Protan Response Times to Red Lights in a Mildly Hypoxic Environment (original) (raw)

Detection and Identification of LED Traffic Signals by Protan Observers

1999

Protan observers have lower spectral sensitivity than color normal observers at long wavelengths of the visible spectrum. Responses of protan and color normal subjects to light emitting diode (LED) and incandescent traffic signals of red and yellow nominal color during simulated daytime viewing conditions are described. Reaction times, missed signal percentages and color identification accuracy were measured. The results indicate that for protans, detection performance to red LED signals was enhanced when the dominant wavelength was moved toward shorter wavelengths, but this shift also appeared to decrease their ability to correctly identify the signal color. Although the yellow LED signal used in this study provided similar detection performance for protans as a yellow incandescent signal, its dominant wavelength was sufficiently long for it to sometimes be confused with red. In general, the results of this study are consistent with the 1994 recommendations of the Commission Internationale de l'Éclairage for signal colors to be seen by color normal and protan observers. Nonetheless, neither detection nor color identification for protans approached that of color normal observers.

The Effects of Exposure to Red and Blue Light on Physiological Indices and Time Estimation

Perception, 1985

The effects of exposure to red, white, and blue lights on time estimation and physiological indices were examined. Sixty subjects were exposed to a total of four presentation series of red, white, and blue lights. There were two phases of the experiment: a verbal estimation phase in which subjects were required to count out loud the length of each color while measures of eyeblinks, skin conductance, pulse volume, heart rate, and EEG activity were obtained; and a production phase in which subjects were required to produce several intervals while measures of EEG were obtained. The data on each dependent measure were subjected to three-way repeated-measures ANOVAS. EEG data were digitized and analyzed with power spectral, peak frequency, percentage of alpha activity, and discriminant analyses. Results indicate that color did not exert consistent significant effects on any of the dependent measures and raise serious questions about the assumption that ‘warm’ colors are more arousing tha...

Color discrimination results from a CRT device: Influence of luminance

Color Research & Application, 1999

In this article, we report new color discrimination ellipsoids calculated from two normal observers, using a CRT device and five values of luminance at each of the five centers recommended by the CIE in 1978 (Col Res Appl 1978;3:149-151). Our main goal was to test the weighting function for lightness adopted by the CIE94 color-difference model (CIE Publication 116, 1995). Although some of the experimental conditions employed here (CRT monitor, small size of the visual field, and controlled exposure time) did not fit those recommended by this model, our results support the weighting function for lightness proposed by CIE94. The only robust trends observed in the ellipsoids obtained were a confirmation of Weber's law and a decrease in the area of the x, y chromaticity ellipses, when the luminance of each reference stimulus increased towards the one of the surround.

Protanopic observers show nearly normal color constancy with natural reflectance spectra

The ability of color-deficient observers to discriminate between illuminant changes and surface-reflectance changes in a scene was tested with natural and Munsell reflectance spectra. To avoid the confounding effects of spatial structure, stimuli were simulations of Mondrian-like colored patterns, presented on a computer-controlled color monitor. Protanopes performed less well than normal trichromats, regardless of the type of reflectance spectra, but they were least disadvantaged with patterns comprising reflectance spectra drawn from urban and rural scenes, more characteristic of the natural environment.

Effect of luminance on color perception of protanopes

Vision Research, 1998

Small-field color-naming performance of two protanopes over a 4-log luminance range was impoverished in comparison with that of normal trichromats, and was more strongly affected by changes in luminance. At 200 cd/m 2 responses to mid-spectral lights were dominated by 'yellow'; with lowering luminance, 'green' and 'red' were increasingly used. In the color spaces derived from these data the first two dimensions for trichromats are red-green and yellow-blue; those of the protanopes appear to be brightness and 'red-blue'. In the protanopes' color space the greater separation of stimuli at 0.2 cd/m 2 suggests that with low luminance their color discrimination improves.

The CN Lantern Test and Different Viewing Distances

Optometry and Vision Science, 2020

This research shows that some color-vision-defective patients could identify railway signal lights correctly if they are working in the yard where sighting distances for signal lights are shorter. PURPOSE: When interpreting railway signal lights, sighting distance can vary depending on the employee's location and job requirements. Individuals with a color-vision-defect may pass railroad employment color vision testing for positions with shorter sighting distances, despite failing to qualify for positions with longer sighting distances. The CN Lantern (CNLan) simulates railway signal lights. We evaluated performance and repeatability on CNLan at different viewing distances in color-normal and color-deficient individuals. METHODS: Fifty-six subjects with normal color vision and 63 subjects with a red-green color-vision-defect participated. The CNLan test was performed at 4.6-, 2.3-, 1.15-, and 0.57-m viewing distance. The test was repeated after 10 days. RESULTS: All individuals with normal color vision passed the CNLan at all distances at both visits without errors. For the group with a color-vision-defect, the pass rate increased from 12% at 4.6 m to 62% at 0.57 m. The repeatability of the CNLan between visits for the color-vision-defective group was very good with AC1 agreement values greater than 0.85. CONCLUSIONS: An increase in retinal illumination was likely responsible for the improved performance as the test distance was decreased. Typical sighting distances in railway yards correspond to the 0.57-m test distance in our study. The results of this study suggest that 62% of the individuals with a red-green color-vision-defect may correctly identify colored signal lights in a railway yard where sighting distances are less than 100 m.

Color vision tests for aviation: comparison of the anomaloscope and three lantern types

Aviation, space, and environmental medicine, 2005

A comparison of the results obtained with the Nagel anomaloscope and the Holmes-Wright Type A, Spectrolux, and Beyne aviation color vision lanterns was undertaken. The Joint Aviation Requirements (JAR) specify pass/fail limits for these four secondary color vision tests and the Ishihara screening test. The results for individuals on all five tests were studied. The color vision of 55 color-vision deficient and 24 color-vision normal subjects, mostly applicant pilots, was assessed using a battery of tests, including the Ishihara plates, the Nagel anomaloscope, and three lanterns. The testing methods and characteristics of the lanterns and anomaloscope were compared. Of the color-deficient applicants, only deuteranomalous trichromats passed more than one of the four secondary JAR tests, but a pass on one test did not reliably predict a pass on another test. Three out of nine protanomalous trichromats passed the Nagel anomaloscope but failed all three lantern tests. Of the normal trich...

Effect of duration on detection by the chromatic and achromatic systems

Perception & Psychophysics, 1984

Detectability was determined as a function of stimulus duration for the chromatic and achromatic systems. For the achromatic system, detectability remains relatively constant for durations ranging from 43 to 1,000 msec, whereas for the chromatic system, detectability increases with duration up to about 500 msec. This suggests that the chromatic system has a more sustained output than the achromatic system. 65