Abbe refractometer

Ernst Abbe (1840–1905), working for Carl Zeiss AG in Jena, Germany in the late 19th century, was the first to develop a laboratory refractometer.

They are also possibly the easiest device to use for measuring the refractive index of solid samples, such as glass, plastics, and polymer films.

The first truly digital laboratory refractometers began appearing in the late 1970s and early 1980s, and no longer depended on the user's eye to determine the reading.

Most digital laboratory refractometers, while much more accurate and versatile than their analog Abbe counterparts, are incapable of readings on solid samples.

The software on most of current instruments offers features such as programmable user-defined scales and a history function that recalls the last several measurements.