Characteristics and management of cyclic esotropia: a scoping review

Cyclic esotropia is a rare form of strabismus characterized by alternating periods of esodeviation, typically occurring in a predictable cycle. Its etiology and treatment remain incompletely understood. This review aims to synthesize current evidence on the characteristics and treatment for cyclic esotropia.

Systematic searches were conducted in Ovid MEDLINE, Ovid Embase, Cochrane registered trials, Web of Science, and Scopus databases. The key terms used for searches were cyclic esotropia and treatment. Two independent reviewers screened the title and abstract of retrieved studies against a prepublished protocol to select relevant studies. No language restrictions were applied.

A total of 55 studies met inclusion criteria, encompassing case reports, case series, and observational studies: 86 cases were identified. Diagnosis was primarily clinical based on cyclic patterns of deviation. Average age was 7 years, with a male:female ratio of about 50:50. Most cases (85%) had a 48 hour cycle (24 hours esotropia, followed by 24 hours of orthotropia), with the majority of the remainder being 92 hours (48 hours esotropia, followed by 48 hours of orthotropia); 12% of cases reported amblyopia. Average refraction was +0.7 sphere. Average deviations were similar for both near (36^Δ) and distance (37^Δ). Bimedial recessions were reported in 28 cases, 95% of which were successful in correcting the esotropia to <10^Δ within 6 months. Nine of 10 cases were successfully treated to <10^Δ using botulinum toxin type A.

Cyclic esotropia remains an enigmatic condition, requiring greater awareness and standardized diagnostic protocols. Although surgery appears effective, more evidence is needed to optimize management and assess long-term stability. Further research should focus on pathophysiological mechanisms and therapeutic approaches.