Petitioner: Haag-Streit AG
`Petitioner: Haag-Streit AG
`
`Ex. 10(cid:20)(cid:19)
`Ex. 1010
`
`

`

`United States Patent
`
`5,838,421
`[11] Patent Number:
`[19]
`Pedack
`[45] Date of Patent:
`Nov. 17, 1998
`
`
`US005838421A
`
`[54] BINOCULAR DIRECT OPTHALMOSCOPE
`
`[57]
`
`ABSTRACT
`
`[76]
`
`Inventor: Henry Pedack, 3228 Iowa Dr,
`Bellingham, Wash. 98226
`
`.
`[21] Appl. No.: 825,742
`[22]
`Filed:
`Apr. 3, 1997
`°
`[St]
`Inte Cl? sssecnnsccrenmmennnenmeis A61B 3/10
`[52] US. Checcs 351/218; 351/221; 351/245
`[58] Field of Search
`351/205, 218
`351/221 45 344
`,
`,
`
`A portable, binocular direct ophthalmoscope. A frame car-
`rying a binocular optical system is suspended for rotation
`about a pivot axis from one end of a support beam; an
`opposite end of the support beam is attached to a handle. A
`beam splitter block mounted to the frame carries an illumi-
`nation source for light emission along an illumination axis
`and into an eye of a subject. Left and right beam splitting
`mirrors attached to the block are symmetrically and
`obliquely disposed on opposite sides of the illumination
`axis. Light reflected back from the subject’s eye is split by
`the beam splitting mirrors into a left-directed beam and a
`right-directed beam, which are each reflected rearward by
`laterally spaced apart deflection mirrors through left and
`right dioptric disk assemblies and thence into the left and
`right eyes of an observer, respectively. This arrangement
`permits positioning the light source and the beam splitting
`mirrors all within a circle normal to the illumination axis of
`U.S. PATENT DOCUMENTS
`diameter no more than 6 to 7 mm,thereby achieving a
`3,315,680
`4/1967 Sillbertrust et al.
`..cccsssssssceesssoee 606/4
`stereoscopic image. In a first embodiment of the invention,
`3,783,874
`ciccccccccceceeeeeees 606/4
`1/1974 Koester et al.
`
`the dioptric disk assemblies are attached to mountsthat slide
`3,984,157 10/1976 Le Vantine wees 351/221
`
`
`within a C-channel attached to the frame for adjustment to
`7/1984 Blaha oo. 351/221
`4,401,551
`
`
`4,711,540 12/1987 Yoshino et al.0...eee 351/214 the interpupillary distance of the observer. In a second
`Sarace afo00 any taaSasnah
`seeesseereeaeeeteereeeeSsoaet
`embodiment, worm gear assemblies interconnected by a
`
`Gsssessssebisssneesicieeess
`tes
`OTS
`€1 Ole
`telescopic coupling rotate dioptric disks when attached lens
`4/1994 Nano oo...eceeeceeeene 351/221
`5,302,988
`power knobs are turned. In a third embodiment, a pair of
`laterally adjustable dioptric disks are provided with radial
`
`
`
`teeth that teeth ofanidlthe .
`ee
`at engage
`the
`teeth
`of an idler gear.
`Priaary Beaniher—uy Mai
`Attorney, Agent, or Firm—Brian J. Coyne
`9 Claims, 11 Drawing Sheets
`
`[56]
`
`References Cited
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`150)
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`[50S
`| 30R
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`p
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`

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`U.S. Patent
`
`Nov. 17, 1998
`
`Sheet 1 of 11
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`5,838,421
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`20
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`FIG. 2
`(Prior Art)
`
`

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`U.S. Patent
`
`Nov. 17, 1998
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`Sheet 2 of 11
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`5,838,421
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`V2
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`| aO
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`T22~
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`FIG. 3
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`FIG. 4
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 3 of 11
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`5,838,421
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 4 of 11
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`5,838,421
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`5,838,421
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`ZLId
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 5 of 11
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`Sheet 6 of 11
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`5,838,421
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`U.S. Patent
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`Nov. 17, 1998
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 7 of 11
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`5,838,421
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 8 of 11
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`5,838,421
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`Nov. 17, 1998
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`Sheet 9 of 11
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`5,838,421
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`Cl‘D4
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`U.S. Patent
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`U.S. Patent
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`Nov. 17, 1998
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`Sheet 10 of 11
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`5,838,421
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`FIG.
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`13
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`Ww)
`OO
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`U.S. Patent
`
`Nov. 17, 1998
`
`Sheet 11 of 11
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`5,838,421
`
`FIG. 14(b)
`
`

`

`5,838,421
`
`1
`BINOCULAR DIRECT OPTHALMOSCOPE
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`
`2
`head mountunit and external a.c. electric power source. The
`head mount unit houses an electric illumination source,
`which directs a focused light beam toward the object of
`regard, and a binocular optical system. The binocular optical
`system includes beam splitting elements to split
`light
`reflected from an object along a viewing axis into left and
`right optical paths. The reflected light
`thereafter passes
`throughleft and right eye pieces having a powerof +1.00 to
`+1.25 diopters. The focused light source is usually mounted
`centrally and above the viewing axis, and powered from a
`wall mounted a.c. transformer and an electric cable. The
`
`10
`
`15
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`20
`
`invention pertains generally to
`The present
`ophthalmoscopes, and moreparticularly to a portable, hand-
`held, binocular ophthalmoscope capable of both direct and
`indirect stereoscopic viewing of the interior of an eye
`through the pupil.
`2. Background Art
`The monocular ophthalmoscope was invented in 1851 by
`beam splitting elements typically include twosets of parallel
`a German physicist, Hermann von Helmholtz. It was an
`mirrors oriented at a 45 degree angle with respect to the
`optical instrument for viewing the inner eye of a subject,
`viewing axis to optically reduce the interpupillary distance,
`comprising a light source, an apertured, concave mirror for
`which permits the observer to view with both eyes through
`reflecting light from the source toward the subject’s eye, and
`a single anterior sight hole. A harness is attached to the head
`magnifying lenses for interposition between an eye of an
`mount unit for mounting the unit to the head of the observer
`observer and light reflected back from the interior of the
`with the eye pieces positioned in front of the eyes of the
`subject’s eye through the aperture in the mirror.
`In its
`observer. When used with a condensinglens, usually of +12
`modern form, the monocular ophthalmoscope convention-
`to +30 diopters and held at arms length, the observer can
`ally has a cylindrical hand grip for housing a battery-
`view an inverted, virtual image of the interior of an eye
`powered,electric light source together with a thumb rheostat
`binocularly and with stereopsis. The magnification can be
`for controlling the intensity of illumination. An optical head
`increased or decreased by changing the powerof the con-
`carried atop the hand grip houses an optical system mounted
`densing lens.
`between anterior and posterior sight holes. Light directed
`Despite the advantages of stereopsis, the head mounted
`upward from a miniature electric lamp or coiled filament in
`binocular ophthalmoscope has several shortcomings. The
`the handle passes through a convex condensing lens and a
`focused light beam is not on the visual axis and only
`reflecting prism or mirror, and thence through the anterior
`partially illuminesthe object of regard. A blind spot typically
`sight hole into an eye of the subject. The reflecting prism or
`occurs. It can only be used in the indirect modality, which
`mirror is mounted such that the upper extremity thereof
`affords just an inverted, virtual image underrelatively low
`covers only the lower portion of the sight holes, thereby
`magnification. Therefore, its use is ordinarily followed by
`permitting light reflected from an eye of the subject through
`switching to a monocular direct ophthalmoscope for more
`the anterior sight hole to proceed on through an optical disk
`detailed viewing under higher magnifications. The instru-
`mounted behind the prism or mirror and on through the
`ment permits only a single viewing distance, which depends
`posterior sight hole.
`on the power of the eyepiece lens. If the observer moves
`Used in the direct modality, while holding the instrument
`closer to the condensinglens, the illumination axis deviates
`in his right hand in a darkened room and with the light
`further away from the line of sight. If the observer moves
`source activated, the observer positions the optical head as
`farther away from the condensing lens,
`the deviation is
`close as possible to the right eye of a seated subject, rotates
`reduced, but the ability of the examinerto do that is limited
`the optical disk to select an appropriate magnifying loupe to
`by the length of his arm. The mobility of the observer is
`neutralize his own and his subject’s refractive error, and
`limited by the attached, wall-mounted external power sup-
`views the interior of the subject’s right eye by peering
`ply. Some persons find a head mounted unit uncomfortable
`through the sight holes with his right eye. Thereafter, the
`and that wearing it may muss upahairstyle.
`observer places the instrumentin his left hand and with his
`left eye similarly examinesthe interior of the subject’s left
`To overcome these deficiencies, what is required is a
`eye. By selecting a series of progressively lower diopter
`portable, hand-held, battery-powered, binocular direct oph-
`magnifying loupes, from +20 to +4 diopters for example, the
`thalmoscope in which the illumination axis and the viewing
`observer can view interior structures in each of the eyes of
`axis are coaxial. Ideally, such an instrument would provide
`the subject, progressing from the cornea, through the iris,
`a true and erect binocular image with stereopsis under direct
`lens, and vitreous to the ocular fundus, which appearto the
`view and user-selectable magnification, variable between
`observer as true and erect images in the direct modality and
`high and low underindirect view. Preferably, the handle of
`magnified up to fifteen times.
`In the indirect modality,
`the instrument should be easily movable from a right side to
`however, the observer, positioned some distance away from
`a left side of the instrumentfor viewing the left eye and right
`the subject, holds the instrument in one hand close to his
`eye of a subject, respectively, and vice-versa.
`own eye, interposes a convex, condensing lens held in his
`Berry, U.S. Pat. No. 4,836,166, disclosed a head-
`other hand between the instrument and the subject, and, with
`mountable instrument for illuminated stereoscopic viewing
`a +2 or +4 diopter lens in the viewing aperture to neutralize
`of body cavities. Berry’s instrument included a centrally and
`his own accommodation, views an inverted, virtual image of
`anteriorly mounted light source that directed a light beam
`the structures of the eye magnified up to four times. Indirect
`toward an inclined, one-way mirror, from which mirror the
`ophthalmoscopyhas two significant advantages over direct
`source beam wasreflected forwardly along an illumination
`ophthalmoscopy:It providesa large field of visionthat gives
`axis toward the object of regard. Light reflected back from
`the observer a good view of the ocular fundus even through
`the object along a viewing axis passed through the one-way
`an undilated pupil and in spite of opacities in the media, and
`mirror and wassplit into left and right optical paths by a pair
`it is not affected by majorrefractive errors in the subject’s
`of juxtaposed, back-to-back prisms, centrally disposed over
`eyes. The disadvantages are the lower magnification and the
`the nose of the examiner. Light following the left and right
`inverted image.
`optical paths wasreflected posteriorly into the left and right
`The binocular indirect ophthalmoscope, which began to
`eyes of the examiner, respectively, by left and right prisms
`come into wide use in the 1950s, conventionally includes a
`disposed laterally and horizontally with respect to the central
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`5,838,421
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`OBJECTS OF THE INVENTION
`
`invention to provide a
`is an object of the present
`It
`portable, hand-held, binocular direct ophthalmoscope
`equipped with a battery-powered light source.
`Another object of the present invention is to provide such
`an instrument for which the illumination axis is coaxial with
`
`3
`4
`
`pair of prisms. This arrangement did make the illumination for projecting a focused beam of light alongafirst, i.e,
`illumination, axis to a patient’s eye, a binocular optical
`axis coaxial with the viewing axis, but placing a one-way
`system for splitting light reflected from the patient’s eye into
`mirror within the path of the reflected light
`tended to
`left and right optical paths for
`transmission through
`produce an unacceptably dim image.
`observer-selectable magnifying lenses and into the eyes of a
`LeVantine, U.S. Pat. No. 3,984,157, disclosed an
`viewer, and hand-held support means for supporting the
`improved monocular ophthalmoscope that
`incorporated
`light beam generating means and the binocular optical
`beam splitting optics to make the viewing axis coaxial with
`system. The light beam generating means includes a light
`the illumination axis, and further incorporated a lighttrap for
`source and means for deflecting the light from the light
`absorbing substantially all of the light not utilized for
`source along the illumination axis.
`In a preferred
`illuminating the retina of the eye of a subject.
`embodiment, the hand-held support meansincludes a cylin-
`Clark et al., U.S. Pat. No. 5,078,469, disclosed a head-
`drical handle, a laterally-extended support beam having a
`mountable binocular optical system comprising left and
`first end rigidly attached to the handle and an opposite free
`right loupes for magnified stereoscopic viewing and illumi-
`end, and a frame rotatably suspended from the free end of
`nation during surgical procedures. Each loupe included a
`the support beam. This arrangement permits easy movement
`beam splitting optical cube having a beam splitting inter-
`of the handle between the left and the right sides of the
`face. Optical fibers supplied direct
`illumination to each
`instrument. The handle is adapted for receiving and storing
`loupe from a light source through a lens system and circular
`electric storage batteries, and equipped with a combination
`polarizing filter for reflection from the beam splitting inter-
`thumb rheostat-on/off switch for controlling and powering
`face outward through an objective lens along an illumination
`the light source in the manner that
`is conventional
`in
`axis to illuminate a field of view. Light reflected from the
`monocular ophthalmoscopes.
`field of view along a viewing axis passed through the
`The binocular optical system is housed and supported by
`objective lens to the optical
`interface where it was
`the frame, and includes beam splitter means positioned on
`transmitted,
`in part,
`to a circular polarizing filter and a
`the illumination axis for receiving and splitting a portion of
`Pechan/Schmidt roof prism on through eyepiece optics and
`the reflected light into a left-directed beam and a right-
`into an eye of an observer. Thus, the illumination axis and
`directed beam; left beam deflecting means for deflecting
`the viewing axis were coaxial, and the polarizing filters
`light from the left-deflected beam along a second axis
`reduced the flare effect
`that otherwise occurs with high
`toward the left eye of an observer; right beam deflecting
`intensity illumination.
`means for deflecting light from the right-deflected beam
`There remains, however, a need for a portable, hand-held,
`along a third axis toward the right eye of an observer; and
`binocular direct ophthalmoscope that overcomes the above-
`means for simultaneously positioning any oneofa plurality
`noted deficiencies of the binocular indirect ophthalmoscope,
`of observer-selectable magnifying loupes on the second and
`that dispenses with the need for
`a monocular
`third axes, respectively. The light source and the means for
`ophthalmoscope, and that can also be used in the indirect
`deflecting light are disposed within the beam splitter means
`modality.
`and substantially coplanar therewith. The light that is split
`by the beam splitter means lies within a circle normal to the
`illumination axis of diameter not exceeding 8 mm.
`In a preferred embodiment,
`the beam splitter means
`comprises a beam splitter block mounted to the frame and
`having left and right front surfaces, which front surfaces are
`symmetrically and obliquely disposed on opposite sides of
`the illumination axis, thereby defining a V-shape surface in
`top planar view. The block has a recessed cavity for receiv-
`ing and mounting a miniature light bulb connected by
`electric cables to the storage batteries. A light source aper-
`ture is aligned on the illumination axis and cut through the
`front surfaces of the block to the cavity. Left and right beam
`splitter mirrors are attached to the left and mnght front
`surfaces of the beam splitter mirrors, respectively, and each
`has a notch cut away adjacentthe illumination axis to permit
`light from the light source to exit the block between the
`beam splitter mirrors.
`the left and right beam
`In a preferred embodiment,
`deflecting means are left and right mirrors mounted to the
`frame on opposite sides of the illumination axis positioned
`to receive left and right deflected beams, respectively, and to
`reflect them rearward along second and third axes through
`left and right dioptric disk assemblies, respectively. The
`dioptric disk assemblies permit the examiner to interpose
`any one of a plurality of magnifying loupes into the second
`and third axes immediately in front of the observer’s left and
`right eyes, respectively.
`Laterally adjustable meansare provided for mounting the
`dioptric disk assemblies to the frame which,
`in a first
`embodiment of the invention, comprise a C-channel
`attached to the frame and left and right dioptric disk assem-
`bly mounts adapted for sliding movement within the
`
`the viewing axis.
`A further object of the present invention is to provide such
`an instrumentthat permits the observer, using one hand only,
`to simultaneously interpose magnifying lenses of succes-
`sively varying powers before each of his own eyes.
`Astill further object of the present inventionis to provide
`such an instrument with a handle that can be easily moved
`back and forth between the right and left sides of the
`instrumentin order to facilitate close up viewing of the left
`and right eyes of a subject, respectively.
`An additional object of the present invention is provide
`such an instrument that can also be used in the indirect
`
`modality.
`Another object of the present invention is to provide such
`an instrument in which the interpupillary distance is adjust-
`able.
`
`Other objects, advantages and details of the invention will
`be explained hereinafter and more fully delineated in the
`appended claims.
`SUMMARYOF THE INVENTION
`
`In order to accomplish the above and other objects, the
`binocular direct ophthalmoscope in accordance with the
`present invention comprises light beam generating means
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`5,838,421
`
`6
`FIG. 14(b) is the same variation adjusted for a desired
`maximum interpupillary distance.
`The terms “left,” “right,” “forward,” and “rear” shall be
`understood throughout as referring to the present invention
`as shownoriented in FIG. 5.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`5
`C-channel, whereby the distance between dioptric disk
`assemblies attached to the mounts can be adjusted. In a
`second, alternative embodiment of the invention, each disk
`assembly is provided with a lens power knob forrotating a
`worm gear around a fourth axis in mating engagement with
`a matching spur gear attachedto the disk assembly, such that
`rotation of a lens power knob sequentially rotates into the
`field of view magnifying loupes of various magnifying
`powers distributed around the periphery of the lens disk.
`indirect
`If one attempts to use a binocular
`Oppositely-directed left and right connecting shafts are
`ophthalmoscope, as such have been knowninthe priorart,
`providedthat are connected to the right and left worm gears,
`in the direct modality to view an eye of a subject,
`it is
`respectively, for rotation therewith,
`the connecting shafts
`impossible to achieve stereopsis. Referring to FIG. 1, it may
`being aligned along the fourth axis and mutually engaged in
`be seen that horizontally adjacent left and nght viewing
`telescopic relation.
`apertures 20, 20' for such an ophthalmoscope, the Topcon
`Model ID-5 for example, together with an overlying illumi-
`In a third, alternative embodiment, an idler gear is inter-
`nation source exit aperture 22, are all positioned within a
`posed between the disk assemblies and mountedto the frame
`circle having diameter D,=35 mm. The distance L, between
`for rotation abouta fifth axis parallel to the illumination axis.
`the left and right viewing apertures is 22 mm. As shown in
`Accircular array of radial teeth are attached to the periphery
`FIG. 2, when such an ophthalmoscopeis placed a distance
`of each disk assembly and meshed for driving engagement
`V equal to 30 mm,moreorless, from the eye E of a subject,
`with the teeth of the idler gear, and meansare attachedto the
`due to the relatively wide distance L,, the optical paths of
`frame for mounting the left and right disk assemblies for
`rays reflected throughthe iris I toward the viewing apertures
`counter-rotational displacement aboutthe fifth axis and for
`20, 20' transmit nonoverlapping images, resulting in diplo-
`rotation about sixth and seventh axes respectively.
`pia instead of stereopsis.
`Accordingly, in the third embodiment, rotation of either disk
`25
`assembly inafirst direction causes rotation of the other disk
`Referring now to FIG. 3, in the present invention hori-
`assembly in a second, opposite direction, and partial semi-
`zontally adjacent left and nght viewing apertures 20, 20' and
`circular displacement of each assembly about the fifth axis
`an illumination source aperture 22 all lie within a circle of
`permits adjusting the ophthalmoscope to accommodate the
`diameter D., equal to 6 or 7 mm andthe distance L, between
`interpupillary distance of the examiner.
`the viewing apertures is only 3 mm. As shownin FIG. 4, the
`narrow distance L, between the viewing apertures, which
`BRIEF DESCRIPTION OF THE DRAWING
`approximates the width of the iris I, permits stereoscopic
`viewing throughout
`the depth of the eye E (shown by
`FIG. 1 is a schematic diagram showing in enlarged,
`hatching) as far back as the ocular fundus,F.
`frontal elevation the positions of left and right viewing
`FIG. 5 showsa first embodimentof the present invention
`apertures and illumination source exit aperture in a binocular
`in rear perspective view. A handle 30 comprises a hollow
`indirect ophthalmoscope of the priorart.
`cylinder that houses one or more dry cell batteries (not
`FIG. 2 is a schematic diagram in top plan view of the same
`shown), closed at a bottom end by screw cap 32. A thumb-
`in direct modality and showing the optical paths of light
`operated, combination rotary rheostat 34 and on/off switch
`reflected from the eye of a subject toward the left and right
`connected in series with the batteries is mounted at an upper
`viewing apertures, resulting in diplopia.
`end of the handle 30. A vertical stanchion 38 is rigidly
`FIG. 3 is a schematic diagram in enlarged, front eleva-
`attached to a left side of the cylinder 30. A horizontally-
`tional view showing the positions of the left and right
`elongated support beam 40 has a nght end 41 rigidly
`viewing apertures and illumination source exit aperture in
`attached to the stanchion 38 and a free left end 42. A
`the present invention; and
`chevron-shaped frame 50, having a centrally-disposed,first
`FIG. 4 is a schematic diagram in top plan view of the same
`V-notch 52 cut away from a rear margin 51 thereof,
`is
`45
`in direct modality and showing the optical paths of light
`pivotally suspended on pivot axis P—P by pivot pin 44
`reflected from the eye of a subject, resulting in stereopsis.
`inserted throughafirst vertical bore (not shown)in the free
`FIG. 5 is a perspective view of a first embodimentof the
`end 42 and through a second vertical bore (not shown)
`present invention as seen from the rear and above and with
`through the frame 50 just forward of the V-notch 52. A
`the handle positioned on the right side of the frame thereof;
`horizontally-elongated C-channel 60 is fixed to an underside
`FIG. 6 is a front, elevational view of the same;
`50U of the frame 50 and comprises a top wall 62, bottom
`wall 64 and front wall 66, as may best be seen in FIGS. 6 and
`FIG. 7 is a bottom view of the same;
`7. Left and nght flanges 56, 56' of the frame 50 project
`FIG. 8 is an enlarged, perspective view of the beam
`partially downward from a front wall 50F thereof, adjacent
`splitter mounting block thereof;
`the front wall 66 of the channel 60. The flanges 56, 56’,
`FIG. 9 is a cross-sectional view thereof taken along line
`together with a rectangular opening cut away from the front
`9—9 of FIG. 8; and
`wall 66, define a forward-facing, rectangular window W
`FIG. 10 is a left side view thereof.
`symmetrically disposed about the vertical pivot axis P—P
`and about the horizontal illumination axis I—I.
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`FIG. 11 is an enlarged, schematic diagram of a second,
`alternative embodimentof the invention utilizing worm gear
`assemblies to rotate nght and left dioptric disks; and
`FIG. 12 is an enlarged, exploded view of telescoping
`shafts thereof.
`
`FIG. 13 is a rear, elevational view of a dioptric disk and
`idler gear drive assembly ofa third, alternative embodiment
`of the invention.
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`FIG. 14(a) is a variation on the dioptric disk and idler gear
`drive assembly of FIG. 13, adjusted for a desired minimum
`interpupillary distance; and
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`The top wall 62 of the C-channel 60 is also cut away to
`form a second V-notch 68 symmetrically disposed about the
`pivot axis P—Pandthe illumination axis I—I, the vertex of
`the notch 68 being adjacent the front wall 66. Both the first
`notch 52 and the second notch 68 include a total of 90
`degrees of angle, bifurcated by a plane defined by the axis
`P—P and I—I (the “I-P plane”) into two equal 45 degree
`angles.
`Referring to FIGS. 5 and 8, vertical left and right mirror
`support plates 90, 90' line the second notch 68 and extend
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`a
`from the bottom wall 64 to the top wall 62. Forward-facing
`beam splitting mirrors 100, 100' are attached to front sur-
`faces of each of the plates 90, 90', and forward, apical
`portions of said mirrors 100, 100' are exposed to incident
`light by third V-notches 102, 102' cut out of the plates 90,
`90°.
`
`the mirrors 100, 100' are
`Referring to FIGS. 8 and 9,
`mounted on front surfaces of a beam splitter block 130
`comprised of left and right vertical, parallelepiped portions
`130L, 130R joined at a 90 degree vertex 130V, which vertex,
`like the first and second V-notches 52, 68, is bisected by the
`I-P plane. The vertex 130V has a vertical bore 130B into
`whichis inserted a miniature halogen bulb 120 connected by
`electric cables 110 to dry cell batteries in the handle 30,
`which serves as an illumination source. An illumination
`source exit aperture 130E comprises third and fourth
`V-notches 140, 140' cut away from left and right mirrors
`100, 100,'and the underlying portions of the block 130,
`respectively, to permit light emitted by the bulb 120 to travel
`forward through a convex focusing lens 120L and thence
`along the illumination axis I—I toward the eye of a subject.
`By keeping the illumination source 22 comprising the bulb
`120 and lens 120L, and the mirrors 100, 100' within a 6 to
`7 mm diameter circle about the illumination axis, the illu-
`mination axis is substantially collinear with the viewing
`axis; compare FIGS. 3, 4, 8 and 9.
`The first embodimentof the invention further includesleft
`and right dioptric disk assemblies, denoted generally by the
`numerals 150, 150', which are mounted for lateral sliding
`adjustment along the C-channel 60. For this purpose, left
`and right dioptric disk assembly mounts 170, 170' are
`provided, being laterally elongated channels of rectilinear
`cross-section adapted to fit and slide smoothly within the
`C-channel 60, as shown for example, in FIGS. 5 and 10. To
`arear wall 64R of each mount 170, 170'is attached a dioptric
`disk assembly 150, 150' by threaded fasteners 150S, respec-
`tively. As shownin FIG. 7, a pair of oppositely-directed slots
`62B, 62B' in the bottom wall 64 of the C-channel 60 extend
`from the left and right ends thereof,
`respectively, and
`threaded bolts with wing nuts 174 extend therethrough and
`through bores in the bottom walls of the mounts 170, 170',
`thereby permitting lateral sliding adjustmentof the positions
`of the dioptric disk assemblies 150, 150'. The left and right
`dioptric disk assemblies 150, 150' each include a housing
`180 upon which a dioptric disk 182 is mounted for rotation
`about horizontal axes D—D and E—E,respectively, and a
`viewing aperture 186. The dioptric disks 182 each have a
`series of magnifying loupes 184 of differing magnifying
`powers distributed around the periphery thereof. Left and
`right deflection mirrors 98, 98' are mounted within the
`C-channel, laterally spaced apart on opposite sides of the
`beam splitting mirrors 100, 100', and angled obliquely with
`respect to the I-P plane. Light incident on the beam splitting
`mirrors 100, 100' is reflected into a left-directed path and
`right-directed path, which respective light beam paths are
`deflected rearward by reflection off the deflection mirrors 98,
`98' along second axis B—B and a third axis C—C,
`respectively, thence through a magnifying loupe 184 of a
`dioptric disk 182 and further rearward through a viewing
`aperture 186 into an eye of an observer.
`An alternative embodiment of the invention is illustrated
`schematically in FIG. 11, wherein left and right worm gear
`drive assemblies, denoted generally by the numerals 200,
`200', are provided for each ofthe left and right dioptric disk
`assemblies 150, 150'. The left and right worm gear drive
`assemblies 200, 200' comprise left and nght worm gears
`202, 202' aligned on a horizontal axis G—Gparallel to, and
`to the rear of, the frame 50, and matching left and night spur
`gears 204, 204' attached to a rear, central portion of theleft
`and right dioptric disks, and in meshed engagement with
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`said spur gears 202, 202', respectively. Right and left lens
`powerknobs 220, 200' are connected to the worm gears 202,
`202', by distal connecting shafts 210, 210'
`for rotation
`therewith. Left and right medial connecting shafts 212, 212'
`connect the spur gears 202, 202' with each other through a
`telescopic coupling 230 that permits lateral movementof the
`worm gear assemblies 200, 200' and associated dioptric
`disks 182, 182' toward and away from each other to adjust
`for the interpupillary distance of the observer. Thus, rotation
`of either lens power knob will cause both dioptric disks 182,
`182' to rotate simultaneously in order to bring a selected
`magnifying loupe 184 onto axes B—B and C—C,respec-
`tively. Preferably, the left and right spur gears 182, 182' have
`opposite thread orientations so that rotation of either lens
`power knob 220, 220' causes the dioptric disks 182, 182' to
`rotate in opposite directions about horizontal axes D—D and
`E—E,as shown bythe arrows 230, 230', respectively. As
`shown in FIG. 12, the telescopic coupling 230 preferably
`includes a shank 240 of square cross-section extending
`medially from the left connecting shaft and a distally-
`extending recess 213 of mating square cross-section in the
`right connecting shaft 212' for receiving said shank 240.
`Accordingly, this alternative embodimentlikewise permits
`adjusting the interpupillary distance to suit the observer.
`FIG. 13 illustrates a third alternative embodiment that
`provides a vertical mounting plate 300 for attachment to the
`frame 50. An idler gear 310 is mounted to the plate 300 for
`rotation about a horizontal axis F—F (not shown) byidler
`gear shaft 302. Left and right dioptric disks 182, 182' are
`mounted to the plate 300 for rotation about horizontal axes
`D—D and E—E(not shown) by dioptric disk shafts 185,
`185'. Each of the dioptric disks 182, 182' is provided with a
`plurality of radial teeth 183, 183' on the periphery thereof, in
`driving engagementwith the teeth 304 of the idler gear. The
`left and right dioptric disk shafts 185, 185' are inserted
`throughleft and right arcuate slots 340, 340' having constant
`radial distance from axis F—F, said slots 340, 340' being
`symmetrically disposed on opposite sides of a vertical plane
`that includes axis F—F. Rotation of the idler gear 310 will
`cause simultaneousrotation of both dioptric disks 182, 182'.
`Reversible means are provided for fixing the left and right
`dioptric disk shafts 185, 185' at a position anywhere within
`said slots 340, 340', respectively, to select a suitable inter-
`pupillary distance.
`In another variation, the vertical mounting plate 300