Which factor increases decentration in GP lenses?

Which factor increases decentration in GP lenses?

• A. Higher center thickness
• B. Lower center thickness
• C. Same center thickness
• D. Increased edge thickness only

Answer: (A)

Center thickness controls how heavy the GP lens is. A thicker center adds more mass, so gravity and the way the eyelids press against the lens during blinking can pull the optic zone away from the pupil, leading to decentration. Reducing center thickness lowers that weight and helps keep the lens centered. Changing only the edge thickness mainly affects edge contour and lid interaction rather than the overall lens weight, so it doesn’t drive decentration as much. So, the factor that increases decentration is a higher center thickness.

Center thickness controls how heavy the GP lens is. A thicker center adds more mass, so gravity and the way the eyelids press against the lens during blinking can pull the optic zone away from the pupil, leading to decentration. Reducing center thickness lowers that weight and helps keep the lens centered. Changing only the edge thickness mainly affects edge contour and lid interaction rather than the overall lens weight, so it doesn’t drive decentration as much. So, the factor that increases decentration is a higher center thickness.