and a distal convex surface267of the second lens268facing a proximal convex surface266of the first lens264. Each of the first and second lenses264,268are separated by an air gap269in which the imaging lenses260combine to focus the resulting image to a focal plane288and onto an electronic imaging element (not shown) of an attached portable electronic device, shown schematically herein as292.

Yet another alternative version of an ophthalmoscope300is depicted inFIGS. 5(a), 5(b)and6. Each of the herein described components can be disposed within a portable housing that enables use with a single hand, such as the housing shown inFIGS. 8 and 9. For purposes of this discussion, however, the instrument housing is not shown in order to better describe the salient features/components of the various illumination and imaging assemblies.

As in the preceding exemplary embodiments that have been described, this ophthalmoscope300includes an illumination assembly308and an imaging assembly310, each being disposed within the instrument housing (not shown). The illumination assembly308comprises a white or multi-color LED312that is configured to be mounted, for example, to a printed circuit board313. As previously noted, the LED312can preferably emit an amber light capable of emitting a light having a wavelength of approximately 590 nm. An aperture stop316is disposed a predetermined distance in front of the LED312and aligned along a defined illumination axis315, as shown inFIGS. 5(b)and6. The aperture stop316, according to this exemplary embodiment, is disposed 3.5 mm in front of the LED312and defined by a spacing of approximately 2.8 mm. A set of condensing lenses319is further aligned with the LED312along the illumination axis315and disposed in front (forward) of the aperture stop316. According to this specific embodiment, the set of condensing lenses319comprise a first lens320and an axially adjacent lens324that are aligned along the illumination axis315between the aperture stop316and a beamsplitter330, the latter optical element also being disposed along a defined optical or imaging axis321of the herein described instrument300. According to this specific embodiment and with reference toFIG. 6, the first lens320is defined by a plano proximal or back surface322facing the LED312and a opposing distal surface323, the latter having a radius of curvature of approximately 14.5 mm. The second adjacent lens324has a proximal surface325facing the first lens320that has a radius of curvature of approximately 19.4 mm and a opposing distal surface327facing the beamsplitter330having a radius of curvature of approximately 22.5 mm. The lenses320and324are separated by an air gap326, which according to this specific embodiment is approximately 1.4 mm. The beamsplitter330includes an angled surface332disposed in relation to the illumination axis315and configured to reflect light emitted from the LED312in order to direct the emitted light toward the distal end of the instrument300. According to this embodiment, the center of the angled surface332is spaced approximately 18 mm from the distal surface327of the second lens324.

Though not shown, light that is reflected from the angled surface332of the beamsplitter330is directed through a set of objective lenses340that combine to focus the light through the pupil of a patient's eye (not shown) and at an angle relative to the imaging axis321of the instrument300. As in the preceding, the light reflected from the angled surface332is first directed through an aperture stop350. The light passing through the objective lens340is narrowed and focused as an illumination spot on the cornea of the eye that is slightly offset laterally relative to the imaging axis321of the instrument300. The remaining illumination directed through the beamsplitter330impinges upon a light sink or trap356in order to prevent back reflection or glare produced by the light source312, condensing lenses319or beamsplitter330. The light sink356is formed from a light absorbing material such as strongly absorbing glass, black paint or other suitable material.

Referring toFIGS. 5(a) and 5(b), the imaging assembly310of this exemplary instrument300comprises a series of optical elements that are aligned and configured along the defined imaging axis321to guide a resulting reflected image from the back of the eye (not shown) to an attached imaging device (e.g., a smartphone380having a liquid crystal display384, and actuable buttons386,388). These optical elements include the set of objective lenses340as well as a set of imaging lenses360, the latter optical elements being disposed proximally in relation to the beamsplitter330. According to this specific embodiment, the set of objective lenses340is defined by a first lens343and a second lens345, each of these lenses343,345being separated by an air gap349. More specifically and according to this embodiment, the first lens343is defined by an outer diameter of 34 mm and an axial length of approximately 8 mm and the second lens345is defined by an outer diameter of 36.5 mm and an axial length of approximately 9.5 mm. The first lens343includes a distal surface344having a radius of curvature of approximately 340 mm and a proximal surface346having a radius of curvature of approximately 36.8 mm. The second adjacent lens345of the set340is defined by a distal surface347having a radius of curvature of approximately 59.6 mm and a proximal surface348having a radius of curvature of approximately 253 mm. The air gap349separating the first and second lenses343,345is approximately 3.9 mm. According to this exemplary embodiment, the working distance (WD) between the front of the eye (not shown) of the patient and the distal surface344of the first lens343is approximately 38 mm.

The aperture stop350is disposed between the objective lens350and the beamsplitter330. According to this embodiment, the aperture stop350has an opening of approximately 27.8 mm to prevent the passage of stray light.

The imaging lenses360according to this specific embodiment are also defined by a pair of spaced lenses362,366, each of the lenses being aligned along the defined imaging axis321and in proximal relation to the beamsplitter330. The first imaging lens362according to this embodiment is defined by a distal surface363having a radius of curvature of approximately 26.9 mm and a proximal surface365having a radius of curvature of approximately 19.1 mm. The second lens366is defined by a distal surface367having a radius of curvature of approximately 27.4 mm and a proximal surface369having a radius of curvature of approximately 55.2 mm. The outer diameter of the second lens366is approximately 20.8 mm wherein the first lens362has an axial length of approximately 4.5 mm and the second lens366has an axial length of approximately 7.0 mm in which an air gap370provided between the first and second lens362,366provides a separation of approximately 2.4 mm.

The herein described imaging assembly310can be axially aligned with the contained camera381(shown schematically inFIG. 5(b)of the smartphone380and supported within the instrument300by suitable means, such as, for example, a support member (not shown) having a peripheral grooved area that is sized to receive the side surfaces of the smartphone380. According to this embodiment, the overall distance between the proximal (rear) wall of the imaging device380and the distal most optical element of the set of objective lenses340is approximately 152 mm. The distance between the cover glass (not shown) of the imaging device380and the proximal surface369of the second imaging lens366is approximately 30 mm.

As in the preceding, the herein described illumination and imaging assemblies are configured in order to create at least a 40 degree field of view that can be suitably imaged and enable enhanced examinations, such as diabetic retinopathy, to be performed by a caregiver and viewed for example on the display384of the attached smartphone380.

Yet another alternative exemplary embodiment is herein described schematically with reference toFIG. 7. According to this version, an ophthalmoscope400includes a housing (not shown for clarity but typified by those depicted, for example, inFIGS. 8 and 9) that retains an illumination assembly (also not shown in this view), as well as an imaging assembly440.

As in the preceding embodiment, the illumination assembly of this instrument400can include an LED that emits white, amber or other colored light, an aperture stop and a set of condensing optics, each being aligned along a defined illumination axis. According to this exemplary embodiment, a beamsplitter432is axially aligned with each of the foregoing elements, the beamsplitter432having an angled surface436that is configured to direct light to the pupil162of a patient's eye160as an illumination spot (not shown). A light sink or trap438aligned with the beamsplitter432is configured to receive excess illumination that is transmitted through the beamsplitter432. The light sink438is formed from a light absorbing material such as strongly absorbing glass, black paint or other suitable material and is configured to reduce the incidence of glare or back reflection in the instrument400from the light source424or beamsplitter432.

The imaging assembly440according to this exemplary embodiment includes an objective lens doublet442that is disposed proximally (i.e., behind) the beamsplitter432and aligned along the defined imaging axis453. The objective lens442is sized and configured to create a suitable field of view (40 degrees).

According to this embodiment, the imaging assembly440further includes a set of relay lenses452as well as a set of imaging lenses460, respectively, each of the latter being linearly disposed along the imaging axis453proximal to the objective lens440and distally arranged in relation to an electronic imaging device480, such as a CCD or a CMOS that can be attached to the proximal end of the instrument400. The electronic imaging device480can be provided as part of a separate device, or can be integral to the instrument400itself, being preferably disposed in a proximal end of the instrument head (not shown) and aligned with the relay lens452, imaging lens460and other optical components of the imaging assembly440along the defined imaging axis453.

According to this embodiment, the beam splitter432is disposed distally forward of the objective lens442and along the imaging axis453of the instrument400. The beam splitter432is aligned with the light source424and is angled approximately 40 degrees relative to the imaging axis453, as depicted by arrows458.

In use and referring toFIG. 7, the light source (not shown) emits light that passes through the condensing lenses (not shown) and impinges onto the angled surface436of the beam splitter432along a defined illumination axis. A portion of the emitted illumination is reflected from the angled surface436of the beam splitter432and toward the eye160of the patient, the latter being shown in schematic form, wherein an illumination spot (not shown) is caused to be directed through the pupil at an angle relative to the imaging axis453and focused upon front of the eye160. The portion of the emitted illumination passes through the beam splitter432and impinges upon the light sink438, which traps any residual illumination and prevents glare or back reflection within the herein described instrument400.

As opposed to the previously described instrument and according to this version, a reflected image of the retina164is sequentially directed through the pupil162along the imaging axis453of the instrument400, through the beamsplitter432and subsequently through the objective lens442. This latter optical element442is appropriately sized to create a field of view of 40 degrees wherein the transmitted image is transmitted through a first retinal focal plane449and subsequently through the relay lens452and a second conjugate retinal focal plane454in which the relayed image is transmitted through the imaging lens460to the proximal end of the instrument400and according to this exemplary embodiment to an electronic imaging element480, such as either directly made integral to the instrument400or as part of a smartphone or other portable imaging device.

Referring toFIGS. 8 and 9, an exemplary instrument500is depicted having an instrument body502and an instrument head504. The instrument head502and body504are defined by an interior that is appropriately sized to retain the illumination and imaging assemblies discussed herein, as well as an electronic imaging device, such as a smartphone520that can be releasably attached within a receptacle516provided at the proximal end512of the instrument body502. When attached, the retained camera of the attached imaging device520is aligned with the imaging axis of the instrument500, the latter axis extending through the major dimension of the instrument head504extending between a distal end508and proximal end512. According to this embodiment and when attached, the rear of the device520is completely accessible, including the display524and the control button528. In addition and according to this embodiment, a lateral portion of the receptacle516is removed to permit access to other control features of the attached device520wherein captured images of the eye can be displayed.

Yet another exemplary embodiment of an ophthalmic instrument600is provided with reference toFIG. 10. The ophthalmic instrument600is defined by an instrument housing604, a front end608being shown in phantom and an opposing rear or proximal end612, the instrument housing604being further defined by an interior615that is appropriately sized for retaining a plurality of components. According to this version, an optical imaging assembly619comprises an objective lens620that is positioned adjacent the front end608of the instrument housing604and a projection lens626positioned proximally therefrom along the imaging axis640of the instrument600. The two lenses620and626are sized and configured to create a suitable field of view (40 degrees) of a target, which according to this embodiment is an eye630, shown schematically and including a pupil634and a retina636in the manner previously described.

According to this embodiment, the imaging assembly619further includes a set of relay lenses628as well as a set of imaging lens638, respectively, each of the latter components being linearly disposed along the defined imaging axis640and in proximal relation to the projection lens626and distally in relation to an electronic imaging device660, such as a CCD or a CMOS that can be attached to the proximal end612of the instrument housing604. For purposes of this embodiment, the electronic imaging device660can be provided as part of a separate device, or can be integral to the instrument600itself, the imaging device660being aligned with the relay lens628and imaging lens638along the defined imaging axis640.

A window644manufactured from an optically transmissive material or a beamsplitter is further aligned along the imaging axis640of the instrument600between the objective lens620and the projection lens626with the window644being acutely angled in relation to an illumination array650that is disposed along an illumination axis654of the instrument600. A plurality of LEDs, herein labeled as S1, S2and S3are defined in the illumination array650, although the specific number of LEDs utilized can be easily varied. The LEDs according to this embodiment are disposed in a side by side fixedly mounted relation on a circuit board655or similar substrate, each LED being configured to emit an amber light having a wavelength of approximately 590 nm. An aperture mask659having a series of appropriate sized holes661is disposed onto the illumination array650, the holes661being aligned with the corresponding LEDs S1, S2, S3of the array650, specifically guiding light to a projection lens664, which is distally disposed along the defined illumination axis654. As shown, light from the illumination array650is directed through the holes661in the aperture mask659and through the projection lens664, the emitted light being reflected by the window644towards the objective lens620. According to this embodiment, an infrared LED670is disposed adjacent the distal side622of the objective lens620in relation to an outer diametral portion thereof. An infrared photodiode676is also provided in relation to an outer diametral portion of the objective lens620, the photodiode676being disposed on an opposite side of the imaging axis640relative to the infrared LED670. Each of the infrared LED670and the photodiode676are inwardly angled toward the front panel of the instrument housing604at its distal end608. According to this embodiment and as schematically shown, the photodiode676is electrically connected to a microcontroller680, the latter being connected to the LED array650and the portable electronic device660.

In operation, the infrared LED670and the photodiode676are positioned such that light from the infrared LED670can be directed to the eye630and more specifically the pupil634of the patient, with light being reflected from the pupil634to the photodiode676only if the instrument600is set at a predetermined working distance (Z), which according to this embodiment is approximately 25 mm. The infrared LED670and the photodiode676herein provide an LED fixation path prior to initiating light from the illumination array650. According to this exemplary embodiment and if the instrument600is set at the correct working distance to the eye630(to the pupil634of the eye), a signal from the photodiode676indicative of the receipt of reflected light from the eye630is provided to the microcontroller680and the illumination array650is enabled for use. If the photodiode676fails to receive an adequate amount of reflected light indicative that the instrument600is either in excess or inside of the proper working distance, the LEDs S1, S2, S3of the illumination array650are caused to blink or to produce another effect that can be visually perceived by the user of the instrument600. Alternatively, the illumination array can be rendered inoperative until the proper working distance has first been established.

Once the proper working distance (Z) has been established, the illumination array650produces an amber or other appropriately colored light that is transmitted to the eye630, as reflected by the window644and transmitted through the objective lens620. Reflected light from the retina636at the back of the eye630is transmitted through the objective lens620, having provided a 40 degree field of view in which the light is transmitted through a retinal image plane through the window644, the projection lens626and the remainder of the imaging assembly619to the portable electronic device660in the manner previously discussed.

According to yet another exemplary embodiment and with reference toFIG. 11, there is shown another version of an ophthalmic instrument700. As in the prior version, the instrument700is defined by an instrument housing704, shown in phantom and only in part, the housing704having a front or distal end708and a rear or proximal end712and in which the housing704is further defined by an appropriately sized interior715. An imaging assembly719arranged in fixed relation within the interior715of the instrument housing704comprises an objective lens720that is disposed adjacent the distal end708of the instrument housing704and a projection lens726proximally disposed along an imaging axis740. Each of the foregoing optical components are similar in terms of design and function to those described in prior embodiments. The imaging assembly719further includes a set of relay lenses728as well as a set of imaging lenses738, each of the foregoing being aligned along a defined optical or imaging axis740, respectively. These latter optical elements according to this exemplary embodiment are defined similarly to those described inFIGS. 7 and 10in terms of their overall function and design and are similarly aligned in proximal relation to the projection lens726and distally aligned along the imaging axis740relative to the imager of a first portable electronic device or “smart device”760, which can for example be an iphone or similar device. In this specific embodiment, a separate second electronic imaging device788is aligned off axis relative to the imaging axis740wherein a beamsplitter744is disposed to direct an image obtained through a condensing lens764and direct same to the imaging device788. This separate electronic imaging device788enables a user, such as physician or clinician, to obtain an advance or preview mode of the intended target (e.g., eye730) prior to actual operation. As in the prior described embodiment, the operation of the ophthalmic instrument700according to this exemplary embodiment is also predicated upon establishing a suitable working distance (Z) as measured between the instrument700and the eye730of the patient. An infrared LED770is disposed in relation to an infrared photodiode776, wherein the LED770and photodiode776are disposed on opposing sides of the imaging axis740of the herein described instrument700at an outer diametral portion of the objective lens720with the output of the photodiode776being linked to a microcontroller780.

According to this version, the wireless imager788can be a Sony QX10 or Sony QX100 camera or other wirelessly connected imaging device that is linked with the display of the smart device760. The reception of a signal from the photodiode776is linked to the microcontroller780, whose output can be shown on the display of the smart device760, indicating an “out of range” or “in range” signal to the user. Given the application of the preview mode described herein, this specific instrument700is preferably a bench top apparatus as opposed to being used for hand-held operation.

It should be noted that each of the foregoing instrument or instrument system designs can commonly include a portable electronic device (e.g., a tablet PC, smartphone) that is integrated directly as part the imaging assembly of the herein described instrument or otherwise as an attached device, as shown for example inFIGS. 8 and 9in which alignment is required between the respective optical systems/assemblies of both the portable electronic device and the instrument based upon some form of mechanically interconnection that specifically achieves the desired alignment. Referring toFIG. 12, there is schematically depicted an ophthalmic diagnostic instrument made in accordance with yet another exemplary embodiment.

The ophthalmic instrument800according to this exemplary embodiment is defined by a housing804having an interior that is appropriately sized for retaining a plurality of components, including an imaging assembly819that enables a 40 degree (or greater) field of view of the eye (not shown) of a patient, as previously discussed, the imaging assembly819including an objective lens820disposed at a distal end808of the instrument housing804and a projection lens830, each aligned along a common imaging axis840. A mobile electronic camera860, such as a Sony QX10 or a Sony QX100 mobile camera, is further configured and aligned with the imaging assembly819along the defined imaging axis840. The mobile electronic camera860is defined by an enclosure864having an interior868that is sized to retain an electronic imager869as well as a mechanism that enables dynamic optical focusing, the imager869being aligned to receive the images from the imaging assembly819and then wireless transmit the captured images to a portable electronic device870, such as a smartphone or tablet PC, which is remotely located using a convenient communication protocol, such as Bluetooth. The enclosure869is further configured for releasable attachment to the front or distal side of the portable electronic device but since the images are wirelessly transmitted there is no requirement for optical alignment when the device is attached to the portable electronic device870.

In this latter embodiment, the operation of the ophthalmic instrument800, including the electronic mobile camera860, can be controlled using software that is resident in the portable electronic device870such as through the user interface of the portable electronic device870. Advantageously and according to this exemplary embodiment, the electronic imager contained within the portable electronic device870does not have to be aligned with the instrument800, thereby providing additional versatility in which the portable electronic device870can be located remotely from the patient.

PARTS LIST FOR FIGS.1-12

It will be readily apparent to those of sufficient skill that other modifications and variations are possible based on the inventive ambits described herein, as well as the appended claims.