Which of the following modifications can enhance tear exchange on an RGP lens?

Enhancing tear exchange on a rigid gas permeable (RGP) lens involves strategies that optimize the interaction between the lens and the tear film. Rounding the optic zone edges is an effective modification because it promotes smoother contact between the lens and the cornea, facilitating a better movement of tears underneath the lens. This rounded edge minimizes the risk of edge trauma to the cornea and allows a more effective flow of tears into and out of the lens, promoting optimal tear exchange.

When the edges are rounded, it creates a more fluid interface that can help in managing the tear film dynamics, ensuring that fresh tears can replenish under the lens while allowing for the removal of any trapped debris or older tears. This is essential for maintaining eye health and comfort for the wearer.

The other options do not contribute effectively to tear exchange. Thickening the lens material may actually limit flexibility and movement, potentially reducing tear exchange. Reducing the overall lens diameter can restrict the area through which tears can flow, while increasing the steepness of the peripheral curves can also result in a tighter fit, which may hinder the necessary tear exchange that keeps the lens comfortable and the cornea healthy.