Overaction of oblique muscles and A - V patterns

Department of pediatric ophthalmology - VNIO

Introduction

• Strabismus with overaction of oblique muscles are common.

• A and V patterns are changes of deviation when patient looks up or down.

• A pattern: increasing divergence in down gaze >10PD

• V pattern: increasing divergence in up gaze >15PD

Inferior oblique overaction

• Primary Inferior oblique overaction– The cause is unknown– Mostly are bilateral– Often associate with congenital esotropia, but

become manifest at 1-2 year of age– Head tilt test nagative– No under action of ipsilateral SO

• Secondary Inferior oblique overaction– Due to superior oblique palsy

Inferior oblique overaction

• Clinical features – Upshoot of adducting eye– Increasing deviation in up-gaze, always cause

V pattern– Bilateral IO overaction cause:

• right hypertropia in left gaze• left hypertropia in right gaze

Superior oblique overaction

• Etiology – Primary superior oblique overaction: The

cause is unknown– Secondary superior oblique overaction:Due to

paresis of contralateral inferior rectus or ipsilateral inferior oblique palsy

Inferior oblique overaction

• Management IO overaction– Weekening procedure:

IO overaction 2+ or more• IO Recession• IO Myectomy • IO Anteriorization

Superior oblique overaction

• Clinical features:– Down shoot of adducting eye on version– A pattern in down gaze– Bilateral SO overaction cause:

• right hypotropia in left gaze• left hypotropia in right gaze

Superior oblique overaction

• Management of SO overaction– SO weakening procedures

• Superior oblique tenotomy• Silicone tendon expander• Split tendon elongation• Posterior tenectomy

Management A,V pattern without obliques overaction

- V pattern

+Transpose MR downward

+ Transpose LR upward

- A pattern

+ Transpose MR up

+Transpose LR down

Thank you for your attention