A set of methods and measurement techniques, used in recording and analysing data on the position and movement of the eyeballs. It is a technology that gives the user the opportunity to interact with the computer as well as with the environment, by means of the eyes. Eye tracking offers the possibility to track those points on the computer screen which the user is looking at.
Eye movements as a tool of communication with the patient
In situations where the patient remains immobilized and is unable to communicate with the environment by speech or gestures, their only available form of contact is the movement of the eyeballs. It is therefore safe to say that in such cases eye tracking opens patients to the world, giving them an opportunity to interact with the environment. On the one hand, it is a very important way of signalling their needs, and on the other hand it is an opportunity to benefit from therapy. Doing exercises with the use of one’s eyes is an excellent form of rehabilitation of important connections in the brain, which in the long run positively affects the patients’ ability to concentrate, as well as their memory and emotions.
What are the functions of eye tracking?
- Tracking the visual activity of the patient
A possibility to check what point of the screen the patient is focusingon. Analysis of all reactions of the patient to the presented visual or visual-auditory stimuli.
- Visual interaction with the device
The patients have the possibility to control the computer by selecting specific, interesting items on the screen using their eyes. These could be text messages, pictograms or letters on a virtual keyboard.
Diagnosis and therapy of eye disorders
Testing for a limited visual field
One of the basic possibilities that eye tracking offers is investigating whether the patient’s visual field covers the whole surface of the screen or if it is limited to a specific area (for example, only the left side of the screen). The ability to move and fixate the eyes is assessed. A visual stimulus is displayed in different areas of the screen and the task of the patient is to focus on it. While the patient is performing this task, it is possible to examine whether they are able to move their eyes in the direction of the stimulus displayed at various points on the screen and then to focus on it. By means of this simple test it is possible to determine the limitations of the visual field.
In case hemispatial neglect is diagnosed, it is possible to propose appropriate exercises that enforce ocusing on the stimuli outside the visual field. Regular exercises can lead to widening of the visual field. “Even if saccadic eye movements – that is moving the eye from one point of a relatively stable visual scene to another – are disturbed, they can be improved by means of training.”(O`Shea, 2012).
Picture 1. Visual field test – focusing on a visual stimulus (here: a lightbulb)
Picture 2. Test result: vision limited on the right side by 40%
Picture 3. Test result after 3 weeks: rehabilitation progress, vision limited by 20%
Testing the control of visual focus
People who have suffered brain damage often have difficulty in focusing their eyes on a chosen area. This does not mean, however, that they cannot use eye tracking to communicate with the world. On the contrary. With dedicated exercises, they can practice the ability to focus their eyes on a limited area, so that finally they can willfully choose the content displayed on the screen – messages, pictures, letters, numbers, etc.
Picture 4. Testing and practicing visual focus on 2 areas
Picture 5. Testing and practicing visual focus on 4 areas
Picture 6. Testing and practicing visual focus on 6 areas
Testing the patient's consciousness and determining the direction of rehabilitation
Neurorehabilitation is a chance for many patients
It is known that damaged nerve cells unfortunatelycannot be repaired. Fortunately, however, there are other mechanisms in the human brain which make itpossible to significantly improve the condition. Professionals who deal with the therapy of such patients know that this is in line with Gerald Edelman’s theory of neural Darwinism (Jonkisz, 2009). It is important that the family of a patient with whom contact by means of speech or gestures is impossible know that the sooner the neurorehabilitation process begins, the greater the chance of sustaining the best possible brain function of the patient. This is possible thanks to the C-Eye® system.
Rehabilitation with C-Eye®
C-Eye® is a very important tool enabling relatives to communicate with patients who have lost the normal ability to signal their needs and wishes due to illness. Thanks to our carefully designed and tested method of visual stimulation, the most important aspects of human existence are supported. These include memory, perception, emotional expression and signalling of needs. In using C-Eye® we give our loved ones a chance to live a dignified life despite the disease, and the training helps to save the connections in the brain which are crucial for non-verbal communication, as well as to activate new ones. It is therefore an excellent form of rehabilitation for the damaged brain and at the same time of contact with the loved ones. It’s a therapy that equalizes opportunities.
Picture 7. Cognition therapy: classifying objects
Picture 8. Speech therapy: understanding words (here: nouns)
Picture 9. Visual-spatial therapy: finding differences between pictures