The outermost surface composition of 11 silicone hydrogel (SiHy) lenses was measured using X-ray photoelectron spectroscopy (XPS) to understand differences in wettability and potential interactions within an ocular environment. The SiHy lenses tested included balafilcon A, lotrafilcon A, lotrafilcon B, senofilcon A, comfilcon A, and somofilcon A reusable 2-week or monthly replacement lenses and delefilcon A, samfilcon A, narafilcon A, stenfilcon A, and somofilcon A daily disposable lenses.