Fig. 1.

a The laser streak of Black and Decker, DL220S, level was projected onto a wall in a dark room 100 cm away from the right eye, 13 cm medial (nasal) to the optical axis, represented by the perpendicular dashed line drawn from the triangular notch at the top of the picture frame. A 13-cm nasal displacement of the laser streak on the dark wall from the optical axis at 100 cm corresponds to approximately 7.5° of temporal displacement of the macula from the optical axis in the fundus photograph seen in b. b Optic nerve head, major vessel and macula in a single photographic frame are shown.