Title : Acute acquired comitant esotropia following long-term low dose atropine use
Abstract:
Purpose: Acute acquired comitant esotropia (AACE) is a rare form of strabismus presenting as a sudden onset, large angle, esotropia in older children and young adults. Of the 3 subtypes, Type 3 is historically associated with myopia and a period of excessive convergence related to close working distances during near work activities. However, in recent years, there has been a spike in case reports linking AACE and excessive smartphone use. This case series details 2 presentations of AACE encountered in children who had been using long-term 0.01% atropine eye drops.
Case Report: A 10-year-old male presented with a sudden onset right esotropia, larger at near than distance, after 4 years of using nightly 0.01% atropine eye drops for progressive myopia. The patient’s parents reported it worsened after intense near work. Similarly, a 14-year-old female presented with a sudden onset alternating esotropia after 3 years of nightly 0.01% atropine use, which was worse at near and in the morning. At the time of AACE onset, the 10 y.o. male had a mean spherical equivalent (MSE) and visual acuity (VA) of R −4.75 D (20/20) L −5.25 D (20/20), and a right esotropia measuring 16 Δ at distance and 20 Δ at near. Four years prior, before atropine treatment was commenced, this patient had an esophoria measuring 1 Δ at distance and 3 Δ at near, which had increased 1.5 years later to 3 Δ at distance and 9 Δ esophoria at near. At AACE onset, the 14 y.o. female had MSE and VA of R −7.25 D (20/25) L −7.50 D (20/25), and an alternating esotropia measuring 20 Δ at distance and 35 Δ at near. Three years prior, before atropine treatment was commenced, the patient had an esophoria of 3 Δ at distance and near, which had increased 2.5 years later to 4 Δ at distance and 6 Δ at near. Both patients were immediately referred to the local hospital’s paediatric ophthalmology department for neuroimaging to exclude intracranial pathology. Medial rectus recession was suggested for both patients after returning normal MRI results. The 10 y.o. male underwent successful surgical correction and binocularity was restored. The 14 y.o. female was lost to follow-up following referral.
Conclusion: Type 3 AACE is reported to be a rare cause of acquired strabismus in adolescents and young adults, and yet there were 2 presentations within a 10-month period in our university-based optometry clinic. Myopic children are known to have shorter working distances and perform near work activities for longer durations without a visual break than other refractive groups, therefore an increased incidence may be expected in a clinical population of young myopes. However, both patients had been long-term users of 0.01% atropine and had a distance and near esophoria prior to treatment, hence we speculate that the additional strain on the binocular vision system due to chronic cycloplegia may have contributed to the decompensation of these esophorias.
