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15 Cards in this Set
- Front
- Back
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How do we test visual fields |
Minimum light intensity detected |
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Absolute threshold for MOL |
Mean number of responses that go from yes to no and vice versa |
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MOC |
5-9 levels of luminance Stimulus is presented and participant give y/n response |
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What type of graph is produced from MOC |
Sigmoidal |
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How are the stimuli presented in MOC |
Random order |
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What shape is the graph if the person has an ocular disease? |
Less defined sigmoidal |
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MOA |
Observer controls stimulus to where it is just about detectable Repeated and mean becomes absolute threshold |
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Disadvantages of MOA |
Threshold criterion will differ between observers Anticipation- they set the level and stimuli based off experience of previous trial rather than current sensory trials |
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MOL |
Stimuli are introduced in an ascending/descending order and once at threshold, the order is reversed and goes in opposite direction. |
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Disadvantages of MOL |
Anticipation Response preservation (This the reason why we test ascending order then descending order and vice versa |
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Staircase method |
Stimulus presented in ascending/descending order When they can detect the stimulus the order is revered until they can't see it and when they can't see it, the order is reversed again. Trials don't stray far from threshold |
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What is the threshold for staircase method |
At the reversal point |
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Forced choice method |
Observer has a choice of 1 of 2 stimuli Criteria is different for scotopic and photopic conditions |
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How does the 2AFC psychometric function differ from the 4AFC |
The 2AFC is a lot steeper than the 4AFC |
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Why does the psychometric function start at 50% |
Starts at 50% as the observer is meant to guess 50%. Therefore the threshold is midway |
