Amblyopia 2 Flashcards
3 types of refractive amblyopia
Meridional amblyopia
Isoametropia amblyopia
Anisometropic amblyopia
Due to uncorrected high astigmatism in one of both eyes
Meridional amblyopia
Why can meridional amblyopia easily be missed?
Due to the orientation of the astigmatism……some children may be able to squint or compensate
Caused by very high refractive error in both eyes
Isometropic amblyopia
So high that a clear retinal image cannot be obtained.
This results in a bilateral decrease in visual acuity.
Child has a normal refractive error with good visual acuity in one eye and a significant refractive error and reduced visual acuity in the other eye
Anisometropic amblyopia
What are some common comments from children with anisometropic amblyopia
“My left eye never sees well”
“Thats my bad eye”
Uncorrected refractive error causes a constant blur that prevents the brain from getting clear information via the visual pathway.
When is the effect of blur most crucial?
In the first years of life, the critical period of development
Amblyopia resulting from a difference of hyperopia between the 2 eyes
Hyperopic anisometropia
Can be affected by as little as +1.00 D
In some cases of hyperopic anisometropia, _________ could develop.
Esotropia
In hyperopic anisometropia, ___________ can be affected, W4D can show __________, and you could also pick up a _________ _________.
Stereopsis, fusion, central scotoma
High unilateral myopia with lesser myopia in the other eye
Myopic anisometropia
Loss of visual acuity in one or both eyes that cannot be improved by corrective lenses
Amblyopia
Can a phoria cause amblyopia?
NO!
In amblyopic patients, could W4D show fusion?
Yes, depending on the severity of the amblyopia
If the patient has a prescription less than -5D in both eyes..
Patient most likely has moderate myopic anisometropia
Patient will most likely not develop amblyopia in this case (for ex, -0.75 DS OD for distance and -3.25 DS OS for near) because both eyes attain clarity at either distance or near.
Obstruction of the line of sight that prevents a clear eMate to form on the retina
Form deprivation
Can form deprivation occur in one or both eyes?
…..yes
Physical obstructions that can lead to amblyopia include….
Congenital cataracts Ptosis Traumatic cataract Corneal alacrity Vitreous opacity Vitreous hemorrhage
What can shaken baby syntrome lead to (in the eye)
Vitreous hemorrhage.
So sad.
What entrance test determines the presence of a strabismus?
COVER TEST!!!!
When the visual axes of both eyes do not intersect at fixation
Strabismus
Strabismus is important because it may a result of…
Stroke
Thyroid disease
Retinal disease
Heterotropia/tropia/strabismus is classified by
The direction of the non-fixating eye
What’re the 3 types of strabismus?
Early onset (within 6 months of birth)
Accommodative
Acquired
What betters the chances of re establishing binocularity after diagnosing amblyopia?
The more time that there is equal visual acuity and binocularity before strabismic disruption
What important information should you obtain about past history of an amblyopic patient?
Occlusion therapy
Glasses/contact
Past surgeries
This will help you plan and make prognosis
The earlier the intervention after the onset of strabismus….
The less the chance of sensory adaptations
Examples of sensory adaptions
Amblyopia
Scotoma/suppression
Anomalous correspondence
___________ implies better prognosis.
Stereopsis
Strabismus prognosis is worse with..
Esotropia
Anomalous correspondence
Constant unilateral strabismus
How to record frequency of strabismus
Constant or intermittent
How to record laterality of strabismus
Right
Left
Alternating
How to record direction of strabismus
Esotropia Exotropia Hypertropia Hypotropia Cyclotropia..?
How to record location of strabismus
Distance
Near
How to record magnitude of strabismus
Measured in PD at distance and near
How to record comitancy of strabismus
Comitancy (or concomitant)
In comitancy (or nonconcomitant)
How to record sensory adaptation of strabismus
Normal correspondence
Anomalous correspondence
Suppression
When patients read out of order or drop letters, after likely correctly identifying the first and last ones
Spatial uncertainty, due to strabismic amblyopia
In strabismic amblyopia, there is risk of injury to which eye?
The non amblyopic eye
What is eccentric fixation?
When amblyopia leads to the patient not using the fovea as a center of the visual axis. Another retinal point will assume the role, and visual acuity is reduced.
What is a unilateral strabismus more likely to do?
Cause amblyopia
What is an intermittent strabismus or an alternating less likely to lead to
Amblyopia
That sure was a shitty question
The later the onset of strabismus….
The better the chance of re establishing binocularity that the patient already developed
Consider a 75 y/o Asian female with a constant left exotropia with a right hypertropia due to a 3rd nerve palsy that occurred at the age of 73. Did this patient previously have binocularity What is the chance of amblyopia in this patient?
75 years old is out of the critical period.
Yes
Low
Consider a 12 month old Caucasian male with a congenital right esotropia that has never seen an eye doctor. Did this patient previously have binocularity? Could his child have amblyopia?
No
Yes
