What is a sign of excessive movement in a rigid gas permeable (RGP) lens?

Excessive edge lift in a rigid gas permeable (RGP) lens indicates that the lens is moving too much on the surface of the eye. This heightened movement can cause various issues, including decreased stability of the lens and potentially leading to discomfort, fluctuating vision, and inadequate tear film exchange.

When the edge of the lens lifts too much, it can create a gap between the lens and the cornea, which might disrupt the optimal fit and the intended tear exchange that is crucial for keeping the eye healthy. This movement can also affect how the lens interacts with the tear film, leading to a greater risk of lens dislocation or discomfort during wear.

In contrast, increased clarity of vision, reduced tear exchange, and improved comfort levels would typically suggest that the lens is fitting well and performing as intended, reflecting proper stability and minimal movement. Thus, excessive edge lift serves as a clear indicator of improper lens fit or excessive movement, making it the correct indication of an issue in this context.