Chengdu AIDI Eye Hospital, Chengdu, China.
Pediatric Ophthalmology and Strabismus Department, Tianjin Eye Hospital, Affiliated Eye Hospital of Nankai University, Clinical College of Ophthalmology of Tianjin Medical University, Tianjin Key Laboratory of Ophthalmology and Vision Science, Tianjin, 300020, China.
BMC Ophthalmol. 2023 Jun 1;23(1):245. doi: 10.1186/s12886-023-02961-x.
To investigate the binocular summation (BiS) of visual acuity (VA) and contrast sensitivity (CS) in children with intermittent exotropia (IXT) before and after surgery and to probe the relationship between the two BiS phenomena and corresponding influencing factors.
This prospective study included 21 IXT children (11 males and 10 females; aged 6-13 years) who underwent strabismus surgery in Tianjin Eye Hospital from January to April 2022. The visual function was assessed preoperatively and 2.95 ± 0.14 months postoperatively, including monocular/ binocular visual acuity (MVA/BVA) at 100% contrast and 2.5% contrast as well as monocular/binocular contrast sensitivity (MCS/BCS), deviation, near and distant stereopsis, and fusion.
All patients had postoperative deviation ranging from 0 to -4 PD. Either preoperative or postoperative BVA at 2.5% contrast was superior to the MVA. The postoperative BiS at 2.5% contrast was significantly superior to the preoperative BiS for 2.5% contrast and postoperative BiS for 100% contrast (P < 0.05). Except for 3 c/d, the MCS and BCS at 6 c/d, 12 c/d and 18 c/d spatial frequencies were all notably improved postoperatively. The postoperative binocular summation ratio of CS (BSR) was highest while interocular difference ratio of CS (IOR) was the lowest at 6 c/d among 4 spatial frequencies. The deviation, distant and near stereopsis, and fusion performance were all remarkably improved after surgery (p = 0.001; p = 0.041; p = 0.000), all of which were not related to BVA at 2.5% contrast, BiS, BSC and BSR. The BCS at middle and high frequencies (6 c/ds, 12 c/ds, and 18 c/ds) was significantly negatively correlated with the BVA at 2.5% contrast, and BSR was irrelevant to the corresponding IOR across different spatial frequencies.
BVA at low contrast and BCS examinations were not equivalent to stereopsis and fusion status, which contributed to the evaluation of binocular function in the real environment and in the different aspects. BVA in 2.5% contrast is related with BCS in moderate and high spacial frequencies (especially 18c/d) but BCS in 6c/d presents more binocular summation of contrast sensitivity. MCS, BCS and the BSR persist inhibition at 3c/d after surgery. The improvement of BCS is better than that of BSR to evaluate the binouclar function in IXT. Those two methods showed different sensitivities to impairment and rehabilitation of binocular summation and inhibition.
探讨间歇性外斜视（IXT）儿童手术前后双眼视力（VA）和对比敏感度（CS）的双眼总和（BiS），探讨两种 BiS 现象与相应影响因素的关系。
本前瞻性研究纳入 2022 年 1 月至 4 月在天津市眼科医院接受斜视手术的 21 例 IXT 儿童（男 11 例，女 10 例；年龄 6-13 岁）。术前和术后 2.95±0.14 个月评估视觉功能，包括 100%和 2.5%对比度的单眼/双眼视力（MVA/BVA）以及单眼/双眼对比敏感度（MCS/BCS）、偏斜、近距和远距立体视、融合。
所有患者术后偏斜度均为 0-4 PD。术前或术后 2.5%对比度下的 BVA 均优于 MVA。术后 2.5%对比度的双眼 BiS 明显优于术前 2.5%对比度的双眼 BiS 和术后 100%对比度的双眼 BiS（P<0.05）。除 3 c/d 外，6 c/d、12 c/d 和 18 c/d 空间频率的 MCS 和 BCS 均明显提高。在 4 个空间频率中，6 c/d 时的 CS 双眼总和比（BSR）最高，CS 眼间差异比（IOR）最低。术后斜视、远距和近距立体视、融合功能均显著改善（p=0.001；p=0.041；p=0.000），与 2.5%对比度的 BVA、BiS、BCS 和 BSR 均无关。中高频（6 c/ds、12 c/ds 和 18 c/ds）的 BCS 与 2.5%对比度的 BVA 呈显著负相关，BSR 与不同空间频率的相应 IOR 无关。
低对比度的 BVA 和 CS 检查与立体视和融合状态不同，有助于评估真实环境和不同方面的双眼功能。2.5%对比度的 BVA 与中高空间频率（特别是 18c/d）的 BCS 相关，但 6c/d 的 BCS 呈现出更好的对比敏感度双眼总和。术后 3c/d 时 MCS、BCS 和 BSR 仍存在抑制。BCS 的改善优于 BSR 评估 IXT 的双眼功能。这两种方法对双眼总和和抑制的损害和康复有不同的敏感性。
