PURPOSE To describe the clinical course of untreated intermittent exotropia (IXT) in children 12-35 months of age followed for 3 years. METHODS We enrolled 97 children 12-35 months of age with previously untreated IXT who had been randomly assigned to the observation arm of a randomised trial of short-term occlusion versus observation. Participants were observed unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, and 6-month intervals thereafter for 3 years. The primary outcome was deterioration of the IXT by 3 years, defined as (1) a constant exotropia ≥10 prism dioptres (∆) at distance and near (i.e., motor deterioration) or (2) treatment prescribed despite not having met motor deterioration. The primary analysis used the Kaplan-Meier method to determine the cumulative proportion of participants meeting deterioration by three years and 95% confidence interval (CI). RESULTS The cumulative probability of deterioration by 3 years was 28% (95% CI = 20%-39%). Of the 24 participants meeting the primary outcome of deterioration, seven met motor deterioration and 17 were prescribed treatment without meeting motor deterioration. The cumulative probability of motor deterioration by 3 years was 10% (95% CI = 5%-19%). CONCLUSIONS Given the modest rate of motor deterioration over three years, watchful waiting may be a reasonable management approach in 12- to 35-month-old children with IXT. To confirm this recommendation would require a long-term randomised trial of immediate treatment versus observation followed by deferred treatment if needed.

中文翻译：

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对 12 至 35 个月大的未经治疗的间歇性外斜视儿童的三年观察。

目的 描述 12-35 月龄儿童未经治疗的间歇性外斜视 (IXT) 的临床病程，随访 3 年。方法 我们招募了 97 名 12-35 个月大的先前未经治疗的 IXT 儿童，他们被随机分配到短期闭塞与观察的随机试验的观察组。除非在随后 3 年的 3 个月、6 个月和 6 个月的时间间隔进行的随访中满足恶化标准，否则对参与者进行观察。主要结果是 3 年时 IXT 的恶化，定义为 (1) 远处和近处的恒定外斜度≥10 棱镜屈光度 (Δ)（即运动恶化）或 (2) 尽管没有遇到运动恶化，但仍进行了治疗。主要分析使用 Kaplan-Meier 方法来确定三年前出现恶化的参与者的累积比例和 95% 置信区间 (CI)。结果 3 年恶化的累积概率为 28% (95% CI = 20%-39%)。在达到恶化这一主要结果的 24 名参与者中，7 名出现运动恶化，17 名接受治疗但未出现运动恶化。3 年后运动退化的累积概率为 10% (95% CI = 5%-19%)。结论鉴于三年内运动功能恶化的速度适中，观察等待可能是 12 至 35 个月大的 IXT 儿童的合理管理方法。为了证实这一建议，需要进行一项长期随机试验，即立即治疗与观察，然后根据需要推迟治疗。