What can cause an RGP lens to displace?

A flat fit of a rigid gas permeable (RGP) lens can lead to displacement because the lens does not align properly with the curvature of the cornea. When the fit is too flat, the lens lacks adequate support and centration on the cornea, causing it to move around more freely than it should. This movement can result in the lens displacing from the ideal position, leading to discomfort, visual disturbances, and potential damage to the corneal surface.

In contrast, a steep fit typically creates better centration and stability as the lens conforms more closely to the cornea's shape. An excessively loose parameter can also contribute to movement, but this would generally result from an improper sizing rather than the lens fitting process itself. High refractive power typically does not correlate with lens displacement; rather, it influences the optical correction and might even affect the thickness and overall weight of the lens, but not the fit in terms of displacement.