Soft contact lens is made up of
B i.e. HEMA Types of Contact Lens Hard Gas permeable (Rigid or semisoft) Soft Made of PMMA (poly methyl metha acrylate) Q Copolymer of PMMA, silicon containing vinyl monomer and cellulose acetate butyrate (CAB) HEMA (hydro? xy methyl metha acrylate) Q Oxygen delivery Poor Moderate to high High Deposits Few Few More Visual clarity Good Clear Need to refocus after a blink Use in astigmatism Possible Possible Less suitable Adaptation Required Required Not required Durability May scratch Do not scratch or tear Tear
PMMA
HEMA
Glass
Silicone