Msp 2 Exam 2

Front 1

what is vection

Back 1

the illusion of motion of one's ENTIRE SELF as a result of motion in one's peripheral visual field

ex: sitting in a stationary car and cars around move foward. it seems like you are moving backwards

Front 2

what is the relationship between vection and illusory motion

Back 2

although it can be caused by visual stimulation, vection is NOT considered to be a category of "illusory" (visual) motion

Front 3

what are characteristics of eye/head motion perception

Back 3

1. subject tracks stimulus with head/eye movement
2. retinal image of moving object remains stationary on fovea
3. info about obj motion involves muscular, EOM, and vestibular system.

Front 4

what are the characteristics of retinal motion perception

Back 4

1. requires motion of the objects image across the retina
2. info about obj motion mainly within "visual" pathways

Front 5

what is the Troxler Effect

Back 5

1. the perceptual disappearance of a STABILIZED RETINAL IMAGE
2. retinal image is stabilized when it moves exactly with the retina, REGARDLESS of any voluntary or involuntary movements of eye

Front 6

what is the relational between the human visual system and light stimulation

Back 6

the human visual system is sensitive to CHANGES in light stimulation

Front 7

under normal conditions...why can't we see retinal blood vessels

Back 7

1. shadow of retinal blood vessels are stabilized retinal images.
2. they move WITH THE RETINA as the eye moves so their position on the retina DOES NOT change

TROXLER EFFECT

Front 8

what is the Purkinje Tree?

Back 8

PURKINJE TREE:
by causing a rapid oscillation of the shadows of the retinal blood vessel across the retinal, you can perceive the pattern of the retinal blood vessel.

Front 9

how is minimum amplitude of perceivable motion effected with retinal eccentricity?

Back 9

INCREASES TOWARD PERIPHERY

foveal: ~20 arc sec or less
20 deg: ~3 arc min
40 deg: ~5 arc min

*detect faster movements at the fovea

Front 10

how is the minimum VELOCITY of perceivable motion effect with a nearby stationary reference stimulus?

Back 10

1. ~10X better in the presence of a nearby stationary reference stimulus
2. ~1-2 arc min/sec WITH reference
3. ~10-20 arc min/sec WITHOUT reference

*decreases with increasing luminance

Front 11

what are the FIVE ways by which an object might appear to move

Back 11

1. real motion
2. autokinetic effect
3. induced motion (motion contrast)
4. aftereffects
5. stroboscopic motion

Front 12

what is the autokinetic effect

Back 12

illusory motion in which a small, stationary object viewed against an otherwise COMPLETELY featureless visual field, will appear to move about randomly within a small area

ex. small, station point of light viewed in the dark will seem to move

Front 13

what is induced motion

Back 13

1. illusory motion in which a stationary object appears to move due to the motion of surrounding obj or contours
2. always perceived to be in the direction opposite to that of the inducing objects

example: moon appears to be moving in the opposite direction of cloud movment

Front 14

what is motion contrast

Back 14

1. a special case of induced motion
2. only operates across very short distances

Front 15

why do we see motion with repeating asymmetric patterns

Back 15

NEURAL IMAGE CONTRAST
1. high contrast points in the optical image are registered BEFORE low contrast point
2. ration of neural responses in the high and low contrast areas of the neural image change over time
3. apparent shift in phase is what activates the local velocity detectors

Front 16

what is the difference between motion ADAPTATION vs. motion AFTER EFFECT

Back 16

1. adaptation: illusory changes in the perception of motion that occur DURING prolonged viewing of moving objects

2. after-effect: illusory perception of motion of stationary objects OR changes in the perception of motion of moving objects AFTER prolonged viewing of moving objects

Front 17

waterfall illusion is an example of...

Back 17

MOTION AFTEREFFECT

Front 18

what is velocity adaptation

Back 18

prolonged viewing of an object moving at a constant velocity may cause a DECREASE in the PERCEIVED speed of motion

Front 19

what is direction specific adaptation

Back 19

motion detection and contrast detection threshold INCREASE during prolonged viewing of moving objects but only for objects moving in the SAME/SIMILAR direction

Front 20

what is stroboscopic motion

Back 20

apparent motion:
1. resulting from the successive presentation of a stimulus at different locations along a continuous path
2. example lights going around a marquee

Front 21

what is KORTE'S LAW

Back 21

1. describes the relationship among various stimulus parameters necessary to maintain optimum PHI motion when any one parameter is changed

Front 22

what is first order motion

Back 22

movement of areas that are defined by their LUMINANCE

Front 23

what is second order motion

Back 23

movement of areas whose contours are defined by TEXTURE

NOT LUMINANCE

Front 24

what is third order motion

Back 24

1. motion defined ONLY by difference in COLOR!!
2. motion defined as figures with NEITHER LUMINANCE NOR TEXTURE boundaries
3. PARVOCELLULAR PROCESSING

Front 25

what are the SEVEN characteristics of NORMAL neonate vision

Back 25

1. small eye (~16.5mm)
2. clear ocular media
3. reasonably good image quality
4. hyperopia and astigmatism common
5. small pupils (miosis)
6. poor control of accomodation
7. foveal photoreceptors are wider, shorter, and more widely spaced than in adults

Front 26

what is coherent motion

Back 26

1. motion of elements that all share the same velocity of motion
2. form from motion
3. Gestalt organizing principal (common fate)
4. evaluates mainly MAGNOCELLULAR processing
5. elevated thresholds in glaucoma and ONH disease

Front 27

what is the braddick limit

Back 27

1. maximum displacement threshold
2. typically ~15 arc minutes

Front 28

what is short range motion

Back 28

1. SECOND order stroboscopic motion
2. within Dmin and Dmax range
3. SOA<100 msec
4. NOT perceived with DICHOPTIC STIMULATION or bright ISI

Front 29

what is long range motion

Back 29

1. FIRST order motion
2. operates with displacement larger than Dmax
3. SOA 100-500 msec
4. works WITH DICHOPTIC stimuli and with bright ISI

Front 30

what does short range and long range motion rely on?

Back 30

both are believed to rely heavily on MAGNOCELLULAR PATHWAYS

Front 31

what is aperture problem?
example?

Back 31

1. receptive fields of neurons signaling visual motion function as viewing apertures
2. the aperture itself can influence perception of the direction of motion within

example: Barber Pole Illusion

Front 32

visual illusions

Back 32

erroneous perception due to incomplete, ambiguous, or contradictory visual information

Front 33

what are some theories that support object recognition

Back 33

1. feature analysis (bottom up)
2. global processing (top down)
3. computational models (newer bottom up)
4. feature integration theory (BOTH)

Front 34

what is analytical introspection

Back 34

STRUCTURALISM:
identify the smallest set of PRIMARY SENSATIONS necessary to uniquely identify any object

ex: a bunch of dots making up a picture

Front 35

what are Pandemonium Models?

this is an example of...

Back 35

FEATURE ANALYSIS:
1. feature demons find vertical lines, acute angles, etc.
2. cognitive demons have ideas about the features of their letters
3. decision demon identifies the letter based on which cognitive demon "yells the loudest"

Front 36

what are GEONS

Back 36

GEOMETRIC ICONS
1. non accidental features, equally recognizable regardless of orientation
2. structures composed of geons should be "viewpoint invariant"
3. we recognize objects by recognizing the spatial combo of the various geons

Front 37

most eyes growth happens within...

Back 37

the first 6 years

Front 38

what ethinicity tends to be more myopic

Back 38

ASIANS

Front 39

what is the most important factor that leads to emmetropization

Back 39

time spent outdoors is most important for proper emmetropization

Front 40

how does form effects myopia

Back 40

1. depriving the eye of form vision promotes axial elongation and myopia (chronic image degradation can cause myopia)
2. the ocular changes in FDM are similar to those associated with childhood myopia
3. the potential for a clear retinal image is essential for normal refractive development

Front 41

what is the role of optical defocus in treatment of refractive error

Back 41

1. optically imposed myopia:
to compensate, the eye must become more hyperopic
2. optically imposed hyperopia:
to compensate, the eye must become more myopic

Front 42

what happens with under corrected patients

Back 42

1. under correction DOES NOT prevent myopic progression in children
2. they actually will become more myopic

Front 43

what is the consequence of traditional correcting lenses

Back 43

as a consequence of eye shape and/or aspheric optical surfaces, "corrected" myopic eyes often experience significant HYPEROPIC DEFOCUS across the visual field

Front 44

AN INTACT FOVEA IS NOT ESSENTIAL FOR NORMAL EMMETROPIZATION

Back 44

AN INTACT FOVEA IS NOT ESSENTIAL FOR NORMAL EMMETROPIZATION

Front 45

what are the implications of human studies of emmetropization

Back 45

1. contribution to myopia, concentrate on factors that are very CONSTANT over time
2. peripheral vision should be considered when assessing the effects of visual experience on refractive development
3. peripheral vision should be taken into account in order to optimize optical treatment strategies for myopia
4. inaccurate accommodation is significant risk factor in myopia
5. spending time outdoors is good for emmetropization

Front 46

what is a better why to correct myopia

Back 46

by increasing the effective curvature of field it would be possible to correct central errors and either correct peripheral errors or induce peripheral myopic defocus

Front 47

photoablation of the fovea does not...

Back 47

photoablation of the fovea does not...
1. interfere with normal emmetropization
2. prevent recovery from induced refractive errors
3. prevent form deprivation myopia
4. prevent compensation for optical defocus

Front 48

what are some normal changes of the pupils and lens with increasing age

Back 48

senile miosis:
1. decreased in retinal illumination
2. increased depth of field

Lens Change:
1. Presbyopia: decrease in AA
2. yellowing of crystalline lens
3. increased light scatter

Front 49

what are some normal changes in refractive error with increasing age

Back 49

1. "with" to "against" the rule shift in astigmatism
2. increase in myopia
3. NO significant change in macular pigment density

Front 50

what happens to luminance to the retina as we age

Back 50

1. reduced light transmittance through smaller pupils
2. less light due to lens change
3. perceptually not tramatic because of light adaptation

Front 51

what happens to spectral sensitivity as we age

Back 51

1. decreased sensitivity for all wavelengths
2. greater decrease for short wavelength sensitivity

Front 52

why does the short wavelength sensitivity decrease more with age

Back 52

1. yellowing of the lens
2. greater sensitivity of SWS cones for metabolic damage (diabetes)

Front 53

how is color vision affected with age

Back 53

1. increase in tritan abnormailities
2. evident in DESATURATED D-15 testing
3. secondary to yellowing of lens, increased macular pigment density and metabolic disease

Front 54

how is contrast sensitivity affect with increasing age

Back 54

1. decrease beginning ~65 yrs.
2. mainly for midrange and high spatial freq
3. due to miosis, lens and vitreous change, as well as increase in density of macular pigment and neural factors

Front 55

how is visual (recognition) acuity impact with age (IMPORTANT)

Back 55

1. mild decrease in high-contrast recognition acuity beginning around 60-65
2. significantly greater decrease found in LOW CONTRAST recognition acuity

*snellen chart DO NOT adequately reflect an older patients loss of visual function in the real world

Front 56

what are two clinical test for disability glare

Back 56

1. brightness acuity tester (BAT)
-high contrast acuity with glare

2. Berkeley Glare Test
-low contrast acuity with glare

Front 57

what happens to disability glare with increasing age

Back 57

1. decreased spatial resolution in presence of bright, surrounding light
2. largely due to LIGHT SCATTER

Front 58

glare recovery with increasing age

Back 58

1. time to read two lines larger than before on the low contrast SKILL card after exposure to bright light
2. ~8x increase from ages 60-80+

Front 59

what happens to flicker perception as we age

Back 59

1. gradual decrease at ~20 years
2. larger decrease at ~70 years
3. both CFF and sensitivity decreases are due to neural factors

Front 60

at birth what does the normal eye look like

Back 60

1. small eye (16.5mm)
2. clear media
3. reasonably good image quality
4. HYPEROPIA and ASTIGMATISM
5. small pupils
6. poor accommdative control
7. photoreceptors are wider and shorter

Front 61

the first eye movements are...

Back 61

1. reflexive
2. saccadic

*existence of these early eye movements is that the neural pathways serving them must exist at birth

Front 62

newborns and tracking

Back 62

infants show little smooth pursuit tracking and mostly SACCADIC TRACKING

Front 63

what pathway is utilized in OKN and smooth pursuit

Back 63

1. different NEURAL PATHWAYS (subcortical) than those involved with conscious perception
2. OKN can exist in people who are perceptually blind

Front 64

what eye movement bias does newborns exhibit

Back 64

1. NASAL BIAS
2. better OKN and smoother pursuit for T-N motion than N-T
3. normally disappears within first 3-5 months
4. persist in infantile onset strabismic amblyopia

Front 65

spectral sensitivity and color vision in new borns

Back 65

1. scotopic/photopic spectral sensitivity (adult shape by 1 month and adult sensitivity by 6 months)
2. R/G discrimination present at 2months (adult level by first year)
3. B/Y develop more slowly

Front 66

what is the contrast sensitivity timeline for newborns

Back 66

1. 0-10wks: improvement at all spatial freq
2. by 2 months: lateral inhibition
3. by 6 months: peak of CSF at adult position
4. ~5 years: increase sensitivity in high spatial freq and cutoff spatial freq

Front 67

when does stereopsis mainly develop in newborns

Back 67

1. little to no stereopsis before 3 months
2. EXTREMELY rapid development between 3-6 months

Front 68

what happens in the first six months of development

Back 68

1. CFF
2. scotopic/photopic luminosity
3. absolute light sensitivity
4. spatial freq of max contrast sensitivity
5. stereopsis (threshold ~1arc min)

Front 69

what happens within the first year of development

Back 69

red/green color vision development

Front 70

what happens between 3-12 years of development

Back 70

1. fine spatial resolution
2. fine relative spatial localization

Front 71

in art what gives rise to depth

Back 71

THREE DISTINCT CHANNELS:
1. form
2. color
3. movement