Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Chemical structure of representative monomers for the preparation of contact lenses. Monomers mainly used in PHEMA-based hydrogel contact lenses are shown with a blue background, and typical monomers used in silicone hydrogel-based contact lenses are shown with a yellow background. Hydrophilic monomers used in both contact lenses are shown in yellow blocks.
