Changes in visual evoked potentials after phosphene electrostimulation in children suffering from myopia

We recorded visual evoked potentials (VEPs) in children suffering from medium and high myopia (3.0 to 6.0 and more than 6.0 D; 28 and 21 patients, respectively); a light flash was used as the stimulus. The VEPs were recorded before and after a curative course of phosphene electrostimulation (PhES; frequency 15 sec⁻¹, 10 to 15 10-min-long everyday sessions). The above course resulted in clear trends toward decreases in the peak latencies of the P60 and P100 VEP components; changes in the latencies of other components were expressed to a lesser extent. In children with medium myopia, the latency of the P60 component decreased, on average, by more than 21% (P < 0.05); in patients with high myopia, the respective decrease was about 12% (P > 0.05). These shifts were accompanied by increases in the mean amplitudes of the P60 and, to a lesser degree, P100 (more expressed in medium myopia). The data obtained allow us to suppose that the PhES course provides increases in the transmission velocity through relay structures of the visual analyzer and in neuronal networks of the visual cortex and also in the number of neuronal units whose activity is reflected in generation of VEPs. Application of the PhES technique is much more effective in relatively moderate myopia. Neirofiziologiya/Neurophysiology, Vol. 40, No. 3, pp. 228–235, May–June, 2008.     

Comparison of the mechanisms of latency shift in pattern reversal visual evoked potential induced by blurring and contrast reduction

Reduction of visual acuity or of the contrast of the stimulus induces a prolongation of the pattern reversal visual evoked potential (PR-VEP) latencies, perhaps because these conditions cause deterioration of the visual capacity to recognize objects and may preferentially activate the slower central retina channel. The PR-VEP was obtained with a video stimulator and 3 kinds of stimuli: total video field, video with a central scotoma and a restricted central stimulus. The subjects were tested under conditions of normal (20/20) and reduced visual acuity (20/200) with 14′ and 56′ checks and 60% contrast, and under conditions of normal visual acuity (20/20) with 14′ checks and with stimulus contrast of 60% and 25%. Blurring increased latencies and decreased amplitudes only with the 14′ checks stimulus but no with 56′ checks, and the amplitudes obtained with the central stimulus became greater than those obtained with a central scotoma. Reducing contrast increased only latency, and there was not difference between amplitudes obtained with a central stimulus or a central scotoma. We conclude that blurring small checks induces a preferential stimulation of receptors in the central retina, but the same effect was not observed when stimulus contrast was reduced.     

Changes in visual evoked potentials observed in humans involved in cleanup work after the Chernobyl’ catastrophe

We studied the parameters of visual evoked potentials (VEP) recorded in humans involved in the cleanup work after the Chernobyl’ catastrophe and in persons of the control group. The VEP evoked by presentation of a reversing chessboard pattern were significantly modified in the group of cleanup workers: in many subjects their shape was drastically changed, the mean latent periods for P100 and N145 waves increased, and their amplitudes significantly dropped. The amplitude of the P200 component somewhat increased in the group of cleanup workers. Possible reasons for the observed changes in the evoked electrical activity and the mechanisms underlying the changes in the visual analyzer of the persons subjected to long-term irradiation are discussed.     

Changes in Bioelectric Activity in the Human Retina after Transcranial Magnetic Stimulation

The human electroretinogram (ERG) was recorded before and after transcranial magnetic stimulation (TMS) in the region of the cortical link of the visual analyzer. TMS at the frequency of 5 Hz in the projection of the cortical link of the visual analyzer significantly increased the amplitude of the ERG b wave; this was most likely associated with changes in the state of neurons of the central links of the visual analyzer, which enter the retina with efferent fibers of the optic nerve and are actively involved in lateral inhibition.     

Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices

Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m²) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (L_min/L_max ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m²) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (L_min/L_max ≥ 80%). Two charts were operating beyond manufacturer’s recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out-performed ETDRS charts in terms of photometric compliance with high contrast acuity standards.     

Electromyographic Manifestations of Hereditary Signs of Extrapyramidal Insufficiency

In clinically healthy kinsmen of patients suffering from Parkinson’s disease, we studied the amplitude/frequency characteristics of EMG activity recorded from flexors and extensors of the elbow joint in order to reveal symptoms of extrapyramidal insufficiency (EPI) in these persons and to propose necessary recommendations to such a risk group. We examined four groups of persons: group 1 consisting of 37 healthy kinsmen of patients with clinical diagnosis of Parkinson’s disease; control group 2 consisting of 20 tested persons whose age was analogous to that of persons of group 1; group 3 including 33 Parkinsonian patients; and group 4 of 24 virtually healthy persons of elderly age, i.e., the group considered to be the control one with respect to group 3. In Parkinsonian patients, the main EPI correlates were the following: (i) significantly increased amplitude of EMG recorded from the arm muscles in the resting state, (ii) bursting discharges in such EMGs generated with a 4-9 sec–1 frequency (type III of EMG), and (iii) abnormally increased coefficients of reflex involvement (CRI) for the muscles of the opposite arm at retention of a load by one arm. One symptom of EPI or another were found in 20 (54.1%) kinsmen of the Parkinsonian patients; in this case, increased EMG amplitudes were observed in 13 persons (35.1%). We also observed significant correlation of the level of rise in the amplitude of the resting EMG with the age of the tested persons. In 29.7% kinsmen of the Parkinsonian patients, burst discharges with a 5-10 sec^–1 frequency were present in their EMGs, while in 16.2% of these persons we observed increased CRIs at retention of a load. For comparison, in the corresponding control group, increased amplitudes of the resting EMG, generation of burst EMG dischargers, and increased CRIs were observed in 15, 5, and 10% of the tested persons, respectively. Therefore, in kinsmen of the Parkinsonian patients, some EMG EPI manifestations were observed 2.3 to 5.9 times more frequently that those in the corresponding control group. For the members of the risk group, recommendations concerning the daily routine (mode of life) and the dietary intake, as well as a list of drugs to be avoided for long-term administration, were proposed.     

Processing of Spatial-Frequency Altered Faces in Schizophrenia: Effects of Illness Phase and Duration

Low spatial frequency (SF) processing has been shown to be impaired in people with schizophrenia, but it is not clear how this varies with clinical state or illness chronicity. We compared schizophrenia patients (SCZ, n = 34), first episode psychosis patients (FEP, n = 22), and healthy controls (CON, n = 35) on a gender/facial discrimination task. Images were either unaltered (broadband spatial frequency, BSF), or had high or low SF information removed (LSF and HSF conditions, respectively). The task was performed at hospital admission and discharge for patients, and at corresponding time points for controls. Groups were matched on visual acuity. At admission, compared to their BSF performance, each group was significantly worse with low SF stimuli, and most impaired with high SF stimuli. The level of impairment at each SF did not depend on group. At discharge, the SCZ group performed more poorly in the LSF condition than the other groups, and showed the greatest degree of performance decline collapsed over HSF and LSF conditions, although the latter finding was not significant when controlling for visual acuity. Performance did not change significantly over time for any group. HSF processing was strongly related to visual acuity at both time points for all groups. We conclude the following: 1) SF processing abilities in schizophrenia are relatively stable across clinical state; 2) face processing abnormalities in SCZ are not secondary to problems processing specific SFs, but are due to other known difficulties constructing visual representations from degraded information; and 3) the relationship between HSF processing and visual acuity, along with known SCZ- and medication-related acuity reductions, and the elimination of a SCZ-related impairment after controlling for visual acuity in this study, all raise the possibility that some prior findings of impaired perception in SCZ may be secondary to acuity reductions.     

Findings from a rapid assessment of avoidable blindness (RAAB) in Southern Malawi

Background

Data on prevalence and causes of avoidable blindness in Malawi are not readily available. The purpose of this study was to determine the prevalence and causes of blindness in persons aged 50 and above in southern Malawi to plan eye care services for the community.

Methodology

A population-based survey was conducted in 7 districts in southern Malawi. Villages were selected by probability proportionate to size within each district. Clusters were further subdivided into segments. A predetermined number of segments were selected randomly in each cluster. The survey team moved from house to house in each segment until they had examined 50 people over the age of 50. Examination consisted of visual acuity measurement with tumbling “E” chart and ocular examination by an ophthalmologist. Participants were categorized by visual acuity. Those who were visually impaired (VA<6/18 in the better eye with available correction) were assigned a main cause of visual loss. Further information was sought from anyone who had received cataract surgery.

Results

A total number of 3,583 persons aged 50 and above were sampled; among these 3,430 (95.7%) were examined. The prevalence of blindness (presenting visual acuity <3/60 in the better eye) among persons aged 50 and above was 3.3% (95% CI 2.5–4.1). Cataract was the most common cause of blindness contributing to 48.2% of all cases, followed by glaucoma (15.8%) and cornea scarring (12.3%). The cataract surgical coverage in blind persons was 44.6%.

Conclusion

The prevalence of blindness and visual impairment in persons aged 50 and above was lower than the WHO estimate for Malawi. The majority of the causes were avoidable, with cataract accounting for approximately half of all cases of blindness. The data suggests that expansion of eye care programs to address avoidable causes of blindness is necessary in this area of southern Malawi.     

康柏西普与雷珠单抗治疗年龄相关性黄斑变性的临床研究

目的:探讨康柏西普联合雷珠单抗治疗年龄相关性黄斑变性(AMD)的临床疗效。方法:选择2015年6月到2016年10月我院收治的60例AMD患者,按随机数字表法分为对照组和治疗组。对照组患者给予康柏西普治疗,治疗组患者给予康柏西普联合雷珠单抗治疗,两组患者均治疗3个月。评价并比较两组患者临床疗效。统计并比较两组患者治疗后的视网膜渗漏总改善率。观察并比较两组患者治疗前后最佳矫正视力和黄斑视网膜厚度。结果:治疗后,治疗组患者的视力提高率为80.00%,明显高于对照组的55.00%,差异具有统计学意义(X~2=4.104,P=0.043)。治疗后,治疗组患者的视网膜渗漏总改善率为92.50%,明显高于对照组的70.00%,差异具有统计学意义(X~2=5.294,P=0.021)。治疗前,两组患者最佳矫正视力、黄斑视网膜厚度比较差异无统计学意义(P0.05);治疗后,两组患者最佳矫正视力均明显大于治疗前,黄斑视网膜厚度均明显小于治疗前,并且治疗组均明显优于对照组,差异均具有统计学意义(P0.05)。结论:康柏西普联合雷珠单抗治疗AMD的临床疗效显著,能够明显提高视力,减轻视网膜渗漏,值得在临床上推广应用。     

'Visual' acuity of the congenitally blind using visual-to-auditory sensory substitution

Sensory Substitution Devices (SSDs) convey visual information through sounds or touch, thus theoretically enabling a form of visual rehabilitation in the blind. However, for clinical use, these devices must provide fine-detailed visual information which was not yet shown for this or other means of visual restoration. To test the possible functional acuity conveyed by such devices, we used the Snellen acuity test conveyed through a high-resolution visual-to-auditory SSD (The vOICe). We show that congenitally fully blind adults can exceed the World Health Organization (WHO) blindness acuity threshold using SSDs, reaching the highest acuity reported yet with any visual rehabilitation approach. This demonstrates the potential capacity of SSDs as inexpensive, non-invasive visual rehabilitation aids, alone or when supplementing visual prostheses.     

Quasi-Monopolar Stimulation: A Novel Electrode Design Configuration for Performance Optimization of a Retinal Neuroprosthesis

In retinal neuroprostheses, spatial interaction between electric fields from various electrodes – electric crosstalk – may occur in multielectrode arrays during simultaneous stimulation of the retina. Depending on the electrode design and placement, this crosstalk can either enhance or degrade the functional characteristics of a visual prosthesis. To optimize the device performance, a balance must be satisfied between the constructive interference of crosstalk on dynamic range and power consumption and its negative effect on artificial visual acuity. In the present computational modeling study, we have examined the trade-off in these positive and negative effects using a range of currently available electrode array configurations, compared to a recently proposed stimulation strategy – the quasi monopolar (QMP) configuration – in which the return current is shared between local bipolar guards and a distant monopolar electrode. We evaluate the performance of the QMP configuration with respect to the implantation site and electrode geometry parameters. Our simulation results demonstrate that the beneficial effects of QMP are only significant at electrode-to-cell distances greater than the electrode dimensions. Possessing a relatively lower activation threshold, QMP was found to be superior to the bipolar configuration in terms of providing a relatively higher visual acuity. However, the threshold for QMP was more sensitive to the topological location of the electrode in the array, which may need to be considered when programming the manner in which electrode are simultaneously activated. This drawback can be offset with a wider dynamic range and lower power consumption of QMP. Furthermore, the ratio of monopolar return current to total return can be used to adjust the functional performance of QMP for a given implantation site and electrode parameters. We conclude that the QMP configuration can be used to improve visual information-to-stimulation mapping in a visual prosthesis, while maintaining low power consumption.     

Snapper rest where they see best: visually mediated choice behaviour of Australasian snapper (Chrysophrys auratus)

The sensory physiology and behaviour of many fish species are strongly affected by light. This short study demonstrates that in the Australasian snapper (Chrysophrys auratus) absolute light intensity governs visual acuity and also guides preference behaviour, with fish choosing to ‘rest where they see best’. Use of the optomotor response to test visual acuity at four light intensities (0.01, 0.05, 1 and 3 μmol s^?1 m²), showed that visual acuity (measured as directional bias) was best at a light intensity of 0.05 μmol s^?1 m² (84.9% directional bias), but weakened at the highest and lowest light intensity (41.1 and 35.3%). When provided with a choice of the same four light environments fish also spent most time in the 0.05 μmol s^?1 m² light environment, while the highest and lowest intensity light environments were usually avoided. Acclimated light intensity (that is daytime light intensity of the home aquarium) was also 0.05 μmol s^?1 m²_. By selecting an environment where visual function is optimised, C. auratus are also optimising the ability to search for prey and to detect predators. The results are discussed with reference to habitat utilisation and thoughts for trawl fishing practices.     

Visual acuity, contrast sensitivity and retinal magnification in a marsupial, the tammar wallaby (Macropus eugenii )

The visual acuity of the tammar wallaby was estimated using a behavioural discrimination task. The wallabies were trained to discriminate a high-contrast (86%) square-wave grating from a grey field of equal luminance (1000–6000 cd m⁻²). Visual-evoked cortical potentials were used to measure the complete contrast sensitivity function. The stimulus was a sinusoidal phase reversal of a sinusoidally modulated grating of various spatial frequencies and contrasts with a mean luminance of 40 cd m⁻². The behavioural acuity was estimated to be about 4.8 cycles/deg. The contrast sensitivity peaked at about 0.15 cycles/deg and declined towards both lower and higher spatial frequencies. The cut-off frequency of the contrast sensitivity function is slightly lower than the behaviourally measured acuity at about 2.7 cycles/deg. The retinal magnification factor was estimated anatomically from laser lesions to be about 0.16 mm/deg. Based on the known ganglion cell density and the retinal magnification factor, an anatomical upper limit to visual acuity of about 6 cycles/deg can be calculated. The differences in estimates of visual acuity between the behavioural and anatomical methods on the one side and physiology on the other side are discussed. Accepted: 28 May 1998     

Effects of Different Levels of Intraocular Stray Light on Kinetic Perimetry Findings

PurposeTo evaluate the effect of different levels of intraocular stray light on kinetic perimetry findings.MethodsTwenty-five eyes of 25 healthy young participants were examined by automated kinetic perimetry (Octopus 900) using Goldmann stimuli III4e, I4e, I3e, I2e, and I1e. Each stimulus was presented with a velocity of 3°/s at 24 meridians with 15° intervals. Four levels of intraocular stray light were induced using non-white opacity filter (WOF) filters and WOFs applied to the clear plastic eye covers of the participants. The visual acuity, pupil diameter, isopter area, and kinetic sensitivity of each meridian were analyzed for each WOF density.ResultsVisual acuity deteriorated with increasing WOF densities (p < 0.01). With a visual acuity of 0.1 LogMAR units, the isopter areas for III4e, I4e, I3e, I2e, and I1e decreased by -32.7 degree² (-0.2%), -255.7 degree² (-2.6%), -381.2 degree² (-6.2%), -314.8 degree² (-12.8%), and -59.2 degree² (-15.2%), respectively; kinetic sensitivity for those stimuli decreased by -0.1 degree (-0.1%), -0.8 degree (-1.4%), -1.6 degree (-3.7%), -2.7 degree (-9.7%), and -1.7 degree (-16.2%), respectively. The pupil diameter with each WOF density was not significantly different.ConclusionKinetic perimetry measurements with a high-intensity stimulus (i.e., III4e) were unaffected by intraocular stray light. In contrast, measurements with the I4e, I3e, I2e, and I1e stimuli, especially I2e and I1e, were affected. Changes in the shape of the isopter resulting from opacity must be monitored, especially in cases of smaller and lower-intensity stimuli.     

Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation

Background

Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a “virtual lesion” in stimulated brain regions, with correspondingly diminished behavioral performance.

Methodology/Principal Findings

Here we investigated the effects of rTMS to visual cortex on subjects'' ability to perform visual psychophysical tasks. Contrary to expectations of a visual deficit, we find that rTMS often improves the discrimination of visual features. For coarse orientation tasks, discrimination of a static stimulus improved consistently following theta-burst stimulation of the occipital lobe. Using a reaction-time task, we found that these improvements occurred throughout the visual field and lasted beyond one hour post-rTMS. Low-frequency (1 Hz) stimulation yielded similar improvements. In contrast, we did not find consistent effects of rTMS on performance in a fine orientation discrimination task.

Conclusions/Significance

Overall our results suggest that rTMS generally improves or has no effect on visual acuity, with the nature of the effect depending on the type of stimulation and the task. We interpret our results in the context of an ideal-observer model of visual perception.     

Prevalence and Outcomes of Cataract Surgery in Adult Rural Chinese Populations of the Bai Nationality in Dali: The Yunnan Minority Eye Study

Purpose

To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in adults of the Bai Nationality populations in rural China.

Methods

We conducted a population-based cross-sectional survey (from randomly selected block groups) of Chinese Bai Nationality aged ≥50 years in southwestern China. Presenting visual acuity (PVA), best corrected visual acuity (BCVA) were recorded and a detailed eye examination was carried out. For all aphakic and pseudophakic subjects identified, information on the date, setting, type, and complications of cataract surgery were recorded. In eyes with VA <20/63, the principal cause of visual impairment was identified.

Results

Of 2133 (77.8% of 2742) subjects, 99 people (129 eyes) had undergone cataract surgery. The prevalence of cataract surgery was 4.6%. Surgical coverage among those with PVA <20/200 in both eyes because of cataract was 52.8%. Unoperated cataract was associated with older age. The main barrier to cataract surgery was lack of awareness and knowledge, cost, and fear. Among the 129 cataract-operated eyes, 22.5% had PVA of ≥20/32, 25.6% had PVA of 20/40 to 20/63, 23.3% had PVA <20/63 to 20/200, and 28.7% had PVA<20/200. With BCVA, the percentages were 42.6%, 23.3%, 10.9%, and 23.3%, respectively. Aphakia (odds ratio [OR], 8.49; P<0.001) and no education (OR, 10.18; P = 0.001) or less education (OR, 6.49; P = 0.014) were significantly associated with postoperative visual impairment defined by PVA, while aphakia (OR, 8.49; P<0.001) and female gender (OR, 4.19; P = 0.004) were significantly associated with postoperative visual impairment by BCVA. The main causes of postoperative visual impairment were refractive error, retinal disorders and glaucoma.

Conclusions

Half of those with bilateral visual impairment or blindness because of cataract remain in need of cataract surgery in Bai population. Surgical uptake and visual outcomes should be further improved in the future.     

Effects of Lead Ions on the Synaptic Responses of Neurons of the Rat Sympathetic Ganglion

Using intracellular recording, we studied the effects of lead ions on the synaptic responses of neurons of the superior cervical ganglion (SCG) of the rat. Three groups of SCG neurons were found; they differed from each other in directions of the changes evoked by Pb²⁺ applications and in their sensitivity to this agent. In two groups of the phasic SCG neurons, Pb²⁺ decreased the amplitude of EPSP evoked by stimulation of the cervical sympathetic nerve with EC₅₀ of (2.2 ± 0.2) · 10^-6 M and (3.55 ± 0.29) · 10^-5 M, respectively. In the tonic neurons, 2 · 10^-6 M Pb²⁺ increased the EPSP amplitude by 27 ± 2%, on average, as compared with the control values. We postulate that the specificity of responses of these three groups of SCG neurons to the action of Pb²⁺ is determined by the different subunit composition of the nicotinic cholinoreceptors in the membrane of these cells.     

Illusions of Visual Motion Elicited by Electrical Stimulation of Human MT Complex

Human cortical area MT⁺ (hMT⁺) is known to respond to visual motion stimuli, but its causal role in the conscious experience of motion remains largely unexplored. Studies in non-human primates demonstrate that altering activity in area MT can influence motion perception judgments, but animal studies are inherently limited in assessing subjective conscious experience. In the current study, we use functional magnetic resonance imaging (fMRI), intracranial electrocorticography (ECoG), and electrical brain stimulation (EBS) in three patients implanted with intracranial electrodes to address the role of area hMT⁺ in conscious visual motion perception. We show that in conscious human subjects, reproducible illusory motion can be elicited by electrical stimulation of hMT⁺. These visual motion percepts only occurred when the site of stimulation overlapped directly with the region of the brain that had increased fMRI and electrophysiological activity during moving compared to static visual stimuli in the same individual subjects. Electrical stimulation in neighboring regions failed to produce illusory motion. Our study provides evidence for the sufficient causal link between the hMT⁺ network and the human conscious experience of visual motion. It also suggests a clear spatial relationship between fMRI signal and ECoG activity in the human brain.     

BDNF regulates the maturation of inhibition and the critical period of plasticity in mouse visual cortex.

Maturation of the visual cortex is influenced by visual experience during an early postnatal period. The factors that regulate such a critical period remain unclear. We examined the maturation and plasticity of the visual cortex in transgenic mice in which the postnatal rise of brain-derived neurotrophic factor (BDNF) was accelerated. In these mice, the maturation of GABAergic innervation and inhibition was accelerated. Furthermore, the age-dependent decline of cortical long-term potentiation induced by white matter stimulation, a form of synaptic plasticity sensitive to cortical inhibition, occurred earlier. Finally, transgenic mice showed a precocious development of visual acuity and an earlier termination of the critical period for ocular dominance plasticity. We propose that BDNF promotes the maturation of cortical inhibition during early postnatal life, thereby regulating the critical period for visual cortical plasticity.     

Cerebral Asymmetry of fMRI-BOLD Responses to Visual Stimulation

Hemispheric asymmetry of a wide range of functions is a hallmark of the human brain. The visual system has traditionally been thought of as symmetrically distributed in the brain, but a growing body of evidence has challenged this view. Some highly specific visual tasks have been shown to depend on hemispheric specialization. However, the possible lateralization of cerebral responses to a simple checkerboard visual stimulation has not been a focus of previous studies. To investigate this, we performed two sessions of blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) in 54 healthy subjects during stimulation with a black and white checkerboard visual stimulus. While carefully excluding possible non-physiological causes of left-to-right bias, we compared the activation of the left and the right cerebral hemispheres and related this to grey matter volume, handedness, age, gender, ocular dominance, interocular difference in visual acuity, as well as line-bisection performance. We found a general lateralization of cerebral activation towards the right hemisphere of early visual cortical areas and areas of higher-level visual processing, involved in visuospatial attention, especially in top-down (i.e., goal-oriented) attentional processing. This right hemisphere lateralization was partly, but not completely, explained by an increased grey matter volume in the right hemisphere of the early visual areas. Difference in activation of the superior parietal lobule was correlated with subject age, suggesting a shift towards the left hemisphere with increasing age. Our findings suggest a right-hemispheric dominance of these areas, which could lend support to the generally observed leftward visual attentional bias and to the left hemifield advantage for some visual perception tasks.