Which hard lens material is described as having the best wettability, the least deposits, and the least flexure?

Which hard lens material is described as having the best wettability, the least deposits, and the least flexure?

• A. PMMA
• B. SA
• C. FSA
• D. HEMA

Answer: (C)

Wettability, deposits, and flexure of hard lens materials hinge on surface energy and the polymer chemistry that governs tear-film interaction and how rigid the material is under eyelid forces. Fluorosilicone acrylate brings together fluorinated and silicone-derivative components that create a surface that promotes a stable tear film spread (better wettability) and resists tear-film protein and lipid buildup (fewer deposits). Its polymer network also provides good dimensional stability, meaning the lens tends to resist bending or flexing under eyelid forces (least flexure) compared with other hard materials. PMMA is very rigid with poor surface properties for tear film and tends to deposit more; conventional silicone acrylates (SA) are more prone to deposits and surface instability despite high oxygen permeability; HEMA is a soft material not classified as a hard lens, so it doesn’t fit the same category. This combination makes fluorosilicone acrylate the best choice for the properties described.

Wettability, deposits, and flexure of hard lens materials hinge on surface energy and the polymer chemistry that governs tear-film interaction and how rigid the material is under eyelid forces. Fluorosilicone acrylate brings together fluorinated and silicone-derivative components that create a surface that promotes a stable tear film spread (better wettability) and resists tear-film protein and lipid buildup (fewer deposits). Its polymer network also provides good dimensional stability, meaning the lens tends to resist bending or flexing under eyelid forces (least flexure) compared with other hard materials.

PMMA is very rigid with poor surface properties for tear film and tends to deposit more; conventional silicone acrylates (SA) are more prone to deposits and surface instability despite high oxygen permeability; HEMA is a soft material not classified as a hard lens, so it doesn’t fit the same category. This combination makes fluorosilicone acrylate the best choice for the properties described.