Color Discrimination and Infant Vision (M1) Flashcards
What are two lights of different wavelength composition that are matched for the eye (human observer cannot tell the difference) called?
metamers
How many spectrally distinct lights plot to one point in the normal CIE diagram?
infinity
What is the point at which all of the protanopic confusion lines converge on a CIE diagram (and where is it located in the diagram)?
protanopic copunctal point (in the bottom right corner)
What is the point at which all of the deuteranopic confusion lines converge on a CIE diagram (and where is it located in the diagram)?
deuteranopic copunctal point (underneath the diagram in the bottom right corner)
What is the point at which all of the tritanopic confusion lines converge on a CIE diagram (and where is it located in the diagram)?
tritanopic copunctal point (in the bottom left corner)
What is the monochromatic light that matches white for each dichromacy type called?
neutral point
What type(s) of dichromatic patients can match all colors along the Rayleigh region?
- protanope
2. deuteranope
Do dichromats match more or less lights to a given point, compared to normals?
more
What is the most common form of color vision deficiency?
deuteranomaly, aka Daltonism (normal L, abnormal M)
What is the inheritance type for a deuteranomalous? 1. Protanomalous? 2. Deuteranope? 3. Protanope? 4. Tritanope? 5. Rod monochromacy? 6
- X-linked recessive
- X-linked recessive
- X-linked recessive
- X-linked recessive
- autosomal dominant
- autosomal recessive
What is more common: congenital tritanopia or acquired tritanopia?
acquired tritanopia
What are the conditions that can lead to acquired tritanopia?
- glaucoma
- diabetic retinopathy
- retinal detachment
- Alzheimer’s disease
- ARMD
- retinitis pigmentosa
What is more common: congenital red-green defects or acquired red-green defects?
both common
What are the conditions that can lead to acquired red-green defects?
- Progressive cone dysfunctions and dystrophies
- Stargardt’s disease (juvenile MD)
- Fundus flavimaculatus
Who is more likely to have a medical condition associated with their color-deficiency: men or women?
women
Why are normal color vision patients considered to be “very colorblind”?
- cannot distinguish colors because metamerically matched
2. cannot distinguish colors because their physical properties do not differ enough
What is the minimum difference in wavelength for two wavelengths to be distinguished (what is this called)?
3 nm (wavelength discrimination threshold)
What are the bandwidths of cones on average?
100nm
What are the assessment types to arrive at a quantitative evaluation of patient visual performance?
- physical continuum
- behavioral measure
- criterion for the relationship
What is the psychometric function used for?
- measure thresholds
2. matching
What causes that problems in determining the psychometric function for detection?
the grey zone
What is the method for determining the psychometric function for detection that has a predetermined range of stimulus values that are presented in random order and continues for all data?
method of constant stimuli
What is the method for determining the psychometric function for detection in which the patient grabs the knob and adjusts its value until the “criterion” is attained?
method of adjustment
What is the method for determining the psychometric function for detection where the examiner adjusts the knob upward from a value that is too low until the criterion is attained?
ascending method of limits
What is the method for determining the psychometric function for detection where the examiner turns it up if “no” and down if “yes” and the threshold is the average of the stimulus values at the reversal points?
staircase method
What is the method for determining the psychometric function for detection where the examiner adjusts the knob downward from a value that is too high until the criterion is attained?
descending method of limits
What is the test type that presents a stimulus on the left or right and a blank on the other side and the patient must guess which side contains the stimulus? 1. What are the benefits? 2. What are the disadvantages? 3
- two-alternative forced-choice
- scoring is easy and can be used on naive observers
- takes a long time and not all measurements can be done this way
What is the test type that presents a letter stimulus and the observer is to guess the letter type? 1. Is it slower of faster than 2AFC? 2
- forced naming
2. faster
Can infants make discriminations based on luminance? 1. What type of experiment is used to determine this? 2
- yes
2. 2AFC (2 alternative forced choice)
Can infants make discriminations based on color? 1. What type of experiment is used to determine this? 2
- 7-week-olds can; 3-week-olds cannot
2. 2AFC
Which color discrimination comes in later than the other?
tritan (s-cone)
