When the PlayStation®4 Pro launches on November 10th, you'll be able to play ESO immediately in native 4K resolution! If you play ESO on PlayStation®4 Pro with a 1080p HD television, you will experience increased graphical fidelity; if you use a 4K monitor, the game will automatically run in 4K.
Tried it yesterday and i can't see any improvement. Maybe it isn't included in the last Patch? Also there are also no additional Options in the Video-Settings Menu.