Certified Paraoptometric (CPO) Practice Exam 2025

What type of lenses correct vision at three different distances, including intermediate?

1. Single vision lenses

2. Bifocal lenses

3. Trifocal lenses

4. Spherical lenses

The correct answer is: Trifocal lenses

The type of lenses that correct vision at three different distances, including intermediate distance, is trifocal lenses. Trifocal lenses are specifically designed to have three distinct optical zones to assist with vision at close range (for reading), intermediate distance (such as computer work), and distance vision (such as looking at objects far away). The use of trifocal lenses allows individuals to seamlessly transition between these various distances without needing to change glasses. In contrast, single vision lenses are designed for one specific distance, whether it be for near or distance vision. Bifocal lenses have only two segments—one for near and one for distance vision, without an intermediate zone. Spherical lenses refer to a specific type of lens shape rather than a progression of vision correction, and they can be single vision or multifocal, but do not specifically address three distances like trifocal lenses do.