Amblyopia pt.2 Flashcards
what 3 things must you make sure of before you start treating someone with amblyopia
- Always carry out fundus & media examination
e. g. poor vision in one eye may not just be due to amblyopia, but can be something more sinister - Always carry out cycloplegic refraction
- Don’t start occlusion if visual acuity is reduced in both eyes
e. g. if put patch over slightly better eye, then can make that eye even worse
list the steps of how you should treat a patient with amblyopia from beginning to end
- Correct any significant refractive errors with glasses
Period of 18-22 weeks constant glasses wear before starting patching for refractive adaptation - Allow vision to plateau before starting patching treatment
- Consider Contact Lenses
what improvement do many patients being treated for amblyopia with glasses alone gain and how many patients’ amblyopia gets resolved fully with glasses alone.
For how long will these patients need to wear these glasses
- 2-3 line improvement
- 27% resolved vision, so never need to patch
- to wear glasses full time for 18-22 weeks/5 months and if still improving then continue to wear
what will you wait for before starting patching treatment on a patient who is being treated with glasses for that time being
- to allow the vision to plateau before starting patching treatment
- even if after 4-5 months the vision is still improving in the amblyopic eye just with glasses, then continue just with glasses and wait until it plateaus off
for which types of patients will you consider using contact lenses to treat their amblyopia
- High refractive error
- High anisometropia
what treatment can you do after refractive adaptation
Occlusion (patching)
how is occlusion (patching) done
- Occlusion (patch) placed on good eye (to make bad eye work)
- Plasters best worn on face and not specs, as specs can slip off and therapy won’t work
what did the results of MOTAS find about the improvement which occurred during patching therapy
- 75% improvement occurred during first 6 weeks
Some further improvement up to 12 weeks - Younger patients improved with less hours patching - so the younger the px started their treatment, the better the prognosis
for which level of acuities does the RCO suggest 2 hours of patching for in the UK
acuities from 0.2 to 0.6 LogMAR (6/9 to 6/24 Snellen)
for which level of acuity does the RCO suggest 6 hours of patching for in the UK
acuities below 0.6 LogMAR (worse than 6/24 Snellen)
list 8 factors that can affect the prognosis of occlusion therapy to treat amblyopia
- Age of onset - earlier the onset of the problem, the worse the prognosis
- Duration of amblyopia - the longer they had, the worse the prognosis
- Type of amblyopia - worst is cataract in one eye congenitally
- Age you commence treatment - older, worse the prognosis
- Other pathology present
- Type of treatment
- Presence of eccentric fixation - further away from fovea, worse the prognosis
- Compliance (research has shown that this is the main predictor of visual outcome)
how does age of onset affect the prognosis of occlusion therapy to treat amblyopia
earlier the onset of the problem, the worse the prognosis
how does the duration of amblyopia affect the prognosis of occlusion therapy to treat amblyopia
the longer they had, the worse the prognosis
how does the type of amblyopia affect the prognosis of occlusion therapy to treat amblyopia
worst is cataract in one eye congenitally
how does the age you commence affect the prognosis of occlusion therapy to treat amblyopia
older, worse the prognosis
how does the presence of eccentric fixation affect the prognosis of occlusion therapy to treat amblyopia
further away from fovea, worse the prognosis
what is the biggest thing to affect the prognosis of occlusion therapy to treat amblyopia
compliance
list 5 things that can be explained to improve communication to a parent in order to improve compliance
Explain why its is important to treat by mentioning:
- DVLA requirements
- Stopped from certain jobs
- Pathology to good eye in later life
- Show parent what they can see
- Explain the SENSITIVE period - If don’t treat now then less able to treat when older
list 3 possible occlusion therapy methods used to exclude light and form
- patches such as plasters (advise on face to avoid peeking)
- hand made cloth to go over glasses or (may peek)
- opaque contact lenses
name an appliance that can be used in occlusion therapy to exclude form vision
blenderm = frosted glass
Better for older/adult patients
name an appliance that can be used in occlusion therapy for producing partial vision
Banger foils = occlusion covering part of the lens
Better for older/adult patients
name 2 advantages of occlusion/patching
- Cheap
- Can specify exact time (as soon as time is up, px can remove patch)
list 4 disadvantages of occlusion/patching
- Cosmetically disfiguring - bullying
- Children can remove easily
- Allergic to elastoplast
- More of a barrier to stereopsis (only improves vision)
name an alternative to occlusion/patching therapy
optical penalisation
what does optical penalisation do
Blurs the visual acuity in the better eye sufficiently to make the worse eye work
what are the 3 types of optical penalisation
- Distance penalisation
- Near penalisation
- Total penalisation
what is near penalisation used for and how is it done
- Encourages the use of the amblyopic eye for close work.
- Instil cycloplegia, Atropine to the better eye.
- Add convex lens to the amblyopic eye to help it see better.
what is distance penalisation used for and how is it done
- Encourages the more amblyopic eye in the distance.
- Adding +3.00 DS to the good eye to blur in the distance.
- Prescribe the optimum correction for the amblyopic eye.
what is total penalisation used for and how is it done
- Encourages the use of the more amblyopic eye at all distances.
- Optimum correction to the amblyopic eye.
- Strong convex lens to the good eye to prevent it from being able to look at distance and near clearly. or…
- Alternatively atropine + strong concave lens in good eye, so will also blur it at near and distance.
- Extra correction can be added via fresnel lenses.
- Used when atropine alone does not work i.e. severe amblyopia.
what are the 2 options of cycloplegic drugs used for optical penalisation and what do they do to the eye
- Atropine ointment
- Atropine drops
- instilled once a week
- prevents accommodation
which form of atropine is better and why
- Atropine ointment
- as it only limits to the eye, and there is less systemic affects than drops
in which extend of amblyopia is atropine effective in
moderate and severe amblyopia
in which type of eyes is the blur affect of atropine more in
hypermetropic eyes
list 5 advantages of atropine
- Cosmetically good (only a dilated pupil seen instead of a patch)
- As effective as patch in treating moderate possibly severe amblyopia
- Excellent compliance (instill once at the weekend) as child cannot take out once in
- Good for manifest latent nystagmus
- When visual acuity stabilised using occlusion
why is atropine good for manifest latent nystagmus and patching isn’t
because with patching, the latent manifest nystagmus increases
list 5 disadvantages of atropine
- Might be allergic to atropine
- Systemic medication
- Not used in people with heart defects e.g. Down’s syndrome
- Takes 2/52 to wear off (Not suitable in older strabismic amblyopes)
- Constantly blurred distance vision (problems older child at school) whereas with patch, can remove when studying
why is atropine a problem for children with a strabismic amblyopia
because during the atropine treatment, a child with weak suppression can decompensate, whereas with a patch they can remove it immediately
who is inverse occlusion used on and how does it work
- Used in eccentric fixation (strabismic amblyopia)
- To disrupt the eccentric viewing point
- Amblyopic eye occluded (all day) 24/7 for the first 2 weeks
- Occlusion then applied in the standard way
how often should you follow up a patient whilst treating their amblyopia and when will you review more regularly than that
- every 3 months at least
- Younger children reviewed more regularly
- More occlusion reviewed more regularly, or if doing for 6 hours, see sooner to see if can reduce to 2 hours
when will you consider stopping occlusion and how will you stop it
- Once visual acuity stable for 2 consecutive visits
- Slowly taper off occlusion
what 4 things can cause higher rate of recurrence of amblyopia
when:
- Better level V-A in amblyopic eye on cessation
- Greater improvement in V-A
- Previous recurrence
- Taper occlusion when V-A plateaus
list 9 possible problems that can occur because of occlusion therapy
- Intractable diplopia (strabismic amblyopia >5 years old)
- Occlusion amblyopia
- Decompensation
- Failure for visual acuity to improve
- Recurrence of amblyopia
- Increase in the angle of deviation
- Allergies from:
Atropine
Occlusion - Bullying
- Infection
how can a patient over 5 years old with a strabismic amblyopia get Intractable diplopia from occlusion therapy
because there is a risk of removing their suppression and can contract diplopia
how can occlusion amblyopia be caused from occlusion therapy and which patients is this more likely to occur in and what should be done to avoid this
- it can cause amblyopia in the good eye when we patch the bad eye
- so must monitor this loosely as the more younger the child, the more likely it is to occur
- see younger children very regularly - every couple of weeks
how can occlusion therapy cause a risk of decompensation
for those with anisometropic amblyopia, as patching can cause a phoria to become a tropia
this 3 contra-indications to treatment of amblyopia whereby you may decide not to treat
- Poorly controlled phorias with poor stereopsis and fusional reserves (may break them down from phoria into tropia)
- Older strabismic amblyopes
- Personal circumstances:
Unable to regularly attend
Significant health problems
what 2 other disorders can amblyopia be associated with
- pathology
or - nystagmus
what is done about a patient who has a pathology associated with their amblyopia
- Ophthalmologist will consider treating (so can patch but get advice from ophthalmologist first)
- Guarded prognosis - let parent know this might now work as they won’t know how much is due to amblyopia and how much is due to a pathology
what is done about a patient who has a nystagmus associated with their amblyopia
- for latent component try atropine - as this keeps the nystagmus to a minimum amplitude
- Test v-a with (CHP)
- Sat in position at school which allows use of the CHP
what 2 things must you assess with a cataract
it’s density and size
what does the prognosis of a cataract correlate with
its density e.g. a nuclear cataract thats most dense can give the worse prognosis
how should a cataract surgery be done on a child and why
- Simultaneous bilateral surgery
- due to risk of general anaesthesia
- child also at risk of developing amblyopia
what is the risk of doing a simultaneous bilateral surgery on a child with cataracts, and how can this be reduced
- The at risk of endophtalmitis, but can use:
- Different trays
- Different irrigating solution
if a cataracts on a child is treated by sequential bilateral surgery, how is the risk of developing amblyopia from this avoided
- a short time period between surgeries
- must put a patch on the eye thats just done (good eye), to try to keep their BSV and potential for stereopsis
when should you wait until to do most cataract surgery on a child/baby and why
- Wait until 4 weeks old
- Risk of glaucoma
list 3 methods of vision correction for children who have a cataract
- contact lenses
- aphakic spectacles
- intraocular lens
which method of vision correction is the most standard method for a child with cataract and name 2 type
- contact lenses
- soft or rigid gas permeable lenses
give 3 reasons why rigid gas permeable lenses may be used for correcting vision on a child with cataract and one possible disadvantage
- Easy to insert-remove
- Wide range powers
- Correct astigmatic errors
- child can rub their eyes and the lens can pop out
why is a IOL a complicated method of vision correction for treating children who have a cataract and what problem can it cause
- as the eye is still growing
- causes increased number of surgeries
what is required when fitting an IOL as a treatment for cataract on a child
- Predicting required power
- Usually under-correct
in which type of cataract is amblyopia treatment not usually needed and what is the median binocular va in LogMAR
- binocular cataract
- 0.4 LogMAR
what va do many children with a unilateral cataract not reach
v-a compatible with reading (median value 0.9 logMAR)
if the decision is made to perform surgery on a child with a unilateral cataract, when should it be done and what should be done after
- within the first 6 weeks
- a patch must be worn 50-70% of all waking hours for many months
what is a disadvantage/risk to wearing an extensive patch following unilateral cataract surgery
it may have an effect on the fellow eye
what is the ideal treatment, other options, considerations and prognosis for a patient Aged 7 years old. R+0.50, L+6.00. Vision R 6/6, L6/36
- Full time glasses, Patch or atropine
- May wish to consider CL’s due to anisekonia
- Start ASAP due to age
- Guarded prognosis due to age
- atropine good because child is at school and patch can cause bullying, but atropine not good as child needs to see when studying, whereas can easily remove patch to study
what is the ideal treatment, other options, considerations and prognosis for a patient aged 4 developmentally delayed LSOT (strabismic amblyopia), Vision not possible as couldn’t do test on the day
- Atropine might be better as child may take patch off
- As no visual acuity monitor fixation closely if swaps stop treatment (watch for alternation to see if vision improving)
what is the ideal treatment, other options, considerations and prognosis for a child 6 years old RXOT, Vision R 1/60, L6/9 (strabismic amblyopia)
- Patch - better
- Evaluate density suppression warn about intractable diplopia
- Atropine not good due to age, as this can make the amb worse and cause diplopia whereby can’t take the atropine out when this happens but can take a patch off
- Guarded prognosis due to age, level of vision
what is the ideal treatment, other options, considerations and prognosis for a child aged 4 years, Vision R 6/60 L 6/6
Latent Nystagmus RSOT
- Atropine (as it reduces the latent nystagmus as it keeps the amplitude low)
- Close supervision
- Monitor does not change to manifest nystagmus
what is the ideal treatment, other options, considerations and prognosis for a child 6 years old. R+0.50, L+6.00, Moderate SOP, Vision R 1/60, L6/9 (anisometropic amblyopia)
- Full time glasses wear, Patch (good as can stop treatment fast if decompensates)
- Monitor binocular functions constantly - as danger of this px decompensating is use atropine
- Atropine may be more disruptive to BSV unable to stop quickly
- Prognosis guarded due to age, level of vision
what is the ideal treatment, other options, considerations and prognosis for a, Child aged 4 years. R +10.00 L+10.00 R 6/18 L6/18
- Full time constant glasses wear
- May wish to give under correct initially if child fail to have improvement in their visual acuity
- Vision usually slow to improve
