METHOD OF EXAMINING AN EYE OF A SQUINTING PERSON BY USE OF A PERISCOPIC DEVICE AND SUCH A PERISCOPIC DEVICE

Abstract

The present invention relates to a periscopic device (3) for examining an eye of a person having an inwardly squinting eye (esotropia). The periscopic device (3) comprises a tube (4), a first mirror (5) arranged inside the first end (6) of the tube (4), and a second mirror (7) arranged inside the second end (8) of the tube (4). In one embodiment of the invention, the first and the second mirrors (5,7) are arranged so that when the person looks through the periscopic device (3) with the inwardly squinting eye (2) while the other eye (1) is being examined, the first and the second mirrors (5,7) (10,11) each deflects the line of sight of the person by an angle of approximately 90°. The periscopic device (3) further comprises a base out prism (9) arranged in front of the first mirror (5) so that, during use of the periscopic device (3), the line of sight of the inwardly squinting eye (2) is deflected towards the first mirror (5). In another embodiment of the invention, the first and the second mirrors (5,7) are arranged non-parallel to each other, and the first mirror (5) is arranged so that when the person looks through the periscopic device (3) with the inwardly squinting eye (2) while the other eye (1) is being examined, the line of sight of the inwardly squinting eye (2) is reflected in the first mirror (5) and towards the second mirror (7).

Claims

1. Periscopic device for examining an eye of a person having an inwardly squinting eye, the periscopic device comprising: a single tube, a first mirror arranged inside a first end of the tube which end is adapted to be placed near the person's one eye, and a second mirror arranged inside a second end of the tube, wherein the periscopic device is dimensioned and shaped so that, when in use, the person can look through the periscopic device from the first end of the tube only with the one eye, while the other eye is exposed for being examined, wherein the line of sight of the one eye is reflected in the first mirror and towards the second mirror, and reflected in the second mirror, wherein: the first and the second mirrors are each arranged so that the first and the second mirrors each deflects the line of sight of the person by an angle of approximately 90°, and the periscopic device further comprises a base out prism arranged in front of the first mirror so that, during use of the periscopic device, the line of sight of the one eye is deflected towards the first mirror, or the first and the second mirrors are arranged non-parallel to each other.

2. Periscopic device according to claim 1, wherein the tube is an outer housing comprising an inner cavity extending at least between the first and second ends of the housing.

3. Periscopic device according to claim 1, wherein the one eye with which the person looks through the periscopic device is the inwardly squinting eye.

4. Periscopic device according to claim 1, wherein the periscopic device comprises a base out prism, and wherein the first and second mirrors are arranged substantially parallel to each other and at an angle of 45° in relation to a longitudinal extension of the tube.

5. Periscopic device according to claim 1, wherein the periscopic device comprises a base out prism, the base out prism having a prism dioptre between 20 and 50, such as between 30 and 45.

6. Periscopic device according to claim 1, wherein the tube has a substantially constant cross sections, and a characteristic dimension of the cross section is 10 to 60 mm, such as 10 to 30 mm or 20 to 50 mm.

7. Periscopic device according to claim 1, wherein the tube is conical and increasing in cross sectional area from the first end towards the second end.

8. Periscopic device according to claim 1 further comprising mounting means at the first end for mounting the periscopic device in a standard glass frame.

9. Periscopic device according claim 8, wherein the mounting means is an annular ring made from a resilient polymer material.

10. Periscopic device according to claim 1, wherein the periscopic device is handheld.

11. Method of examining an eye of a person having an inwardly squinting eye, the method comprising: allowing the person to look through a periscopic device according to claim 1 from the first end of the tube only with the inwardly squinting eye, while the other eye which is exposed is examined, and providing an object to focus on at a location which makes it visible by the inwardly squinting eye looking through the periscopic device.

12. Method of examining an eye of a person having an inwardly squinting eye, the method comprising: allowing the person to look through a periscopic device according to claim 1 from the first end of the tube only with the non-squinting eye, while the inwardly squinting eye which is exposed is examined, and providing an object to focus on at a location which makes it visible by the non-squinting eye looking through the periscopic device.

13. Method of examining an eye of a person having an inwardly squinting eye, the method comprising: allowing the person to look through a periscopic device according to claim 8 from the first end of the tube only with the inwardly squinting eye, while the other eye which is exposed is examined, providing an object to focus on at a location which makes it visible by the inwardly squinting eye looking through the periscopic device, and mounting the periscopic device in a standard glass frame before the examination is performed.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] The periscopic device and the method of using it for examination of a person's eye according to the invention will now be described in more detail with regard to the accompanying figures. The figures show a few ways of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0037] FIG. 1 shows schematically a top view of the principle of an embodiment of the present invention comprising a base out prism.

[0038] FIG. 2 shows schematically how the present invention solves the above mentioned problems related to the eye examination of a person having an inwardly squinting eye. FIGS. 2.a and 2.b show how the line of sight of the eye not under examination is blocked by the examining person. FIG. 2.c shows how the line of sight is changed by use of the present invention.

[0039] FIG. 3 shows a periscopic device having a tube which is conical and increasing in cross sectional area from the first end towards the second end.

[0040] FIG. 4 shows a periscopic device version 1.0 made during the development of the present invention. The periscopic device has mounting means in the form of an annular ring at the first end for mounting the periscopic device in a standard glass frame.

[0041] FIGS. 5.a and 5.b show photos of a prototype version 2.0 made during the development of the present invention.

[0042] FIG. 6 shows a cross section of an embodiment of the present invention.

[0043] FIG. 7 shows schematically the use of another embodiment of the invention resembling the use shown in FIG. 2.c but with a periscopic device not including a base out prism.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0044] FIG. 1 shows schematically a top view of the principle of a first embodiment of the present invention used for examining an eye of a person with an inwardly squinting eye (esotropia). In the example shown in the figure, the left eye 1 looks straight ahead while the right eye 2 squints inwards. When the left eye 1 is to be examined, the periscopic device 3 is placed in front of the right eye 2 which thereby is enabled to focus on e.g. a film at a distance indicated by D in the figure. Hereby it will be easier to keep e.g. a small child still during the examination.

[0045] The periscopic device 3 comprises a tube 4 which can be used to hold the periscopic device 3 by the person being examined or a helper, such as a parent. In the embodiment in FIG. 1, the tube is shown with a very simple geometry for illustrative purposes only. The periscopic device may have other geometries and comprise a housing which is easy to hold, such as having the geometry shown in FIG. 6. A first mirror 5 is arranged inside a first end 6 of the tube 4 which end is adapted to be placed near the person's right eye 2 (in the example shown in the figure). A second mirror 7 arranged inside a second end 8 of the tube 4. The periscopic device 3 further comprises a base out prism 9 arranged in front of the first mirror 5 so that, during use of the periscopic device 3, the line of sight of the inwardly squinting right eye 2 is deflected towards the first mirror 5. As can be seen in FIG. 1, it is hereby obtained that the line-of-sight of the inwardly squinting right eye 2 is changed so that it becomes possible to watch an object, such as a film, located at a position D behind the examining ophthalmologist (not shown).

[0046] The base out prism 9, the first mirror 5 and the second mirror 7 are each arranged so that when the person looks through the periscopic device 3 with the inwardly squinting eye 2 while the other eye 1 is being examined, the line of sight of the person is deflected by an angle of approximately 20° in total. The embodiment shown in FIG. 1 uses mirrors to deflect the line-of-sight, whereas an alternative may be to use first and second prisms arranged at the first end 6 and the second end 8, respectively. Such prisms must be configured and arranged so that the same effect is obtained.

[0047] The tube 4 of the periscopic device 3 shown in cross sectional view in FIG. 1 has a substantially constant cross sections which may e.g. be circular or quadratic. A characteristic dimension of the cross section, such as a diameter or a width, is typically 10 to 60 mm, such as 10 to 30 mm or 20 to 50 mm.

[0048] FIG. 2 shows schematically and in a top view how the present invention solves the above mentioned problems related to the eye examination of a person having an inwardly squinting eye. In the figure, the person 13 being examined, and in particular the eyes and the lines of sight, are shown schematically. The examining person 14, such as an ophthalmologist, is shown looking through an instrument 15 which can be any kind of instrument, typically handheld, used for the examination. FIGS. 2.a and 2.b show how the line of sight of the eye not under examination is blocked by the examining person 14 for both of two possible orientations of the instrument 15. Therefore it will not be possible for the person 13 being examined to see an object 16 to focus on arranged at a location behind the examining person 14. Furthermore, FIGS. 2.a and 2.b show that it can be difficult to examine the inwardly squinting eye. FIG. 2.c shows how the periscopic device 3 can be placed in front of the right eye of the person 13 to thereby induce an inward turning of that eye in order to be able to watch the object 16 to focus on through the periscopic device 3. This results in an outward turning of inwardly squinting eye whereby examination thereof is facilitated.

[0049] FIG. 2 illustrates the examination of the inwardly squinting eye, but the same periscopic device can correspondingly be used for the examination of the other eye by placing the periscopic device in front of the inwardly squinting eye as was shown in FIG. 1.

[0050] FIG. 3 shows a periscopic device 3 with a tube 4 which is conical and increasing in cross sectional area from the first end 6 towards the second end 8.

[0051] FIG. 4 shows a version 1.0 of the present invention the made during the development thereof. The periscopic device 3 has mounting means 12 in the form of an annular ring at the first end 6 for mounting the periscopic device 3 in a standard glass frame (not shown). Such an annular ring 12 may e.g. be made from a resilient polymer material, such as silicone, or metal or plastic.

[0052] FIG. 5 shows photos of a prototype version 2.0. This prototype shown is without the mounting means, but this will be added later. In this embodiment, the tube 4 as shown above is enclosed by a box shaped outer housing, but the working principle is as shown above. The tube 4 as described above may correspond to an open channel through the periscopic device; this is referred to as a tube in the present description. FIG. 5.a shows the periscopic device 3 from the side comprising the base out prism 9; FIG. 5.b shows the periscopic device 3 from the opposite side.

[0053] In any of the embodiments shown above, the tube 4 could in principle be made from a number of materials, but in a presently preferred embodiment it is made from plastic. A typical length of a periscopic device 3 would be 10-15 cm.

[0054] In a method according to the invention, an examination of an eye of a person having an inwardly squinting eye comprises letting the person look through the periscopic device 3 with the inwardly squinting eye 2 while the other eye 1 is examined. An object 16 to focus on is arranged at a location D which makes it visible by the eye looking through the periscopic device 3; such an object 16 may e.g. be a film or a flashing light. As explained in relation to FIG. 2, the periscopic device 3 can correspondingly be used for the examination of the squinting eye by letting the person look through the periscopic device 3 with the other eye.

[0055] So in summary, when combining a traditional periscope with a base out prism 9, it is possible to:

[0056] 1: examine the eyes of a person with an inward squint (esotropia) as the periscopic device 3 allows the person to focus with the squinting eye while the other non-squinting eye is directed straight forward. The eye pointing straight forward can be examined, and to examine the other eye, the periscopic device 3 is then changed to be held in front of the first examined eye. In this way an inward squinting person can have both eyes examined.

[0057] 2: The periscopic device 3 according to the present invention allows the examiner 14 to be close to the person 13 without blocking the view of the fixating eye, thus the periscopic device 3 allows the person 13 to “look around” the examiner 14.

[0058] FIG. 6 shows a cross section of an embodiment of the present invention comprising a base out prism 9 and in which the tube 4 is conical and increasing in cross sectional area from the first end 6 towards the second end 8. The housing of the periscopic device 3 may e.g. be made by injection moulding, typically of a number of pieces which are subsequently assembled after insertion of the first and second mirrors 5,7 and the base out prism 9.

[0059] FIG. 7 shows schematically the use of another embodiment of the invention resembling the use shown in FIG. 2.c but with a periscopic device 3 not including a base out prism. In this embodiment, the periscopic device 3 comprises a tube 4, a first mirror 5 arranged inside a first end 6 of the tube 4 which end is adapted to be placed near the person's eye 2, and a second mirror 7 arranged inside a second end 8 of the tube 4. The first and the second mirrors 5,7 are arranged non-parallel to each other, i.e. with and angle β. The angle typically corresponds to the angle of deflection of 15-22.5°, preferably around 20°, as described above for the embodiment with a base out prism. The first mirror 5 is arranged so that when the person looks through the periscopic device 3 with the right eye 2 (in relation to this figure) while the left eye 1 is being examined, the line of sight of the right eye 2 is reflected in the first mirror 5 and towards the second mirror 7. Hereby the same effect is obtained as for the periscopic device 3 comprising a base out prism 9 as described above.

[0060] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.