Bv Lec 4 Flashcards
What is amblyopia
Visual neuro-developmental condition caused by persistent abnormal visual input in early years of life
What are the 3 requirements to clinically diagnose amblyopia
Presence of amblyogenic factors in the early critical period for visual development
Reduced BCVA after amblyogenic factor is removed
Absence of other pathologies of eye or visual pathways
What is the optical treatment (1st treatment) for amblyopia
Full time wear of glasses or CL
-cycloplegic refraction correcting full anisometropic difference, all myopia/astigmatism, full cyclo if hyperopic and esoT
-min 12wks full time before starting additional Tx
What is the additional therapies (step 2 treatment) for amblyopia
Patching
Atropine penalisation
Bangerter filters (blur over good eye)
Others/efficacy not confirmed
- vision therapy
- binocular TX/videogames, VR systems
What is the post treatment (step 3 Tx) for amblyopia
Follow ups every 6-8wks for at least 2 more visits
Restart active therapy if VA decreases
Maintain full time wear of glasses or CL
Keep refractive correction up to date and fully correct any anisometropia (6-12monthly cyclo if <12 or hyperopic)
What are the clinical types of amblyopia
1) unilateral or bilateral
2) amblyogenic factors (strab/refractive/form deprivation)
3) combined mechanism amblyopia
Visual consequences of amblyopia that is routinely assessed in clinic?
BCVA reduced in one or BE
Fovea crowding/contour interaction
Fixation unstable and poor motor fusion
Unbalanced interlocutors suppression
Reduced stereoacuity
Prevalences of 3 categories of amblyopia
Unilateral strabismic & or anisometropic 1-4%
Bilateral refractive 0.1-0.4%
Unilateral or bilateral form deprivation 0.01%
Prevalence of amblyopia is
4x higher in?
6x higher in?
4x - infants born premature or small for gestational age OR first degree relative with amblyopia
6x children with neuro developmental delays
How to diagnose amblyopia practically
Use crowded VA test
Check pupils and eye health
Check visual deficit matches amblyogenic factor
Confirm vision not getting better on its own
Check it child has >1 diagnosis
Why do we bother to treat unilateral amblyopia
Backup eye
Career opportunities
Binocular functions (Bv only improves as side benefit and not always)
What to check in follow up for optical Tx done every 4-6wks
History - compliance and visual symptoms
Monocular and binocular BCVA
Stereopsis and suppression
Cover test and vergence if Phoria
When to add additional treatments during optical treatment phase
VA improving = continue optical Tx
VA stabilising over 6wks with good compliance
= no additional if <1 line BUT if 2 lines then START
VA not improving = check compliance or amblyopia
What’s goal of additional therapies
To improve vision in the amblyopia eye by penalising the better seeing eye
Additional as still has to wear correction
Starting dose for patching
Mild/moderate amblyopia (VA better than 6/36): min 2hrs/day
Severe (VA worse than 6/36): 6hrs/day
8 Advice for parents for patching
1) MUST CONTINUE FULL TIME GLASSES EVEN WHEN PATCHED
2) Method- correct eye patch, no peeking, parent monitor
3) Hours - best continuously
4) Schedule - school/home, AM/PM
5) Visual activities - sit down, visually engaging
6) Reward systems
7) Warnings as child visually impaired
8) Warning 2 - non amblyopic siblings
How to prescribe atropine penalisation initially
Atropine 1% in non amblyopic eye
Dosage 1 drop daily/2nd day/weekends depend on iris
Warn parents for anticholinergic/Side effects
How to follow up atropine penalisation
Monthly
- compliance: dilated, in correct eye
- VA in fellow eye with pinhole & full cyclo rx
- Va in amblyopic with habitual specs
- Cover Test but stereopsis poor
Effectiveness and ease of compliance between patching and atropine
Patching improves faster in first 3 months but both same outcome at 6 month-3 lines if 3-6yo
Patching takes multiple hrs/day but atropine 1min
Physical side effects and social stigma of atropine vs patching
Patching = irritation with stick on patch Atropine = light sensitivity, ocular irritation, facial flush
Stigma high for patching so avoid school and low for atropine as can’t tell dilated
What is amblyopia regression
reemergence of amblyopia due to residual neuroplasticity so gradual loss in Va or stereopsis gain after stopping active Tx
Who has a higher risk for regression of amblyopia
1) Stopping Tx young age
2) px that improved more in Tx
3) not tapering high does patching
4) not wearing up to date correction
