[Solved] Tobii EyeX measure pupil

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    Hi, I am using Tobii EyeX and I wanted to measure pupil diameter. Is this possible with this Tobii device?


    Thank you for your reply. What about tobii REX? Does it give any information about the pupil?

    Grant [Tobii]

    Hi @fk22, I am afraid that neither the REX, EyeX or C4 products have the pupil size exposed using the Gaze Interaction SDK.

    If you require to measure pupil size, you will need to request a special licence to use the Tobii Pro SDK in conjunction with your eye tracker.

    Further information is available @ http://developer.tobii.com/tobii-sdk-guide/


    Thank you for your reply. Now I am using Tobii EyeX and I wanted to extract the number of blinks. Is there any way to do that? Right now I am getting the gaze points (x,y) on the screen.


    I can use MinimalGazeDataStream for get fixations but when I try to install the EyeX.Framework in visual studion it says:

    Could not install package ‘Tobii.EyeX.Framework 1.8.503’. You are trying to install this package into a project that targets ‘.NETFramework,Version=v3.5,Profile=Unity Full v3.5’, but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.

    What can be the use? How can I change the framework?

    Grant [Tobii]

    Hi @fk22, If you are just getting started in using the eye tracker and the EyeX SDK then I suggest you may find it simpler to get up and running with the new Tobii Core SDK which not only contain a number of different samples which may be useful to you, but also provides support for the NuGet package installer to make running your first samples quickly.
    You can find further information online @ https://tobii.github.io/CoreSDK/articles/getting_started.html

    There is no function straight out of the box that logs the number of blinks during tracking however you do of course have access to the Gaze data stream and could measure period for which no tracking was recorded.. however you would need to consider this might also be as a result of the user looking away from the screen or environmental factors. A degree of of filtering based upon duration of data loss would be necessary.

    However, please bear in mind that if you intended to store the gaze data for analytic or scientific usage, this would again necessitate the acquisition of a special Tobii Pro licence to do so.

    Alex [Tobii]

    I’m affraid the only option for Unity is Tobii Unity SDK. We also don’t recommend using blinking as control input, since human eyes get tired very fast from intentional blinking.

    Currently the only way to get information sbout eye openness in Tobii Unity SDK is to check IsRecent on GazePoint.


    Hi @Fjorda, Did you get pupil diameter?
    I used VRGazeData script and found the diameter.
    PupilDiameter = eye.Pupil.PupilDiameter / 1000f;
    PupilDiameterValid = eye.Pupil.Validity.Valid();

    eye.Pupil.PupilDiameter = 2.572433 mm
    So, I got 2.572433 mm diameter of my eye.

    Simon Smith

    Can someone please tell me:

    a) What is required to get the pupil diameter using a Tobii 4C, regarding licence, SDK’s, etc.
    b) Where is any sample code that does this?



    I join the question. What about it?

    Grant [Tobii]

    Hi @simonsmith, the pupil size and separate eye gaze streams are advanced metrics which are only available with the Tobii Pro SDK

    In order to use the Tobii Pro SDK with the 4C Tracker you must purchase a Research development license.

    To obtain a quote, please get in touch with the licencing team @ https://developer.tobii.com/license-agreement/contact/

    Best Wishes.

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