How does the shape of the cornea influence the fitting of lenses?

The shape of the cornea plays a crucial role in how contact lenses fit on the eye. A well-fitted lens should conform closely to the surface of the cornea to provide optimal vision and comfort. If the cornea has an irregular shape, such as in conditions like keratoconus, the lens may not fit properly, leading to discomfort and visual distortions.

When fitting lenses, the curvature of the cornea is measured, and the lens selected must have a compatible curvature to ensure that it aligns correctly with the eye's surface. This alignment is vital for distributing pressure evenly across the cornea and maintaining a stable position of the lens during blinking and eye movement. Thus, the fitting process is highly influenced by the contour of the cornea, ensuring that the lens not only rests appropriately but also functions effectively for the wearer.

The other choices do not accurately relate to how the corneal shape directly affects lens fitting. For example, while lens thickness is important for fitting, it is not directly regulated by corneal shape. Similarly, color perception and moisture retention are influenced by other factors and are not primary considerations in lens fitting related to the shape of the cornea.