Flashcards in 3. Normal Development of Binocular VIsion Deck (19)
at 1 months, infants appear to have what kind of eye position? why?
slight intermittent exotropic or ortho
due to a large angle kappa (8 to 10 deg)
at what age do infants have a shift to ortho?
around 3 months
at what age does convergence become accurate and consistent in infants?
at 1 month of age, how developed is convergence in infants?
convergence is absent or partial/intermittent but accommodative convergence is present
What does Held propose that accurate convergence is due to?
due to the development of ocular dominance columns and cortical disparity control mechanisms
at what age do kittens develop adult levels of depth perception and steropsis
in human infants, what is the age of onset of stereopsis
when does the switch occur for infants to prefer a fusible stimuli over a non-fusible pattern
3 months and 1 week
where does Held propose that stereo and binocular fusion dvelop?
both develop due to ocular dominance columns and binocularity mechanisms in the visual cortex
how does monocular visual resolution acuity develop in infants? binocular?
monocular: acuity levels off around 6 months of age then begins to improve agian
binocular: tends to just go straight up so that at alittle after 3 months, binocular acuity is better than monocular
when does binocular pupil summation occur in infants?
6 months of age, the response goes up to adult levels
what allows for binocular summation of constriction?
binocular fibers from the cortex develop connections in the pretectum, adding cortical input to the system
pupil constriction is largely....
b. subcortical ?
when is the onset of symmetric monocular optokinetic nystagmus?
around 3 months of age
how do children w/ an unilateral esotropia vs alternate esotropia develop amblyopia?
unilateral=steady increase in the development of amblyopia
what is Vernier acuity aka hyperacuity?
the ability to align things in space (positional sense)
How do Vernier acuity and VA compare at 11 weeks, 14 weeks, and 22 weeks?
11 weeks: vernier acuity much lower than VA
14 weeks: equal
22 weeks: vernier acuity much better than VA
when does the second phase of development occur for vernier acuity to improve again? when does it stop?
4 or 5 yrs old until 10-12 years when vernier is 5x better than grating acuity