To increase tear exchange on a RGP lens, which action is recommended?

To increase tear exchange with a rigid gas permeable (RGP) lens, flattening the peripheral curve is recommended because it creates a better fit on the eye's surface, allowing for more movement during blinking. This movement is crucial because it facilitates the circulation of tears under the lens, enhancing the exchange of tears between the lens and the eye.

When the peripheral curve is flattened, the lens is able to rest less tightly against the cornea, which promotes this movement and improves tear exchange. Consequently, this leads to increased comfort for the wearer and improved ocular health.

Thickening the peripheral curve would generally create a tighter fit, which could limit lens movement and reduce tear exchange. Increasing the lens diameter might improve lens stability but doesn’t necessarily enhance tear exchange directly. Changing to a softer material could affect other factors like comfort and tear exchange in different ways, but it does not specifically address the mechanics of lens movement across the eye, which is essential for optimal tear interchange.