What is the most likely cause for a well-fitting hydrogel lens being repeatedly ejected from the eye?

The most likely cause for a well-fitting hydrogel lens being repeatedly ejected from the eye is lens eversion. When a hydrogel lens eversion occurs, the outer edge or perimeter of the lens flips or turns inside out, preventing it from maintaining its proper position on the cornea. This can happen due to various physical factors, such as the orientation of the lens, the interplay of the lens's curvature with the eye's shape, or improper handling during insertion.

Even a lens that fits well can experience this if there are dynamics in the eyelid movements or if the lens is insufficiently stabilized, leading to an improper fit during blinking. When the lens eversion happens, it can easily be dislodged from the eye by the pressure from the eyelids, resulting in repeated ejections.

The other options could relate to potential issues with contact lens performance but do not directly cause consistent ejection. For example, while a low Dk value might influence oxygen transmission and comfort, it wouldn’t primarily lead to ejection. A high water content could impact lens handling and stability, but it wouldn’t typically cause eversion. A thin lens edge generally aids in comfort and fitting, rather than contributing to dislodgement.