Which condition would most likely increase lens flexure?

Which condition would most likely increase lens flexure?

• A. Decreased center thickness
• B. Increased center thickness
• C. Higher Dk material
• D. Plus power reduces edge thickness

Answer: (A)

Flexure happens when the eyelids bend a contact lens during blinking. The amount a GP lens flexes mainly depends on how stiff the lens is, which is largely set by its center thickness. A thinner center means there’s less material to resist bending, so the lens will flex more under the same eyelid pressure. In contrast, a thicker center makes the lens stiffer and reduces flexure. The material’s Dk value (how permeable it is to oxygen) doesn’t directly change how easily the lens bends. Plus power or edge thickness aren’t the primary factors that determine how much the lens will flex under lid pressure. Therefore, decreasing center thickness would most likely increase lens flexure.

Flexure happens when the eyelids bend a contact lens during blinking. The amount a GP lens flexes mainly depends on how stiff the lens is, which is largely set by its center thickness. A thinner center means there’s less material to resist bending, so the lens will flex more under the same eyelid pressure. In contrast, a thicker center makes the lens stiffer and reduces flexure. The material’s Dk value (how permeable it is to oxygen) doesn’t directly change how easily the lens bends. Plus power or edge thickness aren’t the primary factors that determine how much the lens will flex under lid pressure. Therefore, decreasing center thickness would most likely increase lens flexure.