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Interocular Phase Disparity Tuning of Binocular Contrast Summation Depends on Carrier Spatial Frequency and Orientation. Optom Vis Sci 2022; 99:547-559. [PMID: 35413025 DOI: 10.1097/opx.0000000000001907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SIGNIFICANCE Binocular summation is a sensitive metric of binocular integration. As such, characterization of the mechanisms underlying binocular summation is a key step in translating and applying this knowledge to abnormal binocular systems afflicted with strabismus and amblyopia. PURPOSE Computational models of binocular summation have advocated the operation of mechanisms sensitive to the interocular phase disparity of first order carrier gratings. This study investigated if such generalization depended on carrier spatial frequency and orientation. METHODS Monocular and binocular contrast detection thresholds were measured in nine observers with normal binocular vision. Stimuli comprised Gabor targets presented with one of three spatial frequencies (1, 3, and 9 cpd), two orientations (horizontal and vertical) and five interocular phase disparities (0, +/- pi/2, +/- pi radians). Horizontal and vertical fixation disparities were measured for each binocular threshold condition. Binocular summation ratios (BSR) were computed by dividing the mean monocular detection threshold by the respective binocular detection threshold. RESULTS BSR varied significantly with interocular phase disparity for the 1 cpd and 3 cpd horizontal and vertical gratings. Phase dependency was reduced with the 9 cpd horizontal grating, and absent for the 9 cpd vertical grating, even though BSR exceeded predictions of probability summation. Computational modelling that incorporated the variability of fixation disparity into a vector summation model, predicted a reduction in peak BSR with increasing carrier spatial frequency, but did not account for the reduction of phase sensitivity noted with the 9 cpd stimulus. CONCLUSIONS Binocular summation magnitude is less dependent on interocular phase disparities as carrier spatial frequencies exceed 3 cpd, especially with vertical gratings. While vergence variability due to fixation disparities contribute to the overall reduction in binocular summation magnitude with increasing carrier spatial frequency; however, it does not provide a complete account for the lack of interocular phase disparity tuning noted with high grating spatial frequencies.
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Min SH, Mao Y, Chen S, He Z, Hess RF, Zhou J. A clinically convenient test to measure binocular balance across spatial frequency in amblyopia. iScience 2022; 25:103652. [PMID: 35024586 PMCID: PMC8733258 DOI: 10.1016/j.isci.2021.103652] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/25/2021] [Accepted: 12/13/2021] [Indexed: 11/29/2022] Open
Abstract
Amblyopia is a visual disorder that originates from the brain. It exhibits no pathology in the eye. Studies have shown that measuring both visual acuity and binocular balance for assessing amblyopia could be more helpful. However, tests that measure binocular balance are time-consuming, often exceeding 30 min. Their long test durations prevent them from being used in the clinic. For this reason, we have developed a quick (i.e., about 7 min) and precise tool that quantitatively measures binocular balance of patients with amblyopia. The new test can capture binocular imbalance that is typically exhibited at high spatial frequency in amblyopes. In addition, it has an excellent test-retest reliability and repeatability between two experimental sessions. We hope that our newly developed test can pave the road for physicians and researchers to better assess and diagnose amblyopia and other visual disorders that disrupt binocular balance beyond the laboratory. Measuring binocular balance of amblyopes is difficult and time-consuming (>30 min) We introduce a psychophysical test that is reliable and quick (7 min)
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Affiliation(s)
- Seung Hyun Min
- School of Ophthalmology and Optometry, Affiliated Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China.,McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Yu Mao
- School of Ophthalmology and Optometry, Affiliated Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shijia Chen
- School of Ophthalmology and Optometry, Affiliated Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhifen He
- School of Ophthalmology and Optometry, Affiliated Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Robert F Hess
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Jiawei Zhou
- School of Ophthalmology and Optometry, Affiliated Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Chima AS, Formankiewicz MA, Waugh SJ. Interocular ND filter suppression: Eccentricity and luminance polarity effects. J Vis 2020; 20:35. [PMID: 32735341 PMCID: PMC7424104 DOI: 10.1167/jov.20.7.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The depth and extent of interocular suppression were measured in binocularly normal observers who unilaterally adapted to neutral density (ND) filters (0, 1.5, 2, and 3 ND). Suppression was measured by dichoptically matching sectors of a ring presented to the adapted eye to a fixed contrast contiguous ring presented to the non-adapted eye. Other rings of alternating polarity were viewed binocularly. Rings were defined by luminance (L), luminance with added dynamic binary luminance noise (LM), and contrast modulating the same noise (CM). Interocular suppression depth increased with increasing ND, nearing significance (p = 0.058) for 1.5 ND. For L and LM stimuli, suppression depth across eccentricity (±12° visual field) differed for luminance increment (white) versus luminance decrement (black) stimuli, potentially confounding eccentricity results. Suppression for increment-only (white) luminance stimuli was steeper centrally and extended across the visual field, but was deeper for L than for LM stimuli. Suppression for decrement-only (black) luminance stimuli revealed only central suppression. Suppression was deeper with CM than LM stimuli, suggesting that CM stimuli are extracted in areas receiving predominantly binocular input which may be more sensitive to binocular disruption. Increment (white) luminance stimuli demonstrate deeper interocular suppression in the periphery than decrement (black) stimuli, so they are more sensitive to changes in peripheral suppression. Asymmetry of suppression in the periphery for opposite polarity luminance stimuli may be due to interocular receptive field size mismatch as a result of dark adaptation separately affecting ON and OFF pathways. Clinically, measurement of suppression with CM stimuli may provide the best information about post-combination binocularity.
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Chen Y, He Z, Mao Y, Chen H, Zhou J, Hess RF. Patching and Suppression in Amblyopia: One Mechanism or Two? Front Neurosci 2020; 13:1364. [PMID: 32009874 PMCID: PMC6974542 DOI: 10.3389/fnins.2019.01364] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/03/2019] [Indexed: 01/26/2023] Open
Abstract
Purpose To determine if benefits from occlusion therapy are due to decreased suppression from the fellow eye in children with amblyopia. Methods Ten newly diagnosed amblyopes (7.2 ± 1.4 years old), two with strabismus and eight with anisometropia, participated. Patients were first given a 2-month period of refractive adaptation, followed by occlusion therapy (i.e., patching their fellow eye with an opaque patch for 4 h/day). Visual acuity of the amblyopic eye and interocular suppression were measured before and after 0.5, 1, 2, 4, and 6 months of occlusion therapy. We quantified interocular suppression with a binocular phase combination task. Results Visual acuity (in logMAR) improved from 0.50 ± 0.22 (mean ± SD) to 0.33 ± 0.20 for patients who finished a short-term (2 months) occlusion (A1–A10), from 0.53 ± 0.20 to 0.32 ± 0.22 for patients who finished a medium-term (4 months) occlusion (A1–A9), and from 0.48 ± 0.19 to 0.22 ± 0.10 for patients who finished a long-term (6 months) occlusion (A1–A8). Although their visual acuity significantly improved, their degree of suppression, which was abnormal in all cases, did not change consistently. This was true in all durations of occlusion therapy. Conclusion Reduced suppression from the fixing eye might not be result from occlusion therapy.
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Affiliation(s)
- Yiya Chen
- School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Zhifen He
- School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yu Mao
- School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Hao Chen
- School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Jiawei Zhou
- School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Robert F Hess
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, QC, Canada
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Wang Y, He Z, Liang Y, Chen Y, Gong L, Mao Y, Chen X, Yao Z, Spiegel DP, Qu J, Lu F, Zhou J, Hess RF. The Binocular Balance at High Spatial Frequencies as Revealed by the Binocular Orientation Combination Task. Front Hum Neurosci 2019; 13:106. [PMID: 31001096 PMCID: PMC6454030 DOI: 10.3389/fnhum.2019.00106] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/11/2019] [Indexed: 11/13/2022] Open
Abstract
How to precisely quantify the binocular eye balance (i.e., the contribution that each eye makes to the binocular percept) across a range of spatial frequencies using a binocular combination task, is an important issue in both clinical and basic research. In this study, we aimed to compare the precision of a binocular orientation combination paradigm with that of the standard binocular phase combination paradigm in measuring the binocular eye balance at low to high spatial frequencies. Nine normal adults (average age: 24.6 ± 2.0 years old) participated. Subjects viewed an LED screen dichoptically with polarized glasses in a dark room. The method of constant stimuli was used to quantitatively assess the point of subjective equality (PSE), i.e., the interocular contrast ratio when two eyes are balanced in binocular combination, for stimulus spatial frequencies from 0.5 to 8 cycles/degree. Precision was quantified by the variance [i.e., standard error (SE), obtained from 100 bootstrap estimates] associated to the PSE. Using stimuli whose interocular phase difference at the edge of the gratings was matched at 45°, we found that the orientation paradigm provides more precision than the standard binocular phase combination paradigm, especially at high frequencies (Experiment 1). Such differences remained when using stimuli that had three times larger interocular phase difference (Experiment 2) or displayed at four times higher stimuli resolution (Experiment 3). Our results indicate that a binocular combination tasked based on orientation rather than phase, provides a more precise estimate of binocular eye balance in human adults at high spatial frequencies, thus allowing a binocular balance to be assessed within the spatial region where amblyopes are most defective (i.e., high spatial frequencies).
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Affiliation(s)
- Yonghua Wang
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Zhifen He
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yunjie Liang
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yiya Chen
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Ling Gong
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yu Mao
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Xiaoxin Chen
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Zhimo Yao
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Daniel P Spiegel
- Vision Sciences, Essilor R&D, Center for Innovation and Technology, Singapore, Singapore
| | - Jia Qu
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Fan Lu
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Jiawei Zhou
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Robert F Hess
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, QC, Canada
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Asher JM, Hibbard PB. First- and second-order contributions to depth perception in anti-correlated random dot stereograms. Sci Rep 2018; 8:14120. [PMID: 30237535 PMCID: PMC6148546 DOI: 10.1038/s41598-018-32500-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 09/05/2018] [Indexed: 11/08/2022] Open
Abstract
The binocular energy model of neural responses predicts that depth from binocular disparity might be perceived in the reversed direction when the contrast of dots presented to one eye is reversed. While reversed-depth has been found using anti-correlated random-dot stereograms (ACRDS) the findings are inconsistent across studies. The mixed findings may be accounted for by the presence of a gap between the target and surround, or as a result of overlap of dots around the vertical edges of the stimuli. To test this, we assessed whether (1) the gap size (0, 19.2 or 38.4 arc min) (2) the correlation of dots or (3) the border orientation (circular target, or horizontal or vertical edge) affected the perception of depth. Reversed-depth from ACRDS (circular no-gap condition) was seen by a minority of participants, but this effect reduced as the gap size increased. Depth was mostly perceived in the correct direction for ACRDS edge stimuli, with the effect increasing with the gap size. The inconsistency across conditions can be accounted for by the relative reliability of first- and second-order depth detection mechanisms, and the coarse spatial resolution of the latter.
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Affiliation(s)
- Jordi M Asher
- University of Essex, Department of Psychology, Wivenhoe Park, CO4 3SQ, United Kingdom.
| | - Paul B Hibbard
- University of Essex, Department of Psychology, Wivenhoe Park, CO4 3SQ, United Kingdom
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Skerswetat J, Formankiewicz MA, Waugh SJ. More superimposition for contrast-modulated than luminance-modulated stimuli during binocular rivalry. Vision Res 2017; 142:40-51. [PMID: 29102622 DOI: 10.1016/j.visres.2017.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 08/08/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
Luminance-modulated noise (LM) and contrast-modulated noise (CM) gratings were presented with interocularly correlated, uncorrelated and anti-correlated binary noise to investigate their contributions to mixed percepts, specifically piecemeal and superimposition, during binocular rivalry. Stimuli were sine-wave gratings of 2 c/deg presented within 2 deg circular apertures. The LM stimulus contrast was 0.1 and the CM stimulus modulation depth was 1.0, equating to approximately 5 and 7 times detection threshold, respectively. Twelve 45 s trials, per noise configuration, were carried out. Fifteen participants with normal vision indicated via button presses whether an exclusive, piecemeal or superimposed percept was seen. For all noise conditions LM stimuli generated more exclusive visibility, and lower proportions of superimposition. CM stimuli led to greater proportions and longer periods of superimposition. For both stimulus types, correlated interocular noise generated more superimposition than did anti- or uncorrelated interocular noise. No significant effect of stimulus type (LM vs CM) or noise configuration (correlated, uncorrelated, anti-correlated) on piecemeal perception was found. Exclusive visibility was greater in proportion, and perceptual changes more numerous, during binocular rivalry for CM stimuli when interocular noise was not correlated. This suggests that mutual inhibition, initiated by non-correlated noise CM gratings, occurs between neurons processing luminance noise (first-order component), as well as those processing gratings (second-order component). Therefore, first- and second-order components can contribute to overall binocular rivalry responses. We suggest the addition of a new well to the current energy landscape model for binocular rivalry that takes superimposition into account.
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Affiliation(s)
- Jan Skerswetat
- Anglia Vision Research, Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, CB1 1PT Cambridge, UK.
| | - Monika A Formankiewicz
- Anglia Vision Research, Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, CB1 1PT Cambridge, UK
| | - Sarah J Waugh
- Anglia Vision Research, Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, CB1 1PT Cambridge, UK
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8
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Feng L, Lin H, Chen Y, Wang J, Wang Y, Liao R, Zhou J, Hess RF. The effect of Lasik surgery on myopic anisometropes' sensory eye dominance. Sci Rep 2017; 7:3629. [PMID: 28620156 PMCID: PMC5472567 DOI: 10.1038/s41598-017-03553-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/02/2017] [Indexed: 11/09/2022] Open
Abstract
Lasik is a common surgery for treating anisometropia. In this study, we asked a specific question: what’s the effect of Lasik surgery on anisometropes’ sensory eye dominance? Fifteen myopic anisometropes (mean age: 23 ± 6.9 years old; 6 females) participated in our experiment. We quantitatively measured participants’ sensory eye dominance before and after the Lasik surgery using a binocular phase combination paradigm. We found no significant change of sensory eye dominance within 16 weeks (measured between 8 to 96 days, for one or two repetitions) after the surgery (t(14) = −1.44, p = 0.17). A further following on eight patients showed that patients’ two eyes were much more balanced at 16 weeks or more (measured one or two times between 112 to 408 days) after the surgery (t(7) = −3.79, p = 0.007). Our results suggest that the benefit of Lasik surgery on anisometropes’ sensory eye dominance is not immediate, a long-term ‘adaptation’ period (16 weeks or more) is necessary to enable the surgery to be truly effective.
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Affiliation(s)
- Lixia Feng
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, P.R. China.
| | - Huimin Lin
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, P.R. China
| | - Yao Chen
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, P.R. China
| | - Jiafeng Wang
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, P.R. China
| | - Yonghua Wang
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Rongfeng Liao
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, P.R. China
| | - Jiawei Zhou
- School of Ophthalmology and Optometry and Eye hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China. .,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China.
| | - Robert F Hess
- McGill Vision Research, Dept. Ophthalmology, McGill University, Montreal, PQ, Canada
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Sensory Eye Dominance in Treated Anisometropic Amblyopia. Neural Plast 2017; 2017:9438072. [PMID: 28573051 PMCID: PMC5442429 DOI: 10.1155/2017/9438072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 02/27/2017] [Accepted: 04/11/2017] [Indexed: 11/22/2022] Open
Abstract
Amblyopia results from inadequate visual experience during the critical period of visual development. Abnormal binocular interactions are believed to play a critical role in amblyopia. These binocular deficits can often be resolved, owing to the residual visual plasticity in amblyopes. In this study, we quantitatively measured the sensory eye dominance in treated anisometropic amblyopes to determine whether they had fully recovered. Fourteen treated anisometropic amblyopes with normal or corrected to normal visual acuity participated, and their sensory eye dominance was assessed by using a binocular phase combination paradigm. We found that the two eyes were unequal in binocular combination in most (11 out of 14) of our treated anisometropic amblyopes, but none of the controls. We concluded that the treated anisometropic amblyopes, even those with a normal range of visual acuity, exhibited abnormal binocular processing. Our results thus suggest that there is potential for improvement in treated anisometropic amblyopes that may further enhance their binocular visual functioning.
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Very few exclusive percepts for contrast-modulated stimuli during binocular rivalry. Vision Res 2016; 121:10-22. [DOI: 10.1016/j.visres.2016.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 11/23/2022]
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11
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Feng L, Zhou J, Chen L, Hess RF. Sensory eye balance in surgically corrected intermittent exotropes with normal stereopsis. Sci Rep 2015; 5:13075. [PMID: 26287935 PMCID: PMC4541323 DOI: 10.1038/srep13075] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 07/16/2015] [Indexed: 11/09/2022] Open
Abstract
Surgery to align a deviated or strabismic eye is often done for both functional as well as cosmetic reasons. Although amblyopia is often an impediment to regaining full binocularity in strabismics in general, intermittent exotropes, because their deviation is intermittent, have no amblyopia and some degree of stereopsis. Binocular function, including a balanced ocular dominance, could be expected to be normal after surgical correction if normal levels of stereopsis and visual acuity are postsurgically achieved. Here we used a binocular phase combination paradigm to quantitatively assess the ocular dominance in a group of surgically corrected intermittent exotropes who have normal stereo and visual acuity as defined clinically. Interestingly, we found significant interocular imbalance (balance point < 0.9) in most of the surgically treated patients (8 out 10) but in none of the controls. We conclude that the two eyes may still have a residual sensory imbalance in surgically corrected strabismus even if stereopsis is within normal limits. Our study opens the possibility that a further treatment aimed at re-balancing the ocular dominance might be necessary in surgically treated intermittent exotropia to provide more efficient binocular processing in the long term.
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Affiliation(s)
- Lixia Feng
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, PR China
| | - Jiawei Zhou
- McGill Vision Research, Dept. Ophthalmology, McGill University, Montreal, PQ, Canada
| | - Li Chen
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, PR China
| | - Robert F Hess
- McGill Vision Research, Dept. Ophthalmology, McGill University, Montreal, PQ, Canada
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