Medical devices having homogeneous charge density and methods for making same

A silicone hydrogel formed from a reactive mixture comprising

• major polymerizable components comprising at least one reactive silicone-containing component, at least one reactive ionic monomer, optional reactive hydrophilic components and crosslinker;
• and
• minor polymerizable components selected from the group consisting of visibility tint and dyes, UV absorbers, photochromic compounds, and mixtures thereof;
• wherein said major polymerizable components comprise a single reactive functionality selected from the group consisting of acrylate, methacrylate, acrylamide, and methacrylamide;
• and wherein any polymerizable components in the reaction mixture which have a reactive functionality different than said single reactive functionality are present in a concentration less than 0.5 mol %.