Garretty Tess
a Orthoptic Department, Multidisciplinary Outpatient Building , St James' University Hospital , Leeds , England.
Strabismus. 2018 Sep;26(3):111-117. doi: 10.1080/09273972.2018.1481435. Epub 2018 Jun 11.
Convergence excess esotropia describes a heterophoria with binocular single vision (BSV) on distance viewing that becomes esotropic on accommodation upon near fixation. Prism adaptation test (PAT) is a procedure routinely used to reveal the maximum angle of deviation preoperatively for many types of strabismus and has been shown to improve surgical outcomes; however, it is not conventionally used for convergence excess esotropia.
This study compares the angle of deviation at 1/3 m and 6 m before and after prism adaptation in subjects with convergence excess esotropia to determine if a masked distance angle of deviation can be demonstrated similar to the masked near angle of deviation in some intermittent exotropes. Surgical results are reported.
Fifty-eight children with convergence excess esotropia were prescribed prism adaptation prior to strabismus surgery and 49 met the inclusion criteria. A median increase in the angle of deviation of 20 prism dioptres (PD) was seen at both 1/3 m and 6 m following PAT. These changes were statistically significant (p < 0.001) at both distances. Following one surgical procedure, 83.6% were fully binocular postoperatively.
Prism adaptation frequently reveals an otherwise masked large distance angle of deviation in convergence excess esotropia. Convergence excess esotropia can be subdivided into two categories: true and simulated. Those with true convergence excess exhibit a manifest convergent strabismus when viewing a close object and a small, well-controlled latent strabismus upon fixation of a distant object. Those with simulated convergence excess have a comparable near deviation to those with true convergence excess but can be shown to have a distance deviation that approaches the size of the near strabismus once the normal fusional mechanisms are disrupted by a period of prism adaptation.
集合过强性内斜视是指在远距离注视时具有双眼单视（BSV）的隐斜视，而在近注视时因调节而变为内斜视。棱镜适应试验（PAT）是一种常规用于术前揭示多种斜视最大偏斜角度的方法，已被证明可改善手术效果；然而，它通常不用于集合过强性内斜视。
本研究比较集合过强性内斜视患者在棱镜适应前后1/3米和6米处的偏斜角度，以确定是否能证明存在与某些间歇性外斜视中被掩盖的近距离偏斜角度类似的被掩盖的远距离偏斜角度。报告手术结果。
58例集合过强性内斜视儿童在斜视手术前接受了棱镜适应，49例符合纳入标准。在棱镜适应试验后，1/3米和6米处的偏斜角度中位数增加了20棱镜度（PD）。在这两个距离处，这些变化均具有统计学意义（p < 0.001）。经过一次手术，83.6%的患者术后完全恢复双眼视。
棱镜适应常常揭示出集合过强性内斜视中原本被掩盖的较大远距离偏斜角度。集合过强性内斜视可分为两类：真性和假性。真性集合过强患者在注视近物时表现为明显的集合性斜视，注视远物时表现为小的、控制良好的潜在斜视。假性集合过强患者的近距离偏斜与真性集合过强患者相当，但一旦正常融合机制被一段时间的棱镜适应破坏，可显示其远距离偏斜接近近距离斜视的大小。
