Regarding the Confidence property of OVREyeGaze

Hello, I am currently trying out eye tracking on the MetaQuest Pro.

I want to exclude data when my eyes are closed, so I thought of using the Confidence property of OVREyeGaze, but the value doesn't change at all.

I thought it would vary depending on the progress of the tracking, is that not the case?

I've added Debug.Log to OVREyeGaze.The value in the log remained constant.

private void Update()
{
    if (!OVRPlugin.GetEyeGazesState(OVRPlugin.Step.Render, -1, ref _currentEyeGazesState))
        return;

    var eyeGaze = _currentEyeGazesState.EyeGazes[(int)Eye];

    if (!eyeGaze.IsValid)
        return;

    Confidence = eyeGaze.Confidence;

    // ConfidenceLog
    Debug.Log($"Eye Tracking Confidence: {Confidence}");

    if (Confidence < ConfidenceThreshold)
        return;

    //~~~~~
}