Certified Paraoptometric (CPO) Practice Exam 2025

What are "plus lenses" commonly referred to?

1. Concave lenses

2. Convex lenses

3. Flat lenses

4. Aspheric lenses

The correct answer is: Convex lenses

Plus lenses are commonly referred to as convex lenses. This is because plus lenses are designed to converge light rays that pass through them, creating a point of focus for objects that are positioned at varying distances. They are often used to correct hyperopia (farsightedness) and help individuals focus on near objects more effectively. Concave lenses, the first option, diverge light rays and are used to correct myopia (nearsightedness). Flat lenses do not alter the path of light and are typically not used for corrective purposes in vision. Aspheric lenses refer to a specific lens design that reduces distortion and provides a slimmer profile, but they can be either convex or concave. Therefore, when referring to "plus lenses," the correct term is convex lenses, highlighting their ability to magnify images and bring them into focus.