Flashcards in Binocular and Spatial Vision (M2) Deck (39):
How does depth perception of monocular vision differ from binocular vision?
monocular much worse than binocular
What is the vision of two-eyed vertebrates in which the eyes work together? 1. What is different about theses animals anatomically compared to when function separately? 2
2. partial decussation of the optic nerves
What is a major difference between congenital nystagmus and acquired nystagmus?
oscillopsia is common in acquired
What is the direction of the line of fixation measured from the straight ahead position (with symbol)?
ocular direction (α)
What is the theory that ocular, oculocentric, or egocentric direction is that of the dominant eye? 1. Is this true in most cases? 2
1. dominant eye theory
What does anomalous retinal correspondence (ARC) prevent?
confusion and diplopia
What is the line of sight perpendicular to an extended source (wall, etc) called?
subjective straight ahead (SSA)
What is the ocular disorder in which there are problems with communication between afferent and efferent systems that presents in the first 6 months of life?
infantile nystagmus syndrome or congenital nystagmus
What is the angle between the line of fixation and optic axis? 1. What does this angle indicate? 2
1. gamma (γ)
2. the nasal-temporal division in ambiocular vision
What is the concept of seeing double at any distance other than the distance you are fixating called?
How does brightness perception of monocular vision differ from binocular vision?
Normally the same (luminance of two eyes is the average, no the sum of the luminances of the two eyes)
Which direction is the slow phase for a vestibular nystagmus?
drift towards damaged (hypo) side because sensing body rotation to opposite side
What is harmonious anomalous retinal correspondence (ARC) easily confused with?
lack of correspondence
How does light detection of monocular vision differ from binocular vision?
improved detection with two eyes
How does light adaptation of monocular vision differ from binocular vision?
eyes dark adapt independently of each other
What is the result from stimulation of non-corresponding retinal points? 1. What is it equal to? 2
1. retinal or absolute disparity
2. angular separation of images
What is the visual direction of an object specified relative to the "line of fixation" (with symbol)?
oculocentric direction (β)
What type of eye placement do prey animals generally have? 1. Predator animals? 2
1. laterally placed eyes
2. frontal eyes
For vestibular nystagmus, what direction does the object appear to be moving during the slow phase eye movement? 1. Why? 2
1. opposite the eye movement
2. no body rotation actually occurred
Is the far/near AC/A or the gradient AC/A always larger? 1. Why? 2
2. proximal vergence is not actually constant
What occurs during the adaptation to glasses for a patient?
adapt limb proprioception to match vision
What is the probability light detection equation?
q = 1 - (1 - p)^n
q = prob in two eyes
p = prob in one eye
n = number of eyes
What is it called when one eye is the favored side of the bilateral pair?
Where is the egocenter located in binocular vision?
between the eyes about 10cm behind the plane of the eyes
For acquired nystagmus, what direction does the object appear to be moving during the slow phase eye movement? 1. Why? 2. During fast phase? 3
1. opposite the eye movement
2. alpha is not being sensed
3. suppression and omission during fast phase
How does transient light adaptation of monocular vision differ from binocular vision?
interactions btw the eyes increase the threshold in one eye near the onset and offset of the background in the other eye
What are the ocular signs found in infantile nystagmus syndrome or congenital nystagmus?
2. reduced with convergence
3. pendular in straight ahead and jerk at sides
4. should have null position
5. has unique acceleratory slow phase
6. NEVER have oscillopsia
What is the body reference point for egocentric direction called?
What is the sign convention for the specification of direction?
1. right and up are positive directions (+)
2. left and down are negative direction (-)
What are retinal points (one in each eye) that have the same oculocentric direction called?
corresponding points (β(L) = β(R))
What is the coordinated behavior of the two eyes in the perception of space called?
What are the major benefits of ambiocular vision?
2. better visual acuity (smaller angle γ so better optics)
Because the prismatic effects of plus lenses require the eye to rotate more than the normal amount by moving the image, what is the patient really doing?
patient is pastpointing
What is the theory that ocular, oculocentric, or egocentric direction is the average of the two eyes? 1. Is this true in most cases? 2
1. Cyclopean theory
What happens to the perception of the subjective straight ahead with left neglect?
right side of wall appears closer and left part appears further away
What is the visual direction of an object specified with respect to the straight ahead (with symbol)?
egocentric direction (χ)
What is the specific sensation of depth characteristic of ambiocular vision?
What is the vision of two-eyed vertebrates in which the eyes function separately called? 1. What is different about theses animals anatomically compared to when work together? 2
2. complete crossing of the optic nerves