Ocular lenses are often interchangeable, allowing users to customize their viewing experience based on desired magnification. The most common magnification for a microscope ocular lens is 10x. Additional magnifications of microscope ocular lenses include 12.5x, 15x, and 20x.

The ocular lens typically has a low magnification (10x) and works in combination with the objective lens to achieve a greater magnification power. The objective lens is at the bottom of the eyepiece tube and is responsible for both total magnification of the specimen, as well as the resolving power of the microscope.