Accommodative spasm might influence surgical planning and outcomes in acute acquired distance esotropia in myopia

Introduction: Acute acquired distance esotropia (AADE) is a poorly understood moderate-angle strabismus, affecting young adult myopes and determining bothersome diplopia. Symptoms can be intermittent in the early stages, becoming constant in long-lasting disease. Symptomatic therapy includes prism correction, while surgery is the only curative treatment. However, the latter is affected by high rate of symptoms recurrence with the frequent need for reoperation.

Hypothesis: We hypothesize that AADE could be caused by the increase of the accommodative demand, often secondary to a myopic overcorrection. This condition could determine an increase in induced hyperopia at near, dominated by an excess of accommodation and therefore of convergence. The latter cannot be relaxed at distance and diplopia develops. We speculate that early-stage AADE could be successfully treated by cycloplegic eye drops slowly tapered within three months. On the other hand, surgery remains the only option in long-lasting AADE. In these cases, we propose a new pre-operative assessment of esotropia by asking the patient to fix alternatively a stimulus at near and at distance in order to stimulate the accommodative convergence. This technique allows to unmask the total amount of the angle of deviation and to plan a wider bilateral medial rectus muscle recession avoiding long-term residual esotropia.

Discussion: Currently, AADE curative therapy is surgical regardless of onset time but it is usually affected by poor outcomes. If our hypothesis was to be confirmed, pharmacological treatment could solve early-stage AADE, avoiding any surgery. Furthermore, a wide bilateral medial rectus muscle recession, quantified on the basis of the above mentioned test for measuring the total amount of the strabismus angle, could improve outcomes eliminating the need for reoperation in long-lasting AADE.