Certified Paraoptometric (CPO) Practice Exam 2025

What type of lens design allows for correction at three different distances?

1. Bifocal

2. Monofocal

3. Trifocal

4. Progressive

The correct answer is: Trifocal

The correct answer is that the lens design that allows for correction at three different distances is a trifocal lens. Trifocal lenses are specifically designed with three distinct areas of vision: one for distance, one for intermediate, and one for near vision. This design integrates these three zones into one lens, allowing the wearer to transition between different visual tasks without needing to switch glasses. While bifocal lenses provide correction for two distances (typically distance and near vision), and monofocal lenses are designed to correct for only one specific distance, progressive lenses offer a gradient of vision correction that also accommodates multiple distances. However, the unique feature of trifocal lenses is the clear demarcation of three separate vision zones, which sets them apart in this context.