Temporal Vision Review Questions Flashcards
Compared to figure A (low amplitude), what has changed in figure B (high amplitude)?
High modulation depth
A high temporal frequency stimulus may appear flickering at _____ rates.
Higher
Temporal frequency is given in ‘hertz.’ 1 Hz is _____.
1 cycle/second
1 cycle/degree
Spatial frequency
Time taken by one cycle
Time period
1 cycle/second
Temporal frequency = Hz
Number of cycles of second
Frequency
CFF for scotopic conditions is ____ compared to Photopic conditions.
Lower
When testing under scotopic conditions, CFF is expected to be closest to:
20 Hz
When testing under photopic conditions, CFF is expected to be closest to:
70 Hz
The CFF for a given percentage modulation is 50 Hz. A stimulus of 55 Hz, presented at this given percentage modulation, is seen as:
Steady
What is CFF?
Beyond which a stimulus appears steady (Critical flicker fusion frequency)
Beyond CFF, the stimuli appears steady because ____.
It can’t be resolved (can’t resolve temporal fluctuations)
As the area of the stimulus increases, the CFF ____.
Increases
What happens to the CFF when the area of the stimulus gets to the periphery from the fovea?
Decreases
If we change from 3 degrees stimulus size to 5 degrees stimulus size, what happens to the CFF?
Increases
The detection of high temporal frequency is limited by what?
Speed of the neural processing
Is lateral inhibition for higher or lower temporal frequency?
Lower temporal frequency
The reduction in sensitivity to low temporal frequencies is caused by:
Lateral inhibition (phase lag)
What prevents our visual world from disappearing when we fixate on an object?
Small, inhibitory eye movements
With low temporal frequency, what happens to the edges?
Blurred up
With high temporal frequency, what happens to the edges?
Sharper edges
The saccades affect which temporal frequency, high or low?
Low because it makes the edges blurred up
When the modulation depth is very small, the screen appears _____.
Steady (b/c low amplitude)
The maximal TMTF (Temporal Modulation Transfer Function) value of a young healthy eye is ____ Hz.
10 Hz
At what temporal frequency does the TMTF show maximal sensitivity?
Moderate
When flickering light falls on the retina, nearby blood vessels ____.
Dilate
The visual acuity of amblyopic patients is poorer when measured using a Snellen chart than when measured with isolated optotypes because of:
Simultaneous masking
When a mask reduces sensitivity to previously presented spatially adjacent stimulus, the phenomenon is referred to as:
Meta contrast
When optotypes are surrounded by spatial patterns, the visual acuity ____.
Decreases
Masking in general does what to VA?
Reduces it
When a stimulus’ sensitivity is reduced due to a mask being presented first, the phenomenon is referred to as:
Para contrast
