Optical instruments and microscopes process light waves to enhance an image's clarity or measure the light's properties. Examples of optical instruments include cameras, microscopes, photometers, polarimeters, spectrometers, etc.

While microscopes enhance the magnification of an object using two converging lenses, other optical instruments are used to detect properties of light or optical materials, e.g., light intensity, polarized light dispersion, and refractive index.

Microscopes, meanwhile, are used solely to inspect objects too small for perception by the human eye, such as cells, microscopic organisms, and the composition of a material. In biology, microscopes are often employed to identify a microorganism responsible for a disease.