Which portion of the edge is in contact with the upper lid during the blink cycle?

The anterior zone of a contact lens is the portion that comes into contact with the upper lid during the blink cycle. This part is designed to interact with the eyelid as it moves over the lens, providing a smooth surface that contributes to the overall comfort of wearing contact lenses. The anterior zone's curvature helps facilitate proper movement against the eyelid, minimizing friction and preventing discomfort that could arise from lens interaction during blinking.

In the context of contact lens design, different zones serve distinct purposes. The edge apex, while part of the lens structure, does not play a direct role in contact with the eyelid. The posterior zone is more involved with the fit of the lens on the cornea and the relationship with the tear film, rather than with the upper lid during a blink. Hence, understanding these characteristics affirms why the anterior zone specifically is the correct answer, as it is crucial for ensuring a comfortable and functional lens wear experience.