Flashcards in 2. Normal Development of Monocular Aspects of Vision Deck (22)
at what age are VEPs just detectable at?
1 or 2 weeks of age
when do VEPs start to get smaller in amplitude? why?
6 months of age
response becomes more complex
the latency of VEPs steady decreases until the child is how old?
100 days, reaching 1/10 sec (same as adults)
changes in VEP are dependent on the development of what?
development of the retina
VEP shows a steady inc in VA that levels off around ___ months, then starts again at what age?
6-7 years of age
in kittens, when is visual acuity mature at
3-4 months of age
in kittens, at what age does CSF greatly increase from? until when?
greatly increases from 3-4 weeks until 12 weeks
in humans, at what age does VEP CSF increase greatly from? until when?
increases greatly from a very insensitive 2.5 months until 6 months but still not at adult levels
in cats, how does the CSF develop in 3-4 weeks? 4-5 weeks? 6-7 weeks?
3-4 weeks: cortex becomes active (VA very low)
4-5 weeks: improves rapidly (esp at lower freq)
6-7 weeks: starts to level out
this period is the critical period wehre cats can develop amblyopia
in humans, what is the VEP VA at 2 months? 6 months?
2 months: 20/100
6 months: 20/40
what did the MIT procedure tell us about grating acuity?
grating acuity develops as a function of mature (developmental delays), not age and experience
what did the MIT procedure tell us about CSF in infants?
highly reduced for all spatial frequences in infants (100x less sensitive)
what information does VEP tell us? PL?
VEP shows what information is traveling through the visual system
PL shows how well the infant actually sees and responds to their environment
at what age do VEP and PL findings approach one another?
1-2 years of age
what is the VA for PL at 2 months? 6 months?
2 months: 20/400
6 months: 20/100
why is landolt C a much more accurate measure for amblyopes?
bc reading letters requires position sense while gratings do not..position sense is what is affected in strabismic amblyopia
at 4 weeks, an infant is _____ times less sensitive to light than an adult. and at 18 weeks they are ___ times less sensitive.
what age does light sensitivity approach adult levels?
2 years of age
why does a 3 month old have a lightly higher photopic luminance sensitivity at short wavelengths?
due to differences in optical clarity
why does a 3 month old have colors desaturated? esp in blue/green
reduced pattern vision
at what age do almost all kids respond appropriately to changes in movement direction?
at what age does orientation sense start? at what age does almost every kid have good recognition of chagnes of 30 deg or more?
ability starts at 4 weeks, and by 10 weeks have good recognition