What type of astigmatism can RGPs correct for?

Rigid Gas Permeable (RGP) contact lenses are known for their ability to correct various types of astigmatism due to their firm, structured design that helps to reshape the cornea effectively. RGP lenses can provide optimal vision correction for individuals with both With-the-Rule (WTR) and Against-the-Rule (ATR) astigmatism.

In the case of ATR astigmatism, RGPs can correct up to 2 diopters effectively. This is largely due to the lens's ability to maintain a stable position on the eye, which is crucial for those with higher degrees of astigmatism. For WTR astigmatism, RGPs can correct up to 3 diopters, taking advantage of the lens’s ability to provide a sharper and more defined vision correction by aligning with the steepest axis of the cornea.

Therefore, the option indicating that RGPs can correct both up to 2 diopters of ATR astigmatism and up to 3 diopters of WTR astigmatism is accurate. This means that RGPs are versatile and effective for astigmatism corrections that fall within these specified ranges, which supports the selection of the combined answer