The Collaborative International Dictionary
Optogram
Optogram \Op"to*gram\, n. [Optic + -gram: cf. F. optogramme.] (Physiol.) An image of external objects fixed on the retina by the photochemical action of light on the visual purple. See Optography.
Wiktionary
optogram
n. (context physiology English) An image of external objects fixed on the retina by the photochemical action of light on the visual purple.