glossary

Complete color deficiency affecting the ability to see the color green. There are three possible color vision deficits: red (protan), green (deutan), and blue (tritan). The suffixes ?omaly and ?opia indicate partial and complete color vision deficits, respectively. Therefore, a person who has deuteranopia has a complete green color deficit.

Precise surface cutting using single point turning; cutting height is controlled at all points on the lens.

Optical system with a focal distance of 1m. Refraction defects are measured in diopters (visual insufficiency). Unit of measurement for lens power. It is the reciprocal of the focal length in Meters.