Amblyopia Flashcards
Broadly define amblyopia
A functional loss of vision NOT attributed to pathology.
What is the layman’s term for amblyopia?
“lazy eye”
Up to what age does amblyopia usually develop?
Up to age 6-8
Once amblyopia develops, how long may it persist?
May persist for LIFE once established.
Oversimplified mechanism of action for amblyopia:
- Brain receives ____ image(s)
- Brain wants ___ image(s)
- Eye with _____ picture ____
- Eye with _____ picture ____
Oversimplified mechanism of action for amblyopia:
- Brain receives TWO image(s)
- Brain wants ONE clear image(s)
- Eye with BEST picture WINS
- Eye with WORST picture TURNS OFF
Amblyopia leads to problems with ______ vision
binocular
Precise definition of amblyopia
Reduction in VA to 20/30 or worse in one eye or a two line difference between two eyes in the absence of pathology and with best refractive correction.
Three main causes of amblyopia
- Form deprivation
- Optical defocus/refractive
- Strabismus
(4. Any combo of the above)
Define form deprivation
Physical obstruction along the line of sight
What are three examples of form deprivation
- Congenital cataracts; congenital ptosis
- traumatic cataracts
- Corneal opacities
Results of form deprivation
Prevents a clear, sharp image from reaching the retina
For form deprivation to cause amblyopia, what age does it usually have to occur by?
Usually occurs before age 8 to cause amblyopia.
Degree to which amblyopia develops from form deprivation depends on what two things?
Depends on the
- time of onset
- extent of the form deprivation
What are the 3 main categories of refractive amblyopia?
- Anisometropia
- Meridional
- Isoametropia
Define anisometropia
An unequal refractive error between the two eyes, usually more than 1 diopter difference