Accommodation responds to changing contrast of long, middle and short spectral-waveband components of the retinal image.
We simulated the effects of longitudinal (axial) chromatic aberration and defocus on contrast of the long-, middle- and short-wavelength components of the retinal image to determine whether the effects of chromatic aberration are sufficient to drive accommodation. Accommodation was monitored continuously while subjects (12) viewed a 3 c/deg white sine-wave grating (0.92 contrast) in a Badal stimulus system. The contrasts (amplitudes) of the red, green and blue components of the white grating changed independently to simulate a grating oscillating from 1 D behind the retina to 1 D in front of the retina at 0.2 Hz. Subjects responded strongly to the chromatic simulation but poorly to a luminance control. The results support the hypothesis that focus is specified by the contrast of spectral-wavebands of the retinal image, and that conventional color mechanisms, monitoring chromatic contrast at luminance borders (1-8 c/deg), mediate the signals that specify dioptric vergence.
Kruger
P B
PB
Schnurmacher Institute for Vision Research, State College of Optometry, State University of New York, NY 10010, USA.
Mathews
S
S
Aggarwala
K R
KR
Yager
D
D
Kruger
E S
ES
D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D003118:Color Perception / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology; D013053:Spectrophotometry; D013997:Time Factors