Which fitting approach increases the first-fit success of GP lenses when used with empirical fitting?

• A. Trial-and-error without topography
• B. Scleral lens fitting
• C. Topographical fitting
• D. No fitting technology

Answer: (C)

Topographical fitting leverages a detailed map of the cornea’s shape to tailor GP lens design. In empirical fitting, the lens parameters—especially base curve radius, diameter, and peripheral geometry—are predicted from measured data. When you have corneal topography, you can match the lens more precisely to the eye’s curvature across meridians and any asphericity, leading to better initial alignment, stable tear lens formation, and centration. This close initial match makes the first lens more likely to fit well and require fewer adjustments. Without topography, fitting relies on limited measurements and more trial-and-error, which lowers the chances of a good first fit. Scleral-fitting is a different approach and, while useful in other contexts, does not address GP first-fit success in the same way as topographic data does.