Flashcards in Intro/ Development Deck (33):
vision testing requirements in CA
-VA upon first enrollment and every 3 years thereafter
-Color vision for boys only upon entry into the first grade
what are the AOA guidelines for ages for eye exams?
-by 6 months
-at 3 years
-before 1st grade and every 2 years thereafter
what % of children receive an eye exam before 5 years of age?
prevalence of amblyopia
what ethnic group has a higher prevalence of ambylopia
prevalence of strabismus
prevalence of refractive error
prevalence of ocular disease
prevalence of color vision defects
what anatomy contributes to young children not being able to see 20/20?
-immature cones (short and stumpy)
-fovea is last area of retina to develop morphologically
-immature visual cortex
the VEP method of measuring VA shows what patterns of VA
1mo: 5cpd (20/120)
2.5mo: 7.8cpd (20/77)
6mo: 18cpd (20/33)
12mo: 25cpd (20/24)
about how long does it take for a child to reach 20/20 when measuring VA with preferential looking?
can be up until 3/4 years to see 20/20
(requires more cooperation/attention from the child)
when does contrast sensitivity reach adult like levels?
what is unique about accommodation for an infant?
-variable within 1-3 months
-infants have a large depth of focus
when does accommodation reach adult like levels for low demands?
~ 3-4 months
(but longer latency than adults)
what is the VOR reflex?
vestibulo-ocular reflex: connection between inner ear to EOMs to maintain fixation with head movement changes
what are saccades like in infants
-present at birth
-long latency, wrong direction, short amplitude
is stereopsis present at birth?
when is the onset of stereopsis and when is development spurt?
starts at 3-5 months
-development spurt between 4-6 months
when does stereopsis reach adult like levels
~ 2 years old
(300 sec of arc)
when is the "critical period" for binocular development
up to 3 years old
when is the "sensitive period" for binocular development
up to 10 years old
is binocular fixation and convergence present at birth?
most infants are orthotropic at ___ month(s)
when do infants gain fusion
when do infants' binocular fixation and convergence become adult-like
what are some conditions that prevent development of the cortical circuits underlying stereoscopic vision (causing amblyopia)
what is unique about the anatomy in the newborn eyes
-really steep cornea
-really powerful lens
what changes in the eyes anatomy from newborn to 3-9 months
-cornea loses power
-lose power in lens
-eyeball gets longer
the binocular visual field of normal 6 to 7 month old infants was ___% that of the adults
when does color vision emerge
VEP studies show what emergence for color vision for the different wavelengths
2 weeks: long and medium wavelengths
5 weeks: short wavelengths