An anterior center of gravity in a GP lens tends to cause which effect on lens position?

• A. Superior decentration
• B. Inferior decentration
• C. No effect on position
• D. Improved centration

Answer: (B)

Gravity interacts with how weight is distributed in a GP lens. When the center of gravity is located toward the front of the lens (anterior), the gravitational pull creates a moment that makes the heavier front portion press toward the lower lid side. Since gravity acts downward relative to the eye, this causes the lens to settle toward the inferior part of the cornea, producing inferior decentration. In contrast, balanced or posterior-weighted lenses would behave differently, and a lens with no effect on position would not explain this downward shift. So the anteriorly weighted GP lens tends to sit more toward the bottom of the cornea.