Gas Permeable Contact Lenses Practice Test 2026 – Comprehensive Guide for Fitting, Care, and Patient Education

A flat GP lens often sits high on the cornea with insufficient peripheral alignment, so the edge lacks stable engagement. Increasing the outer optic diameter enlarges the contact area around the eye, letting the edge sit on a more stable scleral region and improving centration and lid interaction. This reduces excessive movement and center-to-edge mismatch that come from a lens that’s too flat. Making the diameter smaller would worsen edge engagement and stability, so the best adjustment is to use a larger diameter.