When analyzing a gas-permeable lens, you measure base curves of 7.58 and 7.84 with a radarscope, and -1.00 and -2.50 on lensometry. What type of toric gas-permeable contact lens design do you have?

The correct answer is a spherical power effect (SPE) bitoric design. In this context, the measured base curves of 7.58 and 7.84 indicate that the lens has two different base curves, which is typical for a toric lens designed to correct for corneal astigmatism. The lensometry measurements of -1.00 and -2.50 suggest that there are two different cylindrical powers incorporated into the lens, aligning with the bitoric design concept.

A spherical power effect bitoric lens is designed to incorporate both the front and back surface curvatures, allowing for the correction of astigmatism at both surfaces effectively. In this case, the lens's behavior aligns with the profile of an SPE bitoric, where the toricity is imparted primarily through the base curves to manage spherical equivalent in a manner that generates different powers depending on orientation.

This is distinct from the other options. A back surface (base curve) toric lens would typically have a single curved back surface for correction without the need for multiple powers, while a front surface toric lens emphasizes the curvature on the front, potentially leading to different optical characteristics. The cylinder power effect (CPE) bitoric would