Spectral efficiency across the life span: flicker photometry and brightness matching.
Spectral efficiency functions were measured for 50 color-normal observers (aged 19-85 years) by means of heterochromatic flicker photometry (HFP) and heterochromatic brightness matching (HBM). Foveally viewed, circular, 1.2 degrees-diameter stimuli were presented as 3-s flashes (50% duty cycle) in Maxwellian view. Monochromatic lights (420-700 nm; 16 wavelengths) were equated to a 100-Td (trolands), broadband white standard in both procedures. In both HFP and HBM, average sensitivity (specified at the cornea) decreased at short wavelengths with increasing age, consistent with age-related increases in the density of the ocular media. The short-wavelength HBM decline was of lower magnitude than the HFP decline. HFP data were modeled by a weighted additive combination of long- and middle-wavelength-cone inputs and density spectra of the ocular media and macular pigment. HBM data were analyzed with an upper envelope of additive and subtractive combinations of log-transformed cone absorption functions. These analyses indicated that HBM sensitivity, specified at the retina by correction for estimated lens and macular pigment density, increased with age in an approximately wavelength-independent manner over a broad range from 420 to 560 nm.
Kraft
J M
JM
Department of Psychology, University of Colorado, Boulder 80309-0345.
Werner
J S
JS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity; D005260:Female; D005425:Flicker Fusion; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D010783:Photometry; D012160:Retina / Q000502:physiology; D012684:Sensory Thresholds; D014796:Visual Perception / Q000502:physiology*