The material of soft lens ?
Types of contact lenses- Depending upon the nature of the material used in their manufacturing, the contact lenses can be divided into three types:- Hard lenses: Made of polymethylmethacrylate (PMMA) Rigid gas permeable (PGR) lenses:- Copolymer of PMMA, silicon-containing vinyl monomer and cellulose acetate butyrate (CAB) are used to manufacture RGP lenses Soft lenses:- These are made up of hydroxymethyl methacrylate (HEMA). Reference : AK Khurana Comprehensive Ophthalmology, 6th edition, pg no. 208 - 209
Polymethylmethacrylate
Hydroxymethylmethacrylate
Silicon
Cellulose acetate Butyrate
Optics and refraction