If a prescription has a cylinder value of +1.50, what effect does this have on the lens?

A cylinder value in a prescription refers to the amount of astigmatism correction required. When a lens has a cylinder value of +1.50, it indicates that the lens is designed to correct astigmatism by compensating for the uneven curvature of the cornea or lens in the eye. Astigmatism occurs when light entering the eye is focused at different points, leading to blurred or distorted vision.

The presence of the cylinder value in the prescription denotes that the lens must be shaped in a specific way to ensure that light is focused correctly onto the retina, addressing the varying refractive powers in different meridians of the eye. Therefore, a cylinder value like +1.50 specifically targets the astigmatic component of the vision, making the correction of astigmatism the primary purpose of this cylinder power.