Left Eye Dominance Research Articles

Evaluation of the effect of ocular dominance on macular microcirculation via swept-source optical coherence tomography angiography

PurposeTo determine the existence of differences in the retinal microcirculation of dominant and non-dominant eyes, as well as of interocular differences in macular microcirculation, using swept-source optical coherence tomography angiography (OCTA). MethodsIn total, 122 eyes of 61 individuals were enrolled in this cross-sectional study. Measurements were taken using the swept-source optical coherence tomography Triton device (Topcon Corp, Tokyo, Japan) coupled with non-invasive OCTA technology. Macular perfusion parameters were assessed, including superficial vascular complex, vascular density of the deep vascular complex, vascular density of the choriocapillaris vascular complex, superficial foveal avascular zone and deep foveal avascular zone. Ocular dominance was determined among individuals with healthy eyes using the hole-in-the-card test. ResultsOcular dominance was found in 68.9 % of right eyes and 31.1 % of left eyes. The mean age of the subjects was 34.45 ± 16.48 years (range: 18–73 years). We found that 16 (30.76 %) males and 22 (31.42 %) females had left-eye dominance (p > 0.05). None of the OCTA parameters differed between the eyes based on dominance (p > 0.05). Central macular thickness and sub-foveal choroidal thickness did not show significant differences (p > 0.05). When comparing interocular parameters, a significant difference was observed only in the inferior sector of the superficial vascular complex (p = 0.04). ConclusionThere was no significant difference in OCTA parameters between dominant and non-dominant eyes. There was no predominant interocular difference in the measurements.

Ocular Dominance and Its Association With Central Corneal Thickness: An Observational Study in Central India.

Background The aim of this study is to determine ocular dominance and its association with central corneal thickness (CCT). These two parameters are of great significance in clinical practice; identifying the dominant eyehelpsin planning cataract surgeries, treatment of presbyopia, monovision correction, etc., and assessing the CCT helps inearly diagnosis and management of keratoconus, glaucoma, contact lens-related complications, and dry eye. Methods A cross-sectional study that involvespatients and volunteers who have come for a checkup to the ophthalmology department of the college hospital. Ninety patients were examined for this study within two months. The hole-in-card test is performed to determine the ocular dominance in people with normal and healthy eyes without any pathologies except refractive errors. Specular microscopy through a non-contact modality will be done to assess thethickness of the central cornea in both eyes. Statistical analysis was done using the paired t-test to compare the patient's eyes and the chi-square test, which helps usassociate ocular dominance and CCT. Results Right eye dominance was seen in the majority of the participants (72.91%), whereas left eye dominance was seen in comparatively fewer participants (27.08%). The CCT of the dominant eye is found to be 520.40± 29.83μm and that of the non-dominant eye is 524.40± 29.37μm. A lower CCT in the dominant eye was seen in 83.33% of the subjects; 14.58% of them had a higher CCT in the dominant eye and 2.08% had the same CCT in both eyes. Conclusion From the observational study that has been made, the majority of the population shows right eye dominance. The CCT is relatively thinner in the dominant eye. About 80-85%of the examined people showed a thinner cornea in the dominant eye. But we cannot generalize that the eye with a lessercorneal thickness will be the dominant eye in all the cases, as a few cases have shown dominance in the eye with a thicker cornea.

Eye dominance and minor physical anomalies in schizophrenia: relations between two biological markers of abnormal neurodevelopment

Background To investigate the frequency of left eye dominance and minor physical anomalies (MPAs) in schizophrenia patients and control subjects and determine the interrelations of these two biological markers of neuronal dysontogenesis in schizophrenia. Subjects and methods Three tests for eye dominance were administered as performance tasks, not preference questionnaires. Seven MPAs were examined. The sample consisted of 180 (98 schizophrenia patients and 82 control subjects). Several statistical methods for examining the eye tests separately and together were used to assess the difference in left-eyedness between schizophrenia patients and control subjects. Results Left eye dominance is significantly higher in schizophrenia subjects. Left-eyed subjects are more stigmatized with MPAs. There is a strong positive correlation between left-eyedness and stigmatization with MPAs in schizophrenia patients. Conclusion As hand dominance is under cultural pressure, eye dominance is culturally independent and is useful and reliable indicator of altered hemispheric lateralization. The significant positive correlations between left-eyedness and MPAs and the high concurrence of these biological markers in schizophrenia patients are a potent indicator of underlying aberrant neurodevelopment.

Combined Foot and Eye Dominance Scale as a useful tool for the assessment of lateralization

IntroductionLateralization is the functional dominance of one of the dual organs of the body: eyes, arms, legs and even ears, during their spontaneous or purposeful actions. The handedness is influenced by many factors like geographic region, genetic and cultural factors as well as sex. The most used assessment for functional lateralization is hand dominance. When assessing foot and eye dominance, however, we find significantly higher left foot dominance as well as very strong left eye dominance in schizophrenic patients versus controls. We consider the explanation of this results is because in Bulgaria, during the communist regime (before 1990) left hand writing was under cultural pressure. Also handedness itself is influenced by other cultural factors as mentioned already. All of the above made us conclude that foot and eye dominance may assess much better the lateralization than hand dominance.ObjectivesThe aim of the study was to investigate the relaibility (internal consistency) of a combined Foot and Eye Dominance Scale in women- patients with schizophrenia and healthy subjects.MethodsA sample of 94 women- scizophrenia patients and healthy controls were assessed with a Combined afaoot and Eye Dominance Scale. It consisted of two subscales Foot Dominance Subscale and Eye Dominance Subscale. The Foot Dominance Subscale included a modified Chapman & Chapman Foot Dominance Scale and a new Complex Task Scales with four foot tests, reflecting on complex tasks. The Eye Dominance Subscale included three eye tests. Scale reliability statistics (item-scale statistics, summary statistics for the items, Cronbach’s alpha), non-parametric Mann-Whitney test and Spearman’s rank correlation coefficient were used.ResultsConsiderable differences were found in the contribution of the single items to the Combined Foot and Eye Dominance Scale. Some items show greater means than other items (from 0,14 to 0,80), which suggested greater phenogenetic component and consequently greater contribution of these items to the total scale mean. The mean correlation between the items of the Combined Foot and Eye Dominance Scale was positive (0,32), indicating good internal consistency of the scale.ConclusionsThe Combined Foot and Eye Dominance Scale more strongly and objectively reflect leftedness and could be a more useful tool for the assessment of lateralization irrespectively of culture and nation. The Combined Scale allows cross-cultural worldwide equivalence to the different studies in different neuroontogenetic diagnoses with presumed abnormal cerebral asymmetry.Disclosure of InterestNone Declared

Objective excyclotorsion increases with aging in adults

ABSTRACT Introduction It has been reported that the disc-fovea angle (DFA), a measure of objective cyclotorsion, increases with age. DFA was measured in three age groups of adults and the effects of age, sex, and laterality on DFA is reported. Methods and Subjects A retrospective study was performed on patients who had a glaucoma checkup or who visited for suspected cataract, who underwent fundus photography between 2013 and 2021. Patients with visual acuity <0.7, axial length >27 mm, strabismus or ocular diseases affecting fusion were excluded. DFA was measured from digital fundus photographs obtained from 249 participants comprising three age groups (group I, 44.4 ± 0.5 years, n = 58; group II, 63.7 ± 3.6 years, n = 129; group III, 81.0 ± 3.8 years, n = 62). The sum of right- and left-eye DFAs is named as total DFA. Results Dunnett’s post-hoc test after ANOVA showed that the left-eye DFA and total DFA of group III were significantly larger than those of group I (p = .01 and p < .01, respectively). Total DFA of female participant (15.6 ± 4.7°, n = 168) was significantly larger than that of male participant (13.9 ± 4.3°, n = 81) (p < .01). The DFA of the left eye (8.2 ± 3.5°, n = 249) was significantly larger than that of the right eye (6.8 ± 3.3°, n = 249) (p < .001). Group III was subdivided based on eye dominance (right eye dominance, n = 36; left eye dominance, n = 13; NA, n = 13). The DFA in the nondominant eye (9.7 ± 4.6°) was significantly larger than that in the dominant eye (7.4 ± 3.7°) (p < .01). Discussion This study found a slight increase of DFA with age. Furthermore, DFA in female or DFA in the left-eye was larger than DFA in male or in the right-eye.

Comparative Analysis of Lateral Preferences in Patients With Resistant Schizophrenia.

BackgroundSchizophrenia is a chronic brain disorder of diverse etiology and clinical presentation. Despite the expansion of treatment methods, between 30 and 50% of cases remain resistant to treatment. In patients with schizophrenia, specifics in the dominant lateralization in the brain function have been discovered. This gave a reason to seek the relation between functional lateralization and the effect of treatment.MethodsOf the 105 people observed with schizophrenia, 45 (42.9%) were treatment resistant, and 60 (57.1%) were considered responders. We compared functional lateralization (hand, foot, and eye) between the two groups. Handedness was ascertained by using the Edinburgh Handedness Inventory. The assessment was made at 12 weeks of treatment.ResultsOf all patients with schizophrenia, 41.89% have mixed lateralization, 53.34% are right winged, and 4.76% of the patients are left winged. Resistance of the symptoms shows that 26 (57.78%) are cross-dominated, 18 (40%) are right winged, and 1 (2.22%) is left winged. In patients with clinical remission, 18 (30%) are of mixed dominance, 38 (63.33%) are right winged, and 4 (6.66%) are left winged. From the results for the separate lateralization of the hand, foot, and eye, we found a significant difference only in terms of the dominance of the eye. In 44 (41.9%) of the patients, we found dominance of the left eye. In patients with resistance, the percentage established by us is higher—at 26 (57.8%). These results indicate that the increased percentage of mixed dominance in patients with schizophrenia is mainly due to left-sided lateralization of the eye, especially in those with resistance to treatment.ConclusionWe find an increased number of patients with cross-dominance left eye dominance in patients with schizophrenia. Cross-dominance and left eye dominance are associated with a higher probability of symptom resistance than other forms of lateralization (left-handed or right-handed). The high percentage of cross-dominance is due to the high percentage of left-sided dominance of the eye.

Eye dominance modulates visuospatial attention

Visuospatial attention has an inherent asymmetry: the leftward bias called pseudoneglect. In typical line bisection tasks, healthy individuals tend to judge the center of a line leftward of the true center, an effect attributed to the right hemisphere dominance in visuospatial attention. Since it has been shown that information perceived by the dominant eye strongly activates the ipsilateral visual cortex, we hypothesized that eye dominance may modulate visuospatial attention bias. Because activation of the left hemisphere induced by left eye dominance should mitigate the right hemisphere dominance in attention, we predicted that right-handed individuals with left dominant eye would show smaller amount of pseudoneglect than right-handed individuals with right dominant eye. We compared the performance at both the perceptual (Landmark) and manual line bisection task of forty right-handed healthy individuals, half of whom had a right dominant eye and the other half a left dominant eye. As predicted, the left eyed dominant group showed smaller, actually not significant pseudoneglect, which was thus greater in the right eye dominant group. The influence of eye dominance on visuospatial attention was present in the Landmark but not the manual line bisection task, in which the amount of visuospatial bias correlated with participants’ degree of (right) handedness. This is the first report of the effect of eye dominance on visuospatial attention within a right-handed population. This finding, by showing the influence of eye dominance on visuospatial cognition, not only helps in better defining intact visuospatial cognition mechanism but also encourages further research to pinpoint the neural basis of such interaction.

Laterality patterns in relation to schizophrenia patients' age at onset

ABSTRACT Based on numerous findings of an abnormal laterality in schizophrenia disorder, we hypothesized that handedness and lateral preferences may affect the age at onset in schizophrenia patients. Two samples of schizophrenia patients, the first a sample of 34 right-handers and 42 left-handers and a replication set of 84 right-handers, were examined with regard to age at onset considering handedness and the four Luria’s signs (arm folding, hand clasping, familial sinistrality and eye dominance) as well as gender. The association between these parameters and age at onset was investigated by means of multiple regression analysis. Our analyses revealed that right-handers with right arm folding and left-handers with left arm folding showed an early age at onset, while in the late age at onset the opposite preferences prevailed. Apart from arm folding, signs of ambilaterality, i.e., left eye dominance in right-handers and familial sinistrality in left-handers were additional predictors for an early age at onset. Remarkably, all observations found in the first right-handed sample were confirmed in the right-handed replication set. We conclude that among the many different factors specific lateral preferences should also be considered in assessing patients who are at risk of psychosis.

Psychophysical Tests Do Not Identify Ocular Dominance Consistently.

Classical sighting or sensory tests are used in clinical practice to identify the dominant eye. Several psychophysical tests were recently proposed to quantify the magnitude of dominance but whether their results agree was never investigated. We addressed this question for the two most common psychophysical tests: The perceived-phase test, which measures the cyclopean appearance of dichoptically presented sinusoids of different phase, and the coherence-threshold test, which measures interocular differences in motion perception when signal and noise stimuli are presented dichoptically. We also checked for agreement with three classical tests (Worth 4-dot, Randot suppression, and Bagolini lenses). Psychophysical tests were administered in their conventional form and also using more dependable psychophysical methods. The results showed weak correlations between psychophysical measures of strength of dominance with inconsistent identification of the dominant eye across tests: Agreement on left-eye dominance, right-eye dominance, or nondominance by both tests occurred only for 11 of 40 observers (27.5%); the remaining 29 observers were classified differently by each test, including 14 cases (35%) of opposite classification (left-eye dominance by one test and right-eye dominance by the other). Classical tests also yielded conflicting results that did not agree well with classification based on psychophysical tests. The results are discussed in the context of determination of ocular dominance for clinical decisions.

Macular thickness and retinal nerve fiber thickness analysis ın ocular dominance

Abstract Objective: To compare macular and peripapillary retinal nerve fiber layer thicknesses of dominant eye and non-dominant eye using optical coherence tomography (OCT). Methods: 104 eyes of 52 healthy young adults were included. Ophthalmological examinations; including measuring refraction, best corrected visual acuity, intraocular pressure (IOP) measurement, slit-lamb biomicroscopy, dilated fundus examination, measuring of central macular thickness (CMT), and peripapillary retinal nerve fiber layer (PRNFL) thickness were performed on each subject. Hole-in-the-card test was used to detect the ocular dominance. Results: There were 25 females (48%) and 27 males (52%) in the study. Eight participants had left eye dominance (15%), forty-four participants had right eye dominance (85%). Mean CMT was 192.5µm in dominant group and 191.9 µm in non-dominant group. There was no statistically significant difference between dominant eye group and non-dominant eye group in either macular thickness or peripapillary retinal nerve fiber layer thickness. Conclusions: No difference between macular and peripapillary retinal nerve fiber layer thicknesses were detected in dominant and non-dominant groups. Further evaluation is needed.

DOES DYSLEXIA DEVELOP FROM LEFT-EYE DOMINANCE?

The purpose of this theoretical analysis and synthesis is to indicate how left-eye sighting dominance may lead to reading failure through dysfunctional right hemisphere letter encoding. Differing compensatory strategies are postulated to lead to outcomes that include the development of the phonologically impaired and phonologically proficient subtypes of dyslexia as well as specific spelling disability. Evidence is presented indicating that these disorders might be prevented by delaying the introduction of letter writing until the age of 8 years. Early childhood speech categorization in children genetically at-risk of developing dyslexia is also considered from this perspective. Convergent support for this premature writing hypothesis is provided by a comparison with the development of the left-hand inverted writing posture.

No Evidence for Genetic Contribution of Ocular Dominance: The Guangzhou Twin Eye Study.

The purpose of this study was to explore the heritability of ocular dominance in a classic twin study. A classical twin study. Twins aged 7 to 19 years enrolled from the Guangzhou Twin Registry received comprehensive eye examinations. Ocular dominance was assessed by the "hole-in-the-card test" by trained optometrists. Zygosity of the participants was confirmed by genotyping in all same-sex twin pairs. The pairwise concordance rate was calculated as the main outcome. After excluding 110 children with anisometropia of 2.0 diopters or greater and 24 children with alternating ocular dominance, a total of 941 twin pairs were identified in the analysis, including 596 monozygotic and 345 dizygotic pairs. Right-eye dominance was present in 59.3% of twins with available data. The pairwise concordance rate was 0.529 and 0.530 in monozygotic and dizygotic twin pairs, respectively (P > 0.5). The tetrachoric correlation was 0.043 and 0.035, respectively. When comparing the young twins and their parents, no significant difference in the percentage of offspring with left-eye dominance was found between right × right parent mating group and non-right × right parent mating groups. Genetic factors may not be involved in ocular dominance in Chinese teens and children.

LATERALITY IN EYE DOMINANCE, EYE ACUITY AND HANDEDNESS AMONG YOUNG UNDERGRADUATES IN BENIN CITY

Eye or ocular dominance is the superiority of one eye whose visual function predominates over the other. Acuity dominance is a situation where the visual acuity in one eye is better than the other eye without an underlying pathology. The aim of this study was to determine if any laterality exist among these variables. This was a cross sectional study. The study comprised of 100 subjects, 55 males and 45 females within the age range of 18-35 years (mean age 25 ±1.77). All subjects were from Ugbowo and Ekehuan campuses of the University of Benin City. Distant visual acuity was measured using the Snellen?s chart. The miles test was used to determine eye dominance, while handedness was recorded by observing subjects as they picked up a pen to write. Among the study population, 63% had the right eye as the better visual acuity (BVA) eye, of this 54% had laterality with the dominant eye. This was statistically significant, (X2 =10.240, p=0.01). Also, 66% of the study population had laterality of BVA eye with handedness. Of this, 57% showed right side laterality while 9% showed left side laterality. This was statistically significant, (X2=9.000, p=0.002). Right eye dominance was recorded in 78% of the study population, of this 70% showed laterality with right handedness. Of the 22% with left eye dominance, only 7% showed laterality with left handedness. This was also statistically significant, (X2 =32.511, p=0.000). There was also no statistical significance between the studied variables and gender

Ocular dominance affects magnitude of dipole moment: an MEG study

To investigate whether the ocular dominance affects laterality in the activity of the primary visual cortex, we examined the relationship between the ocular dominance and latency or dipole moment measured by checkerboard-pattern and magnetoencephalography in 11 right-handed healthy male participants. Participants with left-eye dominance showed a dipole moment of 21.5+/-6.1 nAm with left-eye stimulation and 16.1+/-3.6 nAm with right, whereas those with right-eye dominance showed a dipole moment of 18.0+/-5.2 and 21.5+/-2.7 nAm with left-eye and right-eye stimulation of the infero-medial quadrant visual field, respectively. Thus, the dipole moment was higher when the dominant eye was stimulated, which implies that ocular dominance is regulated by the ipsilateral occipital lobe.

Handedness, eyedness, and hand–eye crossed dominance in patients with schizophrenia: Sex-related lateralisation abnormalities

Schizophrenia is referred to as cerebral lateralisation abnormality. In this study the possible relationships among handedness, eye dominance, and crossed and non-congruent hand–eye dominance in patients with schizophrenia are investigated. A total of 88 patients with schizophrenia and 118 controls were included in the study. The patient group included 60 men and 28 women who ranged in age from 17 to 63 years. Diagnoses were made on the basis of information provided from clinical interviews and Structured Clinical Interview for DSM-IV. Handedness was ascertained by using the Edinburgh Handedness Inventory. Eye dominance was measured only by the near–far alignment test. Patients with schizophrenia had a significantly increased frequency of mixed-handedness and decreased frequency of both right- and left-handedness in comparison with controls. Also, the male patients with schizophrenia had significantly increased frequencies of left eye dominance, crossed hand–eye dominance, and non-congruent hand–eye dominance compared to controls, but not the female patients. Cerebral lateralisation abnormalities in schizophrenia may be associated with sex-related hormonal factors.

The influence of eye dominance on saccade characteristics and slow presaccadic potentials

Characteristics of saccades and presaccadic slow potentials were studied in 36 right-handed men with right (the RE group) and left (the LE group) eye dominance. Three light-emitting diodes located in the center of the visual field (the central fixation stimulus, CFS) and 10 deg to the left and to the right of the center (peripheral stimuli, PSs) were used for stimulation. The subjects performed a task with simple saccades to a PS and a task with antisaccades to the horizontal mirror position of the PS. Monopolar EEGs at 19 derivations and electrooculograms (EOGs) were recorded. Back averaging of the EEG time-locked to the PS onset or the saccade onset was used to obtain slow presaccadic potentials. The saccade characteristics in the RE and LE groups were similar. Differences between them were found only in the antisaccade task. The amplitude of negative presaccadic potentials (NPPs) time-locked to the PS in the frontal cortex was lower in the LE group compared to the RE group. Analysis of potentials time-locked to the saccade onset showed that changes in the slow potentials during the last 50 s before the saccade depended on the saccade direction and reflected the activation of the hemisphere opposite to the saccade direction. The activation of the right hemisphere before left-side saccades was higher in the LE than the RE group. In addition, the amplitude of NPPs was decreased in the frontal area and increased in the left posterior temporal area in the LE group compared to the RE group. The obtained results indicate that the involvement of the frontal cortex in cognitive and motor processes is decreased in subjects with the left eye dominance.

A statistical model for binocular rivalry

A probabilistic model is presented for the phase durations in binocular rivalry experiments. The hypothetical construct of inhibition or reaction inhibition is used to account for the length of the successive phases of left-eye dominance and right-eye dominance. In accordance with Hull's Postulate X.B. it is assumed that the inhibition increases linearly at rate a1 during periods of left-eye dominance and decreases linearly at rate a0 during periods of right-eye dominance. Two different versions of the proposed model are presented: the beta and the Bessel inhibition models. Inhibition fluctuates between the boundaries 0 and 1 in the beta inhibition model and between -infinity and +infinity in the Bessel inhibition model. The transition rates lambda1(t) for switches from a state of left-eye dominance to a state of right-eye dominance, and lambda0(t) for switches from a state of right-eye dominance to a state of left-eye dominance depend on inhibition: lambda1(t)=l1 (Y(t)), lambda0(t)=l0(Y(t)), where l1 is a non-decreasing function and l0 is a non-increasing function. In the beta inhibition model l1(y)=c1/(1 - y) and l0(y)=c0/y. In the Bessel inhibition model l1(y)=u1e(y) and l0(y)=u0/e(y). Special attention is given to the derivation of the expectation of the stationary phase durations.

Eye-hand preference in schizophrenia: sex differences and significance for hand function.

Hand preference and eye dominance were investigated in 73 (30 women, 43 men) schizophrenic patients and 71 (30 women, 41 men) healthy controls. There were significantly more schizophrenic patients and normal controls who were significantly right-hand dominant. However, schizophrenic patients showed a significant excess of left-eye dominance relative to controls (65.8% vs 29.6%; Odds Ratio= 4.75, p< .001). In addition, female schizophrenic patients showed a higher rate of nonright (either left or inconsistent) eye dominance (80%) than male schizophrenic patients (55.8%) and controls (33.3%). Analysis of hand performance on the Purdue Pegboard Test indicated that schizophrenic patients who showed crossed eye-hand dominance scored higher than did patients without crossed eye-hand dominance.

Crossed hand-eye dominance in male psychiatric patients.

Increased incidence of left-eye and crossed hand-eye dominance have been considered as indicating left hemispheric dysfunction in many neuropsychiatric disorders. This study investigates the incidence of left-eye and crossed hand-eye dominance in patience with schizophrenia (n = 68), panic disorder (n = 62), personality disorder (n = 35), heroin addiction (n = 54), and mental retardation (n = 33), in comparison with controls (n = 944). All psychiatric groups, except the group with panic disorder, had significantly greater frequency of left-eye dominance than the control group. Furthermore, all psychiatric groups, except the personality-disordered group, had significantly greater frequency of crossed hand-eye dominance than the control group. These findings further support the evidence of an anomaly in hemispheric lateralization among different psychiatric populations, particularly among those with psychotic symptoms and cognitive deficits.

RIGHT AND LEFT VISUAL CORTEX AREAS IN HEALTHY SUBJECTS WITH RIGHT- AND LEFT-EYE DOMINANCE

The aim of this work was to study the differences between the right- and left-visual cortices in relation to eyedness in healthy subjects. Ocular domi nance was determined by means of the near-far alignment test. To assess visual cortical areas, the right and left sagittal scenograms of cranium by magnetic resonance imaging were used. To calculate the visual cortex areas by using scenograms, Cavalieri s method was used. In the subjects with right-eye dominance, the right visual cortex was larger than the left visual cortex, and vice versa in the subjects with left-eye dominance. The right and left cuneal areas were found to be larger in males than in females. In light of these results, it was concluded that the human eyes are predominantly controlled by the ipsilateral visual cortex.