ABO NOCE Practice Test 2026 - Free Optician Certification Practice Questions and Study Guide

A focimeter is commonly referred to as a lensometer. This instrument is specifically designed to measure the focal power of lenses, particularly in eyewear, to ensure they meet the prescribed optical requirements. A lensometer typically allows the user to determine the prescription of a lens by measuring its curvature and the strength of its optical prescription.

While the other instruments have important roles in the field of optometry and ophthalmology, their functions differ significantly from that of a focimeter. An optometer measures the refractive error of the eye to help in determining the appropriate lens prescription but is not designed solely for analyzing lenses. A refractometer is used primarily to measure the angle of refraction of light in a medium, which is more aligned with assessing the properties of materials rather than lenses. A phoropter is a tool that contains various lenses used during refraction tests for determining an individual's prescription but does not measure lenses directly. Therefore, lensometer is the most accurate term synonymous with focimeter.