The straight line extending from the object seen, through the centre of the pupil, to the macula lutea of the retina. ... Synonym: line of vision. ... (05 Mar 2000) ... 
an imaginary line passing from the midpoint of the visual field to the fovea centralis. See illustration at optic axis.
The central area of the cornea, pupil, and lens that light passes through to reach the retina and be "seen".
Type: Term Definitions: 1. the straight line extending from the object seen, through the center of the pupil, to the macula lutea of the retina. Synonyms: line of vision