The influence of ocular dominance on monovision--the influence of strength of ocular dominance on visual functions

PURPOSE: Monovision is a method of correction for presbyopia. We have reported the advantage of conventional monovision (the dominant eye is corrected for distance). In this study, we investigated the influence of interocular imbalance of dominancy on the visual function. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmologic disease participated. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses with an artificial pupil (diameter: 3.0mm). The dominant eye was corrected for distance, and the difference in lens power between the lenses was 2.5 D. The subjects were classified into two groups by strength of the imbalance of sensory dominance, which was determined by using binocular rivalry. Binocular visual functions (visual acuity at various distances, contrast sensitivity, near stereoacuity) were compared between the two groups. RESULTS: Subjects with strong imbalance of sensory dominance showed decreased near visual acuity as well as decreased binocular summation of contrast sensitivity at low spatial frequencies. On the other hand, near stereoacuity was not affected by the imbalance of sensory dominance. CONCLUSION: These results suggest that strong imbalance of sensory dominance interferes with binocular visual functions in monovision. Thus, the evaluation of ocular dominance is crucial for clinical applications of monovision.     

The effect of ocular dominance on visual field testing.

PURPOSE: During standard automated perimetry (SAP), some patients experience visual disturbances in the tested eye while the other eye is covered with an opaque occluder. It is possible that a binocular interaction producing an inhibitory response in the nonoccluded eye, such as rivalry or Ganzfeld blankout, may be the causative factor, particularly when the dominant eye is occluded. The objective of this experiment was to determine whether subjective visual disturbances occurring during conventional perimetric test conditions were related to ocular dominance and to investigate the effect of these disturbances on measurements made during threshold visual field analysis. METHOD: Ocular dominance was determined by questioning and objective testing on 55 normal subjects. Each subject underwent program 24-2 Full Threshold SAP on a Humphrey Field Analyzer, and an opaque black patch was used to occlude the nontested eye. After testing, patients were asked to report symptoms of visual disturbance characteristic of rivalry or blankout, and the relationship between ocular dominance and visual disturbances was investigated. To determine whether symptoms of rivalry or blankout had affected visual field quantification, comparisons of short-term fluctuation, mean deviation, and false-negative errors were performed between eyes with and without visual disturbances. RESULTS: A total of 24 of 55 subjects reported visual disturbances consistent with rivalry or blankout (44%). Sixteen subjects complained of the phenomenon in one eye, and eight complained of the phenomenon in both eyes. Of the 16 experiencing disturbances in one eye only, nine cases occurred during occlusion of the dominant eye. The association between ocular dominance and visual disturbances was not found to be significant (p > 0.10). No significant differences in short-term fluctuation (p = 0.78), mean deviation (p = 0.64), or false-negative errors (p = 0.10) were found between eyes with and without visual disturbances. CONCLUSIONS: Patients undergoing standard automated perimetry with opaque patch occlusion of the nontested eye often experience visual disturbances consistent with rivalry or blankout, although these disturbances do not cause increased within-test variability or reduced sensitivity as quantified by visual field global indices. In terms of summary visual field indices, ocular dominance does not appear to affect visual field test results.     

Effects of ocular dominance on binocular summation after monocular reading adds

PURPOSE: To investigate the relationship between ocular dominance and binocular summation with monocular reading adds. SETTING: Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, Japan. METHODS: Contrast sensitivities were measured by having subjects view contrast charts at spatial frequencies of 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree after the addition of positive spherical lenses that ranged from +1.0 to +3.0 diopters (D). Through the use of a balance technique, the test group was quantitatively divided into 12 weak and 8 strong ocular dominance subjects on the basis of binocular rivalry. In study 1, binocular contrast sensitivity was measured in the weak and strong ocular dominances by adding a positive spherical lens in front of 1 eye, whereas the other eye was fixed at a corrected distance. RESULTS: In study 1, the binocular summation was observed only after adding positive spherical lenses in the nondominant eye. The differences in binocular contrast sensitivity that occurred after adding a positive spherical lens in the dominant eye versus that seen in the nondominant eye were statistically significant in the strong ocular dominance subjects who had +1.5 D and +2.0 D defocuses (P<.05; analysis of variance). CONCLUSIONS: Binocular summation was effectively maintained with reading adds in the nondominant eye and was significantly influenced by the magnitude of ocular dominance. Evaluating binocular summation after monocular reading adds seems to be a good method to evaluate adaptability to monovision.     

散射对人眼视觉质量影响的研究现状

随着社会发展,对视觉健康提出新要求,以往通过视力及对比敏感度来评估人眼视觉功能存在主观性和局限性,不能真实反映人眼视觉功能。为了追求更敏感准确的客观评价方法,国内外专家对视觉质量进行一些探讨性研究。研究证实散射作为影响人眼视觉质量的一个独立因素,可以对视觉功能做出更科学的评价。关于散射对人眼视觉质量的影响,就近几年国内外的相关研究,本文对此进行综述。     

双眼视训练对间歇性外斜视手术效果影响的临床观察

目的了解双眼视觉训练对间歇性外斜视手术效果的影响。方法将45例间歇性外斜视患者以术后正位、欠矫、过矫分为三组,行术后双眼视觉训练,对三组训练前后的视远立体视锐度及最后眼位正位率进行观察比较。结果三组视远立体视锐度经双眼视觉训练后比术后2周时显著改善P〈0.01;最后眼位正位率三组间比较无显著差异P〉0.05;过矫组比欠矫组最后眼位正位率显著提高P〈0.05。结论双眼视觉功能训练对间歇性外斜视手术疗效和双眼视功能改善十分重要。术前有一定双眼视功能的患者术后早期的轻度过矫,加上双眼视觉训练将有利于达到远期眼位的正位与双眼视功能的发育。     

不同矫正方式对近视患者双眼视功能的影响

目前常用的近视矫正方式有框架眼镜、角膜接触镜以及屈光手术三种.框架眼镜安全廉价,可作为中低度近视且无屈光参差患者的首选,而高度近视或屈光参差近视患者配戴角膜接触镜(包括角膜塑形镜、硬性透气性角膜接触镜、软性角膜接触镜等)更易获得良好的双眼视功能.在减少屈光参差对近视者双眼视功能损害方面,屈光手术也能获得良好的效果.     

Complex binocular interaction and other effects in the visual evoked response.

One article dealing with some of the research on binocular interaction effects being carried out in our laboratory has appeared previously in this Journal (White and Bonelli). In that study, it was found that the amplitude of the visually evoked cortical potential (VER) produced by patterned stimuli viewed with both eyes was directly related to the quality of the retina image. Furthermore, the degree of binocular summation shown by the VERs was also related to image quality, with marked summation occurring when sharply focused patterns were presented but much less evidence of it when the patterns were blurred. In that study the retinal images were reasonably similar, since the degree of blur desired was produced by placing ophthalmic lenses of equal strength before the two eyes. The next situation we decided to test was that in which the images presented to the two eyes were not of the same quality. This paper will deal briefly with some work we have done on that topic, and will also present some other examples of work dealing with binocular interaction and related topics.     

The effect of anisometropia on binocular visual function

PURPOSE: To investigate the effects of anisometropia on binocular vision. METHODS: One to three dioptres of unilateral hyperopia, myopia or astigmatism was induced in 30 normal adults. The effect on binocularity was assessed with the Worth-four dot test, Titmus stereo test and Bagolini's lenses. RESULTS: Binocular vision deteriorated with increasing anisometropia. Spherical anisometropia was more deleterious than astigmatic anisometropia. CONCLUSION: In addition to amblyopia, the potential effect of anisometropia on binocular vision should be considered while prescribing spectacles in young children during the sensitive period.     

High resolution fMRI of ocular dominance columns within the visual cortex of human amblyopes

Non-human primate models suggest that amblyopia has a neural basis in the form of a massive reduction in binocular neurons, and in some cases, a shift in ocular dominance of neural activity toward the unaffected eye. To date, the resolution of neuroimaging has been insufficient to investigate the neural basis of ocular dominance in human amblyopia. We used high spatial resolution (0.5 x 0.5 x 3 mm) functional magnetic resonance imaging (fMRI) to obtain maps of ocular dominance within the visual cortex of adult human amblyopes. fMRI maps of ocular dominance were similar in appearance to maps reported in the literature. For each of six adults with early-onset amblyopia, the number of map pixels corresponding to the unaffected eye was greater than the number corresponding to the amblyopic eye. This shift in ocular dominance was not seen for the two adults with later-onset amblyopia, suggesting that a shift in ocular dominance of neural activity occurs only if amblyopia onset is within the critical period of brain development. Our findings demonstrate how fMRI can non-invasively investigate the neural substrates underlying human amblyopia at the cortical column level.     

High resolution fMRI of ocular dominance columns within the visual cortex of human amblyopes

Non-human primate models suggest that amblyopia has a neural basis in the form of a massive reduction in binocular neurons, and in some cases, a shift in ocular dominance of neural activity toward the unaffected eye. To date, the resolution of neuroimaging has been insufficient to investigate the neural basis of ocular dominance in human amblyopia. We used high spatial resolution (0.5 × 0.5 × 3 mm) functional magnetic resonance imaging (fMRI) to obtain maps of ocular dominance within the visual cortex of adult human amblyopes. fMRI maps of ocular dominance were similar in appearance to maps reported in the literature. For each of six adults with early-onset amblyopia, the number of map pixels corresponding to the unaffected eye was greater than the number corresponding to the amblyopic eye. This shift in ocular dominance was not seen for the two adults with later-onset amblyopia, suggesting that a shift in ocular dominance of neural activity occurs only if amblyopia onset is within the critical period of brain development. Our findings demonstrate how fMRI can non-invasively investigate the neural substrates underlying human amblyopia at the cortical column level.     

儿童眼外伤76例双眼视功能的观察

目的:测定76例经治疗后的眼外伤儿童立体视训练前后双眼视功能,评价双眼视功能训练对眼外伤儿童立体视的影响。方法:收集2006-01/2009-12期间在我院诊治的儿童眼外伤76例76眼,进行一期修复后,即进行双眼视功能训练。使用AIT-1000同视机检查眼外伤儿童训练前后融合和远立体视功能,使用Titmus立体图检查近立体视功能。结果:训练前无双眼视功能者26眼(34%),训练后无双眼视功能者16眼(21%);训练前有融合功能者27眼(35%),训练后有融合功能者48眼(63%);训练前有远立体视功能者23眼(30%),训练后有远立体视功能者29眼(38%),训练前有近立体视功能者14眼(18%),训练后有33眼(43%)。经统计分析,双眼视功能在训练前后的差异具有统计学意义。结论:对眼外伤儿童及时行双眼视功能训练,有助于重建患儿的双眼视功能。     

视物距离对知觉性优势眼的影响

目的研究基于Gabor识别的知觉性优势眼（OSD）是否会因视物距离的改变而发生变化。方法实验研究。OSD定量通过计算机辅助的心理物理学方法完成。经分视系统为60例健康受检者的两眼分别呈现Mordrian噪声和Gabor信号。在Mordrian噪声持续减弱而Gabor信号不断增强的过程中,受检者探测到Gabor信号的阈值被记录为眼知觉指数（OSI）。两眼各测试50次OSI。两眼间差异经标准化即为该受检者的眼优势指数（ODI）。ODI绝对值>2,则该受检者优势眼明确,OSI取值较小的眼别即优势眼别;否则无明确优势眼。分别在6 m的远距和60 cm的近距各进行一次测试。采用配对t检验测试ODI的变化是否显著。结果在距离对知觉性优势眼类型的影响的分析中,31例（52%）受检者的知觉性优势眼在远距和近距的检测中保持一致,26例（43%）受检者在不同距离下出现了有显著优势眼和无显著优势眼之间的转换,另有3例（5%）受检者出现了优势眼眼别的互换。在距离对知觉性优势眼影响的量化分析中,受检者的平均ODI由远距的－1.88±2.71变为近距的－0.72±2.95,表明在近距时知觉优势向平衡方向偏移（P＜0.01）。同时,45例（75%）受检者在远距某一眼相对优势的情况下,会在近距离检测中表现为优势向对侧眼（即原优势较弱眼）偏移的现象,另有15例（25%）受检者情况相反。向原优势较弱眼偏移的平均偏移量（2.66±0.32）明显大于向原优势较强眼的偏移量（1.04±0.25）,差异有统计学意义（P＜0.01）。结论视物距离对知觉性优势眼存在影响。远距某一眼的知觉优势会在距离变近时向对侧眼发生偏移。近距视物时,双眼的知觉优势较远距更趋向平衡。     

连续闪烁抑制法测量的知觉性优势眼与立体视觉的关系

目的通过定量测量双眼的相对知觉优势,探索精细立体视觉是否只能出现在双眼相对平衡者中。方法实验研究。共38名受检者参加了实验。对每个受检者通过连续闪烁抑制法来定量双眼的相对知觉优势,并计算相对知觉优势指数（ODI）。18名受检者双眼相对平衡（无明确优势眼,ODI绝对值<2）,20名受检者双眼相对不平衡（有明确优势眼,ODI绝对值≥2）。受检者的立体视觉通过随机点图形来评估,测量受检者能达到的最佳立体视力（Dmin）和达到最佳立体视力所需要的最短时间（Tmin）。利用独立样本t检验来测试双眼平衡组与不平衡组之间的差异,Pearson相关分析来量化Tmin、Dmin与优势眼程度的相关性。结果双眼相对平衡与不平衡受检者的Dmin分别为42.9″±23.5″和60.5″±50.4″,差异无统计学意义。但是,双眼平衡受检者所需达到最佳立体视力的最短时间为（148.8±69.1）ms,显著短于双眼不平衡组[（353.2±262.9）ms]（t=3.2,P<0.01）。Tmin与眼优势程度呈正相关（r=0.58,P<0.01）。结论精细立体视觉也可以出现在双眼不平衡者中,但需要更长的反应时间。     

Effect of stimulus size on binocular summation within the binocular visual field

PURPOSE: To study the influence of stimulus sizes on binocular summation using the modified Octopus 201 combined with a space synoptophore. METHODS: Four normal subjects, aged 21 to 26 were tested. Using the SARGON program, we designed a new program to test 37 points in the central 6 degrees visual field. Sensitivity of the central 6 degrees visual field under monocular and binocular conditions was measured while the fusion patterns were displayed on the space synoptophore. The visual fields were measured at stimulus sizes 1, 3, and 5. RESULTS: The visual sensitivity under binocular conditions was higher than under monocular conditions for all the stimulus sizes. Binocular summation for stimulus size 1 was present in a flat form, for stimulus size 3 in a convex form, and for stimulus size 5 in a concave form in the central 6 degrees visual field. CONCLUSION: Binocular summation differed in stimulus size and retinal eccentricity. Binocular summation for stimulus size 3 increased in the fovea and it increased for stimulus size 5 in the peripheral area in the central 6 degrees visual field.     

Clinical evaluation of ocular and visual functions in insulin-dependent juvenile diabetics

Ocular and visual functions were evaluated in 30 insulin-dependent diabetics, aged 12 to 20 years, and 30 age- and sex-matched nondiabetics. The test and control groups were compared in terms of visual resolution, accommodative ability, color discrimination, functional retinal reserve, and afferent optic nerve function. These results were considered along with the blood-glucose level, crystalline lens, fundus appearance, level of diabetic control, and disease duration. No widespread differences in ocular or visual function were found between the test and control groups. Measures of accommodative ability, functional retinal reserve (photostress recovery time), and blood-glucose level best differentiated the two groups. This study suggests that in-office evaluation of accommodation and functional retinal reserve may be sensitive indicators of early visual functional deficits in the presence of minimal anatomical changes associated with diabetes.     

模拟屈光间质混浊对蓝/黄视野检查结果的影响

目的 探讨屈光间质混浊对蓝/黄视野检查结果的影响.方法 对21例（21眼）正常人和15例（15眼）有早期视野损害、12例（12眼）有中晚期视野损害的原发性开角型青光眼配戴透光率为75%的毛玻璃镜片,戴镜前后,应用OCTOPUS 101全自动视野计（Interzeg INC,Switzerland）G2程序的Normal分程序进行W/W和B/Y视野检查,将所得结果进行分析比较.结果 正常组所有受检眼B/YP检查,校正概率图中无暗点.戴毛玻璃镜片后21眼在校正概率图中均出现相对性暗点,暗点弥漫性分布于中心视野0～30度范围内.配戴毛玻璃镜片前后视野指数比较,视网膜光敏感度均值（MS）降低;平均缺损（MD）、缺失方差（LV）、矫正缺失方差（CLV）增大,差异具有非常显著性（P＜0.0001）.早期POAG组配戴毛玻璃镜片后与配戴毛玻璃镜片前,B/Y视野指数比较,MS降低,MD增高,均有显著差异（P＜0.0001）,LV和CLV无显著差异.计算校对概率水平小于5%的视野缺损点数,配戴毛玻璃前后B/Y检查法测得的缺损点数均明显多于W/W检查法（P＜0.0001）;配戴毛玻璃前与配戴毛玻璃后,B/YP检测的视野缺损点数之间无显著差异（P＞0.05）,暗点位置无明显变化.中晚期青光眼组配戴毛玻璃镜片后与配戴前视野指数比较,MS、LV、CLV降低,MD增高,差异均有显著性（P＜0.05）,W/W,B/Y及加毛玻璃后B/Y视野检查,视野缺损点数分别两两比较,均无显著差异（P＞0.05）,暗点位置无明显变化.结论 模拟屈光间质混浊可使B/Y视野检查平均光敏感度普遍降低,但不影响POAG患者原有暗点的发现.     

The absence of lateral congruency between sighting dominance and the eye with better visual acuity

The notion that in subjects with normal binocular vision (i.e. non-strabismic cases) the eye showing sighting dominance will also most likely be that individual's better-sighted eye has proved to be persistent. A review and analysis of the literature has now demonstrated, across several population groups, the fallacy of this belief. In fact, the occurrence of lateral congruency between sighting dominance and the eye with better visual acuity is at a statistical level no greater than chance would predict. Some clinical implications of this outcome are considered.