Amblyopia Flashcards
what is amblyopia?
- loss of visual acuity in one or both eyes that cannot be improved by corrective lenses
- pathology is absent
- shows no potential of 20/20 vision
does a strabismus always indicate amblyopia?
-nope
decrease in VA for amblyopia is caused by…
- pattern vision deprivation
2. abnormal binocular interaction
can amblyopia be caused by reduced VA due to a disease?
nope
when should you be suspicious of amblyopia?
-loss of at least 2 lines of VA that is NOT caused by disease or correctable by refractive correction
amblyopia can cause (like 9 things)
- reduced VA
- dysfunction of accommodation
- poor eye alignment
- reduced contrast sensitivity
- bad spacial judgments
- poor resolution
- brain induces monovision
what percent of the population in the US has amblyopia?
2-4%
what is the critical period?
- the critical period ends around 8-10
- after this, it is really hard to correct it and you’re probably stuck
is amblyopia unilateral or bilateral?
can be either
why is it called the critical period?
- visual system is still developing so it can be molded
- neurological and sensory development of visual system is not impaired yet
during the critical period, what helps with the development of the visual system and visual potential?
- stimulation
- thats why treatment is better during the critical period
abnormal visual input result in what during and after the critical period?
during: blurred image, brain tries to fix it
after: blurred image, but not a halt to the sensory development of the visual system (brain is not moldable anymore)
what happens if you treat amblyopia TOO early?
-you can interrupt the emmetropization process and natural change their eyes can make
why does amblyopia occur? (in general with pathways and such)
-the visual pathway fails to develop properly due to inadequate stimulation, which could cause dissimilar images and binocular dysfunction
what are the two most common causes of amblyopia?
- strabismus(eyes not aligned on the target at the same time)
- anisometropia (difference in refractive error between eyes)
can a phoria cause amblyopia?
no!!!!!!!!!!!!!!!!!!!! because both eyes are working together with a phoria
what are the three types of refractive amblyopia?
- Meridional
- isoametropia
- anisometropia
what is meridional amblyopia?
-caused by uncorrected high astigmatism in one or both eyes
why can meridional amblyopia easily missed?
-because kids can squint and compensate
what is isoametropic amblyopia?
- caused by very high refractive error in BOTH eyes
- so high that a clear retinal image cannot be obtained
what change in VA is experienced with isoametropic amblyopia?
-bilateral decrease in VA (both eyes)
with a kid with high uncorrected hyperopia in both eyes, should you immediately expect him to get to 20/20 corrected vision?
-nope. initially VA will stay reduced in both eyes
high hyperopia can SOMETIMES cause what kind of deviation?
esotropia
a 4 year old with high hyperopia hasn’t started school yet, will you/ they notice an eye deviation?
- nope
- they have had no motivation to accommodate or focus, so there is not strabismus yet