Which statement is NOT true regarding a GP lens with a thin central thickness?

• A. It has greater oxygen transmission
• B. It has better centration
• C. It is better at reducing flexure
• D. It tends to drop inferiorly on the eye

Answer: (C)

Thin central thickness makes a GP lens lighter and more flexible, which changes how it sits on the eye and responds to eyelid pressure and gravity. Because the center is thinner, oxygen has a shorter path to reach the cornea, so oxygen transmission is improved. A lighter, less bulky center also means the lens can settle more readily with the eyelids, which often helps it align closer to the visual axis, improving centration. However, the idea that a thin center reduces flexure isn’t correct—thinner, less rigid lenses flex more under eyelid and corneal forces, not less. This increased flexure can contribute to less stable positioning and is a reason why the statement about reducing flexure is not true. The thinner center can also be influenced by lid dynamics and gravity in a way that tends to promote inferior decentration, so that tendency is consistent with thinner centers.