What type of contact lens adjustment could correct a situation where the lens is not providing adequate vision due to fitting?

A proper fit of a contact lens is crucial for optimal vision and comfort. If a lens is not providing adequate vision, one common adjustment that can lead to improvements is altering the base curve. The base curve is the curvature of the back surface of the lens that conforms to the shape of the cornea. Adjusting the base curve can help ensure that the lens sits appropriately on the eye, which is essential for correct positioning over the visual axis and for promoting proper tear exchange under the lens.

When the base curve is too steep or too flat relative to the shape of the cornea, it can lead to unclear vision or discomfort. By making an adjustment to the base curve, the lens can achieve a better fit, allowing for optimal alignment with the cornea and thereby enhancing visual acuity.

In contrast, changing the lens material or altering the color of the lens does not directly address the physical fit on the eye, nor does it typically provide a solution for vision clarity related to fitting issues. Increasing the lens diameter can contribute to better centration or cover larger areas of the cornea but may not necessarily resolve the vision problem related to an inadequate fit in terms of curvature.