Managing amblyopia/strabismus

Question 1

List the different tx options for strabismus

Answer 1

Ergonomics 
Refractive correction
Orthoptic exercise
Prism 
Surgery

Question 2

Ergonomics

Answer 2

Consider tasks/hobbies
E.g. near work
Regular breaks
WD?

Question 3

Refractive correction for strab

Answer 3

Full rx any decomp phoria/tropia 
>1.5d hyperopia
>1d myopia
>1d astigmatism 
>1d anisometropia

Question 4

Tx for full/partial accom tropia

Answer 4

May be refractive +1 other tx(s)

Full rx can worsen xop

Question 5

Orthoptic exercises

Answer 5

Build muscle strength
Measured using FRs
Increasing FR/decreasing Sx = exercises working
CI - Pen-to-nose 2min 4xday - npc should increase - review 2-3months
Stereograms - physiological dip - divergent deviations -> near exercise
Convergent deviations -> dist exercises

Question 6

Prism tx

Answer 6

Mod-large deviations
Should only partially correct - encourage Fusional vergences to build
Last option

Question 7

Sheards criteria

Answer 7

Amount of phoria should be less than the opposing FR

E.g. 10d xop should have at least 20d +ve FR

Question 8

Percival’s criteria

Answer 8

XOP: 2/3xop - 1/3PFR
SOP: 1/3(total FRs) - NFR

Question 9

Prism adaptation

Answer 9

When overprescribe prism
Use FD to assess
Leave prism for 3min
If phoria returns = adaptation
Unsafe to prescribe

Question 10

Amblyopia - refractive correction

Answer 10

Full rx
Ftw
Cls>specs - reduce aniseikonia
- review after 18wk - still amblyopic -> patch

Question 11

Amblyopic - occlusion therapy

Answer 11

Depends on age / amblyopia type
5-8yo
Patching (6months)
Va diff 0.3-0.6logmar -> 3hrs
Va diff 0.7-1.3logmar -> 6hrs daily 

Low dose atropine

Question 12

Strabismic amblyopia tx

Answer 12

Patching <8yo

After critical period less effective - may cause adaptation - breakdown- diplopia