The influence of ocular dominance on monovision--the interaction between binocular visual functions and the state of dominant eye's correction

PURPOSE: To examine the interaction between binocular visual functions and the correction of the dominant eye, i.e., for far vs. near vision in monovision. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmological disease were examined. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses (difference in lens power between the lenses: 2.5 D) with an artificial pupil(diameter: 3.0 mm). Visual acuity at various distances, contrast sensitivity, and near stereoacuity were measured while the dominant eye determined by the hole-in-card test (sighting dominance) was corrected for far and near vision. RESULTS: Binocular visual acuity was better than 1.0(20/20) at all distances. When the dominant eye was corrected for distance, the binocular visual acuity at 0.7 m was better than the monocular visual acuity; contrast sensitivity was better within the spatial frequency range of 0.5-4.0 cycles per degree, and near stereoacuity by Titmus stereo tests improved. CONCLUSION: These results suggest that dominant eyes should be corrected for far vision for better binocular summation at middle distances, and near stereoacuity.     

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.     

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。     

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.     

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.     

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。     

Role of visual acuity, stereoacuity, and ocular dominance in monovision patient success.

Monovision (MV) contact lens correction of presbyopia induces substantial reductions in stereoacuity and small reductions in binocular visual acuity (VA). This study examined those effects in a group of successful and a group of unsuccessful MV patients. Compared to performance with a full binocular correction, the unsuccessful group demonstrated significant losses in both functions. These reductions were smaller in the successful group and of marginal statistical significance only for stereoacuity. Laterality of sighting dominance and laterality of distance/near correction had minimal effect on the results.     

The relation of functional visual acuity measurement methodology to tear functions and ocular surface status

Purpose  

To investigate the relation of functional visual acuity (FVA) measurements with dry eye test parameters and to compare the testing methods with and without blink suppression and anesthetic instillation.     

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.     

Association of ocular dominance and anisometropic myopia

PURPOSE: To determine the association between ocular dominance and degree of myopia in patients with anisometropia. METHODS: Fifty-five subjects with anisometropic myopia were recruited. None of them had amblyopia. Refractive error and axial length were measured in each subject. Ocular dominance was determined using the hole-in-the-card test and convergence near-point test. RESULTS: There was a threshold level of anisometropia (1.75 D) beyond which the dominant eye was always more myopic than the nondominant eye. Of the 33 subjects with anisometropia of < or =1.75 D, the dominant eye was more myopic in 17 (51.5%) subjects. Dominant eyes, determined by the hole-in-the-card test, had a significantly greater myopic spherical equivalent (-5.27 +/- 2.45 D) than nondominant eyes (-3.94 +/- 3.10 D; P < 0.001). Dominant eyes also had a longer axial length than nondominant eyes (25.15 +/- 0.96 mm vs. 24.69 +/- 1.17 mm, respectively; P < 0.001). The difference was more evident in those subjects with higher anisometropia (>1.75 D), but was not significant in those with lower anisometropia (< or =1.75 D). Similar results were obtained using the convergence near-point test. CONCLUSIONS: The present study shows that the dominant eye has a greater degree of myopia than the nondominant eye in subjects with anisometropic myopia. Taking ocular dominance into account in the design of randomized clinical trails to assess the efficacy of myopia interventions may provide useful information.     

The dependence of the range of fusion on some selected functions of the visual system. Part II: Accommodation and dominance

This present study is the continuation of Part I of the research into the range of fusion in which the difference between both eyeballs as far as convergent fusion is concerned was described. The phenomenon was called "visual unevenness of the range of convergent fusion". This part of the study is devoted to the analysis of the relationship between the unevenness of the fusion, ocular dominance and accommodation. A lower range of convergent fusion was observed in the dominant eye with the higher accommodation, In contrast, a higher range of fusion was observed in the not dominant eye with lower accommodation. The authors think that the phenomenon of ocular unevenness of the range of convergent fusion does not depend on the peripheral part of visual organ. In fact, it does seem to point out to a cortical process. The authors suggest that quantitative tests on amplitude of fusion should be carried out first on the first eye and then on the other. The results obtained from both eyes should be compared with each other.     

The influence of gender on the ocular surface.

PURPOSE: Dry eye is more prevalent among women than men. To examine whether gender influences the ocular surface, conjunctival goblet-cell density was monitored for a 30-day period. Changes in goblet-cell density are a sensitive marker for ocular surface disease. METHODS: Six men and twelve women who were free from ocular surface disease were sampled by impression cytology on the inferior bulbar conjunctiva every other day for 30 days. Samples were analyzed for goblet-cell content. The mean age of the subjects was 24 years for the men and 25.4 years for the women. A minimum of 200 epithelial cells were scored per microscopic field examined. RESULTS: There is a statistically significant difference in goblet-cell count between men and women over the 30-day test period. The mean goblet-cell count measured for men was 3.75% +/- 1.04%, while the mean count for women was 2.545% +/- 0.8%. When the data on women were replotted with reference to the menstrual cycle, the largest and longest depression of goblet-cell count occurs midcycle, around the time of ovulation. A significant difference in goblet-cell count was also noted when subjects using oral contraceptives (3.065% +/- 0.98%) are compared with those not using oral contraceptives (2.28% +/- 0.92%). CONCLUSION: It appears there may be a reproductive hormonal influence on conjunctival goblet-cell count.     

The stimulus-response functions of visual systems

Two commonly used forms of presenting photoreceptor functions are compared: the incident light function, which represents photoresponses as a function of the total light intensity (stimulus plus background), and the increment stimulus function, which represents photoresponses as a function of light increments. The changes in these two functions with increasing background light are analyzed. If the receptor adapts to light according to Weber's law, the changes are very similar. The increment stimulus functions are often adequate in studies of excitation and adaptation mechanisms, while the incident light functions are more explicit when interest is focused on contrast sensitivity.     

The effects of raloxifene hydrochloride on ocular hemodynamics and visual function

Objective To assess the comprehensive effects of raloxifene hydrochloride on retinal, choroidal and retrobulbar hemodynamics and on visual function in post-menopausal women. Design Twenty-four post-menopausal women (age 55 ± 3.8 years) were recruited for this cross-sectional study: 12 received placebo and 12 received raloxifene hydrochloride 60 mg once a day for 3 months. Baseline measurements of both groups included heart rate (HR), blood pressure (BP), visual acuity, contrast sensitivity and intraocular pressure (IOP) for both eyes. A comprehensive ocular blood flow (OBF) assessment was obtained for each patient in a randomly chosen study eye. Retinal blood flow data was obtained using confocal scanning laser Doppler flowmetry [Heidelberg Retinal Flowmeter (HRF)]. Color Doppler imaging (CDI) was used to assess retrobulbar hemodynamics in the ophthalmic, central retinal, short nasal and temporal posterior ciliary arteries. Baseline vision and hemodynamics in post-menopausal subjects were compared using paired Student’s t tests, and the percentage change in baseline versus 3-month parameters was analyzed. Results There were no statistically significant differences between 3 months of raloxifene therapy and placebo in terms of age, HR, arterial or mean BP, visual acuity, contrast sensitivity, IOP or retinal or retrobulbar blood flow. Conclusion Raloxifene therapy at 60 mg/day had no clinically significant impact on BP, IOP or OBF in post-menopausal women.     

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.     

影响老视眼视觉质量的关键因素

老视是与年龄相关的进行性眼调节力下降,老视的矫正不仅重视视力,而且要注重视觉质量。研究影响老视眼视觉质量的关键因素有利于寻求矫正老视的有效手段,达到提高视觉质量的目的。本文就人眼视觉质量的评价、非手术因素、人工晶状体植入、传导性角膜成形术及准分子激光手术等对老视眼视觉质量的影响进行综述。