Ped Ophthalmology - Exam 1 Flashcards
Infants should be able to follow an object by ______
3 months of age
What is amblyopia?
A functional reduction in the visual acuity of an eye, either unilaterally or bilaterally, caused by disuse or misuse during the critical period of visual development
_____ is the MC cause of pediatric visual impairment
Amblyopia
What is the underlying cause of amblyopia?
In first few years of life, brain must learn to see or interpret images. In amblyopia, the brain receives a poor image from the eye and thus does not “learn to see well”
Vision loss occurs in this case because nerve pathways between the brain and eye are not properly stimulated
What are the risk factors for amblyopia?
prematurity
SGA
family hx
neurodevelopmental delay
What are the 3 classifications of amblyopia?
strabismus
refractive
deprivational
_______ misalignment of the visual axes of the two eyes. Why does it occur?
strabismus amblyopia
One eye may turn in, out, up, or down
Occurs because the foveas of the two eyes are presented with two different and unfusable images.
The visual cortex suppresses the image from one eye in order to avoid having diplopia; long-term suppression of one eye results in strabismic amblyopia
_______ One or both eyes having a refractive error causing an imbalance between the eyes. What is the underlying cause?
refractive amblyopia
The foveas of the two eyes are presented with different image clarity d/t unequal uncorrected refractive errors; the image in one eye is not focused on the fovea at the same time as the other
_______ Obstruction by a cataract or complete ptosis prevents formation of a formed retina
deprivational amblyopia
_____ is the MC type of amblyopia. When is it detected?
refractive amblyopia
Often detected at an older age (4-5) because they lack obvious external abnormalities
Is refractive amblyopia more common in near sighted or farsighted pts?
farsighted pts (hyperopic)
______ is the least common but most severe form of amblyopia. What is the underlying cause?
Deprivational Amblyopia
It results from vision deprivation, typically a result of interruption of the visual axis or severe distortion of the foveal image (Congenital cataracts, ptosis, congenital corneal opacities, vitreous hemorrhage)
How do you test a pre-verbal child for amblyopia?
fixation reflex
testing involves moving a visual target to and from the child’s visual space, each eye being tested by occluding the fellow eye
Children who have amblyopia will rarely maintain fixation with amblyopic eye when both eyes uncovered
Besides the fixation test, what is one additional test in pre-verbal children for amblyopia?
**_____ is the single best screening device in verbal children (3 or older)
**test visual acuity using the allen/snelling chart
snellen chart is measured at 20 feet
What are some indications for amblyopia referral?
failure of visual acuity test worse than 20/40 in 3-5 years old or worse than 20/30 in 6+ years old
greater or equal difference in visual acuity between OD and OS
abnormal red reflex
asymmetry of vision
abnormal ocular alignment
unilateral ptosis
**______ is the gold standard of amblyopia tx
eye patching on the good eye to make the pt use their “bad” eye
What are the 4 different directions of strabismus description?
What is ocular instability of infancy? When does it typically resolve?
Unsteady ocular alignment often sporadically present in newborns until the first few months of life
Usually resolves around 3 months of age after child is able to fix and follow
______ the apparent esotropia that occurs in children with a wide nasal bridge and or large epicanthal folds during the first few years of life. How does it makes the pt’s eyes look?
Pseudostrabismus
making the eye appear esotropic, particularly when the child looks in lateral gaze
______ is the primary screening technique for strabismus. What is another name for it? How its it performed?
corneal light reflex
Hirschberg test
Accommodation target using a small toy used w/ the ophthalmoscope light standing several feet from the child.
Hold the light and toy in the same hand and use the light to reflect on both eyes at the same time
What will a normal corneal light reflex test show?
A normal test will reveal that the light reflects off the same position on each eye
What is this?
esotrophy strabismus
_____ is when the child is asked to visually fixate on a target at distance or near. What is the name? What does the PA do next?
cover test
The examiner briefly covers one eye while observing the opposite eye for movement
