Change Slider Value(for volume) in VR using gaze interaction

Hi guys. I have a slider that changes the volume of an audio but right now I still have to drag the handle of the slider so the value will change. That is not how I want it to be because the VR app I'm developing relies fully on gaze interaction with timer and no clicking. So, what I want to happen is that when I gaze in a specific point in the slider the value will be set to that point. Just like how the Play button for example plays when the gaze timer is up. I hope what I'm asking is possible. Thank you. All help will be really appreciated.