Question

Which of the following could cause a patient's rigid contact lens to displace frequently and pop out without cause?

1) excessive posterior peripheral curve
2) insufficient peripheral curve
3) steep base curve relationship
4) flat base curve relationship

Answer 1

A patient's rigid contact lens may frequently displace or pop out if there is a flat base curve relationship, meaning the base curve of the lens is too flat compared to the cornea's curvature.

Step-by-step explanation:

If a patient's rigid contact lens is frequently displacing and popping out, the likely cause could be a flat base curve relationship. A properly fitting contact lens is essential for comfort and visual clarity. If the base curve of the lens is too flat compared to the curvature of the cornea, the lens may not adhere well to the eye's surface, causing it to pop out easily. Conversely, a steep base curve would fit too tightly and could cause discomfort but wouldn't typically lead to the lens popping out. The base curve must be selected to match the curvature of the cornea tightly enough to stay in place but not so tight as to cause discomfort or restrict oxygen to the cornea.