Correct lens fitting for keratoconus

What should a lens fitted for keratoconus do?

A lens fitted for keratoconus should:

a. Flatten the apex

b. Ride high

c. Align the apex

d. Ride low

Answer:

A lens fitted for keratoconus should align the apex of the cornea and not change its shape or position.

Explanation:

In the context of fitting a lens for keratoconus, the objective is to align the apex of the cornea with the lens, not to alter the shape or position of the cornea. Keratoconus is a condition that causes the cornea to thin and bulge into a cone shape, resulting in impaired vision. Prescription contact lenses for this condition are usually converging lenses, as these lenses can reshape the incoming light and align it with the apex of the cone-shaped cornea, making images much clearer.

Concave lenses, on the other hand, would be ineffective as they would scatter the light even more, exacerbating the vision issues caused by keratoconus.