B13 Flashcards
1
Q
What are 3 things you must have to have normal bino vision?
A
- VA has to the similar in both eyes and produce comparable cortical images in corresponding retinal areas
- muscles must work correctly
- images from each retina must be fused into a single image
2
Q
What are 9 advantages of bino vision?
A
- visual efficiency and performance
- vision-motor tasks
- sports and gaming
- reading proficiency
- a spare eye
- larger bino field/blind spot coverage
- better appreciation of dynamic relation between body and environment
- single vision
- depth perception
3
Q
What are 7 problems with abnormal bino vision?
A
- asthenopia
- diplopia
- rivalry
- amblyopia
- eccentric fixation
- suppression
- anomalous correspondence
4
Q
If someone has no stereo what does this mean?
A
They have no bino vision
5
Q
The collection and integration of information received at the retina and transmitted to the cortex
A
Sensory fusion
6
Q
T/F: if is sensory fusion is affected by any condition, integration of the images from the 2 eyes will be abnormal
A
True
7
Q
What is the fundamental part of vision?
A
Sensory
8
Q
Name 7 causes of motor dysfunction
A
- disease
- incomitancies
- latent manifestations (phorias)
- manifest deviations
- vergence quality (facility)
- vergence quantity (amplitude)
- nystagmus
9
Q
When should motor problems be treated?
A
They should be treated last after identified sensory and integrative problems have been treated
10
Q
Name 5 causes of integrative problems
A
- disease
- aniseikonia (different size retinal images)
- suppression
- anomalous retinal correspondence
- horror fusions (inability to fuse)
11
Q
Name the 5 causes of sensory dysfunction
A
- disease
- refractive error
- amblyopia
- eccentric fixation
- accommodative insufficiency and infacility
12
Q
What is considered normal single bino vision?
A
Bifoveal with no deviation
13
Q
What is considered abnormal bino vision regarding the fovea?
A
When the fovea of one eye projects with a non fovea point of the other eye
14
Q
Is misalignment usually present with abnormal bino vision?
A
Yes
15
Q
Localized the visual percept in a visual direction that is relative to the direction of the fovea
A
Retinal area/element
16
Q
If the eyes are properly aligned, an image is received on ___ areas of the retinas
A
Matching
17
Q
If the eyes are functioning normally, will the images will be the same size and color?
A
Yes
18
Q
What 4 things does the stimulus perceive when the retinal areas is stimulated?
A
- brightness
- color
- form
- direction
19
Q
T/F: matching retinal elements have different visual directions
A
False. They have the same visual direction
20
Q
Considered the retinomotor zero point
A
Fovea
21
Q
T/F: all points in space falling along the visual line have the same visual direction
A
True
22
Q
This is used to build interpretation of 3D images in space
A
Visual direction
23
Q
What 2 things are normal when there is precise and clear bifoveal fixation?
A
Bino vision and fusion
24
Q
If there is abnormal bino vision is the visual direction the same or different?
A
Different
25
What is the principal visual direction and the center?
Fovea
26
In strabismus, this is when a non-fovea point assumes the characteristics of the principal visual direction
Eccentric fixation
27
Is visual direction subjective or objective?
Subjective
28
Is the line of direction subjective or objective?
Objective
29
The line that connects an object with its image on the retina
Line of direction/visual axis
30
When the visual axes of the fovea intersect at a fixation point
Binocular fixation
31
When objects simultaneously stimulate the fovea of both eyes, the object is in the ___ subjective visual direction
Same
32
When only one line of direction goes to fixation
Monocular fixation
33
The ability for visual neurons to process direction and to identify fixed direction in space
Local sign
34
A pair of points in each eye when stimulated appear to lie in the same visual direction
Corresponding retinal points
35
T/F: any disruption at the fovea will lead to a disruption in visual direction
True
36
A point 1 degree nasal to the fovea in one eye corresponds to a point ___ to the fovea in the other
1 degree temporal
37
A plane in space where all points appear to have the same depth
Horopter
38
T/F: points not on the horopter are seen by different retinal areas, producing double
True
39
A circle that passes through the center or the rotation of both eyes and the fixation points
Vieth-Muller Circle
40
Does the vieth-muller circle become bigger or smaller when the point of fixation is nearer?
Smaller
41
A narrow band around the horopter that allows objects from disparate/dissimilar retinal points to be seen as single
Panum’s Fusional Area
42
Panums fusional area is ___ around fixation and becomes ___ into the periphery
Narrow around fixation and becomes broad into the periphery
43
What is the purpose of panums fusional area broadening in the periphery?
- to maintain vision because of eccentricity
| - to eliminate diplopia in the periphery
44
Does eccentricity increase or decrease vision?
Decrease
45
T/F: The panums fusional area for a sharply focused fast object is not as wide a for a fuzzy and slow moving target
True
46
T/F: fusion is possible if a target falls within the panums fusional area with little disparity
True
47
What is physiological diplopia?
Diplopia that is elicited by points off the horopter
48
When is physiological diplopia seen?
When a target does not lie on the horopter and is outside the panums area
49
When we have diplopia will the retinal elements be in the same or different directions?
2 different directions
50
When 2 nasal retinal elements do not have the same visual direction, this will cause ____ which is ___ the horopter
Causes uncrossed diplopia beyond the horopter
51
When 2 temporal retinal elements do not have the same visual direction, this will cause ____ which is ___ the horopter
Cause crossed diplopia before the horopter
52
When will the image fall on the horopter?
When the visual direction is on the temporal retinal element OS and a nasal retinal element OD
53
The unification from both eyes to form a perception
Fusion
54
Fusion needs similar ___ and ____
Shape and size
55
Why does fusion near the fovea only tolerate little dissimilarity between images
Because of the small receptive field
56
Where is dissimilarity tolerated?
In the periphery where receptive fields are larger
57
Integration of images on corresponding retinal points to form a single percept.
Sensory
58
Vergence movement to maintain retinal images at corresponding retinal points.
Motor
59
Deviation between the empirical horopter and the vieth muller circle
Hering-holler and deviation
60
Are disparities perceived as one in the panums fusional vertical or horizontal?
Horizontal
61
Name 3 characteristics of the peripheral VF
- reduce VA due to increased eccentricity
- larger receptive field
- diplopia is less bothersome because of the expanded panums fusional area
62
____ of the optic nerve at the chiasm gives rise to retinal elements that are corresponding retinal points
Decussation
63
Decussation is important for what 2 things?
Bino vision and stereo
64
List the pathway of processing visual information to a single perceived image
Visual info—> optics nerve—> optic tract —> LGN —> Visual cortex—> single perceived image
65
T/F: Physiological diplopia means the patient can only use one eye
False. The patient can use both eyes
66
T/F: Corresponding retinal points that have the same visual direction DO NOT give information about depth or the 3D quality.
True
67
Images are projected differently with one eye at a time
Binocular disparity
68
When precepts from both eyes merge, why is there depth?
Because the disparity in the projection of the individual eyes
69
Does horizontal or vertical retinal disparity offer depth?
Horizontal
70
Is stereo a higher form of bino or mono cooperation?
Bino
71
Is depth perception considered a bino or mono cue?
Mono cue
72
What type of monocular cues does depth perception have?
- object overlap
- object size
- shadows
- perspective
73
Depth perception is seen in what 2 things?
Local stereo and 3D movies
74
Is stereo learned or acquired?
Automatically acquired
75
When will a child develop stereo?
6 months
76
Is depth perception learned or acquired?
Learned. You get it from experience and learning how to judge distance
77
Mono Cue: same distant subject appear smaller than the same subject at near
Linear perspective
78
Mono cue: an object in front covers an object that is behind.
Occlusion
79
Mono Cue: an object that is near appears to have a shorter excursion than a distal object when you move your head. (Closer objects appear to move faster)
Motion parallax
80
Mono Cue: solid objects cast a shadow. The position of the shadow shows depression and elevations
Shadow/shade
81
Mono Cue: if an object is bigger, it is judged as nearer.
Size of known object
82
Mono Cue: the object that interrupts contour of another is seen as being in front.
Overlaying contour
83
Simultaneous binocular perception of dissimilar objects that are projected in the same direction
First degree fusion
84
Single simultaneous, binocular perception of identical targets with dissimilar parts (suppression check)
Second degree fusion
85
Fusion of disparate targets, resulting in a 3D percept.
3rd degree fusion
86
Theory: There is a one to one retino-cortical relationship between the eyes. A given retinal area (point AR) shares a common subjective visual direction with an area of the other retina (point AL).
Correspondence and disparity theory
87
When dissimilar retinal areas are stimulated by one object, what is reported?
Diplopia
88
Does depth increase or decrease with disparity?
Increases
89
If disparity persists, what occurs?
Diplopia
90
Does disparity increase or decrease the quality of stereo?
Decreases
91
T/F: The receptive field of a visual neuron/cell is the part of the visual field that can influence the firing of that cell.
True
92
T/F: neurons that can be maximally and simultaneously stimulated are likely involved in binocular vision.
True
