Color Vision Part 4
What lightbulbs can you use for color vision testing?
1. Macbeth's easel lamp 2. non-standard fluorescent tubes - Richmond lamp 3. 100 watt tungsten bulb w/ C daylight glasses 4. indirect sunlight
What is the Y axis for the Rayleigh equation for a normal trichromat?
17
Farnsworth-Munsell 100-Hue test, Protan deficiency
1st order
Farnsworth-Munsell 100-Hue test, Deutan deficiency
2nd order
Farnsworth-Munsell 100-Hue test, Tritan deficiency
3rd order
What is the X axis for the Rayleigh equation for a normal trichromat?
45
What are examples of an arrangment test?
Farnsworth D-15 Lanthony D-15 100 Hue
What test is good for picking up acquired color deficiencies?
HRR - good at blue/yellow
What was the original test for color blindness?
Holmgren's Worsted Yarn
What D-15 test helps you determine milder defects?
Lanthony D-15
What is used to test S cones?
Moreland Equation
What is tested by the Farnsworth Lantern (FALANT)?
ability to distinguish red from green lights
The majority of acquired color deficiencies are ___ (red/green; blue/yellow).
blue/yellow - but there are still red/green
Severity of anomalous color vision is based on number of ___ seen when measured Farnsworth D-15.
cross-overs
What are the inherited color anomalies?
dichromats anomalous trichromats
True or false. Pseudoisocrhomatic tests work to differentiate dichromats and anomalous tritanopes.
false
True or false. Everything looks dimmer to a protanope at all wavelengths compared to a normal trichromat.
false - it depends on the wavelengths - some wavelengths will appear brighter to a protanope and some will appear dimmer - red (greater than 640nm) will look dimmer and green (less than 546nm) will look brighter
True or false. Ishihara picks up blue/yellow defects.
false - only red/green
True or false. The nagel anomaloscope checks for all color deficiencies.
false only red green not tritans
Deutan anomalous color cross over
follow along deutan axis
The 15 color caps in the Farnsworth D-15 form a ___ within the CIE diagram.
hue circle
What illuminant on the CIE diagram is the standard for color vision testing?
illuminant C (~6800) A is lower (~ 2800) B is middle (~ 4800)
What test is good for picking up inherited R/G deficiencies?
ishihara
Why is illuminant C ideal?
it simulates indirect sunlight
What is the shared color confusion line?
lines that protans and duetans struggle with
Matches seen by protanope on Nagel Anomaloscope
luminance changes hue changes
How do we differentiate deuteranopia from protanopia?
luminance function - protanopes (missing L cones) displace toward shorter wavelength - deuteranopes (missing M cones) displace toward longer wavelength
Matches seen by deuteranope on Nagel Anomaloscope
luminance stays the same - but they see more than the one match seen by the normal trichromat
How many matches will a dichromat or an anomalous trichromat make on a Nagel Anomaloscope?
multiple - all along confusion line
What is the only instrument that can distinguish between anopia (dichromats) and anomaly (anomalous trichromats)?
nagel anomaloscope
How many matches will a normal trichromat make on a Nagel Anomaloscope?
only 1 - 546 (green) and 679 (red) to make 570 (yellow)
What test differentiates protans from deutans?
pseudoisochromatic plates - protan won't see red 2 - deutans won't see 6
What plots the x axis on the nagel anomaloscope?
red to green - bottom half
The radius of the hue circle on the Lanthony D-15 is ___ (smaller; larger) than the Farnsworth D-15.
smaller
What is the Rayleigh equation?
somewhere along the x axis, there is a match for somehwere along the y axis
How do anomalous trichromats perform compared to dichromats and normal trichromats?
they are somewhere in between in protanomaly: - L cones luminance functions shifts toward M cones (to the left) in deuteranomaly: - M cone luminance functions shifts toward L cones (to the right)
The top half of the bapartite field on a nagel anomaloscope changes in ___ while the bottom half changes in ___.
top half = luminance bottom half = hue
True or false. All the color caps on the Farnsworth-Munsell 100 hue test have the same saturation, brightness, but a different hue.
true
The top half of the bitartite field on a nagel anomaloscope is always ___.
yellow
What plots the y axis on the nagel anomaloscope?
yellow field - the luminance
