The VIVE Focus Vision, VIVE Focus 3, and VIVE XR Elite fully support Eye and Facial Tracking in both the PC VR and standalone versions of VRChat for avatars that support VRCFT.
This can be accomplished via a combination of VIVE Hub, and the VRCFT application configured to use the VIVE Streaming Face Tracking Module.
You can find a detailed step-by-step guide, along with links to all of the necessary resources in this tutorial on the VIVE Forum.