When a GP lens is judged to be too flat, which base-curve adjustment is recommended?

When a GP lens is judged to be too flat, which base-curve adjustment is recommended?

• A. Steepen
• B. Flatten
• C. No change
• D. Switch to toric

Answer: (A)

When a GP lens is too flat, the suggested adjustment is to steepen the base curve. A flatter posterior surface sits higher on the cornea and tends to move more and decenter. By steepening the base curve (making the lens curvature tighter, i.e., a smaller radius), the lens grips the cornea more snugly, improving centration and reducing excessive movement. Flattening would loosen the fit and worsen movement, while no change won’t fix it; switching to a toric design addresses corneal astigmatism rather than a flat-fit issue unless toricity specifically necessitates a toric GP, which is a separate consideration.

When a GP lens is too flat, the suggested adjustment is to steepen the base curve. A flatter posterior surface sits higher on the cornea and tends to move more and decenter. By steepening the base curve (making the lens curvature tighter, i.e., a smaller radius), the lens grips the cornea more snugly, improving centration and reducing excessive movement. Flattening would loosen the fit and worsen movement, while no change won’t fix it; switching to a toric design addresses corneal astigmatism rather than a flat-fit issue unless toricity specifically necessitates a toric GP, which is a separate consideration.