HOT TOPICS IN AMBLYOPIA
SRC 2008
LIONEL KOWAL
When to worry [and
when not to worry]
about strabismus and
amblyopia
NOT TO WORRY…
When it all ‘fits’
Right age / anisohyperopia / glasses help vision
and alignment….
4 year old
ET L D: 25∆, N: 35 ∆
 R 6/8, L 6/24
R +3, L +4
Glasses
 L 6/24  6/18  6/12
 Patching  6/10  6/9
 ET 25/35  phoria 12 / ET’ 25
 Bifocals  orthotropia

WHEN TO WORRY….
Lateral incomitance
ET or XT greater to L or R gaze
ET greater on lateral gaze 6th
XT …. Brainstem / INO
WHEN TO WORRY….
Resistant amblyopia
Check the pupil for afferent
defect
Re-examine the disc and
retina
WHEN TO WORRY….
ET Distance > Near
Raised intra cranial pressure
6th nerve palsy
WHEN TO WORRY….
Abnormal morphology
Is the disc / macula normal? ..size …shape
...pigmentation
If you find it difficult to be sure it’s OK or
not, others probably will too
Best test for a suspicious disc:
show to someone else
Abnormal morphology
2008: Hi- tech imaging helps
BUT
Sub - expert HRT OFTEN misleading
When
to operate in
strabismus and when
not to operate in
strabismus.
…& ‘why wasn’t this
done years ago?’
When to operate in strabismus…
WHY DO I OPERATE?
TO MAKE THIS PATIENT’S LIFE BETTER
Better visual system
 Stabilise/ improve amblyopia
 Better peripheral field [ET]
 Better binocularity

AND…


Normal appearance and improved psychosocial
development
Better motor co-ordination
When to operate in
strabismus…
Better outcome if
Constantly misaligned < 4
mo [child] or < 12 mo [adult]
Angle ≤ 50 ∆ ET, ≤ 35 ∆ XT
When NOT to operate in
strabismus…
 Very
variable strabismus
 Patient
expectations ≠ mine
+4DS, ET 30∆.
Straight forever sc not realistic
When NOT to operate …
Despite adequate
education, parents remain
opposed. Anti - surgery
websites - death rates &
complications exaggerated
DON GETZ

“The best "cure" rate is 11%”
 USA >20 deaths per year for
strabismus surgery
When NOT to operate …
?Under- trained surgeon.
 Clearly a factor in other surgical areas
 ~20 ophthalmologists are Fellowship trained in
peds or strabismus
 >20% of private strabismus surgeries in
Australia [billed through Medicare] are done by
2 ophthalmologists
 ?reason for declining numbers [fewer repeat
surgeries because so many are done by
experts]
‘Why wasn’t this done
years ago?’
20 yo with 30∆ ET or XT dating back
to childhood more likely to have
PERMANENT paradoxical diplopia
after alignment surgery than the
same surgery in a 5 yo
 Childhood visual system more
flexible - ARC less likely to be
profound / persistent in a child than
an adult

 Delaying
surgery ‘till
s/he’s old enough to
decide for him/her- self’
can mean deferring it to a
time when a good cosmetic
and functional result is no
longer possible
Is full time occlusion dead?
Factors that influence outcome of
amblyopia treatment fall into two
categories:

those that relate to the underlying
conditions (condition factors) and

those that relate to its treatment
(treatment factors).
Treatment factors
1.
Optimal refraction - regularly
re-checked
2.
Occlusion method & dose
3.
Accuracy of alignment
Occlusion method / dose
 PEDIG:
75+% get better
with 2h/d [<6/24] or 6h/d
[<6/120]
CAN MORE OCCLUSION GET
EVEN BETTER RESULTS?
Is full time occlusion dead?
MOTAS
Lines of residual
amblyopia @ end of
treatment
0
%
0-1
57
0-2
69
0-4
83
30
IS
MORE
EVEN
BETTER?
THE IOWA STUDIES
Amblyopia Treatment Outcomes.
WE. Scott.. JAAPOS April 2005




Retrospective review of patients who had fulltime occlusion [24 h/d or all waking hours].
600 pts followed for av. 7 y after the cessation
of full-time patching. 90% ≥ 1 year.
Success : ≥ 20/30 or better or equal VA by
fixation pattern - seen in 96%
60% attained equal visual acuity.
Amblyopia Treatment Outcomes.
WE. Scott..

Younger patients required less occlusion time to
endpoint and had a better visual outcome (P <
0.0001).
Initial VA related to best VA attained (P < 0.0001).

Incidence of occlusion amblyopia 25.8%.

Amblyopia Treatment Outcomes.
WE. Scott..
Looks like more = better
BUT
> 2ce risk of occlusion amblyopia
Assume equal fixation = equal acuity
< 100% followup
PEDIG - RECRUITING….
•Treatment of residual
amblyopia 6/9 to 6/15.
•Compare intensive treatment
[8 h/d of patching + daily
atropine] with glasses alone
IS MORE EVEN BETTER?
For
most children with
amblyopia - probably not
For some - maybe
…….stay tuned!