In Update 21, this ability replaced Stealthy, which decreased your stealth detection radius and damage done while in stealth. It was likely changed to avoid confusion with the Bosmer of the same name, itself renamed to Hunter's Eye in the same patch.
Stealthy: Reduce detection radius by 3m and Increase damage from Stealth by 10% → Lunar Blessings: Increases your Max Health, Magicka, and Stamina by 825.