HOT TOPICS IN AMBLYOPIASRC 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 +4Glasses 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 incomitanceET 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 pressure6th nerve palsy

WHEN TO WORRY….

Abnormal morphologyIs 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 BETTERBetter 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

<50% of the amblyopic deficit corrected in 23%

Lines of residual amblyopia @ end of treatment

%

0 30

0-1 57

0-2 69

0-4 83

IS MORE EVEN BETTER?

THE IOWA STUDIES

Amblyopia Treatment Outcomes.

WE. Scott.. JAAPOS April 2005 Retrospective review of patients who had full-

time 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!