Certified Paraoptometric (CPO) Practice Exam 2025

Which lens type typically has powers for viewing at two distances?

1. Trifocal lenses

2. Multi-focal lenses

3. Spherocylindrical lenses

4. Bifocal lenses

The correct answer is: Bifocal lenses

Bifocal lenses are specifically designed to provide clear vision at two distinct distances, typically for both near and far viewing. They achieve this by incorporating two different optical powers within a single lens. The upper portion of the lens is generally for distance vision, while the lower segment is for near vision, which aids individuals who are experiencing presbyopia—a common condition that affects the ability to focus on close objects as one ages. Trifocal lenses, on the other hand, offer three different viewing distances, as they are divided into sections for near, intermediate, and distance vision. While multi-focal lenses can include designs similar to bifocals and trifocals, their terminology is broader and does not specifically designate two distances like bifocals do. Spherocylindrical lenses are designed to correct for both spherical and cylindrical errors in vision but do not focus on providing multiple viewing distances. Therefore, bifocal lenses are the correct answer as they fulfill the requirement of having power options for two specific distances.