DOS_august_2009

Tearsheet

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Management of Amblyopia or pirate patches. Compliance is the key word so proper
tome and effort should be devoted to counsel the child
1. Amblyopia is unilateral or bilateral diminution of vision and parent and reinforced on each visit.
due to a cortical developmental defect due to form vision
deprivation or abnormal interaction due to media opacity, Age Occlusion of Occlusion of
refractive error or strabismus, which can be fully corrected dominant eye Amblyopic eye
in treated in time, that is early childhood. It may be unilateral 0 – 2 years 2 days 1 day
(including bilateral but asymmetric) or bilateral with equally 3 year 3 days 1 day
subnormal vision in each eye. 4 years 4 days 1 day
5 years 5 days 1 day
2. An associated manifest squint can be easily detected/ 6 years 6 days 1 day
confirmed by a cover test, whereby the apparent straight and more 6 days 1 day
eye is covered, if there is a true manifest squiint the other
(apparently deviating) eye will move to take up fixation. 1. Monitoring and follow-up: Since infants are more
The exceptions like the other eye having no perception of susceptible to occlusion amblyopia, they should be
light, having incomitant strabismus making it incapable to followup weekly or fortnightly. Older children may be
move or having an eccentric fixation, when it already is seen monthly.
fixating from the eccentric point despite the squint. If the
squint is convergent or vertical it is usually strabismic 2. Occlusion needs to be continued till full recovery occurs
amblyopia. In case of divergent squint look for other or till two consecutive visits, despite good compliance show
causes of poor vision. no further improvement. If despite good compliance it
fails to improve for 2-3 months, it should be investigated
3. A clinical ophthalmic examination for a proper cycloplegic for any missed case of organic defect and labelled as
refraction in addition to fundus examination and fixation occlusion failure. In some cases Levodopa – Carbidopa
pattern should be done. In case of refractive error full drugs in addition to occlusion may be tried under
refractive correction is given. A fully accommodative monitoring of liver function tests. Pleoptics has a limited
esotropia may get corrected for squint in other situations role.
like partially accommodative esotropia or intermittent
divergent squint, also proper refractive correction is 3. Maintenance Occlusion: is essential other wise regression
desirable. is possible, atleast till 8-9 years of age. This may be done
by patching part time patch weekly or every- Sunday
4. A fundus examination should rule out any organic cause patch, or penalization of the dominant eye and monitored
of diminution of vision prior to blindly subjecting a child on follow-up Penalization may be done in the form of
to occlusion therapy. In some situations a trial of occlusion atropine ointment h.s. in the dominant eye or /also
may still be given in presence of a condition like created deprivation of the hyperopic correction (combined optical
retinal detachment to give the benefit of doubt for an and pharmacological penalization) over-correction by
element of amblyopia in addition to the organic disease. hyperopic (plus glasses) or Nail vanish over the dominant
eye may also be tried.
5. Occlusion therapy: In case of unilateral amblyopia regime
of alternate eye patching (occlusion), preferably an 4. High hyperopia (usually more than + 2.5 Ds) high myopia
occlusive skin patch is started, the alternation is done with (Over-4DSph) or astigmatism (over 1.5 DC) can result in
the dominant eye patched for full day (all waking hours) Ametropic or Iso-ametropic amblyopia. For this
for the number of days as per the age of the child and the condition usually proper correction of glasses is sufficient.
amblyopic eye given a breather of one day in each cycle. In case of presence of unequal refractive error or unequal
At no time is the patch removed from both eyes. vision or any deviation occlusion will be required as in (5)
above.
This alternation rhythm ensures occlusion for an effective
period and also protects the child from the danger of
occlusion amblyopia, a deprivation amblypia due to the
patch itself, if prolonged more than prescribed. While
skin patches (ready made like Opticlude or home made
from micropore tape rolls) are the best, the other lesser
alternatives are spectacle patch, rubber occluders (Doyne’s)

Author
Pradeep Sharma MD
Dr. R.P. Centre for Ophthalmic Sciences, AIIMS,
Ansari Nagar, New Delhi

76 DOS Times - Vol. 15, No. 2, August 2009