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85 Cards in this Set

  • Front
  • Back
Which cells in the ocular dominance histogram are monocular?
1 and 7
Which eye does category 1 cells receive from?
contralateral eye
Which eye does category 7 cells receive input from?
ipsilateral eye
Which category is bincocular and receive equal input from both eyes?
Which categories are dominated by the contraleteral eye but also binocular?
2 and 3
which categories are dominated by the ipsilateral eye but also binocular?
5 and 6
The period wchi the visual system can be influenced by environmental manipulation
critical or sensitive period
What is the duration of the critical period?
7 to 9 years of age w/ the first two being the most critical
T/F ocular dominance columns are initially organized prior to and independent of visual experience
Congenitally blind individuals are better at localizing sounds than sighted people, why?
increased cortical area devoted to auditory input
reduction in vision secondary to monocular deprivation during the critical period
T/F amblyopia results from an abnormal eye
False. it is due to abnormal cortical development
What three factors diagnosis amblyopia?
-monoc occlusion
What three factors can cause occlusion amblyopia?
-monoc congenital cataract
-lid ptosis
-patching b/c of a dz
conditon where the two eyes have unequal refractive errors
Anisometropic Amblyopia occurs most commonly with what 3 types of refractive errors?
-conpound hyperopic anisometropia
-simple hyperopic anisometropia
-antimetropia (myopic)
T/F the pt will have greatly reduced stereopsis with anisometropic amblyopia.
How could vision loss be helped in anisometropic amblyopic pts?
-correction during the critical period
anisometropia in which both eyes are myopic is referred to as ...
compound myopic anisometropia
T/F Amblyopia develops in constant unilateral deveiations more so than alternating or nonconstant deviations?
What is the predicted acuity and sterescopic vision in a person who has alternating amblyopia?
-good vision
-little to no stereoscopic vision
what effect will strab pts not see?
-the tilt aftereffect
What is the tx for amblyopia?
-patch the nonamblyopic eye
T/F short periods of pathcing are as effective as longer periods for the tx of moderate amblyopia in children
True, you would do this by use of a cycloplegic or patching
occurs when a child progresses through the critical period with one visual meridian focused and the other out of focus
-meridional amblyopia
how much astigmatism do neonates usually manifest?
0.75 to 2.00D
Caucasian neonates are likely to show what type of astigmatism?
Chinese neonates are more likely to have type of astigmatism?
The amount of the astigmatism found in neonates generally decreases over what time?
the first 5 to 6 years of life
T/F It is generally not advisable to optically correct low to moderate amounts of astigmatism in infants
How much astigmatism should there be and what type before correcting it?
At least 2.00 D and especially with ATR
what common sx does ATR astig have?
-Asthenopia (child will not want to read)
T/F pts born with dense bilateral cataracts that are removed w/in the first 187 days of life appear to have permanently reduced ability to discriminate among similar faces, a task taht also apparently involves higher cortical areas
T/F Myopia parents are more liekly ot have myopic children
when do most growth of the eyeball occur?
first 6 years of life
suturing an animal's eyelid closed at birth or optically blurring the retinal image early in life leads to the development of axial myopia - this is evidence for what theory
-environmental role in the development of myopia
What type of refractive error are we born with?
-slight amount of hyperopia (less than 2.50D) during the first year of life
What is the resolution acuity of a 1 month old infant?
the optokinetic nystgmus response consist of which two movements?
-slow following mvmt (smooth pursuits) folled by fast compensatory eye movement (saccade)
OKN is useful in what type of pts?
-mentally retarded
T/F A pt could have impaired vision, yet show a normal OKN response
The behavrious whc infants prefer to view the patterned stimulus
perferntial looking (PL)
if the examiner is required to guess which side the pattern is on the procedure is called
forced-choice preferential looking (FPL)
what is the percentage correct that will elicit's the infant's grating acuity
-75% correct
T/F teller acuity cards have lower reliability
When are adult levels of 20/20 acuity reached?
3 to 5 years of age
what accounts for the porr acuity of infants?
-immaturities in the retina, particularly the foveal cones
FPL suggests that adults levels of resolution acuity are reached by what age?
between 3 and 5
VEP suggests that adult lvls of resolution acuity are reached by what age?
6 to 8 months
What is the difference in outcome of the FPL and VEP due to?
-the greater cognitive demans associated wtih FPL
CSF for 1 month old infants does not have a band-pass form. What does this suggest?
-the lateral interconnections w/in the retina, which are responsible for lateral inhibition have not fully developed
CSF is adult-like at what age
-9 YO
When does vernier acuity mature
-matures rapidaly during the first year or so
When does vernier acuity become adult like?
6-8 years old
Why does vernier acuity develop later in life?
-slow maturation of the cortex
When does stereoacuity mature?
-6 mo. (1 min of arc)
the retinal and cortical immaturities that slow the development of graing and vernier acuity have little effect on the (blank)
-maturation of temporal resolution
What is the critical flicker fusion frequency of a 1 mo. old
40 Hz
when is the scotopic sensitivity function adult like?
1 mo. of age
When does the scotopic sensitivty function b/c adult like at an early age?
-it is det by the absorption characteristics of rhodopsin and does not depend on postreceptoral processing
when tdoes the absolute sensitivty of the scoptopic system for a stimulus of 507nm develop?
6 mo. of age
Preferential viewing has been used to examin what color discrimination?
-red-green and blue-yel
when does rudimentary red-green discrimination arise?
2nd mo of life
T/F blue-yel discrimination has not been well understood
When are infants able to discriminate b/w two monkey faces?
6 mo.
CFF and the forms of the scoptopic and photopic sensitivy function show adult-liek characteristics w/in (blank)
the first 6 months
Grating and vernier acuity improve rapidly during the (blank), but then slowly mature until the child is (blank) and (blank)
-first year
-3 to 5
-6 to 8
T/F the critical period for the development of stereopsis may terminate at a younger age than the critical period for the development of vernier acuity
What tests can be use to examine the vision of children earlier on in life?
-the cover and Hirshberg tests
how does contrast sensitivy change as we age?
remains constant until 65 YO and declines rapidly after that
What contributes to reduced contrast senstivity?
-nuclear sclerosis
-senile miosis
-aging neural elements
What is the size of a pupil of a typical 20 YO?
5.3 mm
What is the typical size of a pupil in a 60 YO?
3.2 mm
how much light reaches the eye of a 60 YO?
-one third of the retinal illumination of a 20 YO
what is an adv of a sm pupil?
increase depth of field
yellowing of the crystalline lens is called a ...
-nuclear sclerosis
How does resolution acuity change as a person ages?
-it is maintained till 65 to 70 YO
T/F visual acuity measured under conditions of reduced contrast, reduced illumination, or added glare shows marked reductions in the elderly, especially in the very old
The tine it takes for visual acuity to recover following exposure to a birhgt light (disability glare recovery) also increase with age
Does the weber fraction change in the elderly?
-no, b/c the senile miosis and nuclear sclerosis reduce the retinal illumination produced by the increment and background by the same amount
How does standard visual field and UFV change as a person ages?
-standard visual field does change
-UFV decreases, particularly beyond the age of 50 years
what color discrimination b/c increasing more difficult as an individual ages?
T/F sensitivity to temporal modulation decreases in the aging eye at all temporal frequencies
How does steropsis change in the elderly?
b/c increasingly elevated beyond the age of 50 YO
How does astimatism change in the elderly?
increases in dioptric power in teh horizontal meridian relative to the vertical meridian .... shifts from WTR to ATR