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Flashcards in B13 Deck (92):
1

What are 3 things you must have to have normal bino vision?

-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

What are 9 advantages of bino vision?

-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

What are 7 problems with abnormal bino vision?

-asthenopia
-diplopia
-rivalry
-amblyopia
-eccentric fixation
-suppression
-anomalous correspondence

4

If someone has no stereo what does this mean?

They have no bino vision

5

The collection and integration of information received at the retina and transmitted to the cortex

Sensory fusion

6

T/F: if is sensory fusion is affected by any condition, integration of the images from the 2 eyes will be abnormal

True

7

What is the fundamental part of vision?

Sensory

8

Name 7 causes of motor dysfunction

-disease
-incomitancies
-latent manifestations (phorias)
-manifest deviations
-vergence quality (facility)
-vergence quantity (amplitude)
-nystagmus

9

When should motor problems be treated?

They should be treated last after identified sensory and integrative problems have been treated

10

Name 5 causes of integrative problems

-disease
-aniseikonia (different size retinal images)
-suppression
-anomalous retinal correspondence
-horror fusions (inability to fuse)

11

Name the 5 causes of sensory dysfunction

-disease
-refractive error
-amblyopia
-eccentric fixation
-accommodative insufficiency and infacility

12

What is considered normal single bino vision?

Bifoveal with no deviation

13

What is considered abnormal bino vision regarding the fovea?

When the fovea of one eye projects with a non fovea point of the other eye

14

Is misalignment usually present with abnormal bino vision?

Yes

15

Localized the visual percept in a visual direction that is relative to the direction of the fovea

Retinal area/element

16

If the eyes are properly aligned, an image is received on ___ areas of the retinas

Matching

17

If the eyes are functioning normally, will the images will be the same size and color?

Yes

18

What 4 things does the stimulus perceive when the retinal areas is stimulated?

-brightness
-color
-form
-direction

19

T/F: matching retinal elements have different visual directions

False. They have the same visual direction

20

Considered the retinomotor zero point

Fovea

21

T/F: all points in space falling along the visual line have the same visual direction

True

22

This is used to build interpretation of 3D images in space

Visual direction

23

What 2 things are normal when there is precise and clear bifoveal fixation?

Bino vision and fusion

24

If there is abnormal bino vision is the visual direction the same or different?

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