Sensory causes of diplopia - profound Abnormal Retinal Corrspondence ARC LIONEL KOWAL MELBOURNE Financial disclosure: There’s no $ in ARC - stick to cataracts

Introduction ARC & suppression in strabismus are common & prevent symptomatic diplopia in the presence of frank tropia. ARC prevents confusion about straight- aheadedness and can allow some binocularity despite strabismus. When strabismic eyes are straightened, ARC usually resolves quickly. Unresolved ARC will cause (paradoxical) diplopia despite straight eyes. If the ARC is profound the diplopia may persist. Profound ARC can often be predicted pre-operatively

Results n=9 Retrospective chart study. Ages were XT. All : definite or probable childhood-onset strab 2: first surgery under age 5 7: first surgery 16 or older [16,20, 24, 25, 38,43,62] Risk of paradoxical diplopia due to profound ARC was appreciated pre-operatively in 3 1/3: postop suppression, & no postop diplopia

Typical pt - having first XT surgery in her 40’s All measurements are ET. Diplopia is all uncrossed

SH - 1st ET surgery in her 20’s LET 20∆, amblyopia 6/30 since childhood. Early recurrence of ET after Rs+Rc After 2nd surgery, straight with ‘new’ visual field in the temporal field of LE Xed Diplopia on her L in her ‘new’ field - ARC only in her new field Diplopia resolved in 2 mo

Results Symptoms disappeared in 2-8 weeks ARC for near disappeared before distance Using Fresnel ∆ for diplopia did not hinder resolution of symptoms 1: diplopia persisting after 8 months 1: paradoxical ‘ARC’ with the pseudofovea of infantile esotropia acting in exotropia

Conclusion Most BUT NOT ALL patients with postop paradoxical diplopia due to ARC resolve after surgical alignment. Deferring alignment surgery to adulthood is a risk factor in this cohort