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Biomedical subjects

J D Moreland

Publications and source records attributed to J D Moreland.

17 recordsLinked to original sources
PubMed1978

Temporal variations in anomaloscope equations.

Temporal variations in the value of blue/green derived from the equation: 'Blue' + 'Green' = 'Cyan' + 'Yellow', seem to be of two kinds. Those found in a cross-sectional study of 167 normal eyes in the age range 13--83 years could be attributed to progressive changes in lens absorbance. Individual cyclic variations in short-term (12 h) and long-term (11 months) longitudinal studies could not be attributed to the lens.

Adolescent↗
PubMed1978

Further observations on the extramacular chromatic mechanisms.

Monochromatic targets presented at 30 degrees excentricity on orange, magenta and blue backgrouds are used. A small monochromatic light, 476 nm on orange, 551 nm on magenta and 621 nm on blue, is flashed at 3 cps-1 on the centre of the targets. The size of the targets is varied and their luminance adjusted using neutral filters until the flashing light is just not visible. This method allows the study of chromatic mechanism sensitivity and of retinal interactions (summation and inhibition). Some observations in normal as well as in pathological conditions are presented.

Adult↗
PubMed1978

Acquired 'tritan' deficiencies in macular pathology.

14 patients with maculopathy (18 eyes affected, 10 eyes clinically normal) were examined using the HRR plates, the Farnsworth F2 (tritan) plate, the Farnsworth panel D15 test, the Nagel anomaloscope (model I) and on a 'blue-green' equation for 2 degrees and 11 degrees fields on the Moreland anomaloscope. The correlation of tritan-like responses to each test and the differences between the 2 degrees and 11 degrees equations are discussed.

Adult↗
PubMed1978

Optimization of stimuli for trit-anomaloscopy.

Free-choice colour matches were made by 50 young normal trichromats on an anomaloscope. Six equations, of the kind 'blue' + 'green' = 'cyan' + 'yellow', were used in which the stimuli were defined by narrow-band well blocked interference filters. The stimuli were selected so that the instrument controls, which varied the quantities (blue/green), (cyan/yellow) and (cyan + yellow), were nearly independent controls for hue, saturation and brightness respectively. 'Yellow', 'green' and 'cyan' were fixed at 589, 499 and 480 nm, respectively, and the least interindividual variation in blue/green was found for 'blue' in the region 430-439 nm. This and a similar finding in the pilot study of Moreland and Young agree with expectations based on the density spectrum for macular pigment measured by Ruddock. Matches made by a few selected subjects, when the saturation control was locked at a position for the population mean, in the presence of large but typical saturation differences, were the same as when all three controls were used.

Adult↗