Visual Perimeter Measurement

Abstract

In one example of the invention a patient display is provided on which a fixation graphic or video is shown in substantially the centre of the display, and then target graphics or video are shown at different positions on the display about the centre. A test subject is positioned in front of the patient display at a known distance, and a camera captures an image of the test subject's eyes, to allow gaze direction determination to be performed. The captured images are displayed to a clinician user by a controlling test application, the clinician making a determination based on the images as to whether the test subject saw a target graphic or video when it was displayed. The clinician user then makes an appropriate input into the controlling test application, which also logs the position at which the target image was displayed. By displaying target graphics at multiple locations on the screen and logging the clinician inputs, the controlling test application is able to build up a plot of the peripheral vision field of the test subject. This plot can then be graphically displayed to the clinician user, and stored with the test results for future clinical use.

1 . A peripheral vision measurement system, comprising:
 a subject video display arranged to display test images to a test subject;   a camera arranged to capture images of the test subject;   a user video display arranged to display captured images of the test subject to a user; and   one or more processors arranged to control the subject and user video displays, the user display being controlled so as to be augmented with at least one indicator relating to the position of a test image on the subject display.   
     
     
         2 . A system according to  claim 1 , wherein the at least one indicator is positioned in the user display at a corresponding position to the position of a test image in the subject display. 
     
     
         3 . A system according to  claim 1 , wherein one or more characteristics of the indicator are changeable so as to indicate to the user the present state of a test image in the subject display. 
     
     
         4 . A system according to  claim 3 , wherein the one or more characteristics include one or more selected from the group comprising: a shape of the indicator; and a colour of the indicator. 
     
     
         5 . A system according to  claim 3 , wherein a first characteristic of the indicator has a first value or state when a test image is about to be displayed to the test subject at an indicated location, the first characteristic changing to a second value or state after the test image has been displayed at the indicated location. 
     
     
         6 . A system according to  claim 1 , wherein the one or more processors are further arranged to use determination data as to whether the test subject has seen a test image when displayed on the subject video display, said determination data being recorded against the position of the test image when displayed on the subject video display, whereby to collate measurement data indicative of the peripheral vision field of the test subject. 
     
     
         7 . (canceled) 
     
     
         8 . A system according to  claim 1 , wherein the subject video display is arranged to display a fixation image to the test subject, in addition to the test images. 
     
     
         9 . A system according to  claim 8 , wherein the fixation image and test images are both video images, playback of at least part of the video content being substantially continuous from the fixation image to the test image. 
     
     
         10 . (canceled) 
     
     
         11 . A system according to  claim 6 , wherein if the determination data indicates that the test subject has not seen a first test image, an additional test image is subsequently shown to the test subject at a related position on the subject display closer to the test subject's line of sight. 
     
     
         12 . A system according to  claim 11 , wherein the related position at which the additional test image is displayed has substantially the same or similar rotational angular position as the first test image, and a smaller angular magnitude. 
     
     
         13 . A system according to  claim 11 , wherein at least one second test image at a different rotational angular position to the first test image is displayed to the user before the additional test image. 
     
     
         14 . A system according to  claim 6 , wherein multiple test images are shown to the test subject at different positions on the subject display and multiple determination data received relating to the multiple positions stored such that a set of peripheral vision test results is created, the system further comprising one or more storage media arranged to store the set(s) of test results, and from which the set(s) of test results can be retrieved for later viewing. 
     
     
         15 - 16 . (canceled) 
     
     
         17 . A system according to  claim 1 , and further comprising a graphical user interface to permit the user to define a set of test locations at which test images will be displayed to the test subject on the subject display device. 
     
     
         18 . A peripheral vision measurement system, comprising:
 a first display device arranged to display a fixation image to a test subject, and to intermittently display a plurality of test images; and   a processor arranged to collate data relating to whether the test subject saw a test image at a particular location on the first display device, whereby to measure the peripheral vision field of the test subject;   wherein the fixation image and the test images are video images, playback of at least part of the content of the video images being substantially continuous between the fixation image and the test images.   
     
     
         19 - 21 . (canceled) 
     
     
         22 . A peripheral vision measurement method, comprising:
 displaying test images to a test subject;   capturing images of the test subject;   displaying the captured images of the test subject to a user;   wherein the captured images of the test subject are augmented with at least one indicator relating to the position of a test image displayed or to be displayed to the test subject.   
     
     
         23 . A peripheral vision measurement method, comprising:
 displaying a fixation image to a test subject on a display device;   intermittently displaying a plurality of test images to the test subject; and   collating data relating to whether the test subject saw a test image at a particular location on the display device, whereby to measure the peripheral vision field of the test subject;   wherein the fixation image and the test images are video images, playback of at least part of the content of the video images being substantially continuous between the fixation image and the test images.   
     
     
         24 - 26 . (canceled)