8.1.6: Manage children presenting w/ anomaly of BV Flashcards
Describe spectacle correction in tx of children with BV issue?
Correct any significant refractive errors, allow a period of 16 weeks for adaptation before
commencing occlusion therapy, allow VA to plateau
Describe occlusion therapy in tx of BV issue?
The fixating eye is prevented from taking part in the act of vision so that the patient is forced
to use the amblyopic eye
What is the managment of amblyopia?
o Assess likelihood of decompensation or intractable diplopia - if likely may not treat
o Discuss treatment options with parents advantages and disadvantages, if visual deficit progresses investigate
further
o Factors – Age of onset, duration of amblyopia, type of amblyopia, age you commence treatment, other
pathology, type of treatment, compliance, presence of eccentric fixation
o Occlusion Period – 6/9 to 6/24 – 2 hours of patching / Below 6/24 – 6 hours of patching
o Average compliance 48% - 120 hours = 0.1 LogMAR improvement, younger the px larger the improvement
o Importance – DVLA requirements, pathology to good eye in later life, critical period, explain to both parent
and child enlist help of teachers.
o Contra-indication – poorly controlled phoria, older strabismic amblyopes, failure to regularly attend
o Advantage of occlusion – Cheap, can specify time, can use in severe amblyopes
o Disadvantage of occlusion - Cosmetically disfiguring, Compliance child can remove, Allergy to Elastoplast
What are the risks of occlusion?
- Intractable Diplopia:
o Rare
o Covering good eye, child using other eye they have suppressed, they then overcome the suppression and get diplopia
o Strabismic amblyopia
o Higher risk in older children (8/9yo) – monitor px
o Sbisa bar (density of suppression) assessed to monitor throughout treatment
o Occlusion immediately stopped – parent remove patch immediately and phone clinic
o Patients can re-suppress
- Intractable Diplopia:
- Amblyopia develops in the other eye- rare in part time occlusion
- Dissociation in decompensating strabismus – px has BSV – the eyes aren’t fusing – end up with manifest squint
- Allergic reaction:
o Skin reaction in conventional occlusion
o Allergy to atropine- local or systemic
- Allergic reaction:
Describe optical penalisation? distnace, near and total? when is it used?
Blurs the VA in the better eye sufficient to make the worse eye work for those who can’t tolerate occlusion therapy, treatment of amblyopia by optical reduction of form at all distances, achieved with alteration of spectacle correction or cycloplegic drugs.
* Distance Penalisation: +3.50DS added to non-amblyopic eye
* Near Penalisation: Cycloplegia in the non-amblyopic eye with full correction and a hypermetropic lens (up to 3.00DS) in the amblyopic eye.
* Total Penalisation: High hypermetropic lens added to non-amblyopic eye to induce blur at both near and distance.
* When is it used?
o When cooperation with patching is poor or non-existent.
o Patients with latent nystagmus.
When cover one eye it can get worse – so this is not physically covering eye (e.g. patching) then may not cause this
o No improvement with other treatment.
o When atropine alone is not enough to reduce acuity sufficiently.
Describe atropine penalisation?
- Prevents accomm & blurs vision at near fixation. Instilled 2 consec days a week (Sat & Sun)
Useful in mild to moderate amblyopia in 3-7 yrs old
+ves:
o cosmetically good
o Used when child refuses patch
o Good for manifest latent nystagmus
o Used when VA does not improve with occlusion therapy
-ves:
o px may be allergic
o interaction with systemic meds
o NOT TO BE USED IN HEART DEFECTS
o 2/52 to wear off
o cannot be used in severe amblyopia
o constant blurred vision
o not suitable for older strabismic amblyopes
o light sensitivity
How often should you review a child undergoing tx for BV anomaly?
Review Px at least every 3 months, younger px reviewed more regularly, more occlusion reviewed
more regularly.
Once VA stable for 2 consecutive visits considering stopping, taper off occlusion
Describe stimulus deprivation amblyopia?
- Difficult to treat, little or no llight enters eye
e.g. Haemangioma, corneal scar, vitreous bleed, ptosis, congenital cataract - full Rx & constant wear
- total occlusion preferrable - risk of occlusion amblyopia
- if pathology dates from birth progression is poor - pathology from early infancy much better
- likelihood of BSV poor with unilateral cataract
Describe strabismic amblyopia?
- Constant or near constant childhood squint
- occlusion or atropine
- ask parent to watch for swapping fixation
- risk of itractable diplopia in older children
Prognosis:
o depends on age of onset (constant & intermittent), initial VA, age tx started, associated pathology, eccentric fixation
Describe ansiometropic amblyopia?
At least 1D difference - more common in hyperopes as never clear, meridional (astig), myopes (one eye distance, one for near)
- FT glasses wear
- No need for occlusion if VA consistently improving
- Less risk of occlusion to older cildren than strabismic amblyopia
- Supplemented with near work
- Marked anisometropia may want to consider CL
Prognosis:
o high myopia not good
o once optimum VA obtained continue with FT wear
o amblyopia less likely to occur in presence of BSV
o high anisekonia may occur
Describe meridional amblyopia?
- mod-high degree of uncorrected astigmatism
- unilateral or bilateral
- more risk of oblique astigmatism
Describe ametropic amblyopia?
- usually bilateral
- high degree of bilateral refractive error (likely hyperopia) goes uncorrected during critical period
- blurred vision in BEs at all distances
- > 6D hypermetropia (can’t be compensated using accom)
Describe organic amblyopia?
- Reversible
o Toxic amblyopia – not always reversible – often associated w/ optic nerve dysfunction
Painless, progressive, bilateral vision loss
Dyschromatopsia
May also be referred to as “toxic optic neuropathy”
Nutrional Amblyopia - Vitamin B12 deficiency
- Seen in patients with extreme diets- reports in patients with ASD
- May see complete/incomplete recovery with improved diet/vitamin intake
o But vision may not be back to full level
o May see in children with autism spectrum disorder: they have safe foods due to sensory issue but if rest of vitamins are not supplemented in their diet then they may develop this
Other common causes - Alcohol- may be associated with B12 deficiency
- Tobacco
- Antimalarials e.g., Chloroquine
- Anticancer treatments e.g., Vincristine
- Irreversible
o Not able to be treated – no lesion
Nystagmus – never get a clear image so cannot develop good vision
Albinism (usually associated w/ nystagmus)
What are the estimation of grades of BV?
o Grade 1 (Simultaneous Perception) – tested by showing two dissimilar but not mutually antagonistic pictures (bird and cage)
o Grade 2 (Fusion) – Ability of the two eyes to produce a composite picture from two similar pictures each one incomplete in one small different detail
o Grade 3 (Stereopsis) – Ability to obtain an impression of depth by the superimposition of two pictures of the same object which have been taken from slightly different angles
What is the strabismus management - constant XOT, intermittent near XOT, intermittent distance XOT?
Constant XOT (c or s spx)
* Mgmt:
o Surgery: MR resection to strengthen the muscle
o Botox
Intermittent near XOT
* Orthoptic Exercises
* Base IN Prism
* MR Resection
Intermittent Distance XOT
* Orthoptic Exercises
* Base IN Prism
* True: Lateral Rectus Recession
* Simulated: Medial Rectus Resection, Lateral Rectus Recession
True Intermittent Distance XOT: Distance deviation is larger than near
Simulated Intermittent Distance XOT: Distance deviation is the same size than at near
