US3300269A

US3300269A - Fibre-optics time resolved perimeter for testing peripheral vision

Info

Publication number: US3300269A
Application number: US229321A
Authority: US
Inventors: Donald H Schultz
Original assignee: Laubman and Pank Pty Ltd
Current assignee: Laubman and Pank Pty Ltd
Priority date: 1961-10-13
Filing date: 1962-10-09
Publication date: 1967-01-24
Anticipated expiration: 1984-01-24
Also published as: DE1202024B; GB1016185A

Description

Jan. 24, 1967 D. H. SCHULTZ 3,300,269

. FIBRE-OPTICS TIME RESOLVED PERIMETER FOR TESTING PERIPHERAL VISION 2 Sheets-Sheet 1 Filed Oct. 9, 1962' MuE/YrvQ pan/44p 1 ScA/n Lf Jan. 24, 1967 D. H. SCHULTZ 3,

FIBRE-OPTICS TIME RESOLVED PERIMETER 1 FOR TESTING PERIPHERAL VISION Filed Oct. 9, 1962 2 Sheets-Sheet a:

United States Patent 3,300,269 FIBRE-OPTICS TIME RESOLVED PERIMETER FOR TESTING PERIPHERAL VISION Donald H. dchultz, Glen Osmond, South Australia, Australia, assignor to Laubman & Pank Proprietary Limited, Adelaide, South Australia, Australia Filed Oct. 9, 1962, Ser. No. 229,321 Claims priority, application Australia, Oct. 13, 1961,

' 10,202/ 61 6 Claims. (Cl. 35124) This invention relates to a fibre-optics time resolved perimeter suitable for diagnostic analysis of the peripheral field.

In the diagnosis of peripheral field vision the usual tests are subjective and require a patient to concentrate on a fixed point while a technician introduces objects to the side of the patient and requests the patient to indicate when the objects come into vision. This is a subjective test which requires great skill on the part of the technician due to the tendency of the patients attention to wander while the test is being conducted. To overcome this it is known to utilise a flashlight of high power but short duration which includes a proportion of ultraviolet light, this ultra-violet light illuminating fluorescent material painted on a screen, the fluorescent material normally not being distinguishable from the rest of the screens surface. With this arrangement however a number of screens are required and the device is not as simple as a small instrument. Furthermore, the period of flash of an electronic flashlight is insuflicient in some cases to accurately impress upon the memory of a patient the number of illuminated spots which are observed.

The main object of this invention is to provide an in strument which will assist in the diagnosis of malfunctioning of that portion of the retina of the eye which is sensitive to rays of light entering the eye from points other than directly in front of the eye.

In its simplest form the invention consists of a light source, a base support, a series of optical fibres each communicating at one end with the light source and terminating at its other end at spaced points in the base support, apertured coding means between the optical fibres and the light source positionable in any one of a series of positions, the apertures being alignable with the ends of different groups of optical fibres when the coding means are disposed in different positions.

An embodiment of the invention is described hereunder with reference to and is illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of the interconnected components of a time resolved perimeter,

FIG. 2 is a central section through the instrument itself,

FIG. 3 is a front view of the rear optical fibre support disc, drawn to an enlarged scale,

FIG. 4 is a corresponding view of the coding disc, drawn to a similarly enlarged scale,

FIG. 5 is an end view of the base support of the perimeter, and

FIG. 6 is a greatly enlarged section showing the end of an optical fibre in the base support.

According to this embodiment a peripheral field light source consists of an electric bulb 10 in a lamp holder 11, and a condensing lens 12 is disposed in the path of light rays from the bulb 10, the power for the bulb 10 passing through a transformer 13. Disposed in the path of light from the condensing lens is a series of parallel optical fibres 14 which are secured at their light entry ends in a support disc 15 through which they pass, the optical fibres 14 being curved at their other ends to terminate in a concave spherically shaped base support 16,

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each of the fibres 14 being supported at its front end in the base support as shown in FIG. 6, the fibres being disposed radially at their forward terminal ends in relation to a central point of the spherical base support 16. In this embodiment the centre is disposed on a radius of nineteen millimeters from the surface of the base support, and the instrument is so arranged that the entrance pupil of a human eye can be disposed approximately at the centre. The lamp holder 11, condensing lens 12, optical fibres 14, support disc 15 and base support 16 are all contained within a hollow circular casing 17. The optical fibres used are allyl diglycol carbonate, although of course glass or quartz or any other optical fibres which pipe light can be used. These are supported inter mediate their ends by a support member 20 to prevent possibility of damage due to rough handling or other causes.

Disposed directly in front of an observers eye when correctly positioned in relation to the instrument is a fixation assembly which consists of a small low powered globe 21 constituting a fixation light source arranged to be continuously illuminated from batteries (not shown) in a battery case 22 while an observer is being tested and a lens 23 in an aperture in the base support 16. The globe 21 is in a slidable saddle 24 which has an aperture 25 in its base, the apparatus 25 being alignable with the end of any one of a group of five optical fibres 26. These optical fibres 26 terminate in a block 27 aligned with the lens 23, this arrangement giving a variable fixation point which in turn gives the instrument finer resolving power.

Between the condensing lens 12 and the entry end of the optical fibres 14 is disposed a coding disc 30 which is apertured as shown in FIG. 4 and arranged so that various points of light can be illuminated for any one position of the disc 30. It is usual for an observer to be able to remember having seen at least four spots of light if they are temporarily flashed on, and for this reason the coding disc 30 is arranged so that in any one position not more than four optical fibres 14 receive light from the light bulb 10 when it is energised.

A photographic shutter arrangement 31 is disposed between the light bulb 10 and the condenser lens 12, and this is set to a speed of between one tenth and one twentieth of a second, which is found to be the optimum speed for this instrument, although the speed can be widely varied outside these limits.

The manner in which the device is used is as follows:

The fixation assembly is connected to a power source and the instrument is positioned in approximately the correct relationship to an observers eye, that is with the entrance pupil of the eye coinciding with the centre of curvature of the base support. The shutter 31 is 0perated with the coding disc in different positions, and for each position a plurality of optical fibres are illuminated. The observer is asked how many spots he has seen, and by this means it is possible to determine which areas of the observers eye are malfunctioning if any. For example the observer may see only two or three spots when the coding disc is in a certain position where four fibres are illuminated, and this will indicate that there is a blind spot at -a field of, say, side vision.

In the diagnosis of certain diseases it is known that a patient is not responsive to certain colours entering the eye from certain angles, and coloured filters may be inserted to determine the patients condition. For example tobacco poisoning and alcoholic poisoning can be checked in this manner.

The arrangement of the coding disc can of course be widely varied, but according to the embodiment illustrated seventeen optical fibres are arranged in concentric rings around the base support, and the coding disc is arranged to rotate through six twelve degree angles, but be positioned in any one of the siX positions by means of the spring-loaded ball assembly 33. This arrangement can give a full scanning of the peripheral field.

The device can of course be varied, and it is not necessary that the ends of the optical fibres should terminate in a spherical base support, nor that the fibres should exactly be directed to the centre of entrance of the observers pupil, since the light emanating from the ends of the fibres does not pass outwardly in a narrow beam. If desired the whole assembly may be mounted in such a way that rotation through one hundred and eighty degrees brings the instrument into mirror image position for the other eye.

It is not essential that the variable fixation point arrangement described in the above embodiment be used, and a single fixation point may if desired be employed, but it is possible by controlled variation of the fixation position to scan appropriate adjacent retinal areas originally stimulated. This arrangement is of special significance in investigating field losses in glaucoma for example and also in hemianopsia and sector losses.

The instrument described in the above embodiment can be varied to explore in greater detail areas of special significance within the thirty degree paracentral field corresponding to the range of conventional campimeters, scotometers and tangent screens, such as the Bjerrum screen, and the same technique is involved, with a greater elaboration of fibre distribution and coding and fixation in order to provide greater resolving power of the method. Clearly the subtended angle of the target area is much less in all directions than in the above described embodiment.

The time period of illumination of the optical fibres can of course be controlled by means other than the photographic shutter arrangement described above, and it has, for example, been found that an electronic flash provides satisfactory results, notwithstanding the short time period.

What I claim is:

1. A fibre-optics time resolved perimeter comprising a casing, a peripheral field light source in one end of the casing, a base support in the other end of the casing, the base support being concave and of such dimension as to shield the field of vision of a patients eye when positioned in front thereof, a pattern of apertures each extending through the base support, an opaque fibre end support member in the casing between the base support and the light source, a pattern of apertures each extending through the fibre end support member, a series of optical fibres within the casing each terminating at its one end in a said aperture in the base support and terminating at its other end in a said aperture in the fibre end support member, an opaque coding member movably secured to the casing and disposed contiguous with the fibre end support member but between the fibre end support member and the light source, and a pattern of apertures each extending through the coding member selectively alignable with the apertures through the fibre end support member in 'difierent groups of not more than four upon movement of the coding member, said light source illuminating fibres which terminate in the base support in the peripheral field of vision of an eye when positioned adjacent to and in front of the base support.

2. A fibre-optics time resolved perimeter comprising a casing, a peripheral field light source in one end of the casing, a base support in the other end of the casing, the base support being concave and of such dimension as to shield the field of vision of a patients eye when positioned in front thereof, a pattern of apertures each extending through the base support, an opaque fibre end support member in the casing between the base support and the "peripheral field light source, a pattern of apertures each extending through the fibre end support member, a series of optical fibres within the casing each terminating at its one end in a said aperture in the base support and terminating at its other end in a said aperture in the fibre end support member, a viewing lens in the base support, an apertured member within the casing and aligned with the viewing lens, a fixation light source secured relative to the casing, at least one optical fibre extending between the fixation light source and terminating in an aperture in said apertured member thereby constituting a fixation point centrally of the peripheral field of vision, an opaque coding disc rota-tably secured within the casing and disposed contiguous with the fibre end support member but between the fibre end support member and the peripheral field light source, a pattern of apertures each extending through the coding disc selectively alignable with the apertures through the fibre end support member in different groups of not more than four upon movement of the coding member within the casing, said peripheral field light source illuminating fibres which terminate in the base support in the peripheral field of vision of an eye when positioned adjacent to and in front of the base support.

3. A fibreoptics time resolved perimeter comprising a casing, :a peripheral field light source in one end of the casing, an outwardly concave spherical base support in the other end of the casing, a pattern of apertures each extending through the base support in the direction of the center of spherical curvature, the base support being of such dimension as to shield the field of vision of a patients eye when positioned in front thereof and the apertures being in the peripheral field of vision, an opaque fibre end support member in the casing between the base support and the peripheral field light source, a pattern of apertures each extending through the fibre end support member, a series or" optical fibres within the casing each terminating at its one end in a said aperture in the fibre end support member, terminating at its other end in a said aperture in the base support and directed at its terminal end toward the center of spherical curvature of said base support, a viewing lens in the base support, an apertured member within the casing and aligned with both the viewing lens and said center of spherical curvature, a fixation light source secured relative to the casing, at least one optical fibre terminating at one end adjacent the fixation light source and at the other in an aperture in said apertured member thereby constituting a fixation point centrally or" the peripheral field of vision, an opaque coding member movably secured within the casing and disposed contiguous with the fibre end support member but between the fibre end support member and the peripheral field light source, and a pattern of apertures each extending through the coding member selectively alignable with the apertures through the fibre end support member in different groups upon movement of the coding member within the casing.

4. A fibre-optics time resolved perimeter comprising a casing, a peripheral field light source arranged for continuous illumination in one end of the casing, the base support being concave and of such dimension as to shield the field of vision of a patients eye when positioned in front thereof, a base support in the other end of the casing, a pattern of apertures each extending through the base support, an opaque fibre end support member in the casing between the base support and the light source, a pattern of apertures each extending through the fibre end support member, a series of optical fibres within the cas ing each terminating at its one end in a said aperture in the base support and terminating at its other end in a said aperture in the fibre end support member, an opaque cod ing member movably secured within the casing and disposed contiguous with the fibre end support member but between the fibre end support member and the light source, a pattern of apertures each extending through the coding member selectively alignable with the apertures through the fibre end support member in different groups of not more than four upon movement of the coding member within the casing, and a photographic shutter between the light source and the coding member, said light source illuminating fibres which terminate in the base support in the peripheral field of vision of an eye when positioned adjacent to and in front of the base support.

5. A fibre-optics time resolved perimeter comprising a casing, a peripheral field light source in one end of the casing, an outwardly concave spherical base support in the other end of the casing, a pattern of apertures each extending through the base support in the direction of spherical curvature, the base support being of such dimension as to shield the field of vision of a patients eye when positioned in front thereof and the apertures being in the peripheral field of vision, an opaque fibre end support member in the casing between the base support and the peripheral field light source, a pattern of .apertures each extending through the fibre end support member, an intermediate fibre support member in the casing between the base support and the fibre end support member, a plurality of apertures in the intermediate fibre support member, a series of optical fibres each terminating at its one end in a said aperture in the fibre end support member and at its other end in a said aperture in the base support, said optical fibres being disposed in the apertures in the intermediate fibre support member and being supported thereby intermediate their ends, a viewing lens in the base support, a block in the intermediate fibre support member aligned with the viewing lens, an aperture in said block, a fixation light source secured relative to the casing, at least one optical'fibre terminating at one end adjacent the fixation light source and at the other in the aperture in said block to constitute therewith a fixation point centrally of the peripheral field of vision, an opaque coding disc rotatable within the casing and disposed between the peripheral field light source and the fibre end support but contiguous with the fibre end support member, a pattern of apertures each extending through the coding member and selectively alignable with the apertures of the fibre end support member in different groups of not more than four upon rotation of the coding disc, a condenser lens in the casing between the coding member and the light source, and a photographic shutter in the casing between the condenser lens and the light source.

6. A fibre-optics time resolved perimeter comprising a casing, a peripheral field light source in one end of the casing, a base support in the other end of the casing, the

base support being concave and of such dimension as to shield the field of vision of a patients eye when positioned in front thereof, a pattern of apertures each extending through the base support, an opaque fibre end support member in the casing between the base support and the light source, a pattern of apertures each extending through the fibre end support member, an intermediate fibre support member in the casing and between the base support and the fibre end support member, a plurality of apertures in the intermediate fibre support member, a series of optical fibres each terminating at its one end in a said aperture in the fibre end support member and at its other end in a said aperture in the base support, a viewing lens in the base support, a block in the intermediate fibre support member aligned with the viewing lens, a pattern of apertures in said block, a fixation light source secured relative to the casing, a plurality of optical fibres each terminating at one end adjacent the fixation light source and at the other in a said aperture in said block, selecting means on the casing disposed between said optical fibres and fixation light source movable to illuminate one fibre at a time, an opaque coding member movable within the casing and disposed between the peripheral field light source and the fibre end support member but contiguous with the fibre end support member, a pattern of apertures each extending through the coding member and selectively alignable with the apertures of the fibre end support member in diiferent groups of not more than four upon movement of the coding member, a condenser lens in the casing between the coding member and the light source, and a photographic shutter in the casing between the condenser lens and the light source.

References Cited by the Examiner UNITED STATES PATENTS 2,507,909 5/ 1950 Kaysen. 2,717,529 9/1955 Alexander 35131 2,938,666 5/1960 Rand.

FOREIGN PATENTS 732,304 2/ 1943 Germany. 694,128 7/ 1953 Great Britain.

DAVID H. RUBIN, Primary Examiner.

Claims

1. A FIBRE-OPTICS TIME RESOLVED PERIMETER COMPRISING A CASING, A PERIPHERAL FIELD LIGHT SOURCE IN ONE END OF THE CASING, A BASE SUPPORT IN THE OTHER END OF THE CASING, THE BASE SUPPORT BEING CONCAVE AND OF SUCH DIMENSION AS TO SHIELD THE FIELD OF VISION OF A PATIENT''S EYE WHEN POSITIONED IN FRONT THEREOF, A PATTERN OF APERTURES EACH EXTENDING THROUGH THE BASE SUPPORT, AN OPAQUE FIBRE END SUPPORT MEMBER IN THE CASING BETWEEN THE BASE SUPPORT AND THE LIGHT SOURCE, A PATTERN OF APERTURES EACH EXTENDING THROUGH THE FIBRE END SUPPORT MEMBER, A SERIES OF OPTICAL FIBRES WITHIN THE CASING EACH TERMINATING AT ITS ONE END IN A SAID APERTURE IN THE BASE SUPPORT AND TERMINATING AT ITS OTHER END IN A SAID APERTURE IN THE FIBRE END SUPPORT MEMBER, AN OPAQUE CODING MEMBER MOVABLY SECURED TO THE CASING AND DISPOSED CONTIGUOUS WITH THE FIBRE END SUPPORT MEMBER BUT BETWEEN THE FIBRE END SUPPORT MEMBER AND THE LIGHT SOURCE, AND A PATTERN OF APERTURES EACH EXTENDING THROUGH THE CODING MEMBER SELECTIVELY ALIGNABLE WITH THE APERTURES THROUGH THE FIBRE END SUPPORT MEMBER IN DIFFERENT GROUPS OF NOT MORE THAN FOUR UPON MOVEMENT OF THE CODING MEMBER, SAID LIGHT SOURCE ILLUMINATING FIBRES WHICH TERMINATE IN THE BASE SUPPORT IN THE PERIPHERAL FIELD OF VISION OF AN EYE WHEN POSITIONED ADJACENT TO AND IN FRONT OF THE BASE SUPPORT.