Certified Paraoptometric (CPO) Practice Exam 2025

Which lens has the same power across all areas and is used for correcting myopia or hyperopia?

1. Spherical lens

2. Cylindrical lens

3. Multifocal lens

4. Aspheric lens

The correct answer is: Spherical lens

A spherical lens is designed with a uniform curvature across its entire surface, resulting in consistent optical power throughout the lens. This property ensures that it can effectively focus light entering the lens, making it suitable for correcting conditions like myopia (nearsightedness) and hyperopia (farsightedness). In contrast, cylindrical lenses have a varying curvature that addresses astigmatism by bending light differently in one direction, while multifocal lenses contain multiple areas for different viewing distances, making them unsuitable for conditions that require a single lens power. Aspheric lenses are designed to reduce distortion and aberrations by having a gradual change in curvature, but they still do not provide the uniform power that a spherical lens offers. Thus, a spherical lens is the ideal choice for correcting myopia or hyperopia with consistent optical measurements across the entire lens surface.