Consecutive Esotropia after Surgical Correction of Intermittent Exotropia

Cho, Yoonae A; Yoo, Chungkwon

Abstract

Intentional overcorrection is recommended immediately after surgery of intermittent exotropia for its superior long-term prognosis. However, esotropia can develop in 6~15%, especially in children less than 4 years of age, and bring about the problems such as diplopia, suppression, decreased vision and impaired binocular single vision. The purpose of this study is to evaluate the factors possibly associated with its occurrence. A retrospective study was conducted on the 22 patients with consecutive esotropia, which had developed after surgical correction of intermittent exotropia. They underwent unilateral or bilateral medial rectus muscle recession for correction of esotropia. The mean angle of exodeviation before intermittent exotropia surgery was 30.0+/-5.2 PD(prism diopters)(23~40 PD). The mean angle of esodeviation at surgery for consecutive esotropia was 24.1+/-10.3 PD(10~55 PD). Before surgery of intermittent exotropia, 13 of the 16 patients(81.3%)had showed lateral incomitancy. No significant difference was found between age at surgery and consecutive esotropia. High AC/A ratio had been present preoperatively in only one patient. No patient showed A-V pattern preoperatively. Out of the 17 patients who had undergone bilateral lateral rectus recessions for intermittent exotropia, 10(58.8%) patients had either lateral rectus muscle recessed by 7.5 mm or more. Four of the 5 patients(80%)had a medial rectus resected by 5 mm or more. This study suggests that consecutive esotropia after intermittent exotropia surgery can develop more likely in the patients who have had lateral incomitancy, excessive recession of lateral rectus muscle by 7.5 mm or more, or excessive resection of medial rectus muscle by 5 mm or more.