Visual Field Conditions Research Articles

A Suspicious Cup Disc with High Intraocular Pressure (IOP) and Normal Perimetry: A Rare Self Case Report

Background: Intraocular pressure (IOP) assessment involves evaluating the force exerted by aqueous humor on the internal surface of the anterior eye. Elevated IOP poses a substantial risk for glaucomatous optic neuropathy and is a key modifiable clinical risk factor. This study aims to explore cases of ocular hypertension coupled with optic nerve cupping, suspected to be glaucoma, providing comprehensive details of examination results, diagnosis, and subsequent management.
 Case presentation: A 23-year-old Asian male underwent an ocular examination, revealing average IOP levels measured using non-contact tonometry. Despite no complaints, consecutive measurements noted 28 mmHg for the right eye and 26 mmHg for the left eye. Initial assessments by a glaucoma specialist indicated open-angle anterior chambers. Optical coherence tomography revealed cup disc ratios of 0.7 to 0.8 for both eyes. Medication (Timol) was prescribed, adjusting with oral citicoline and brinzolamide. The diagnosis evolved to juvenile open-angle glaucoma (JOAG). Visual field testing showed normal results. Discontinuation of treatment led to reclassifying the diagnosis as ocular hypertension and scheduling follow-up OCT examinations for five years.
 Conclusion: The patient exhibited corneal thickness ≥610 μm, CDR ≥0.7 μm, IOP >25 mmHg, and maintained good visual field conditions. Additional research is essential to understand the correlation between corneal thickness and other eye conditions. Recognizing potential overdiagnosis due to high IOP and large CDR emphasizes the need for meticulous clinical assessment and advanced diagnostic examinations to distinguish physiological and pathological conditions.

Rapid campimetry - a novel robust kinetic approach for visual field screening in glaucoma.

To investigate the robustness and variability of a novel kinetic visual field (VF) screening method termed rapid campimetry (RC). In RC visual field (VF) screening is enabled via kinetic-based testing on any computer (10°/4.7 s at 40-cm viewing distance) and high contrast in a dark room (1 cd/cm2). In experiment (1): 30 participants [20 healthy participants (HC), 5 glaucoma patients (GLA) and 5 patients with cataract (CAT)] were included to test the intra-session variability (fatigue effect) and the following effects on RC: room illumination (140 cd/m2), ±3 D refractive errors, media opacity. In experiment (2): Inter-session variability (1-3 weeks apart) was assessed in 10 HC and 10 GLA. Since RC detects absolute scotomas, the outcome measure was the size of physiological (blindspot) and pathological (glaucoma) scotomas in degrees. A repeated measures ANOVA was employed in experiment 1 and intraclass correlation (ICC) in experiment 2. Neither the size of the blindspot nor the VF defects differed significantly between the different testing conditions. For intra-session variability, the average bias of blindspot size was -0.6 ± 2.5°, limits of agreement (LOA), in comparison to 0.3 ± 1.5° for VF defects, both with ICC of 0.86 and 0.93, respectively. For the inter-session repeatability, the average bias and LOA for blindspot size was 0.2 ± 3.85° in comparison 1.6 ± 3.1° for VF defects, both with ICC of 0.87 and 0.91, respectively. RC was robust to suboptimal testing VF conditions and showed good-to-excellent reliability between VF testing visits holding high potential for teleophthalmology.

Effect of auditory deprivation on adaptive locomotion: Interaction with lower visual field occlusion

Auditory stimuli have been suggested to play a role in adequately controlling movement; however, their influence is not fully understood, particularly regarding dynamic behaviors, such as adaptive locomotion. This study aimed to investigate whether auditory deprivation affects adaptive locomotion. In particular, we aimed to elucidate the role of the auditory sense in obstacle avoidance by manipulating the visual field, which provides crucial sensory information for movement control. Sixteen participants approached a 15-cm obstacle located 6 m away and stepped over it under four different conditions that combined two factors: the hearing condition controlled by wearing earmuffs with and without holes, and the lower visual field condition controlled by carrying opaque white and transparent boards. Spatiotemporal variables during the approach to the obstacle were measured using an electronic walkway, whereas foot clearance over the obstacle was assessed using a motion-capture system. Participants who experienced auditory deprivation and lower visual field occlusion demonstrated greater variability in step length when approaching the obstacle compared with the other conditions. The leading and trailing foot clearances were higher under lower visual field occlusion conditions. Furthermore, when participants were under conditions of auditory deprivation, greater variability was observed in the clearance of the leading foot. These results suggest that auditory information contributes to movement stabilization during adaptive locomotion. Our findings provide evidence that auditory and visual senses complement each other during motor actions, indicating that adaptive locomotion can be influenced by the integration of multiple sensory inputs.

Genetic, environmental and other risk factors for progression of retinitis pigmentosa.

Retinitis pigmentosa (RP) is a commonly inherited disease of the retina, which is characterized by progressive loss of visual function due to specific genetic mutations. There are many risk factors that may have effect on the progression of RP, such as inheritance patterns, genotype, gender, age, smoking, physical activity, and other demographic and environmental factors. Baseline visual field conditions, changes of ellipsoid zone, photoreceptor layer thickness, and choroidal structure are reported to be the phenotype risk factors for RP progression. Moreover, aqueous flare and high-sensitivity C-reactive protein are probable inflammation biomarkers for assessing the progression of RP. Increased oxidative stress is considered to be one of the potential factors for the existence of RP. The risk factors can be combined to form a corresponding prediction model to predict disease progression. This review is to summarize the current literature that studies the genetic, environmental, phenotypic, demographic, inflammatory and other risk factors of RP progression and discuss the most reliable risk factors that could provide predictive models.

Sex Differences in the Visuomotor Control of Obstacle Crossing When Walking Are Not Age Related.

To ensure stable obstacle crossing when walking, visual information is required two steps before reaching the obstacle. As possible age-related sex differences in visuomotor control have not been investigated, we assessed sex differences in obstacle crossing while walking, as examined by toe clearance (TC) and postural stability. Participants were 14 younger and 14 older adults (equal numbers of men and women) who wore goggles for visual field adjustment while obstacle crossing during gait. We manipulated three visual field occlusion conditions (total, lower, and no visual field occlusions) two steps before the obstacle and analyzed the TC of the lead limb, and the participants' step width and root mean square of trunk acceleration as indices of postural stability. We found a significant interaction between sex and visual condition in step width, with men showing larger step width values than women in all visual field conditions. Moreover, while women showed no step-width differences across visual field conditions, men had a larger step width with the lower visual field occluded than in the other visual conditions. We found no other significant sex differences. Our results suggest that men may be more dependent than women on the upper visual field for postural stability during obstacle crossing. Sex differences in visuomotor control were not affected by age.

Review of Metagnosis: Revelatory Narratives of Health and Identity

Review of Metagnosis:Revelatory Narratives of Health and Identity Dana Howard Danielle Spencer's book, "Metagnosis: Revelatory Narratives of Health and Identity," does many things. It is a work of autotheory, putting Spencer's own embodied narrative in constant conversation with the testimony of others along with a remarkably diverse set of critical and theoretical approaches. In the book, Spencer coins a new term, "metagnosis", which occurs when one is newly diagnosed in adulthood with a lifelong condition. The book explores Spencer's own metagnostic experience involving her eyesight along with chronicling the experiences of others to highlight the ways in which newfound knowledge of a diagnosis can in itself transform us. Born with strabismus—"misaligned eyes," Spencer is practiced at negotiating the meaning of having a non-normative visual experience and presentation. For the most part, growing up with the condition and frequently subjected to medical attention because of it, Spencer remained largely unconcerned about whether or not she saw differently. But, as the book chronicles, in adulthood, after enduring subpar medical treatment and a series of frustrating surgeries, Spencer is additionally diagnosed with a different visual field condition, homonymous hemianopia, that was likely sustained in infancy, but which up until the diagnosis neither she nor her various doctors had detected. Spencer describes how she discovers in her orthoptist's office that she can see only half of the visual world of each eye. This discovery leads to a deep ambivalence on Spencer's part—which includes feelings of physical vulnerability, shame that the condition had gone unnoticed for so long, as well as relief for not having to suffer through the stigma and exclusion that may have come with the additional medical diagnosis in childhood. It also leads to a theoretical examination of the limited narrative and theoretical resources that avail us in trying to make sense of such revelatory experiences and the frustrating inexplicability that such transformative experiences can have for others. This intimate narrative approach democratizes theory. As Spencer says near the end of the book, [End Page E-1] "[k]nowledge is not simply illuminated, but is itself profoundly informed by our way of looking." [306] Metagnosis invites us to inhabit Spencer's own way of looking as she engages in critical theoretical analysis of the epistemic and practical stakes related to medical diagnosis and other identity altering revelatory discoveries. The book is also a work of profound interdisciplinary engagement, bridging conversations happening across siloed academic and cultural spaces. The book draws widely and creatively from biomedicine, medical humanities, philosophy, disability studies, cultural studies, literature, film, oral history, and personal narrative. Ultimately, Spencer argues that metagnosis, the experience, "is largely about navigating different forms of knowledge." [20] The book critically interrogates the insights growing out of multiple disciplines with respect and attention; each of these disciplines is treated as a possible source of knowledge, albeit fallible and incomplete. It will be an important resource for readers from multiple perspectives. Finally, the book is responding to a kind of epistemic injustice, that is, to a systemic and distinctive wrong done to people in their capacity as knowers and inquirers.1 Specifically, the book habituates us as readers to attend to and work towards mitigating the hermeneutical injustice we (and others) may face as biomedical subjects—that is, as people to be diagnosed. Hermeneutical injustice, a term popularized by Miranda Fricker and critically developed by theorists like José Medina, Luvell Anderson, and Kristie Dotson, is the phenomenon where a person is unfairly disadvantaged in their capacities to make sense of their own experience.2 Hermeneutical injustice happens when certain stories remain untold, not merely because people are systemically excluded from and discredited within the collective discursive community, but also because -as a result of this exclusion and discredit - people lack the shared language to actually tell their stories in a way that makes sense to them. At its core, the book's project is to identify and provide a new shared language. The book offers us the narrative resources needed to make sense of a distinctive kind of diagnostic experience that has heretofore remained conceptually obscure and personally isolating. In naming the experience of metagnosis, Spencer writes...

Effect of Intraocular Lens Biomaterials on the Treatment of Primary Angle Closure Glaucoma

To explore the effect of phacoemulsification along with intraocular lens (IOL) implantation on the treatment of primary angle closure glaucoma (PACG), a total of 50 patients (54 eyes) with PCG who had undergone surgery were selected as the research objects, in which, there were 16 eyes with the acute PACG in pre-clinical stage, 20 eyes with acute PACG during acute attack, and 18 eyes with chronic PACG, and all patients received phacoemulsification along with IOL implantation therapy. The patient’s best corrected visual acuity, anterior chamber (AC), anterior depth, intraocular pressure (IOP), visual field, and fundus conditions were measured during the operation, after the operation, and during the follow-up period. The postoperative visual acuity of the patients with three types of PACG was greatly corrected, in which 30 eyes had corrected visual acuity above 0.5, and there were statistically significant differences (SSDs) (P < 0.05); angle closure of 54 eyes had different degrees of improvement, the opening degree of the acute angle closure is better than that of the chronic angle closure, and there were SSDs (P < 0.05); each of 54 eyes showed different degrees of deepening in the central AC, and there were SSDs (P < 0.05); postoperative IOP decreased greatly in all 54 eyes, and there were SSDs (P < 0.05). In conclusion, the IOL implantation based on phacoemulsification can effectively treat the PACG, at the same time reduce IOP, promote angle opening, enhance vision field of the patients, and ultimately achieve the purpose of improving surgical success.

Visual field differences in temporal synchrony processing for audio-visual stimuli.

Audio-visual integration relies on temporal synchrony between visual and auditory inputs. However, differences in traveling and transmitting speeds between visual and auditory stimuli exist; therefore, audio-visual synchrony perception exhibits flexible functions. The processing speed of visual stimuli affects the perception of audio-visual synchrony. The present study examined the effects of visual fields, in which visual stimuli are presented, for the processing of audio-visual temporal synchrony. The point of subjective simultaneity, the temporal binding window, and the rapid recalibration effect were measured using temporal order judgment, simultaneity judgment, and stream/bounce perception, because different mechanisms of temporal processing have been suggested among these three paradigms. The results indicate that auditory stimuli should be presented earlier for visual stimuli in the central visual field than in the peripheral visual field condition in order to perceive subjective simultaneity in the temporal order judgment task conducted in this study. Meanwhile, the subjective simultaneity bandwidth was broader in the central visual field than in the peripheral visual field during the simultaneity judgment task. In the stream/bounce perception task, neither the point of subjective simultaneity nor the temporal binding window differed between the two types of visual fields. Moreover, rapid recalibration occurred in both visual fields during the simultaneity judgment tasks. However, during the temporal order judgment task and stream/bounce perception, rapid recalibration occurred only in the central visual field. These results suggest that differences in visual processing speed based on the visual field modulate the temporal processing of audio-visual stimuli. Furthermore, these three tasks, temporal order judgment, simultaneity judgment, and stream/bounce perception, each have distinct functional characteristics for audio-visual synchrony perception. Future studies are necessary to confirm the effects of compensation regarding differences in the temporal resolution of the visual field in later cortical visual pathways on visual field differences in audio-visual temporal synchrony.

Effects of simulated peripheral visual field loss on the static postural control in young healthy adults

BackgroundIntegration of visual, vestibular, and proprioceptive sensations contributes to postural control. People with peripheral visual field loss have serious postural instability. However, the directional specificity of postural stability and sensory reweighting caused by gradual peripheral visual field loss remain unclear. Research questionWhat are the effects of peripheral visual field loss on static postural control? MethodsFifteen healthy young adults participated in this study. The participants were asked to stand quietly on a foam surface. Three conditions of virtual visual field loss (90°, 45°, and 15°) were provided by a head-mounted display, and ground reaction forces were collected using a force plate to calculate the displacements of the center of pressure (COP). ResultsThe root mean square (RMS), mean velocity, and 95% ellipse area of COP displacements in the horizontal plane increased, and RMS in the anteroposterior (AP) direction was unchanged under the smallest visual field condition compared to the largest one. The power spectrum density of COP displacements in the low-frequency band was decreased and that in the medium-frequency band was increased in the AP direction. SignificanceDuring quiet standing of young healthy adults with peripheral visual field loss, increased peripheral visual field loss resulted in lower postural stability. Postural stability in the AP direction was maintained contrary to the functional sensitivity hypothesis. Peripheral visual field loss reduced the weighting of the visual input and increased that of the vestibular input in the AP direction to maintain equilibrium.

Keep your head down: Maintaining gait stability in challenging conditions.

Peripheral vision often deteriorates with age, disrupting our ability to maintain normal locomotion. Laboratory based studies have shown that lower visual field loss, in particular, is associated with changes in gaze and gait behaviour whilst walking and this, in turn, increases the risk of falling in the elderly. Separately, gaze and gait behaviours change and fall risk increases when walking over complex surfaces. It seems probable, but has not yet been established, that these challenges to stability interact. How does loss of the lower visual field affect gaze and gait behaviour whilst walking on a variety of complex surfaces outside of the laboratory? Specifically, is there a synergistic interaction between the effects on behaviour of blocking the lower visual field and increased surface complexity? We compared how full vision versus simulated lower visual field loss affected a diverse range of behavioural measures (head pitch angle, eye angle, muscle coactivation, gait speed and walking smoothness as measured by harmonic ratios) in young participants. Participants walked over a range of surfaces of different complexity, including pavements, grass, steps and pebbles. In both full vision and blocked lower visual field conditions, surface complexity influenced gaze and gait behaviour. For example, more complex surfaces were shown to be associated with lowered head pitch angles, increased leg muscle coactivation, reduced gait speed and decreased walking smoothness. Relative to full vision, blocking the lower visual field caused a lowering of head pitch, especially for more complex surfaces. However, crucially, muscle coactivation, gait speed and walking smoothness did not show a significant change between full vision and blocked lower visual field conditions. Finally, head pitch angle, muscle coactivation, gait speed and walking smoothness were all correlated highly with each other. Our study showed that blocking the lower visual field did not significantly change muscle coactivation, gait speed or walking smoothness. This suggests that young people cope well when walking with a blocked lower visual field, making minimal behavioural changes. Surface complexity had a greater effect on gaze and gait behaviour than blocking the lower visual field. Finally, head pitch angle was the only measure that showed a significant synergistic interaction between surface complexity and blocking the lower visual field. Together our results indicate that, first, a range of changes occur across the body when people walk over more complex surfaces and, second, that a relatively simple behavioural change (to gaze) suffices to maintain normal gait when the lower visual field is blocked, even in more challenging environments. Future research should assess whether young people cope as effectively when several impairments are simulated, representative of the comorbidities found with age.

Using natural viewing behavior to screen for and reconstruct visual field defects.

There is a need for simple and effective ways to screen for visual field defects (VFD). Watching a movie is a simple task most humans are familiar with. Therefore we assessed whether it is possible to detect and reconstruct visual field defects based on free viewing eye movements, recorded while watching movie clips. Participants watched 90 movie clips of one minute, with and without simulated visual field defects (sVFD), while their eye movements were tracked. We simulated homonymous hemianopia (HH) (left and right sided) and glaucoma (small nasal arc, large nasal arc, and tunnel vision). We generated fixation density maps of the visual field and trained a linear support vector machine to predict the viewing conditions of each trial of each participant based on these maps. To reconstruct the visual field defect, we computed “viewing priority” maps and maps of differences in fixation density of the visual field of each participant. We were able to classify the simulated visual field condition with more than 85% accuracy. In simulated HH, the viewing priority distribution over the visual field indicated the location of the sVFD in the simulated HH condition. In simulated glaucoma the difference in fixation density to the control condition indicated the location of the sVFD. It is feasible to use natural viewing behavior to screen for and reconstruct (simulated) visual field defects. Movie clip viewing in combination with eye tracking may thus provide an alternative to or supplement standard automated perimetry, in particular in patients who cannot perform the latter technique.

Disentangling the interaction of sex differences and hemispheric specialization for face processing – Evidence from ERPs

Recent studies on face processing and its hemispheric lateralization suggest that inconsistencies in earlier findings might be partially explained by sex differences, as findings from event-related potential studies indicated a more asymmetric functioning of the visual cortex during face encoding in men, whereas women seemed to display a more bilateral activation pattern. The aim of this study was to further investigate the role of sex differences in hemispheric specialization during face recognition. Fifty-four healthy participants (27 females and 27 males) engaged in a familiarity decision task in which famous and unfamiliar faces were presented in a lateralized tachistoscopic fashion with unilateral und bilateral presentation modes and measurement of event-related potentials and behavioral responses. Results showed a clear N170 component for males and females in all experimental conditions. No hemispheric differences of the N170 were observed in the bilateral condition and both groups showed larger right-hemispheric than left-hemispheric N170 amplitudes in the left visual field condition. In the right visual field condition, however, only female participants showed significantly larger left-hemispheric compared to right-hemispheric N170 amplitudes, whereas male participants did not show such a modulation. The effect corresponds to a greater responsivity of left-hemispheric processes underlying the N170 component in female participants. Further analyses revealed N170 differences in the left and right hemisphere for females only, when stimuli were presented unilaterally. In contrast, this modulation of N170 amplitudes was only observed in the left hemisphere in males. The results suggest a stronger hemispheric lateralization in men than in women during face processing.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma.

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma.Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions.Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02).Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Preoperative planning for a multi-arm robot-assisted minimally invasive surgery system

The preoperative preparation of robot-assisted minimally invasive surgery is more critical and complicated than traditional minimally invasive surgeries. The crucial issues in preoperative planning are presented and investigated in this paper, in which a new dexterity index IICV and an intracorporeal collaboration space index IICS are proposed for robot-assisted minimally invasive surgery. The kinematic performance of the robotic manipulator, the visual field conditions, and the cooperation space of the instrument are considered. A set of multi-objective preoperative optimization methods based on non-dominated sorting genetic algorithm 2 (NSGA-II) is designed, which is used to simultaneously optimize the incision placement and the initial pose of the manipulator. The simulation experiment results show that the preoperative planning scheme obtained by the optimization algorithm can provide a relatively superior operating environment for robot-assisted minimally invasive surgeries.

The effect of visual field condition on kinetic in upper extremities and e.m.g in lower extremities while performing reaching in normal adults.

[Purpose] The aims of this study was to investigate mean velocity and angle of shoulder joint, activation of tibialis anterior and gastrocnemius according to both eyes, dominant eye and non-dominant eye condition during reaching task in normal adults. [Subjects and Methods] Our research recruited 24 participants (male 11, female 13) in Silla University. Participants were performed reaching out movement by conditions of both eye, dominants eye, non-dominants eye. The target was placed at 45 degree diagonal direction and distance far away 130% of their arm length. Kinetic analysis of the upper extremities was investigated by QUALISYS 3-dimensional motion analysis system. Muscle activation were measured by EMG during reaching tasks. The collected data were statistically processed using the SPSS for win version 20.0. [Results] There was a significant difference of shoulder joint velocity of flexion, abduction and internal rotation according to visual field condition during reaching tasks. There was no significant difference of shoulder joint angle and muscle activation according to visual field conditions during reaching tasks. [Conclusion] In conclusion, visual field has an influence on shoulder joint velocity. Therefore, the visual field may be to play an important role in reach performance.

Medical review licensing outcomes in drivers with visual field loss in Victoria, Australia

BackgroundGood vision is essential for safe driving and studies have associated visual impairment with an increased crash risk. Currently, there is little information about the medical review of drivers with visual field loss. This study examines the prevalence of visual field loss among drivers referred for medical review in one Australian jurisdiction and investigates factors associated with licence outcome in this group.MethodsA random sample of 10,000 (31.25 per cent) medical review cases was extracted for analysis from the Victorian licensing authority. Files were screened for the presence of six visual field‐related medical conditions. Data were captured on a range of variables, including referral source, age, gender, health status, crash history and licence outcome. Prevalence analyses were univariate and descriptive. Logistic regression was used to assess factors associated with licence outcomes in the visual field loss group.ResultsApproximately 1.9 per cent of the 10,000 medical review cases screened had a visual field loss condition identified (n = 194). Among the visual field loss group, 57.2 per cent were permitted to continue driving (conditional/unconditional licence). Primary referral sources were the police, self‐referrals and general medical practitioners. Key factors associated with licence test outcomes were visual field condition, age group, crash involvement and referral to the Driver Licensing Authority's Medical Advisors. Those who were younger had a crash involvement triggering referral and those who were referred to the Medical Advisors were more likely to have a positive licensing outcome.ConclusionThe evidence base for making licensing decisions is complicated by the variable causes, patterns, progressions and measuring technologies for visual field loss. This study highlighted that the involvement of an expert medical advisory service in Victoria resulted in an increased likelihood that drivers with visual field loss will be allowed to continue driving. Further research is warranted to explore issues relating to severity of field loss and the capacity for compensation.

The magnitude of the central visual field could be detected by active middle-late processing of ERPs

This study investigated the changes in event-related potential (ERP) waveforms under different central visual field conditions using a three-stimulus oddball paradigm. Circular checkerboards were presented in the center of a computer screen with a visual angle of 5°, 10°, 20°, or 30°, which were regarded as target stimuli. The ERP waveforms were analyzed separately for different stimulus conditions. Participants responded more slowly and had lower accuracy for the 30° visual field level than the other three visual field levels. The ERP results revealed that the amplitudes of target P2 gradually increased from the 5° to 20° visual field conditions, while they decreased abruptly in the 30° visual field condition. Regional effects showed that the amplitudes of target P2 were larger from the occipital electrodes than that from the temporal sites. Besides the negative-going deflection of target N2 and visual mismatch negativity (vMMN) components having an increasing tendency with expansion of the visual field, there was also a trend that the amplitudes of target P3 were decreased and the peak latencies were prolonged with increasing visual field ranges. In addition, the latencies of the difference P3 had a similar trend to the latencies of the target P3, and all the differences were more obvious at the 30° visual field level. The study demonstrated that middle-late components of ERPs can reflect changes in the visual field to some extent.

The effects of visual field conditions on kinetic analysis in upper extremities and EMG in lower extremities during reaching task

The effects of visual field conditions on kinetic analysis in upper extremities and EMG in lower extremities during reaching task

Effect of Visual Field Constriction on Visual Search in Orderly Array and Random Array Cancellation Tasks

The cancellation task is a visual search task requiring rapid and accurate placement of a mark through each occurrence of a specific target displayed in an array of distractors on a sheet of paper. This study of 30 university students was conducted to examine the effects of visual field constriction on visual search in the cancellation task. Participants administered the orderly array cancellation task and the random array cancellation task while their visual fields were unrestricted (full vision), or restricted to 5°, 10°, or 15° by tunnel vision simulation goggles. The number of errors, time to completion, and the performance score as an index of cancelling efficiency were calculated. Results showed that the time to completion and the performance score were significantly greater in the random array cancellation task than in the structured array cancellation task, and in the narrowest visual field condition (5°) than in other visual field conditions (10°, 15°, and full vision). These results suggest that the visual search efficiency was degraded when the visual field was restricted to be less than 5° in the orderly and random array cancellation tasks used for this study.

Word and pseudoword superiority effects in a shallow orthography language: the role of hemispheric lateralization.

The word superiority effect (WSE) has made it possible to demonstrate the automatic activation of lexical-orthographic entries in reading. The observation of this effect is important since it led to experimental support of the main cognitive reading models. These models were mostly developed on English data, hence the verification in different orthography systems is relevant. The present study tested WSE in Italian, a language in which this effect was predicted to be less constant given the highly consistent correspondence between orthography and phonology. Moreover, the presentation of the items in a lateralized visual field condition allowed testing of assumptions about the roles of the right and left hemispheres in written word recognition and, in particular, on the hemispheric lateralization of lexical processing. Two experiments were conducted with undergraduate students who had to recognize a target letter within a word, pseudoword, or nonword. In Experiment 1, prime and probe letters were in the same letter case, while in Experiment 2 they were in different letter cases. Error rates and reaction times were analyzed with mixed models. The results showed a superiority of pseudowords (pseudoword superiority effect; PSE) over illegal strings with no evidence of a clear superiority of words over pseudowords for both left and right visual field presentations. This suggests that in Italian, the sub-lexical route could play a major role in reading and that this route relies on a visual-perceptual orthographic coding concerning familiarity of letter combinations, which is also available to the right hemisphere.