glossary

A unit of power of a lens, the reciprocal of the focal length of the lens.

A visualization of two images from one object; images may be horizontal, vertical or oblique.

A general term for color vision abnormalities. Heritable dyschromatopsias include red (protan), green (deutan), and blue (tritan) color vision deficits. These deficits may be partial (-omaly) or complete (-opia). Red and green color vision defects are X-linked while loss of the blue receptor (tritanopia) is inherited in an autosomal recessive fashion.