Department of Mechatronics Engineering, Konkuk University Glocal Campus, Chungcheongbuk-do, Republic of Korea.
Department of Ophthalmology, Research Institute of Medical Science, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
PLoS One. 2023 Feb 16;18(2):e0281392. doi: 10.1371/journal.pone.0281392. eCollection 2023.
To determine the relationship between consecutive esotropia (ET) and passive duction force (PDF) in patients with intermittent exotropia (XT).
The study enrolled 70 patients in whom PDF was measured under general anesthesia prior to XT surgery. The preferred eye for fixation (PE) and the nonpreferred eye for fixation (NPE) were determined using a cover-uncover test. The patients were subdivided into two groups according to the angle of deviation at 1 month postoperation: (1) consecutive ET (CET group), >10 prism diopters (PD) of ET; and (2) non-CET (NCET group), ≤10 ET or residual exodeviation. The relative PDF of the medial rectus muscle (MRM) was obtained by subtracting the ipsilateral PDF of the lateral rectus muscle (LRM) from the PDF of the MRM.
The PDFs for the LRM in the PE in the CET and NCET groups were 47.28 g and 58.59 g, respectively (p = 0.147), and 56.18 g and 46.59 g for the MRM (p = 0.11), and in the NPE were 59.84 g and 55.25 g, respectively, for the LRM (p = 0.993), and 49.12 g and 50.53 g, respectively, for the MRM (p = 0.81). However, in the PE, the PDF in the MRM was larger in the CET group than in the NCET group (p = 0.045), which was positively associated with the postoperatively overcorrected angle of deviation (p = 0.017).
An increased relative PDF in the MRM in the PE was a risk factor for consecutive ET after XT surgery. Quantitative evaluation of the PDF could be considered when planning strabismus surgery to achieve the desired surgical outcome.
探讨间歇性外斜视（XT）患者连续内斜视（ET）与被动牵引力量（PDF）的关系。
本研究纳入了 70 名在 XT 手术前全身麻醉下测量 PDF 的患者。使用遮盖-去遮盖试验确定注视时的优势眼（PE）和非优势眼（NPE）。根据术后 1 个月的偏斜角度，将患者分为两组：（1）连续 ET（CET 组），ET>10 棱镜度（PD）；（2）非 CET（NCET 组），ET≤10 或残留外斜视。通过从内侧直肌（MRM）的 PDF 中减去同侧外直肌（LRM）的 PDF，获得 MRM 的相对 PDF。
CET 组和 NCET 组 PE 时 LRM 的 PDF 分别为 47.28 g 和 58.59 g（p = 0.147），MRM 分别为 56.18 g 和 46.59 g（p = 0.11），NPE 时 LRM 分别为 59.84 g 和 55.25 g（p = 0.993），MRM 分别为 49.12 g 和 50.53 g（p = 0.81）。然而，在 PE 时，CET 组的 MRM PDF 大于 NCET 组（p = 0.045），且与术后过矫正的偏斜角度呈正相关（p = 0.017）。
PE 时 MRM 的相对 PDF 增加是 XT 手术后连续 ET 的危险因素。在计划斜视手术以获得理想的手术效果时，可以考虑对 PDF 进行定量评估。
