What factor can suggest a poor lens fit during a fitting?

Excessive movement of the lens during blinking is a key indicator of a poor lens fit. When a contact lens moves too much on the eye, it suggests that the lens is either too loose or not adequately stabilized on the cornea. Ideally, a well-fitting lens should have minimal movement, allowing it to stay in place while still enabling natural movement and blinking. An excessive amount of movement can lead to discomfort or irritation, as the lens may not maintain proper alignment with the eye. Additionally, significant movement can affect vision clarity and increase the likelihood of lens displacement or even loss from the eye.

While comfort after insertion plays a significant role in the wearability of the lens, it does not effectively indicate fit in the way that movement does. Corneal curvature is also an important factor in lens fitting; however, it serves more to guide the selection of appropriate lens parameters rather than directly indicating fit quality. The thickness of the lens material influences the lens's overall performance and comfort, but again, it is not a direct measure of how well the lens sits on the eye.

Thus, observing lens movement is a critical aspect of evaluating fit, making it the most indicative factor in this context.