Illinois Vision Certification Practice Test

Which lens type is utilized to correct astigmatism?

1. Convex lenses

2. Concave lenses

3. Cylindrical lenses

4. Multifocal lenses

The correct answer is: Cylindrical lenses

Cylindrical lenses are specifically designed to correct astigmatism, which is a common refractive error caused by an irregular shape of the cornea or lens. In a healthy eye, the cornea is symmetrically curved, allowing light to focus evenly on the retina. However, in astigmatism, the curvature is more pronounced in one direction than another, leading to blurry or distorted vision. Cylindrical lenses have different optical powers in different orientations, allowing them to counteract the uneven curvature of the cornea. By using these lenses, light is focused properly onto the retina, effectively correcting the vision problem associated with astigmatism. Other lens types, such as convex, concave, and multifocal lenses, serve different purposes. Convex and concave lenses correct nearsightedness and farsightedness, respectively, while multifocal lenses are designed for people who need correction for both distance and near vision. Therefore, cylindrical lenses are the unique solution for addressing the specific challenges posed by astigmatism.