- optic nerve and neural pathways (optic neuritis MS)
what are some exceptions to Kollner's Rule of thumb?
Glaucoma, papilledema, and dominantly inherited optic atrophy (all are optic nerve disorders) may be associated with B/Y (tritan) color vision deficits rather than the predicted R/G deficits
hm... Kollner’s Rule is a “Rule of Thumb” (which rhymes with dumb)
Many if not most (if not ALL) acquired red-green defects also exhibit blue-yellow defects
Exceptions to Kollner’s Rule include glaucoma,
papilledema, & all optic nerve disorders, which maybe associated with a blue/yellow defect
Acquired defects may be UNILATERAL
Congenital are always bilateral
what is blackbody radiator?
a (theoretical) perfect radiator of electromagnetic energy, the spectral characteristics of which are defined entirely by the blackbody’s temperature
what is color temperature?
The color temperature of a light source is that temperature (in degrees Kelvin) of a blackbody radiator that produces the same spectral output as that of the real light source.
“Color temperature” should be used to describe only incandescent light sources
what is correlated color temperature?
The correlated color temperature is the temperature of a blackbody radiator that produces an output that most closely matches the color of the light emitted from a real non-incandescent source
what are some CIE "standard illuminants"?
D (daylight) illuminants (D55, 65, 75)
We need a standardized light source when doing color testing so we have consistent results. We want a light source that emits all wavelengths of light as equally as possible so it won’t affect the testing
what is spectural locus on CIE?
the curved part of the CIE that has all the spectral wavelengths
what is purple locus of CIE?
the straight part at the bottom
what are non-spectral purples?
these colors are not made up by a single wavelength.You have to mix more than one wavelength to get these colors
what is Planckian Locus of CIE?
the line of various standard illuminants
all of these are considered white light
blackbody radiator "color temperature"
explain illuminant A
Definition: Blackbody radiator at 2856° K
CIE Source: Gas-filled coiled-tungsten filament lamp with a fused-quartz envelope or window operating at 2854° K
Function: Serves as standard for illuminants B & C
explain illuminant B
color temp: 4874° K
CIE Source: Illuminant A + 1 cm thick double cell optical glass container (Davis-Gibson filter) filled with liquid chemical solutions B1 and B2
Function: Mimics direct sunlight at noon (poorly)
explain illuminant C
Color Temperature: 6774° K
CIE Source: Illuminant A + 1 cm thick double cell optical glass container (Davis-Gibson filter) filled with liquid chemical solutions C1 and C2
Function: Mimics average direct Northern sunlight but lacks power in near UV range important for fluorescent materials
Illuminant C is the illuminant for which nearly all clinical color vision tests were designed (approx best by MacBeth lamp)
explain illuminant D
Represent measured spectra under different conditions of natural daylight
Correct for weaknesses of the other standard illuminants (A, B, & C) in near UV
The D illuminants have no standard sources(Instead, there are standard tests to be passed)Illuminant D65 is an acceptable substitute for Illuminant C for color vision testing
Correct for weaknesses of the other standard illuminants (A, B, & C)
in near U
explain illuminant D65
Recommended for “Natural” Daylight
Correlated Color Temperatures: 6500° K
CIE Standard Source: NONE → functional tests are provided
Acceptable substitute for Illuminant C in clinical color vision testin