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Chen X, Liu J, Xu Z, Zhuang Y, Zhou Y, He Y, Yao Y, Yuan J, Feng L, Ye Q, Wen Y, Jia Y, Lu ZL, Lin X, Li J. Binocular Summation With Quantitative Contrast Sensitivity Function: A Novel Parameter to Evaluate Binocular Function in Intermittent Exotropia. Invest Ophthalmol Vis Sci 2024; 65:3. [PMID: 38165705 PMCID: PMC10768712 DOI: 10.1167/iovs.65.1.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/04/2023] [Indexed: 01/04/2024] Open
Abstract
Purpose 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. Methods 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. Results 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. Conclusions 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.
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Affiliation(s)
- Xiaolan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zixuan Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yijing Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yusong Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yunsi He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Ying Yao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Junpeng Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lei Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingqing Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yun Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yu Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zhong-Lin Lu
- Division of Arts and Sciences, NYU Shanghai, Shanghai, China
- Center for Neural Science and Department of Psychology, New York University, New York, New York, United States
- NYU-ECNU Institute of Brain and Cognitive Neuroscience, Shanghai, China
| | - Xiaoming Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jinrong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Liao J, Li Y, Zhang W. Binocular summation of visual acuity and contrast sensitivity in children with intermittent exotropia. BMC Ophthalmol 2023; 23:245. [PMID: 37264304 DOI: 10.1186/s12886-023-02961-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/05/2023] [Indexed: 06/03/2023] Open
Abstract
PURPOSE 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. METHODS 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. RESULTS 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. CONCLUSION 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.
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Affiliation(s)
- Jun Liao
- Chengdu AIDI Eye Hospital, Chengdu, China
| | - Yueping Li
- 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.
| | - Wei Zhang
- 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.
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Xu M, Peng Y, Zheng F, Yu H, Zhou J, Zheng J, Wang Y, Hou F, Yu X. The Effects of Orthoptic Therapy on the Surgical Outcome in Children with Intermittent Exotropia: Randomised Controlled Clinical Trial. J Clin Med 2023; 12:jcm12041283. [PMID: 36835820 PMCID: PMC9964836 DOI: 10.3390/jcm12041283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/04/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND To assess the clinical effectiveness of orthoptic therapy in the postoperative stabilisation and rehabilitation of binocular function in children with intermittent exotropia (IXT) after surgery. METHODS This was a prospective, parallel, randomised controlled trial. A total of 136 IXT patients (aged from 7 to 17 years) who had been successfully corrected at 1 month after surgery were enrolled in this study, and 117 patients (58 controls) completed the 12-month follow-up visit. The primary outcome was established as the proportion of patients with suboptimal surgical outcomes, which were defined as: (1) exodeviation ≥10 prism diopters (PD) at distance or near using the simultaneous prism and cover test (SPCT), or (2) constant esotropia ≥6 PD at distance or near using SPCT, or (3) loss of 2 or more octaves of stereopsis from baseline. The secondary outcomes were the exodeviation at distance and near using the prism and alternate cover test (PACT), stereopsis, fusional exotropia control and convergence amplitude. RESULTS The cumulative probability of suboptimal surgical outcome by 12 months was 20.5% (14/68) in the orthoptic therapy group and 42.6% (29/68) in the control group. There was a significant difference between these two groups (χ2 = 7.402, p = 0.007). Improvements in stereopsis, fusional exotropia control and fusional convergence amplitude were found in the orthoptic therapy group. A smaller exodrift was found in the orthoptic therapy group at near fixation (t = 2.26, p = 0.025). CONCLUSIONS Early postoperative orthoptic therapy can effectively improve the surgical outcome as well as stereopsis and fusional amplitude.
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Affiliation(s)
- Meiping Xu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Yiyi Peng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
| | - Fuhao Zheng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Huanyun Yu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Jiawei Zhou
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Jingwei Zheng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Yuwen Wang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Fang Hou
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, China
- National Clinical Research Center for Ocular Diseases, Wenzhou 325027, China
| | - Xinping Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
- Correspondence: ; Tel.: +86-13695854678
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Xu M, Chen Y, Peng Y, He Z, Jiang J, Yu X, Hou F, Zhou J, Qu J. Binocular Summation Is Intact in Intermittent Exotropia After Surgery. Front Med (Lausanne) 2021; 8:791548. [PMID: 34993215 PMCID: PMC8724027 DOI: 10.3389/fmed.2021.791548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022] Open
Abstract
Purpose: To determine binocular summation of surgically treated intermittent exotropia (IXT) patients by measuring the contrast threshold. Methods: We recruited 38 surgically treated IXT patients aged 8–24 years and 20 age-matched healthy controls. All participants had normal or corrected-to-normal visual acuity (Snellen ≥ 20/20) in both eyes. The IXT patients had undergone the surgery at least a year prior to the study. Twenty-one of them obtained good alignment and 17 experienced a recurrence of exotropia. We measured the observers' monocular and binocular contrast sensitivities (CS) at six spatial frequencies (1.5, 3, 6, 12, 18, 24 cycles/degree) as an index of visual information processing at the threshold level. Binocular summation was evaluated against a baseline model of simple probability summation based on the CS at each spatial frequency and the area under the log contrast sensitivity function (AULCSF). Results: The exo-deviation of IXTs with good alignment was −6.38 ± 3.61 prism diopters (pd) at 33 cm and −5.14 ± 4.07 pd at 5 m. For the patients with recurrence, it was −23.47 ± 5.53 pd and −21.12 ± 4.28 pd, respectively. There was no significant difference in the binocular summation ratio (BSR) between the surgically treated IXT patients, including those with good alignment and recurrence, and normal controls at each spatial frequency [F(2,55) = 0.416, P = 0.662] and AULCSF [F(2,55) = 0.469, P = 0.628]. In addition, the BSR was not associated with stereopsis (r = −0.151, P = 0.365). Conclusion: Our findings of normal contrast sensitivity binocular summation ratio in IXT after surgical treatment suggest that the ability of the visual cortex in processing binocular information is intact at the contrast threshold level.
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Affiliation(s)
- Meiping Xu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Yiya Chen
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Yiyi Peng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Zhifen He
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Jun Jiang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Xinping Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Fang Hou
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
| | - Jiawei Zhou
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
- *Correspondence: Jiawei Zhou
| | - Jia Qu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Wenzhou, China
- Jia Qu
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