Abstract

In the central retina grating resolution is proportional to cone density, whereas in the peripheral retina resolution is proportional to the sampling density of ganglion cells.¹ For red and green cones, density is maximal at 0 deg of eccentricity but for blue cones at 1 deg of eccentricity.² When the red and green cones are strongly light-adapted by bright long-wavelength light, the perception of dim short-wavelength stimuli remains mediated by blue cones only. Sine wave gratings with 90% contrast were generated on a white (P4) CRT screen. The screen was covered with a blue filter (Lee 141, transmitting wavelengths shorter than 575 nm) and metal cloth (open surface 25%) woven of thin (0.0025-mm) steel wires. The light from two slide projectors was projected through yellow filters (Wratten 16, transmitting wavelengths longer than 555 nm) onto the metal cloth. The average luminance of the blue grating field was 2.3 phot. cd/m², and the average luminance of the yellow adapting field was 750 phot, cd/m² corresponding to 610 scot. cd/m². Blue-cone resolution was found to have its maximum of 5 cycles/deg at 1 deg of eccentricity. At eccentricities of 1-20 deg, blue-cone acuity was directly proportional (1:5) to the acuity measured without the yellow adapting field.

© 1988 Optical Society of America