GB2105057A

GB2105057A - Binocular vision eye testing apparatus

Info

Publication number: GB2105057A
Application number: GB08215227A
Authority: GB
Inventors: Noel Cherry Evans
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-08-28
Filing date: 1982-05-25
Publication date: 1983-03-16
Also published as: GB2105057B

Abstract

This invention relates to eye testing apparatus for diagnosis of binocular vision defects. The apparatus comprises a panel having two concentric patterns 1, 2, thereon, each pattern composed of a complementary colour and means for illuminating the panel. The apparatus may incorporate a pair of filters adapted to be arranged in use each in the line of sight of the panel by a respective one of a user's eyes. <IMAGE>

Description

SPECIFICATION Eye testing apparatus This invention relates to eye testing apparatus, particularly, but not exclusively to apparatus for diagnosis of binocular vision defects and ocular motor anomalies.

According to this invention eye testing apparatus comprises a panel having two concentric patterns thereon, each pattern composed of a complementary colour and means for illuminating the panel.

The term concentric used in this specification refers to patterns having a common centre point.

Preferred patterns may have a common centre of symmetry or common axes of symmetry. The patterns may also incorporate indices or other features which are not concentric. The patterns preferably should be strongly dissimilar to enable a user to eas ilydistinguish between them.

Preferably, the apparatus also incorporates a pair of filters of the aforesaid complementary colours, each adapted in use to be located in the line of sight of the panel by a respective one of a users eyes.

In use of the apparatus one of a pair of complementary coloured filters is placed in the line of sight of a respective eye of a user and the illuminated panel is viewed. Each pattern is only seen by a respective one of the users eyes. Analysis of the user's viaual function may be deduced from the user's report on the appearance and relative position of the patterns or their absence from the filed of view. This invention has an advantage in that the visual effects are striking and have a high impact on a user, facilitating diagnosis with children.

Preferably the panel is illuminated by transmitted light so that each pattern disappears completely when viewed through the filter of the complementary colour. Alternatively the panel may be formed by an image projected onto a white screen The patterns are preferably chosen so that a maximum amount of information may be deduced from the user's report. The patterns are preferably noncircular so that relative rotation of the perceived patterns may be detected, providing an indication or measure of cyclophoria of cyclotorsion. One pattern may be disposed within another so that a binocular vision defect may cause apparent overlap of the inner pattern on the outer pattern. Preferably the inner pattern is arranged so that the extent of overlap may be easily described by a user. One pattern may be arranged to be rotatable relating to the other to facilitate estimation of cyclophoria.

According to a first preferred embodiment of the invention a first pattern comprises a square and a second pattern comprises a multiplicity of dots arranged to form a cross located within the square. Preferably the dots have a diameter which is different to the thickness of the lines of the square.

This embodiment is preferably arranged so that a certain predetermined angular deviation between a user's eyes causes a dot comprising an outer part of the cross to appear coincident with part of the square. A deviation which is double the aforesaid predetermined deviation causes a dot comprising an inner part of the cross to appear coincident with the square. This enables a quantitative estimation of the deviation. Prisms may be used in conventional manner to compensate for larger deviations. Preferably the said predetermined angular deviation amounts to half of a prism dioptre. The cross is preferably composed of five dots.

According to a second preferred embodiment of the invention a first pattern comprises a circle and a second pattern comprises a cross disposed within the circle.

According to a third preferred embodiment of the invention the patterns comprises a circle of a first colour disposed within a square of the second colour, a triangle of each colour disposed within the circle and there is a central white dot. The complementary colours may be red and green although any convenient complementary colours may be used.

The patterns may be provided with a surround which is visible through both filters, for example, a white surround. Use of such a surround facilitates appraisal of fusion-compensated ocular functions.

The patterns may be provided with independent variable illumination for use in cases when defects in a user's visual function are such that intensification of the brightness of one pattern is necessary for it to be perceived.

Apparatus in accordance with the invention may form part of an optician's conventional wallmounted testing apparatus.

The invention will be better appreciated from the following description, by way of examples with reference to the accompanying drawings, of which: Fig. 1 illustrates a panel in accordance with the invention; Fig. 2 illustrates a second panel; Fig. 3 illustrates a third panel; and Fig. 4 illustrates use of apparatus in accordance with the invention.

The panel shown in Figure 1 comprises a four red circular regions 1,3 arranged in a cross contained in a green square 2. The panel is formed by overlaying sheets of green and red plastics material which have been cut out to reveal the colour of the other sheet.

The region where the complementary colours overlap appears black. The horizontal and vertical separation between the regions 1, 3 and between the regions 1, 3 and square 2 are multiples of a dimension which has been chosen to represent a deviation of 2 prism dioptre. Thus if the square has a dimension of 12 cm the angle subtended at a distance of 6 metres between two adjacent regions or between an outer region e.g. 3 and the square 2 is 2 prism dioptre.

Figure 2 shows a similar panel to that of Figure 1, comprising a green square 4 containing a red circle 5 and a white central square 6. A red triangle 7 and a green triangle 8 are contained in the circle 5.

Figure 3 shows a tn r-. panel comprising a red cross 9 disposed within E; green circle 10 disposed within a white square 11.

Illumination of the white regions 6, 11 shown in Figures 2 and 3 serves to provide a reference which can be seen by both eyes of a user. This allows for appraisal offusion-compensated ocular functions.

Use of the three illustrated panels for appraisal of binocular vision is similar in each case. When the panel is viewed by a user having a red filter over one eye and a green filter over the other, each eye sees only the green and red patterns respectively. If the binocular function is perfect the patterns are seen in their true juxtaposition. A binocular defect may, for example, cause the cross shown in Figure 1 to appear shifted to the left relative to the square or indeed it may be absent from the field of vision. In the latter extreme case the cross may be restored to the field of vision by means of prisms inserted in the line of sight in a conventional manner. Rotation of the cross relative to the square may also be observed and assessed.

The red and green colours may be interchanged as convenient or may be replaced with other complementary colours.

Figure 4 shows a diagrammatic arrangement in which a panel 12 is disposed in a mounting 13. A lamp (not shown) contained in the mounting provides transmitted illumination of the panel. A patient is seated at a predetermined distance from the panel e.g. 6 metres, and views the panel through a pair of red and green filters 14 each located in the line of sight of the panel from a respective one of his eyes.

The panel shown is that illustrated in Figure 3 although any panel in accordance with the invention may be employed. The mounting 13 may form part of a conventional optician's wall-mounted testing apparatus.

Claims

1. Eye testing apparatus comprising a panel having two concentric patterns thereon, each pattern composed of a complementary colour and means for illuminating the panel.

2. Apparatus as claimed in claim 1, including a pair of filters of the said complementary colours adapted in use to be located in the line of sight of the panel by a respective one of a user's eyes.

3. Apparatus as claimed in claim 1 or 2, wherein the panel is illuminated by transmitted light.

4. Apparatus as claimed in claim 1 or 2, wherein the panel comprises an image projected onto a screen.

5. Apparatus as claimed in any preceding claim, wherein said patterns are non-circular.

6. Apparatus as claimed in any preceding claim, wherein one pattern is disposed within the other.

7. Apparatus as claimed in any preceding claim, wherein the distance between features of the patterns correspond to predetermined angular deviations.

8. Apparatus as claimed in any preceding claim, wherein one pattern comprises a square and the other pattern comprises dots disposed within the square.

9. Apparatus as claimed in claim 8, wherein five dots are arranged in the form of a cross.

1 G. Apparatus as claimed in any of claims 1 to 7, wherein one pattern comprises a circle and the other pattern comprises a cross disposed within the circle.

11. Apparatus as claimed in any of claims 1 to 7, wherein one pattern comprises a circle and a triangle and, the second pattern comprises a square and a triangle, the triangles being disposed within the circle and the circle being disposed within the square.

12. Apparatus as claimed in any preceding claim, wherein the complementary colours are red and green.

13. Apparatus as claimed in any of claims 2 to 12, wherein the panel includes a portion visible through both of the filters.

14. Apparatus as claimed in claim 13, wherein said portion is white.

15. Apparatus as claimed in any preceding claim, wherein each pattern is provided with means of independent, variable illumination.

16. Apparatus as claimed in any preceding claim wherein one pattern is rotatable relative to the other.

17. Apparatus substantially as hereinbefore described with reference to and as illustrated in any of Figures 1 to 4 of the accompanying drawings.