Which statement best describes the relation between central thickness and flexure in GP lenses?

Which statement best describes the relation between central thickness and flexure in GP lenses?

• A. Thin central thickness is associated with more flexure
• B. Thin central thickness is associated with less flexure
• C. Central thickness does not affect flexure
• D. Flexure depends only on material and is independent of thickness

Answer: (A)

Flexure in GP lenses is about how easily the lens bends under eyelid pressure and tear-film forces. The rigidity of a lens comes from its geometry and the material; for a given material, increasing the central thickness makes the lens stiffer (bending stiffness rises sharply with thickness), so it resists bending more. Conversely, thinning the center reduces rigidity, allowing more deformation. Since central thickness directly changes how much the lens can bend under the same forces, a thinner center leads to more flexure. So the best statement is that a thin central thickness is associated with more flexure. The idea that thickness doesn’t matter or that only the material controls flexure isn’t accurate because geometry (thickness) has a strong influence on bending behavior.

Flexure in GP lenses is about how easily the lens bends under eyelid pressure and tear-film forces. The rigidity of a lens comes from its geometry and the material; for a given material, increasing the central thickness makes the lens stiffer (bending stiffness rises sharply with thickness), so it resists bending more. Conversely, thinning the center reduces rigidity, allowing more deformation. Since central thickness directly changes how much the lens can bend under the same forces, a thinner center leads to more flexure.

So the best statement is that a thin central thickness is associated with more flexure. The idea that thickness doesn’t matter or that only the material controls flexure isn’t accurate because geometry (thickness) has a strong influence on bending behavior.