US3131695A

US3131695A - Ophthalmic instruments

Info

Publication number: US3131695A
Application number: US137214A
Authority: US
Inventors: Keeler Charles Henry
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-09-12
Filing date: 1961-09-11
Publication date: 1964-05-05
Anticipated expiration: 1981-05-05

Description

May 5, 1964 c. H. KEELER OPHTHALMIC INSTRUMENTS 2 Sheets-Sheet 1 Filed Sept. 11, 1961 FIG.9.

FIG.10.

R O T N E V N T hdewvh ATTORNEYS May 5,1964

C. H. KEELER OPHTHALMIC INSTRUMENTS 2 Sheets-Sheet 2 Filed Sept. 11, 1961 l NV ENTO R C zar [es/ven *jlf eeler- AT TORN EYS United States Patent 3,131,695 OPHTHALMIC INSTRUMENTS Charles Henry Keeler, Sefton Lawn, Clewer Green, Windsor, England Filed Sept. 11, 1961, Ser. No. 137,214 Claims priority, application Great Britain Sept. 12, 1960 10 (Ilaims. (Cl. 128-395) This invention relates to ophthalmoscopes. It is an object of the invention to provide an ophthalmoscope which, in addition to being capable of use in the same manner as a conventional ophthalmoscope can also be employed to perform certain additional functions notably the detection and treatment of eccentric fixation of the macula of a patient. Hitherto, it has been necessary to employ two or more separate instruments in carrying out pleoptics treatment, viz., one instrument for diagnosis and another to produce a macula after-image. The present invention enables both phases of detection and treatment of eccentric fixation to be undertaken with a single instrument.

According to the present invention there is provided an ophthahnoscope incorporating a compound graticule holder adapted to be detachably secured to the focusing column of the instrument, said holder comprising a stationary portion containing a first graticule for determining eccentric fixation of the macula of the eye of a patient and a slidable portion containing a second graticule adapted automatically to be displaced to a position in which it is superimposed on said first graticule, means being provided whereby simultaneously with said dis placement the extra-macula retina of the eye can be subjected automatically to continuous or intermittent illumination of predetermined intensity and time duration to produce a macula after-image.

The invention is illustrated by way of example in the accompanying drawings in which:

FIGURE 1 is a perspective view showing an ophthalmoscope according to the invention held by an operator during treatment of a patient.

FIGURE 2 is a fragmentary perspective view showing the compound slide located over the focusing tube of the ophthalmoscope and the macula occlusion graticule being partially inserted into position within the slide.

FIGURE 3 is a fragmentary perspective view showing the macula occlusion graticule fully inserted into the slide and locked in position.

FIGURE 4 is a fragmentary perspective view showing the macula occlusion graticule pulled outwardly to energise the automatic mechanism and thus expose the graticule, located in the stationary portion.

FIGURE 5 is a fragmentary perspective view showing a red-free graticule about to be inserted into a peripheral slot in the wall of the ophthahnoscope beneath the compound slide.

FIGURE 6 is a fragmentary perspective view showing the red-free graticule located in the operative position.

FIGURE 7 is a plan view, drawn to an enlarged scale, showing a movable. graticule holder.

FIGURE 8 is a sectional side view taken on the line 8-8 of FIGURE 7.

FIGURE 9 is a plan view showing a star graticule which remains permanently in position within the graticule holder.

FIGURE 10 is a plan view showing a red-free graticule.

FIGURE 11 is a side view partly in section, and drawn to an enlarged scale, showing a compound slide according to the invention, and

FIGURE 12 is a cross-sectional view taken on the line 1212 of FIGURE 11.

Referring to the drawings the ophthalmoscope is of known form such as that described in United Kingdom specification No. 665,531 and designated generally by the reference numeral 1. The ophthalmoscope incorporates a focusing tube 2 which is adjustable by means of the focusing button 3 (FIGURES 5 and 6). The focusing tube 2 is adapted to support a compound graticule holder in accordance with the invention. The graticule holder comprises a fiat body portion 4 having at one end a circular aperture 5 containing a star graticule 6 which is fixedly located therein. The body portion 4 is formed with an elongated opening 7 on its upper face, the opening 7 communicating with the aperture 5 (see FIGURE 12). The side walls of the opening 7 are formed with a dovetail groove 8. Another graticule holder 9 is arranged for sliding movement with respect to the body portion 4, the holder 9 having inclined sides 10 which interlock with the dovetail groove 8 in the elongated opening 7 in the body portion 4. The holder 9 is formed at its forward end with an aperture 11 containing an occluder graticule 12 having a central opaque area 13 (shown as a black spot). The sliding graticule holder 9 has a lateral slot 14 therein, for a purpose hereinafter described, and is also provided with a projection 15 for manipulation purposes. The body portion 4 is formed with a longitudinal aperture 16 (FIGURES 11 and 12) within which is slidable a tubular plunger 17 which encloses a coil spring 18 (FIGURE 12) fixedly attached at one end to the outer end of the plunger and at the opposite end to a screw 19. The forward end of the plunger 17 is formed with a peripheral groove 20 engageable by a spring-pressed detent 21 (FIGURES 11 and 12) when the plunger 17 is pulled outwardly by means of a projection 22 on the outer end of the plunger 17, the detent being released from engagement with the groove 20 on the plunger 17 through the medium of a Bowden wire control 23. The plunger 17 is rotatable within the aperture 16 in the body portion 4 so that the projection 22 assumes a position in which it lies in a horizontal plane so as to permit the graticule holder 9 to be slid into position in the body portion. Thereafter, the plunger 17 is rotated so that the projection 22 is in a vertical position in which position it enters the slot '14 in the movable graticule holder 9, thus causing. the plunger 17 and consequently the holder 9 to be advanced or retracted within the body 4 as desired. The upper face of the movable graticule holder 9 carries an electric contact 24 which is adapted to effect engagement with

contacts

25 and 26 carried by a block of insulating material 27 mounted on the upper surface of the body portion 4, the

contacts

25 and 26 being connected to an electric transformer (not shown) housed in a separate container (not shown) incorporating a rheostat control which is adjustable to provide up to a maximum current of about 1 amp. The said container houses a time switch, a graduated dial being provided on the top of the container whereby the switch can be set to provide illumination of predetermined time duration. To enable the compound slide to be fixedly attached to the focusing tube 2 a set-screw 28 is provided. The ophthalmoscope is pro vided with a peripheral slot 29 which accommodates a graticule having a red-free, i.e. clear, aperture 30 therein and carrying a projecting arm 31 which is engageable with the trigger 32 of the Bowden wire control.

In using the instrument for the diagnosis of eccentric fixation and after-image treatment of a patient, the size of spot occluder graticule is selected and inserted into the focusing tube 2 of the ophthalmoscope. The sliding gnaticule holder 9 is then inserted into the elongated opening 7 in the body portion 4 and urged inwards as far as it will go, the projection 22 on the plunger 17 being turned upwardly into the vertical position when it entered into the slot 14 in the holder 9, thus coupling the plunger 17 and the holder 9 together. The holder 9 Patented May 5., 1964- is then pulled outwardly until the detent 21 has entered the peripheral groove 20 in the plunger 17 thereby exposing the lstar graticule 6 to the light beam. The redfree slide is then inserted into the slot 29 so that the arm 30 is engaged by the trigger 32 of the Bowden control. The transformer rheostat control and time switch are now set to alford the required conditions when operated. The star graticule which is permanently in position is now focused onto the macula of the eye of the patient and the degree of eccentricity of fixation determined. The Bowden wire control is then actuated causing the red-free slide to be removed from the light path and simultaneously the graticule holder 9 will be released so that it moves forward and the spot occluder '13 is superimposed on the star graticule 6. The electric contacts on the graticule holder 9 and the block 27 respectively will effect engagement thus completing the electrical circuit and causing an intense w te light to be projected onto the eXtra-macula retina, thereby dazzling the area in which retinoception is taking place, but, at the same time protecting the macula and hence stimulating it. The after-image thereby produced can be prolonged or intensified by the conventional flashing light technique, for which purpose an alternator unit incorporated in the electrical circuit can be brought into operation upon actuating a suitable switch. The effect is to inhibit the false macula and to stimulate the eye to correct foveal fixation.

The spot occluder graticule in the holder 9 can, if desired, be substituted by a red-free filter (FIGURE 10) having a clear central aperture which the operator centres on the fovea, the alternator unit being brought into operation to impart intermittent light flashes to the foveal area.

I claim:

1. In an ophthalmoscope having a focusing tube, a compound graticule holder detachably mounted on said focusing tube, said holder including a body portion, a tfirst graticule for determining eccentric fixation of the macula of the eye of a patient, said first graticule being disposed in said body portion, a slidable member slidably disposed in said holder, a second graticule disposed in said slidable member, means operatively engaging said slid-able member to maintain said second graticule in a position remote from said first graticule, means automatically displacing said slidable member to superimpose said second graticule over said first graticule, and means operated simultaneously with the displacement of said slidable member to subject the extra-macula retina of the eye to continuous or intermittent illumination of predetermined intensity and time duration to produce a macula after-image.

2. An ophthahnoscope according to claim 1, wherein said body portion comprises a flat body having a circular aperture therein in which said first graticule is fixedly mounted, said fiat body having an elongated opening on the upper face thereof which opening communicates with said aperture, the side walls of said opening being formed with a dovetail groove.

3. An ophthalmo'scope as claimed in claim 1 wherein said second graticule is a red-free graticule.

4. An ophthalmoscope according to claim 2, wherein said slidable member is formed with an aperture at its forward end containing said second graticule, the sides of said slidable member being inclined so as to interlock with the grooves in the side walls of the elongated opening in said fiat body.

5. An ophthalmoscope according to claim 1, wherein said engaging means includes a longitudinal bore formed in said body portion which receives a spring-actuated plunger carrying means whereby said slidable member can be coupled thereto and advanced or retracted with respect to the body portion.

6. An ophthalmoscope according to claim 5 wherein the forward end of said plunger is formed with a peripheral groove, a spring-pressed detent disposed in said body portion to engage said groove when the plunger is in the fully advanced position, means being provided for releasing said detent from engagement with said groove to cause said slidable portion to be retracted to superimpose the second graticule over the first graticule.

7. An ophthalmoscope according to claim 1, wherein the slidable member carries an electric contact, contacts disposed on a member carried by said body portion and engageable with said electric contact so as to be energised by electric current means controlled by a rheostat to provide the illumination of predetermined intensity and time duration.

8. An ophthalmoscope as claimed in claim 7, wherein means are operatively connected to :said electric current means to prolong or intensify the after-image by intermittent light flashes.

9. An ophthalrnoscope according to claim 1, wherein said first graticule is a star graticule and said second graticule is a spot occluder graticule.

10. An ophthalmoscope according to claim 1, wherein a red-free slide is disposable within the illumination path, and means operatively connected to said red-free slide to automatically displace same when the second graticule has been superimposed over the first graticule.

References Cited in the file of this patent UNITED STATES PATENTS 1,698,124 De Zeng Jan. 8, 1929 2,821,977 Ga ssman Feb. 4, 1958 2,986,068 Mandaville May 30, 1961

Claims

1. IN AN OPHTHALMOSCOPE HAVING A FOCUSING TUBE, A COMPOUND GRATICULE HOLDER DETACHABLY MOUNTED ON SAID FOCUSING TUBE, SAID HOLDER INCLUDING A BODY PORTION, A FIRST GRATICULE FOR DETERMINING ECCENTRIC FIXATION OF THE MACULA OF THE EYE OF A PATIENT, SAID FIRST GRATICULE BEING DISPOSED IN SAID BODY PORTION, A SLIDABLE MEMBER SLIDABLY DISPOSED IN SAID HOLDER, A SECOND GRATICULE DISPOSED IN SAID SLIDABLE MEMBER, MEANS OPERATIVELY ENGAGING SAID SLIDABLE MEMBER TO MAINTAIN SAID SECOND GRATICULE IN A POSITION REMOTE FROM SAID FIRST GRATICULE, MEANS AUTOMATICALLY DISPLACING SAID SLIDABLE MEMBER TO SUPERIMPOSE SAID SECOND GRATICULE OVER SAID FIRST GRATICULE, AND MEANS OPERATED SIMULTANEOUSLY WITH THE DISPLACEMENT OF SAID SLIDABLE MEMBER TO SUBJECT THE EXTRA-MACULA RETINA OF THE EYE TO CONTINUOUS OR INTERMITTENT ILLUMINATION OF PREDETERMINED INTENSITY AND TIME DURATION TO PRODUCE A MACULA AFTER-IMAGE.