State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China.
Division of Arts and Sciences, NYU Shanghai, Shanghai, China.
Invest Ophthalmol Vis Sci. 2024 Jan 2;65(1):3. doi: 10.1167/iovs.65.1.3.
Intermittent exotropia (IXT) is the most common form of strabismus. Surgery can potentially improve binocular function in patients with IXT. We aimed to evaluate binocular function using a novel parameter-binocular summation ratio (BSR), measured using quantitative contrast sensitivity function (CSF) in patients with IXT before and after surgery.
Prospective study of 63 patients with IXT and 41 healthy controls were consecutively enrolled and underwent quantitative CSF testing binocularly and monocularly. BSR was calculated by dividing the CSF of the binocular value by the better monocular value. Forty-eight patients with IXT underwent strabismus surgery. BSR, stereoacuity, fusion ability, and strabismus questionnaires were assessed pre-operatively and 2 months postoperatively.
Sixty-three patients with IXT (median age = 9 years) compared with 41 healthy controls showed a worse mean BSR based on all CSF metrics at baseline (the area under the log CSF [AULCSF], spatial frequency [SF] cutoff, and contrast sensitivity at 1.0-18.0 cpd SF). All 48 patients with IXT showed successful alignment after surgery, and there were significant improvements in BSR based on the AULCSF, SF cutoff, and contrast sensitivity at 6.0, 12.0, and 18.0 cpd SF, respectively. The distance stereoacuity and fusion ability also improved after surgery, and a better BSR was associated with better stereoacuity and fusion. For strabismus questionnaires, the psychosocial subscale scores improved postoperatively, whereas the functional subscale scores did not change.
BSR based on quantitative CSF can characterize binocular function across a range of spatial frequencies and can be used as a supplemental measurement for monitoring binocularity in patients with IXT in clinical settings.
间歇性外斜视（IXT）是最常见的斜视类型。手术可能会改善 IXT 患者的双眼功能。我们旨在通过使用新型参数——双眼总和比（BSR）评估 IXT 患者手术前后的双眼功能，该参数通过定量对比敏感度功能（CSF）测量得出。
连续纳入 63 例 IXT 患者和 41 例健康对照者，对其进行双眼和单眼定量 CSF 测试。BSR 通过将双眼 CSF 值除以较好的单眼值来计算。48 例 IXT 患者接受斜视手术。术前和术后 2 个月评估 BSR、立体视锐度、融合能力和斜视问卷。
63 例 IXT 患者（中位数年龄=9 岁）与 41 例健康对照者相比，在基线时所有 CSF 指标的平均 BSR 均较差（对数 CSF [AULCSF] 面积、空间频率 [SF] 截止值和 1.0-18.0 cpd SF 对比度敏感度）。所有 48 例 IXT 患者手术后均获得成功矫正，BSR 在 AULCSF、SF 截止值和 6.0、12.0 和 18.0 cpd SF 的对比度敏感度方面均有显著改善。术后距离立体视锐度和融合能力也得到改善，较好的 BSR 与较好的立体视锐度和融合能力相关。对于斜视问卷，术后社会心理亚量表评分提高，而功能亚量表评分没有变化。
基于定量 CSF 的 BSR 可全面描述不同空间频率的双眼功能，可作为临床监测 IXT 患者双眼功能的补充测量。
