px with amblyopia Flashcards
what are the clinical characteristics of amblyopia
no symptoms
px may rub eyes/ close an eye
signs of amblyopia
- decrease in va
- fixation preference 0 child may prefer to use one ye over the other
- eccentric fixation
unsteady fixation
poor accomodation - poor depth perception
- squinting /shutting an eye
- head tilting
what is MBLYOPIA
- DEVELOPMENTAL DISORDER OF THE VISUAL SYSTENM CHARACTERISED BY A DECREASE IN VISION IN THE AFFEECTED EYE AND A DISRUPTION OF bINOCULAR FUCNTIONAL VISION
what causes amblyopia
reduced vision in 1 eye caused by abnormal visual development early in life. The weaker or lazy - eye often wanders inwards or outward.
what are the types of amblyopia
refractive
strabismic
deprivation
reverse
what is cause of unilateral amblyopia
constant strabismus
anismometropia
visual deprivation( catarcats,ptosis, opaque cornea, prolonged uncontrolled patching , prolonged unilateral cycloplegia)
-
what causes bilateral amblyopia
cataracts of equal density
high uncorrected hypermmetropia
high uncorrected astigmatism
nystagmus
strabismic amblyopia
result of manifest strabismus
aniesemetropic amblyopia
result of significant difference in the refractive errors of the 2 eyes / where one eye will have th visual advantage of all distances
ametropic amblyopia
result of high degree of uncorrected bilateral refractive error
meridional amblyopia
uncorrected astigmatism
stimulus deprivation
lack of adequate stimuli is n early life
may be uni/bi/complete/partial
when should treatment start and stop
treat as early as possible Babies can be patched –need to be careful not to induce iatrogenic amblyopia due to occlusion
- Continue treatment until no improvement in visual acuity after 2 consecutive review visits (at least 6 weeks apart)
- Treatment of amblyopia DOES NOT have to stop at age 8 years
Refractive correction
- correct ametropia
FT wear - process can take up to 16 weeks or longer
- Review refractive correction frequently (over 12 –16 weeks).
- Anisometropic amblyopes
what is strabismic amblyopia
caused by active suprression
to get rid of cdiplopia and confusion
-may be complicated by eccentric fixation
by anomalous retinal correspondence
how much patching
10mins- 8-10hrs
Opaque and total occlusion is the standard (alternative occlusion can use attenuating filters –
Bangerterfoils/filters) but these vary in their attenuation.
2 hours of patching (with near activities) as effective as 6 hours for moderate amblyopia (mean
of 6/18 ~ 4 line difference) – strabismic, anisometropic or combination.
* 6 hours of patching as effective as full-time patching in severe amblyopia (mean 6/48~ 7 line
difference).
Recurrence can occur if treatment stopped (25% of successful treatment can recur after
stopping) –weaning off treatment (patching) may lessen recurrence rate.
* Shorter patching duration may help compliance rather than full time occlusion.
* Review every 6 weeks (6weeks for optimal affect). If no improvement check compliance.
* If no improvement after 6 weeks consider referral or reconsider potential.
orthoptic management for amblyopia
Orthoptic treatment
* Seen both by orthoptist and optometrist.
* Give full prescription
* Monitor vision and prescription every 3months
* Possible prism given or patching given – dependent on case
* Checks fusional reserves
* If strabismic problem – surgery available to tighten or loosen muscle.
referral
Amblyopia
Routine to be seen within 4-6 weeks of referral. Give full prescription in the meantime.
squint/strabismus Routine to be seen within 4-6 weeks of referral. Give full prescription in the meantime.
reduced vision Routine – follow prescribing guidelines.
moderate amblyopia
severe amblyopia
6/12-6/30
6/30-6/120
patching
4hrs for all type of amblyopia
no additional benefit beyond 400hrs
atropine 1% weekends
1% weekends , review 1 week to check acuity in dominant eye
monitor closely for iatrogenic by checking best corrected acuity in dominant eye at each follow up visit
how does penalisation work?
atropine/ointment /drops
prevent accomodation of fellow wy w
encourages amblyopic eye to fixate at near
side effectsects ( photophobia/ eye pain HA/skin irritation/facial flushing )
when is occlusion therapy stopped
- when px vision has improved and remained stable over 3 consecutive visits
- once the patch has been stopped Childs vision monitored to ensure it not reduce again. in some children it will recess this can be rectified by reintroducing the patch for a short period of time
- px has been compliant and has worn the patch. but here ahas not been significant improvement of vision
-poor compliance
