Introduction to Color Vision and Stereo Flashcards
Who discovered spectrum (light through a prism breaks or refracts into colors)? In what year?
Sir Isaac Newton in 1666.
How many fundamental colors are there? What colors are they?
- ROY G BIV.
Perception of color depends on what?
The wavelength of light.
True or False: Light change produces color perception change.
False. Wavelength change produces color perception change.
How many photo-pigments are in the human retina?
- Short, Medium, and Large wavelength light. (Blue, Green, Red).
Who discovered the Trichromatic Theory of Color Vision? In what year?
Thomas Young in 1802
What type of color vision deficiency is monochromat?
Only one pigment in the retina instead of three.
Loss of specific information is known as what?
Univariance.
True or False: In monochromat,, once wavelength is absorbed, the information regarding its wavelength is shown as a color.
False. Information is lost.
How many photo pigments are in the retina for a dichromat?
2.
True or False: The univariance theory for dichromat applies, and you get two apparently different stimuli known as metamers.
False. Apparently identical, but physically different stimuli.
What percentage of the population has a hereditary color vision deficiency?
4.5%.
Does color vision deficiency affect activities at school or work?
Yes.
True or False: Red-blue deficiency is more common in males?
False. Red-green.
What is the prevalence of color vision in males and females?
8% males, 0.40% females.
True or False: Loss of color vision may be acquired at any age due to any disease of the optic nerve or optic tract.
True.
What are three things that can occur due to pathologies affecting color vision?
Optic neuritis, glaucoma, tumors.
True or false: In Kollner’s Law, lesions of the inner layers of the retina cause a yellow-blue color vision defect.
False. Outer layer.
True or false: In Kollner’s Law, lesions of the outer layers of the retina and optic nerve cause a red-green color vision defect.
False. Inner layer.
What are some characteristics of acquired color vision loss?
Usually unilateral, recent history of color naming errors, changed over time, is difficult to classify using color vision tests.
What are three ways color vision screening can be done?
Pseudoisochromatic Plate Test, Ishihara Test, and HRR Color Vision Test.
True or False: In PPO 1, color vision screening technique that will be used is Psudoisochromatic Plate Test.
False. HRR Color Vision Test.
Why is HRR a better color vision screening technique than the other two?
Good for illiterate patients, better clinical diagnosis of color defect, designed under standardized illumination (standard illuminant C).
Is HRR done monocularly or binocularly in a screening environment?
Binocularly.
How far from the patient should the HRR test be done?
70 cm.
True or False: Passing HRR is 3 or more correct on plates 1 through 4.
False. PLates 7 through 10.
Are these considered to be limitation of color vision screening? Non-optimum illumination, limited attention span of children, shyness, fear, poor cooperation, child afraid to guess.
Yes.
True or False: During color vision screening, pathology and hereditary related defects are at interest.
False. Only looking for congenital/hereditary defects; not pathology related defects.
True or False: Screen patients with the most frequently encountered problems.
True.
Which plates are considered demonstration plates and which are considered as the actually testing plates?
Plates 1 through 4 are demonstration plates while plates 7-10 are testing plates.
What is considered passing and referring?
3 or more correct for plates 7 through 10. Anything less than 3 is referred.
True or False: Color vision screening is done one eye at a time.
False. Both eyes screened together.
The binocular visual perception of three dimensional space based on retinal disparity is called what?
Stereopsis.
When does retinal disparity occur?
The eyes are set slightly horizontally different in the skull, about 65 mm apart.
True or False: Depth perception can’t occur without binocular vision.
False. Can occur without binocular vision.
What does the brain use to aid in depth perception?
Monocular cues.
how many monocular cues are used to aid in depth perception?
7.
What monocular cue is when small retinal images are further away? (Like an images further back in the page seems smaller).
Apparent Size.
What monocular cue is when nearer images conceal further away images? (A shape on top of shape on top of another shape).
Interposition.
What monocular cue is when water, vapor, dust make distance objects indistinct and relatively color desaturated? (Looking at the mountains from far away).
Clarity.
What monocular cue is when light falling on an object creates a shadow; the shadow is interpreted as falling behind the object; brighter objects are closer? (Like a cracker and it shadow).
Shading.
What monocular cue is when physically parallel lines converge to a vanishing point at the horizon? (Like train tracks).
Geometric Perspective.
What monocular cue is when velocity of a distant target appears slower than the target moving at same velocity at near? (Difference between a tiger running at distance and at near).
Relative Velocity.
What monocular cue is when head movements make near objets appear to move in the opposite direction, whereas distant objects seem to move in the same direction? (Like place one finger in front of the other and tilting your head).
Motion Parallax.
Which two monocular cues are known as kinetic cues?
Relative velocity and motion parallax.
Is apparent size known as static cue or kinetic cue?
Static cue.
Is interposition known as static cue or kinetic cue?
Static cue.
Is clarity known as static cue or kinetic cue?
Static cue.
Is shading known as static cue or kinetic cue?
Static cue.
Is geometric perspective known as static cue or kinetic cue?
Static cue.
Is relative velocity known as static cue or kinetic cue?
Kinetic cue.
Is motion parallax known as static cue or kinetic cue?
Kinetic cue.
Random Dot Stimuli was created in what year?
1960.
True or False: For the Random Dot Stimuli, dots are shifted slighting to provide a disparate cue at the neocortex.
False. Striate cortex lamina.
Does shape emerge in Random Dot Stimuli test? What type of stereo is Random Dot Stimuli testing for?
Yes; Gross.
What stereo card should be used at a distance of 50 cm for the Random Dot Stimuli Test?
504” stereo.
What stereo card should be used at a distance of 100 cm for the Random Dot Stimuli Test?
252” stereo.
True or False: Random Dot Stimuli Test is a quick test to help identify students with strabismus or amblyopia that were previously missed with other testings.
True.
Stereo Testing is completed at what distance from the patient?
50 cm.
Out of 4 tries, what is considered passing during a Stereo Testing?
3 or more out of 4 is considered passing.
