Sighting ocular dominance magnitude varies with test distance

Background

Ocular dominance can be defined as the preference of an individual for viewing with one eye over the other for particular visual tasks. It is relevant to monovision contact lens wear, cataract surgery and sports vision. Clinically, the measurement of ocular dominance is typically done at an arbitrary distance using a sighting test, such as the hole‐in‐card method that has a binary outcome. We investigated the effect of test distance on ocular dominance measured using a binocular sighting test that provided a continuous measurement of dominance.

Methods

Ten participants with normal binocular vision took part in this study. Their binocular sighting ocular dominance and phorias were measured at one, two, four, eight and 10 metres. During the dominance tests participants made a binocular alignment judgment and then were asked to indicate the relative alignment of each eye using a visual analogue scale as a reference.

Results

Eight participants had strong ocular dominance (five right, three left). For these participants, there was a significant increase in the magnitude of dominance with increasing test distance (p < 0.001). This could not be fully explained by changes in convergence demand. Two participants showed very weak ocular dominance across all test distances (p > 0.05), despite changes in convergence demand.

Conclusion

When ocular dominance is present, its magnitude varies significantly with test distance. This has significant implications for the accurate measurement of ocular dominance in the clinic and may reflect the neural processes that influence eye preference.

     

间歇性外斜视青少年不同类型优势眼与注视眼的关系

探讨间歇性外斜视（IXT）青少年不同类型优势眼与注视眼（非偏斜眼）的关系。方法：系列病例研究。选取2018年7-12月于湖南爱尔眼视光研究所就诊的IXT青少年患者43例，屈光全矫后分别使用卡洞法测量注视性优势眼，使用集合近点法测量运动性优势眼，使用基于Gabor信号识别的连续闪烁抑制法测量知觉性优势眼，并采用眼位控制力评分观察受检者的远距离客观控制力来判定注视眼。采用Kappa一致性检验比较优势眼与注视眼的一致性，采用单因素Logistic回归分析双眼知觉性优势差异和优势眼与注视眼一致性程度的关系。结果：43例IXT患者中，注视性优势眼、运动性优势眼及知觉性优势眼均与注视眼呈现出中度一致性（Kappa值分别为0.46、0.43、0.68，均 P<0.001）。30例有明确双眼知觉优势差异的患者，其知觉性优势眼与注视眼高度一致（Kappa值= 0.86，P<0.001），而注视性优势眼、运动性优势眼与注视眼的一致性仍为中度一致性（Kappa值= 0.57，P=0.002；Kappa值=0.44，P=0.006）。单因素Logistic回归分析显示IXT患者的双眼知觉性优势差异是知觉性优势眼与注视眼一致性程度的影响因素（B=0.53，OR=1.70，P<0.001），即双眼优势差异越大，知觉性优势眼与注视眼一致性的概率越高。结论：青少年IXT患者的注视性优势眼、运动性优势眼、知觉性优势眼均与注视眼有一致性，但知觉性优势眼与注视眼的一致性更为紧密，尤其当患者有明确知觉优势差异时，知觉性优势眼检查比注视性优势眼和运动性优势眼检查来确定注视眼更为可靠。     

Sighting dominance in patients with macular disease

PURPOSE: To study sighting dominance by comparing macular disease patients undergoing surgical treatment with controls. METHODS: We studied visual acuity and sighting dominance in 92 macular disease patients, 27 of whom were assessed for both outcomes. We also studied visual acuity and sighting dominance in 412 controls. Sighting dominance was evaluated using the hole-in-card test. RESULTS: Among the controls, 70% showed right sighting dominance, and 30%, left sighting dominance. On the other hand, in patients with macular disease, right sighting dominance was demonstrated in 51%, and left in 49%; that is, 24% showed sighting dominance of the affected eye and 76%, of the fellow eye. During follow-up, sighting dominance of three of the 27 macular disease patients shifted from the affected eye to the fellow eye, which showed improvement in visual acuity. CONCLUSION: This study raises the possibility of sighting dominance shifting in patients with macular disease. There were differences among cases in the timing of the shift in sighting dominance, indicating that visual acuity may not be the only factor influencing sighting dominance. Further study is needed to confirm the factors contributing to sighting dominance.     

Sensory ocular dominance based on resolution acuity,contrast sensitivity and alignment sensitivity

Background: Ocular dominance is the superiority or preference of one eye over the other in terms of sighting, sensory function (for example, visual acuity) or persistence in binocular rivalry. There is poor agreement between sighting and sensory dominance and findings are equivocal on the possible neural basis of ocular dominance and its significance. Thus, there are questions on the meaning and importance of ocular dominance. Despite the lack of clarity in this area, ocular dominance is used clinically, for example, as the basis for decisions on monovision in contact lens wear and on treatment of anomalies of binocular vision. Methods: Sighting dominance and three types of sensory dominance (based on resolution acuity, contrast sensitivity and alignment sensitivity) were compared within individuals, with the main aim of determining whether sensory dominance is consistent across spatial visual functions. Results: Our findings indicate that each type of sensory dominance is insignificant in most individuals and in agreement with previous work that sensory and sighting dominance do not generally agree. Conclusion: These results demonstrate not only that different types of ocular dominance are not in agreement but also that in the normal visual system sensory dominance as measured here is insignificant in most individuals with normal vision.     

Sighting dominance: An explanation based on the processing of visual direction in tests of sighting dominance

This study investigated the meaning of sighting dominance by examining its relationship to the processing of visual direction. In one experiment subjects' behavior in two sighting tests was evaluated. The data indicated that the reference point used in the tests is not the dominant eye but a central point consistent with the location of the visual egocenter. In a second experiment sighting dominance and the location of the egocenter were measured. The results indicated that the sighting eye is the eye nearest to the egocenter. Further analysis confirmed that sighting tests involve the processing of visual direction specified from the egocenter. The findings suggest that one eye is used in sighting tests because the tests force monocular viewing. The meaning of sighting dominance within the context of sighting behavior was discussed with the conclusion that sighting dominance is best understood as a residual effect caused by the egocenter being to one side of the midline and by the monocular demands of sighting tests.     

优势眼分型及临床研究进展

根据检查方法不同,优势眼可以分为注视性优势眼、运动性优势眼和知觉性优势眼。注视性优势眼主要与视觉方向及定位相关,运动性优势眼主要与双眼注视视差及融合功能相关,知觉性优势眼主要与双眼竞争相关。前两者主要是定性概念,而知觉性优势眼可以通过心理物理学方法对双眼优势差异进行量化研究。优势眼检查方法结果相互之间缺乏一致性,原因目前尚未得知,推测可能大部分正常人群本来就不具有稳定的优势眼。有研究推测单眼视疗法的成功与否不在于选择注视性优势眼矫正看远或看近,而可能取决于双眼知觉性优势差异的大小。关于不同类型优势眼在单眼视疗法中所起的作用,以及优势眼与屈光不正,特别是近视发展的关系,还需要进一步研究证实。     

Ocular dominance testing

Clinicians typically apply the distance correction to the dominant sighting eye when fitting monovision contact lenses on presbyopic patients. This study investigates if this form of dominance testing correlates with a second type of dominance testing, the eye that will accept the least plus power when viewing a distance target binocularly. The plus lens test more closely simulates the condition under which the patient will be using the monovision correction. The theory is that the nondominant eye will accept more plus to blur than the dominant eye. Our study population consisted of subjects from the ages of 10 to 72 years. Fifty (64%) of the 78 subjects preferred the same eye by the plus lens testing as they did for sighting dominance. Seven subjects (9%) showed the opposite eye dominance with the plus lens test, and 21 subjects (27%) demonstrated no preference in the plus lens testing. The results could indicate that same-eye dominance on both tests may enhance the changes of a successful monovision adaptation.     

Effects of dominant and nondominant eyes in binocular rivalry.

PURPOSE: To investigate the relation between sighting and sensory eye dominance and attempt to quantitatively examine eye dominance using a balance technique based on binocular rivalry. METHODS: The durations of exclusive visibility of the dominant and nondominant eye target in binocular rivalry were measured in 14 subjects. The dominant eye was determined by using the hole-in-card test (sighting dominance). In study 1, contrast of the target in one eye was fixed at 100% and contrast of the target in the other eye was varied from 100% to 80% to 60% to 40% to 20%, when using rectangular gratings of 1, 2, and 4 cycles per degree (cpd) at 2 degrees, 4 degrees , and 8 degrees in size. In study 2, contrast of the target in the nondominant eye was fixed at 100% and contrast of the target in the dominant eye was varied from 100% to 80% to 60% to 40% to 20%, when using a rectangular grating of 2 cpd at 4 degrees in size. RESULTS: In study 1, the total duration of exclusive visibilities of the dominant eye target; that is, the target seen by the eye that had sighting dominance was longer compared with that of the nondominant eye target. When using rectangular gratings of 4 cpd, mean total duration of exclusive visibility of the dominant eye target was statistically longer than that of the nondominant eye target (p < 0.05). In study 2, reversals (in which duration of exclusive visibility of the nondominant eye becomes longer than the dominant eye when the contrast of the dominant eye target is decreased) were observed for all contrasts except for 100%. CONCLUSIONS: The dominant sighting eye identified by the hole-in-card test coincided with the dominant eye as determined by binocular rivalry. The contrast at which reversal occurs indicates the balance point of dominance and seems to be a useful quantitative indicator of eye dominance to clinical applications.     

Eye preference within the context of binocular functions

Background Eye preference refers to an asymmetric use of the two eyes, but it does not imply a unitary asymmetry between the eyes. Many different methods are used to assess eye preference, including eyedness questionnaires and sighting tasks that require binocular and monocular alignment of a target through a hole in the middle of a card or funnel. The results of these coarse accounts of eye preference are useful as a first screening, but do not allow for graded quantification of the manifested asymmetry in binocular vision. Moreover, they often concern only a rather selective range of binocular functions. The aim of the present study was to further differentiate eye preference within the context of other binocular functions as measured in standard optometric tests, and to validate their relation to questionnaire data of eyedness.Methods Conventional accounts of eye preference (German adaptation of Corens questionnaire and a sighting task) were compared with various optometric tests of binocular function within a sample of 103 subjects. Examination included visual acuity and accommodation in each eye, stereoscopic prevalence, suppression due to binocular rivalry, fixation disparity (Mallett test).Results Sighting dominance was leftward in 32% and rightward in 68% of the cases and was highly correlated (Kendalls _b=0.70) with eyedness. Further significant associations were restricted to stereoscopic prevalence which correlated with sighting dominance (_b=0.55), eyedness (_b=0.50), and rivalry dominance (_b=0.28).Conclusion Eye preference seems to be essentially reflected by eyedness, sighting dominance, and stereoscopic prevalence, but largely unrelated to fixation disparity, accommodation, and visual acuity.     

Ocular dominance reverses as a function of horizontal gaze angle

Ocular dominance is the tendency to prefer visual input from one eye to the other [e.g. Porac, C. & Coren, S. (1976). The dominant eye. Psychological Bulletin 83(5), 880-897]. In standard sighting tests, most people consistently fall into either the left- or right eye-dominant category [Miles, W. R. (1930). Ocular dominance in human adults. Journal of General Psychology 3, 412-420]. Here we show this static concept to be flawed, being based on the limited results of sighting with gaze pointed straight ahead. In a reach-grasp task for targets within the binocular visual field, subjects switched between left and right eye dominance depending on horizontal gaze angle. On average, ocular dominance switched at gaze angles of only 15.5 degrees off center.     

Patterns of binocular suppression and accommodation in monovision

The binocular depth of focus of monovision wearers was compared to the sum of the two monocularly determined depths of focus. Observers fell into three groups based upon ocular sighting dominance. Complete binocular summation of the monocular depths of focus was observed in subjects without a preferred fixating eye. Subjects who preferred to fixate with one eye had difficulty suppressing blur of that eye while the binocular target was within the depth of focus of the nonpreferred eye. A third group showed partial summation of the two monocular depths of focus. Similar patterns of accommodative response, measured objectively with the SRI optometer, were observed in subjects wearing monovision corrections. Accommodative response to sinusoidal variations in blur was controlled primarily by the dominant sighting eye. These results demonstrate the effectiveness of interocular suppression of anisometropic blur in monovision correction and the influence of ocular dominance upon this suppression process.     

主导眼与眼部疾病的相关性研究进展

主导眼是双眼中具有视觉输入优势的一眼,又称优势眼、主视眼,通常分为注视性主导眼、知觉性 主导眼和运动性主导眼。关于主导眼的研究一直未曾间断,近年来有学者对主导眼的形成机制、测量 方法及与相关疾病的关系进行了大量研究。现笔者就主导眼与眼部疾病的相关性研究现状进行综述。     

Sighting dominance and egocentric localization

Theories of the perception of visual direction use, either a hypothetical "projection center" midway between the two eyes, or the line of sight of the sighting dominant eye, as a reference point for egocentric localization. Seventy-five observers made judgments of the visual straight ahead. Their judgments varied as a function of both viewing condition and eye dominance. Judgments were biased toward the side of the viewing eye during monocular exposure, while binocular judgments were intermediate in their placement. Both monocular and binocular judgments were shifted in the direction of the sighting dominant eye, suggesting that the reference point for visual localization lies between the midpoint of the interocular axis and the line of sight of the sighting eye.     

Research Progress on Sensory Eye Dominance

When analyzing and synthesizing visual information from both eyes into a three-dimensional image at the visual neural center of the brain, the visual information from the two eyes is not processed equally. There is competition and inhibition between the eyes during this binocular visual process. One eye usually has a larger, weighted contribution to the vision neural network than the contralateral eye, and it is the neural basis of sensory eye dominance. Observers with strong sensory eye dominance (SED) tend to have abnormal binocular vision. Sensory eye dominance can be quantitatively measured in the laboratory using psychophysical methods. It can also be manipulated through refractive correction, occlusion or perception learning. Research progress in sensory eye dominance will provide a new treatment approach for clinical binocular disorders, especially in the fields of amblyopia and laser refractive surgery.     

视知觉优势在眼科临床应用中的研究进展

在大脑高级视中枢把来自双眼的视觉信息进行分析综合成一个具有立体感图像的过程中,双眼的视觉信息并不是均等的被处理,而是存在眼间竞争与抑制,由此产生了知觉优势,过强的知觉优势带来双眼视的异常。借助双眼分视和计算机生成的心理物理视觉测试程序,可以定量测定知觉优势强度,并通过光学矫正、遮盖或视知觉学习实时调控知觉优势。知觉优势的相关基础理论也延伸应用到眼科临床诊疗尤其是斜弱视的诊疗中,并有望为解决激光角膜屈光手术后双眼视异常相关的临床问题提供新思路。现就视知觉优势在眼科临床应用中的研究进展进行综述。     

Factors influencing interocular blur suppression

An Important feauture of monovision correction is the ability of the binocular system to suppress blur from the defocused eye (interocular blur suppression). We conducted a study with three subjects and found that interocular blur suppression improved with higher levels of monocular defocus (addition powers in monovision) but was not affected by the eye defocused (sighting dominant or non-domninant) or by pupil size. The selection and management of monovision patients may be assisted by an understading of the understanding of the underlying suppression preocesses.     

Relative image size, not eye position, determines eye dominance switches

A recent paper examined eye dominance with the eyes in forward and eccentric gaze [Vision Res. 41 (2001) 1743]. When observers were looking to the left, the left eye tended to dominate and when they were looking to the right, the right eye tended to dominate. The authors attributed the switch in eye dominance to extra-retinal signals associated with horizontal eye position. However, when one looks at a near object on the left, the image in the left eye is larger than the one in the right eye, and when one looks to the right, the opposite occurs. Thus, relative image size could also trigger switches in eye dominance. We used a cue-conflict paradigm to determine whether eye position or relative image size is the determinant of eye-dominance switches with changes in gaze angle. When eye position and relative image size were varied independently, there was no consistent effect of eye position. Relative image size appears to be the sole determinant of the switch.     

Ocular Dominance in Open-angle Glaucoma: The Shifting Trend Depending on Stage of the Disease

PurposeTo investigate the characteristics and distribution of ocular dominance in primary open-angle glaucoma eyes. In addition, we tried to catch any trend of ocular dominance according to the stage of disease.MethodsTwo hundred participants with bilateral open-angle glaucoma underwent ocular dominant testing by “the hole-in-a-card” test. Using optical coherence tomography, macular ganglion cell-inner plexiform layer, as well as circumpapillary retinal nerve fiber layer thickness were measured and compared according to ocular dominance. Of the two eyes of one subject, the eye with less glaucomatous damage based on mean deviation was considered to be the “better eye” in our study.ResultsOcular dominance was in the right eye in 66% of the population and ocular dominance was positioned in the better eye in 70% of the population (p = 0.001 and p = 0.002, respectively). In conditional logistic regression analyses, right eye and better mean deviation were significantly associated with ocular dominance (p = 0.001 and p = 0.002, respectively). Ocular dominance tends to be present in the better eye and this trend was more apparent as the severity of glaucoma increased. Intereye comparison of visual field indices and retinal nerve fiber layer thickness between dominant versus nondominant eye become apparent in moderate and advanced glaucoma whereas it was not as apparent in early glaucoma.ConclusionsIn glaucomatous eyes, laterality and severity of glaucoma determined ocular dominance. Intereye difference between nondominant and dominant eyes increased with the severity of glaucoma. Our findings suggest the existence of potential reciprocal interactions between ocular dominance and glaucoma.     

tPA参与眼优势柱可塑性的研究进展

哺乳动物的初级视皮层神经元具有眼优势，左、右眼优势的双眼细胞是按垂直于皮层表面的柱状交替排列的，即形成眼优势柱。在可塑性关键期内，初级视皮层对视觉输入的变化非常敏感，单眼剥夺将导致眼优势柱由被剥夺眼向开放眼移动。在此之前，双眼视觉输入的差异已经作为始动因素干扰兴奋-抑制平衡，产生一系列与可塑性相关的中介性信使物质，共同作用于组织型纤溶酶原激活剂，增强其蛋白水解效应，为视皮层的结构重组创造有利环境，从而在树突棘水平上．将快速的功能变化和经验依赖性神经环路的重构联系起来。     

Ocular dominance and patient satisfaction after monovision induced by intraocular lens implantation

PURPOSE: To elucidate the relationship between ocular dominance and patient satisfaction with monovision induced by intraocular lens implantation. SETTING: Eye Clinic, Kitasato University School of Medicine Hospital, Sagamihara, Kanagawa, Japan. METHODS: The durations of exclusive visibility of dominant- and nondominant-eye targets were measured in 16 patients with successful monovision and 4 patients with unsuccessful monovision to determine the characteristics of ocular dominance. The dominant eye was determined using the hole-in-card test (sighting dominance). The contrast of target in nondominant eye was fixed at 100%; the contrast of target in the dominant eye varied (ie, 100% to 80% to 60% to 40% to 20%) using rectangular gratings of 2 cycles per degree that were 4 degrees in size. RESULTS: In the successful monovision group, the reversal thresholds (ie, exclusive visibility of the nondominant eye crosses over that of the dominant eye) were displayed only at low decreasing contrast (80% and 60%). However, in the unsuccessful monovision group, the reversal thresholds were at high decreasing contrast (20%) or not at all. The reversal thresholds in patients with unsuccessful monovision were at a significantly lower contrast than in patients with successful monovision (P<.05). CONCLUSIONS: Success and patient satisfaction in monovision patients were significantly influenced by the magnitude of ocular dominance. The balance technique seems to be a good method to evaluate the quantity of ocular dominance and prospectively evaluate the monovision technique.