Eye tracking

[GlebDvornikov]

 Can you please tell me if anyone knows the answers to the eye tracking capabilities on the Vive Pro 2 and Vive Focus 3 helmets? I'm interested in:

1. Is there some kind of API or some kind of software capability with these devices to measure the size of the eye pupil as well as track its direction?

2. Is there some program or API that will allow us to pull this data, also wondering if it is even possible to pull this data and in what form it will be pulled?

3. Is there some program or API that will allow us to record somewhere or track eye tracking parameters (pupil size and eye direction) and maybe some more) simultaneously, more precisely, while the application (game) is running, and then, accordingly, somehow pull out this data in some form. 
To be more specific, I would like to understand if there is a possibility to record and subsequently extract the above data while playing a roller coaster game in order to check and analyze a person's stress state.