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visual perception nbeo.txt
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At what age should you be seeing 20/100 (6 cycles/degree)?
6 mo
What is the expected VA at birth?
20/600 (1 cycle/degree)
When are children expected to be seeing 20/20?
3-5 yrs
What is the expected VA at 1 yr?
20/50 (12 cycles/degree)
What does Lax criteria mean?
High sensitivity and high false positives
What does strict criteria mean?
High specificity and high false negatives
What does sensitivity mean?
Probability of a test giving a positive result given that the signal(disease) is present
Disease present =positive
What does specificity mean?
Probability of a test giving a negative result when signal(disease) is not present
What is a false positive?
Saying there is a signal when there really isn't
What is a false negative?
Not saying there is a signal, when really there is
At what nanometer is photopic vision most sensitive?
555 nm
At what nanometer is scotopic vision most sensitive?
507 nm
What is Abney's law?
Different lumens from different wavelengths being summed together as total lumens
What are lambert surfaces?
Surfaces that scatter light equally in all directions
How sensitive is photopic vision?
Low sensitivity
How sensitive is scotopic vision?
twice as sensitive as photopic
What is special about 650 nm wavelength?
At this wavelength, there is no difference between photopic and scotopic sensitivities
Dusk, both photopic and scotopic is being used
What is the Purkinje shift?
After 650nm, shorter wavelengths become brighter in scotopic vision and visa versa
What is Weber's Law?
How well we pick out a spot of light on a dark background
Light adaptation
Rod saturation
What is ricco's law?
Any number of photons within a given set diameter photopic or scotopic will appear as only one light
What is bloch's law?
Regardless of number of photons is a given time, it will appear as one single light
Photopic 10ms
Scotopic 100ms
What is the stiles-crawford effect?
The angle at which light strikes cones strongly affects the light
What is dicromacy?
Missing one of three cones
protanope
deuteranope
tritanope
what is anomalous trichromacy?
Have all 3 pigments, but one is weaker
what does an acquired blue/yellow defect typically mean?
Outer retinal disease
What does an acquired red/green defect typically mean?
Inner retinal disease
Optic nerve
Visual pathway
What is hue?
Color
What is color saturation?
How vivid the color is
How do you determine MAR?
600/snellen denominator
Divide cycles by degree by 30 to get snellen form
Author
cjensen20
ID
305120
Card Set
visual perception nbeo.txt
Description
Visual Perception NBEO
Updated
2015-07-13T11:47:09Z
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