Risk Factors for Visual Impairment in an Uninsured Population and the Impact of the Affordable Care Act.

PubMed

Guo, Weixia; Woodward, Maria A; Heisler, Michele; Blachley, Taylor; Corneail, Leah; Cederna, Jean; Kaplan, Ariane D; Newman Casey, Paula Anne

2016-01-01

To assess risk factors for visual impairment in a high-risk population of people: those without medical insurance. Secondarily, we assessed risk factors for remaining uninsured after implementation of the Affordable Care Act (ACA) and evaluated whether the ACA changed demand for local safety net ophthalmology clinic services one year after its implementation. In a retrospective cohort study of patients who attended a community-academic partnership free ophthalmology clinic in Southeastern, Michigan between September 2012 - March 2015, we assessed the prevalence of presenting with visual impairment, the most common causes of presenting with visual impairment and used logistic regression to assess socio-demographic risk factors for visual impairment. We assessed the initial impact of the ACA on clinic utilization. We also analyzed risk factors for remaining uninsured one year after implementation of the ACA private insurance marketplace and Medicaid expansion in the state of Michigan. Among 335 patients, one-fifth (22%) presented with visual impairment; refractive error was the leading cause for presenting with visual impairment. Unemployment was the single significant risk factor for presenting with visual impairment after adjusting for multiple confounding factors (OR = 3.05, 95% CI 1.19-7.87, p=0.01). There was no difference in proportion of visual impairment or type of vision-threatening disease between the insured and uninsured (p=0.26). Seventy six percent of patients remained uninsured one year after ACA implementation. Patients who were white, spoke English as a first language and were US Citizens were more likely to gain insurance coverage through the ACA in our population (p≤ 0.01). There was a non-significant decline in the mean number of patient treated per clinic (52 to 43) before and after ACA implementation (p=0.69). Refractive error was a leading cause for presenting with visual impairment in this vulnerable population, and being unemployed significantly increased the risk for presenting with visual impairment. The ACA did not significantly reduce the need for our free ophthalmology services. It is critically important to continue to support safety net specialty care initiatives and policy change to provide care for those in need.

Risk Factors for Visual Impairment in an Uninsured Population and the Impact of the Affordable Care Act

PubMed Central

Guo, Weixia; Woodward, Maria A; Heisler, Michele; Blachley, Taylor; Corneail, Leah; Cederna, Jean; Kaplan, Ariane D; Newman Casey, Paula Anne

2017-01-01

Purpose To assess risk factors for visual impairment in a high-risk population of people: those without medical insurance. Secondarily, we assessed risk factors for remaining uninsured after implementation of the Affordable Care Act (ACA) and evaluated whether the ACA changed demand for local safety net ophthalmology clinic services one year after its implementation. Methods In a retrospective cohort study of patients who attended a community-academic partnership free ophthalmology clinic in Southeastern, Michigan between September 2012 – March 2015, we assessed the prevalence of presenting with visual impairment, the most common causes of presenting with visual impairment and used logistic regression to assess socio-demographic risk factors for visual impairment. We assessed the initial impact of the ACA on clinic utilization. We also analyzed risk factors for remaining uninsured one year after implementation of the ACA private insurance marketplace and Medicaid expansion in the state of Michigan. Results Among 335 patients, one-fifth (22%) presented with visual impairment; refractive error was the leading cause for presenting with visual impairment. Unemployment was the single significant risk factor for presenting with visual impairment after adjusting for multiple confounding factors (OR = 3.05, 95% CI 1.19–7.87, p=0.01). There was no difference in proportion of visual impairment or type of vision-threatening disease between the insured and uninsured (p=0.26). Seventy six percent of patients remained uninsured one year after ACA implementation. Patients who were white, spoke English as a first language and were US Citizens were more likely to gain insurance coverage through the ACA in our population (p≤ 0.01). There was a non-significant decline in the mean number of patient treated per clinic (52 to 43) before and after ACA implementation (p=0.69). Conclusion Refractive error was a leading cause for presenting with visual impairment in this vulnerable population, and being unemployed significantly increased the risk for presenting with visual impairment. The ACA did not significantly reduce the need for our free ophthalmology services. It is critically important to continue to support safety net specialty care initiatives and policy change to provide care for those in need. PMID:28593201

[Cataract surgery and its impact on balance and autonomy in elderly].

PubMed

Raynal, M; Aupy, B; Jahidi, A; Ettien, D; Le Page, P; Briche, T; Kossowski, M; Pailllaud, E

2009-01-01

Cataract is a major cause of visual impairment among elderly. Cataract surgery improves visual afferencies and can have an impact on balance. The present study assessed the impact of cataract surgery upon balance and autonomy in elderly. We realized clinical examinations and objective tests the day before surgery and 2-months later. The initial cohort consisted of 66 patients that had to undergo a cataract surgery. Their mean age was 79 +/- 0.5. For logistic reasons, only 33 patients have been completely evaluated before and after surgery. Each patient underwent a history and examination that have assessed autonomy, walking, visual and then cochleo-vestibular functions including bone vibratory test and dynamic computerized posturography (Equitest). After 2 months, cataract surgery had no incidence on balance. The fear of falling has stayed the same whereas the number of falls has been noticeably reduced by surgery. The overall score of Equitest has shown an increase in visual dependence after surgery. Although cataract surgery has no incidence on autonomy, it may improve the quality of life among older people by leisure activities recovery. An early physical rehabilitation facilitated by visual improvement after surgery can also prevent visual dependence and autonomy loss. We recommend vestibular rehabilitation in elderly with major visual dependence.

Altered white matter in early visual pathways of humans with amblyopia.

PubMed

Allen, Brian; Spiegel, Daniel P; Thompson, Benjamin; Pestilli, Franco; Rokers, Bas

2015-09-01

Amblyopia is a visual disorder caused by poorly coordinated binocular input during development. Little is known about the impact of amblyopia on the white matter within the visual system. We studied the properties of six major visual white-matter pathways in a group of adults with amblyopia (n=10) and matched controls (n=10) using diffusion weighted imaging (DWI) and fiber tractography. While we did not find significant differences in diffusion properties in cortico-cortical pathways, patients with amblyopia exhibited increased mean diffusivity in thalamo-cortical visual pathways. These findings suggest that amblyopia may systematically alter the white matter properties of early visual pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

Visual Spatial Cognition in Neurodegenerative Disease

PubMed Central

Possin, Katherine L.

2011-01-01

Visual spatial impairment is often an early symptom of neurodegenerative disease; however, this multi-faceted domain of cognition is not well-assessed by most typical dementia evaluations. Neurodegenerative diseases cause circumscribed atrophy in distinct neural networks, and accordingly, they impact visual spatial cognition in different and characteristic ways. Anatomically-focused visual spatial assessment can assist the clinician in making an early and accurate diagnosis. This article will review the literature on visual spatial cognition in neurodegenerative disease clinical syndromes, and where research is available, by neuropathologic diagnoses. Visual spatial cognition will be organized primarily according to the following schemes: bottom-up / top-down processing, dorsal / ventral stream processing, and egocentric / allocentric frames of reference. PMID:20526954

Visualization of the chains of risks under global climate change

NASA Astrophysics Data System (ADS)

Yokohata, T.; Nishina, K.; Takahashi, K.; Kiguchi, M.; Iseri, Y.; Sueyoshi, T.; Yoshimori, M.; Iwase, K.; Yamamoto, A.; Shigemitsu, M.; Honda, Y.; Hanasaki, N.; Masaki, Y.; Ito, A.; Iizumi, T.; Sakurai, G.; Okada, M.; Emori, S.; Oki, T.

2014-12-01

Anthropogenic climate change possibly causes various impacts on human society and ecosystem. Here, we call possible damages or benefits caused by the future climate change as "climate risks". Many climate risks are closely interconnected with each other by direct cause-effect relationship. In this study, the major climate risks are comprehensively summarized based on the survey of studies in the literature using IPCC AR5 etc, and their cause-effect relationship are visualized by a "network diagram". This research is conducted by the collaboration between the experts of various fields, such as water, energy, agriculture, health, society, and eco-system under the project called ICA-RUS (Integrated Climate Assessment - Risks, Uncertainties and Society). First, the climate risks are classified into 9 categories (water, energy, food, health, disaster, industry, society, ecosystem, and tipping elements). Second, researchers of these fields in our project survey the research articles, and pick up items of climate risks, and possible cause-effect relationship between the risk items. A long list of the climate risks is summarized into ~130, and that of possible cause-effect relationship between the risk items is summarized into ~300, because the network diagram would be illegible if the number of the risk items and cause-effect relationship is too large. Here, we only consider the risks that could occur if climate mitigation policies are not conducted. Finally, the chain of climate risks is visualized by creating a "network diagram" based on a network graph theory (Fruchtman & Reingold algorithm). Through the analysis of network diagram, we find that climate risks at various sectors are closely related. For example, the decrease in the precipitation under the global climate change possibly causes the decrease in river runoff and the decrease in soil moisture, which causes the changes in crop production. The changes in crop production can have an impact on society by changing the food price or food supply. Changes in river runoff can also make an impact on the hydropower efficiency. Comprehensive pictures of climate risks and their interconnections are clearly shown in a straightforward manner by the network diagram. We will have a discussion how our results can be helpful for our society to recognize the climate risk.

The Association of Visual Impairment With Clinical Outcomes in Hemodialysis Patients

PubMed Central

Hong, Yu Ah; Kim, Suk Young; Kim, Su-Hyun; Kim, Young Ok; Jin, Dong Chan; Song, Ho Chul; Choi, Euy Jin; Kim, Yong-Lim; Kim, Yon-Su; Kang, Shin-Wook; Kim, Nam-Ho; Yang, Chul Woo; Kim, Yong Kyun

2016-01-01

Abstract Visual impairment limits people's ability to perform daily tasks and affects their quality of life. We evaluated the impact of visual impairment on clinical outcomes in hemodialysis (HD) patients. HD patients were selected from the Clinical Research Center registry a prospective cohort study on dialysis patients in Korea. Visual impairment was defined as difficulty in daily life due to decreased visual acuity or blindness. The primary outcome was all-cause mortality and the secondary outcomes were cardiovascular and infection-related hospitalization. A total of 3250 patients were included. Seven hundred thirty (22.5%) of the enrolled patients had visual impairment. The median follow-up period was 30 months. The Kaplan–Meier curve and log-rank test showed that all-cause mortality rates (P < 0.001) as well as cardiovascular and infection-related hospitalization rates (P < 0.001 and P < 0.001) were significantly higher in patients with visual impairment than in patients without visual impairment. In the multivariable analysis, visual impairment had significant predictive power for all-cause mortality (Hazard ratio [HR], 1.77, 95% confidence interval [CI], 1.21–2.61, P = 0.004) and cardiovascular hospitalization (HR 1.45 [1.00–1.90], P = 0.008) after adjusting for confounding variables. Of these 3250 patients, 634 patients from each group were matched by propensity scores. In the propensity score matched analysis, patients with visual impairment had independently significant associations with increased all-cause mortality (HR 1.69 [1.12–2.54], P = 0.01) and cardiovascular hospitalization (HR 1.48 [1.08–2.02], P = 0.01) compared with patients without visual impairment after adjustment for confounding variables. Our data demonstrated that visual impairment was an independent risk factor for clinical adverse outcomes in HD patients. PMID:27175661

Amblyopia: neural basis and therapeutic approaches.

PubMed

Bretas, Caio César Peixoto; Soriano, Renato Nery

2016-01-01

Abnormalities in visual processing caused by visual deprivation or abnormal binocular interaction may induce amblyopia, which is characterized by reduced visual acuity. Occlusion therapy, the conventional treatment, requires special attention as occlusion of the fellow normal eye may reduce its visual acuity and impair binocular vision. Besides recovering visual acuity, some researchers have recommended restoration of stereoacuity and motor fusion and reverse suppression in order to prevent diplopia. Recent studies have documented that the amblyopic visual cortex has a normal complement of cells but reduced spatial resolution and a disordered topographical map. Changes occurring in the late sensitive period selectively impact the parvocellular pathway. Distinct morphophysiologic and psychophysical deficits may demand individualization of therapy, which might provide greater and longer-lasting residual plasticity in some children.

Impact of Pulsation Activity on the Light Curves of Symbiotic Variables

NASA Astrophysics Data System (ADS)

Marsakova, Vladyslava I.; Andronov, Ivan L.; Chinarova, Lidia L.; Chyzhyk, Maksym S.; Andrych, Kateryna D.

2015-12-01

We used long-term visual amateur observations of several symbiotic variables for detection of periods that may be caused by pulsation. The examples of multiple periodicities are discussed individually in each case.

Motivation and short-term memory in visual search: Attention's accelerator revisited.

PubMed

Schneider, Daniel; Bonmassar, Claudia; Hickey, Clayton

2018-05-01

A cue indicating the possibility of cash reward will cause participants to perform memory-based visual search more efficiently. A recent study has suggested that this performance benefit might reflect the use of multiple memory systems: when needed, participants may maintain the to-be-remembered object in both long-term and short-term visual memory, with this redundancy benefitting target identification during search (Reinhart, McClenahan & Woodman, 2016). Here we test this compelling hypothesis. We had participants complete a memory-based visual search task involving a reward cue that either preceded presentation of the to-be-remembered target (pre-cue) or followed it (retro-cue). Following earlier work, we tracked memory representation using two components of the event-related potential (ERP): the contralateral delay activity (CDA), reflecting short-term visual memory, and the anterior P170, reflecting long-term storage. We additionally tracked attentional preparation and deployment in the contingent negative variation (CNV) and N2pc, respectively. Results show that only the reward pre-cue impacted our ERP indices of memory. However, both types of cue elicited a robust CNV, reflecting an influence on task preparation, both had equivalent impact on deployment of attention to the target, as indexed in the N2pc, and both had equivalent impact on visual search behavior. Reward prospect thus has an influence on memory-guided visual search, but this does not appear to be necessarily mediated by a change in the visual memory representations indexed by CDA. Our results demonstrate that the impact of motivation on search is not a simple product of improved memory for target templates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact behavior of graphite-epoxy simulated fan blades

NASA Technical Reports Server (NTRS)

Cook, T. S.; Preston, J. L., Jr.

1977-01-01

The response of a graphite-epoxy material, Modmor II/PR-286, to foreign object impact was investigated by impacting spherical projectiles of three different materials - gelatin, ice, and steel - on simulated blade specimens. Visual and metallographic inspection revealed three damage mechanisms: penetration, leading edge bending failure, and stress wave delamination and cracking. The steel projectiles caused penetration damage regardless of the impact location and angle. For the ice and gelatin particles impacting the leading edge, failure was due to large local bending strains, resulting in significant material removal and delamination damage.

Scoliosis brace design: influence of visual aesthetics on user acceptance and compliance.

PubMed

Law, Derry; Cheung, Mei-Chun; Yip, Joanne; Yick, Kit-Lun; Wong, Christina

2017-06-01

Adolescent idiopathic scoliosis is a common condition found in adolescents. A rigid brace is often prescribed as the treatment for this spinal deformity, which negatively affects user compliance due to the discomfort caused by the brace, and the psychological distress resulting from its appearance. However, the latter, which is the impact of visual aesthetics, has not been thoroughly studied for scoliosis braces. Therefore, a qualitative study with in-depth interviews has been carried out with 10 participants who have a Cobb angle of 20°-30° to determine the impact of visual aesthetics on user acceptance and compliance towards the brace. It is found that co-designing with patients on the aesthetic aspects of the surface design of the brace increases the level of user compliance and induces positive user perception. Therefore, aesthetic preferences need to be taken into consideration in the design process of braces. Practitioner Summary: The impact of visual aesthetics on user acceptance and compliance towards a rigid brace for scoliosis is investigated. The findings indicate that an aesthetically pleasing brace and the involvement of patients in the design process of the brace are important for increasing user compliance and addressing psychological issues during treatment.

The quality of life impact of peripheral versus central vision loss with a focus on glaucoma versus age-related macular degeneration

PubMed Central

Evans, Keith; Law, Simon K; Walt, John; Buchholz, Patricia; Hansen, Jan

2009-01-01

Purpose It is well accepted that conditions that cause central vision loss (CVL) have a negative impact on functional ability and quality of life (QoL), but the impact of diseases that cause peripheral vision loss (PVL) is less well understood. Focusing on glaucoma and age-related macular degeneration (ARMD), the effects of CVL and PVL on QoL were compared. Methods A systematic literature review of publications reporting QoL in patients with CVL or PVL identified 87 publications using four generic (Short-Form Health Survey-36 and -12, EuroQoL EQ-5D and Sickness Impact Profile) and five vision-specific (National Eye Institute Visual Function Questionnaire-51, -39, and -25, Impact of Vision Impairment and Visual Function-14) QoL instruments; 33 and 15 publications reported QoL in ARMD and glaucoma, respectively. Results QoL was impaired to a similar extent by diseases associated with PVL and CVL, but different domains were affected. In contrast to ARMD, mental aspects appeared to be affected more than physical aspects in patients with glaucoma. Conclusions The differential impact upon QoL might be a function of the pathology of the diseases, for example potential for blindness and better ability to perform physical tasks due to retention of central vision may explain these observations in glaucoma. PMID:19684867

Evaluating visual function in cataract.

PubMed

Elliott, D B

1993-11-01

This paper reviews recent research on the evaluation of visual function in cataract. Visual impairment in cataract is principally caused by increased intraocular forward light scatter. It is assumed that visual acuity (VA) measurements assess the impact of narrow angle light scatter. This also makes the measurement of high spatial frequency contrast sensitivity (CS) unnecessary. However, VA measurements alone are an inadequate assessment of visual impairment in some patients with cataract. In addition, it is suggested that a measurement of wide-angle light scatter is required. This can be evaluated directly using the van den Berg Straylightmeter, or indirectly using low spatial frequency CS or disability glare (DG) tests. The following are discussed: (1) the relative usefulness of these tests; (2) how they can be incorporated into the decision as to when to extract a cataract; and (3) the importance of considering binocular visual function.

Other drug use does not impact cognitive impairments in chronic ketamine users.

PubMed

Zhang, Chenxi; Tang, Wai Kwong; Liang, Hua Jun; Ungvari, Gabor Sandor; Lin, Shih-Ku

2018-05-01

Ketamine abuse causes cognitive impairments, which negatively impact on users' abstinence, prognosis, and quality of life. of cognitive impairments in chronic ketamine users have been inconsistent across studies, possibly due to the small sample sizes and the confounding effects of concomitant use of other illicit drugs. This study investigated the cognitive impairment and its related factors in chronic ketamine users with a large sample size and explored the impact of another drug use on cognitive functions. Cognitive functions, including working, verbal and visual memory and executive functions were assessed in ketamine users: 286 non-heavy other drug users and 279 heavy other drug users, and 261 healthy controls. Correlations between cognitive impairment and patterns of ketamine use were analysed. Verbal and visual memory were impaired, but working memory and executive functions were intact for all ketamine users. No significant cognitive differences were found between the two ketamine groups. Greater number of days of ketamine use in the past month was associated with worse visual memory performance in non-heavy other drug users. Higher dose of ketamine use was associated with worse short-term verbal memory in heavy other drug users. Verbal and visual memory are impaired in chronic ketamine users. Other drug use appears to have no impact on ketamine users' cognitive performance. Copyright © 2018. Published by Elsevier B.V.

Psychological impact of anti-VEGF treatments for wet macular degeneration-a review.

PubMed

Senra, Hugo; Ali, Zaria; Balaskas, Konstantinos; Aslam, Tariq

2016-10-01

To review the current literature on the psychological impact of anti-VEGF treatments for wet age-related macular degeneration (wAMD), in terms of patients' experiences of receiving these treatments, and the impact of these treatments for patients' mental health and quality of life. We critically analyzed current literature evaluating psychological impact of anti-VEGF treatments for wAMD. Primary searches of PubMed, Science Direct, and Web of Science were conducted in July and August of 2015. We reviewed all papers on the topic published until August 5, 2015. Our literature search found 14 papers addressing the psychological impact of anti-VEGF treatments for wAMD. Results highlighted potential anxieties and experiences of pain caused by receiving regular intravitreal injections. A positive visual outcome of anti-VEGF therapy is associated with positive vision-related QOL outcomes, although such association seems to be dependent on improvements on visual acuity. In the literature reviewed, patients receiving anti-VEGF treatments showed a prevalence rate of depression between 20 and 26 %. Although anti-VEGF treatments can cause some anxiety and being experienced as a stressful event, especially in the beginning of the treatment, preliminary findings suggest a potential benefit for long-term vision-related quality of life. Further longitudinal and qualitative research should bring more evidence on the positive and negative effects of these treatments on patients' long-term mental health.

[Impairment of safety in navigation caused by alcohol: impact on visual function].

PubMed

Grütters, G; Reichelt, J A; Ritz-Timme, S; Thome, M; Kaatsch, H J

2003-05-01

So far in Germany, no legally binding standards for blood alcohol concentration exist that prove an impairment of navigability. The aim of our interdisciplinary project was to obtain data in order to identify critical blood alcohol limits. In this context the visual system seems to be of decisive importance. 21 professional skippers underwent realistic navigational demands soberly and alcoholized in a sea traffic simulator. The following parameters were considered: visual acuity, stereopsis, color vision, and accommodation. Under the influence of alcohol (average blood alcohol concentration: 1.08 per thousand ) each skipper considered himself to be completely capable of navigating. While simulations were running, all of the skippers made nautical mistakes or underestimated dangerous situations. Severe impairment in visual acuity or binocular function were not observed. Accommodation decreased by an average of 18% ( p=0.0001). In the test of color vision skippers made more mistakes ( p=0.017) and the time needed for this test was prolonged ( p=0.004). Changes in visual function as well as vegetative and psychological reactions could be the cause of mistakes and alcohol should therefore be regarded as a severe risk factor for security in sea navigation.

Vitreoretinal interface abnormalities in middle-aged adults with visual impairment in the UK Biobank study: prevalence, impact on visual acuity and associations.

PubMed

McKibbin, Martin; Farragher, Tracey; Shickle, Darren

2017-01-01

The aim of this study was to determine the prevalence of vitreoretinal interface abnormalities (VRIA), the degree of visual impairment and associations with VRIA among adults, aged 40-69 years, in the UK Biobank study. Colour fundus photographs and spectral domain optical coherence tomography images were graded for 25% of the 8359 UK Biobank participants with mild visual impairment or worse (LogMAR >0.3 or Snellen <6/12) in at least one eye. The prevalence and contribution of VRIA to visual impairment was determined and multinomial logistic regression models were used to investigate association with known risk factors and other predetermined socioeconomic, biometric, lifestyle and medical variables for cases and matched controls. The minimum prevalence of any VRIA was 17.6% and 8.1% in the eyes with and without visual impairment, respectively. VRIA were identified as the primary cause of visual impairment in 3.6% of eyes. Although epiretinal membrane and vitreomacular traction were the most common VRIA, the degree of visual impairment was typically milder with these than with other VRIA. Visual impairment with a VRIA was positively associated with increasing age (relative risk ratio (RRR) 1.22 (95% CI 1.07 to 1.40)), female gender (RRR 1.28; 1.08 to 1.52) and Asian or Asian British ethnicity (RRR 1.60; 1.10 to 2.32). VRIA are common in middle-aged adults in the UK Biobank study, especially in eyes with visual impairment. VRIA were considered to be the primary cause of visual impairment in 3.6% of all eyes with visual impairment, although there was variation in the degree of visual impairment for each type of VRIA.

Vitreoretinal interface abnormalities in middle-aged adults with visual impairment in the UK Biobank study: prevalence, impact on visual acuity and associations

PubMed Central

Farragher, Tracey; Shickle, Darren

2017-01-01

Objective The aim of this study was to determine the prevalence of vitreoretinal interface abnormalities (VRIA), the degree of visual impairment and associations with VRIA among adults, aged 40–69 years, in the UK Biobank study. Methods and analysis Colour fundus photographs and spectral domain optical coherence tomography images were graded for 25% of the 8359 UK Biobank participants with mild visual impairment or worse (LogMAR >0.3 or Snellen <6/12) in at least one eye. The prevalence and contribution of VRIA to visual impairment was determined and multinomial logistic regression models were used to investigate association with known risk factors and other predetermined socioeconomic, biometric, lifestyle and medical variables for cases and matched controls. Results The minimum prevalence of any VRIA was 17.6% and 8.1% in the eyes with and without visual impairment, respectively. VRIA were identified as the primary cause of visual impairment in 3.6% of eyes. Although epiretinal membrane and vitreomacular traction were the most common VRIA, the degree of visual impairment was typically milder with these than with other VRIA. Visual impairment with a VRIA was positively associated with increasing age (relative risk ratio (RRR) 1.22 (95% CI 1.07 to 1.40)), female gender (RRR 1.28; 1.08 to 1.52) and Asian or Asian British ethnicity (RRR 1.60; 1.10 to 2.32). Conclusions VRIA are common in middle-aged adults in the UK Biobank study, especially in eyes with visual impairment. VRIA were considered to be the primary cause of visual impairment in 3.6% of all eyes with visual impairment, although there was variation in the degree of visual impairment for each type of VRIA. PMID:29354705

Relation Between Near Work and Myopia Progression in Student Population

PubMed Central

Muhamedagic, Lejla; Muhamedagic, Belma; Halilovic, Emina Alimanovic; Halimic, Jasmina Alajbegovic; Stankovic, Aleksa; Muracevic, Bedrana

2014-01-01

Aim To determine relation between near work and myopia progression in student population. Causes of myopia occurrence are not sufficiently explained. Methods This retrospective-prospective, descriptive research included 100 students with verified myopia up to -3 Dsph. Ophthalmological examination and measurement diopter-hours variable (Dh) were done twice, in the period from January 2011 until January 2012. Results A multivariate regression analysis of impact on the difference of distance visual acuity without correction to the right and left eye and difference of automatic computer refractometry in cycloplegia of both eyes indicates that, diopter-hours variable (Dh) had statistically significant impact on increase of distance visual acuity difference (right eye OR: I measurement–Dh 1.489, II measurement–Dh 1.544, p<0.05; left eye OR: I measurement–Dh 1.602, II measurement–Dh 1.538, p<0.05) and automatic computer refractometry in cycloplegia (right eye OR: I measurement 1.361, II measurement 1.493, p<0.05; left eye OR: I measurement 0.931, II measurement 1.019, p<0.05) during both measurements. Conclusion Near work cause the increase of myopia. This research opened a perspective for other researches on the impact of near work on myopia. PMID:24944532

Influence of lateral discomfort on the stability of traffic flow based on visual angle car-following model

NASA Astrophysics Data System (ADS)

Zheng, Liang; Zhong, Shiquan; Jin, Peter J.; Ma, Shoufeng

2012-12-01

Due to the poor road markings and irregular driving behaviors, not every vehicle is positioned in the center of the lane. The deviation from the center can cause discomfort to drivers in the neighboring lane, which is referred to as lateral discomfort (or lateral friction). Such lateral discomfort can be incorporated into the driver stimulus-response framework by considering the visual angle and its changing rate from the psychological viewpoint. In this study, a two-lane visual angle based car-following model is proposed and its stability condition is obtained through linear stability theory. Further derivations indicate that the neutral stability line of the model is asymmetry and four factors including the vehicle width and length, the lateral separation and the sensitivity regarding the changing rate of visual angle have large impacts on the stability of traffic flow. Numerical simulations further verify these theoretical results, and demonstrate that the behaviors of diverging, merging and lane changing can break the original steady state and cause traffic fluctuations. However, these fluctuations may be alleviated to some extent by reducing the lateral discomfort.

Chemical Stockpile Disposal Program Final Programmatic Environmental Impact Statement Volume 3: Appendices A-S

DTIC Science & Technology

1988-01-01

nerve and blister agents evaluated in this appendix have been especially formulated to cause -major injuries or death to enemy forces in wartime...days. Hallucinations, particularly of visual type. Patients may exhibit selfdestructive acts l Seizures may occur, but true convulsions arc rare l Rare...lesions produced in experimental animals by GB and interprets the damage as caused by convulsions or seizure activity that kill neurons (nerve cells

Plasma measurement by optical visualization and triple probe method under high-speed impact

NASA Astrophysics Data System (ADS)

Sakai, T.; Umeda, K.; Kinoshita, S.; Watanabe, K.

2017-02-01

High-speed impact on spacecraft by space debris poses a threat. When a high-speed projectile collides with target, it is conceivable that the heat created by impact causes severe damage at impact point. Investigation of the temperature is necessary for elucidation of high-speed impact phenomena. However, it is very difficult to measure the temperature with standard methods for two main reasons. One reason is that a thermometer placed on the target is instantaneously destroyed upon impact. The other reason is that there is not enough time resolution to measure the transient temperature changes. In this study, the measurement of plasma induced by high-speed impact was investigated to estimate temperature changes near the impact point. High-speed impact experiments were performed with a vertical gas gun. The projectile speed was approximately 700 m/s, and the target material was A5052. The experimental data to calculate the plasma parameters of electron temperature and electron density were measured by triple probe method. In addition, the diffusion behavior of plasma was observed by optical visualization technique using high-speed camera. The frame rate and the exposure time were 260 kfps and 1.0 μs, respectively. These images are considered to be one proof to show the validity of plasma measurement. The experimental results showed that plasma signals were detected for around 70 μs, and the rising phase of the wave form was in good agreement with timing of optical visualization image when the plasma arrived at the tip of triple probe.

Visual Health and Visual Healthcare Access in Refugees and Displaced Persons: A Systematic Review.

PubMed

Bal, Sila; Duckles, Anne; Buttenheim, Alison

2018-06-02

Vision impairment is a significant global health concern. Still, there remains a gap in our knowledge of visual health in refugees. We conducted a systematic review of the distinctive eye care needs of refugees. We screened PubMed, EMBASE, and Web of Science through February 17, 2017 for studies that focused primarily on visual health in refugees. Risk of bias was assessed using the National Heart, Lung, and Blood Institute quality assessment tools. 26 studies were included in the final review. The prevalence of blindness ranged from 1.3 to 26.2%. Trachoma was the leading infectious cause. Only four studies assessed vision-related care. Time/location of displacement, social unrest, and sanitation impacted severity of eye disease. Refugees have unique eye care needs. Public health interventions should target eye care at every stage of displacement. Providers may use these results to inform future research and improve visual healthcare access in refugee groups.

Epidemiology, aetiology and management of visual impairment in children.

PubMed

Solebo, Ameenat Lola; Rahi, Jugnoo

2014-04-01

An estimated 19 million of the world's children are visually impaired, while 1.4 million are blind. Using the UK as a model for high income countries, from a population-based incidence study, the annual cumulative incidence of severe visual impairment/blindness (SVL/BL) is estimated to be 6/10 000 by age 15 years, with the incidence being highest in the first year of life. The population of visually impaired children within high, middle and lower income countries differ considerably between and within countries. The numerous and mainly uncommon disorders which can cause impaired vision result in heterogeneous population which includes a substantial proportion (for SVI/BL, the majority) of children with additional systemic disorders or impairments whose needs differ substantially from those with isolated vision impairment. Paediatricians and other paediatric professionals have a key role in early detection and multidisciplinary management to minimise the impact of visual impairment (VI) in childhood.

Expanded DEMATEL for Determining Cause and Effect Group in Bidirectional Relations

PubMed Central

Falatoonitoosi, Elham; Ahmed, Shamsuddin; Sorooshian, Shahryar

2014-01-01

Decision-Making Trial and Evaluation Laboratory (DEMATEL) methodology has been proposed to solve complex and intertwined problem groups in many situations such as developing the capabilities, complex group decision making, security problems, marketing approaches, global managers, and control systems. DEMATEL is able to realize casual relationships by dividing important issues into cause and effect group as well as making it possible to visualize the casual relationships of subcriteria and systems in the course of casual diagram that it may demonstrate communication network or a little control relationships between individuals. Despite of its ability to visualize cause and effect inside a network, the original DEMATEL has not been able to find the cause and effect group between different networks. Therefore, the aim of this study is proposing the expanded DEMATEL to cover this deficiency by new formulations to determine cause and effect factors between separate networks that have bidirectional direct impact on each other. At the end, the feasibility of new extra formulations is validated by case study in three numerical examples of green supply chain networks for an automotive company. PMID:24693224

Expanded DEMATEL for determining cause and effect group in bidirectional relations.

PubMed

Falatoonitoosi, Elham; Ahmed, Shamsuddin; Sorooshian, Shahryar

2014-01-01

Decision-Making Trial and Evaluation Laboratory (DEMATEL) methodology has been proposed to solve complex and intertwined problem groups in many situations such as developing the capabilities, complex group decision making, security problems, marketing approaches, global managers, and control systems. DEMATEL is able to realize casual relationships by dividing important issues into cause and effect group as well as making it possible to visualize the casual relationships of subcriteria and systems in the course of casual diagram that it may demonstrate communication network or a little control relationships between individuals. Despite of its ability to visualize cause and effect inside a network, the original DEMATEL has not been able to find the cause and effect group between different networks. Therefore, the aim of this study is proposing the expanded DEMATEL to cover this deficiency by new formulations to determine cause and effect factors between separate networks that have bidirectional direct impact on each other. At the end, the feasibility of new extra formulations is validated by case study in three numerical examples of green supply chain networks for an automotive company.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Like; Kang, Jian, E-mail: j.kang@sheffield.ac.uk; Schroth, Olaf

Large scale transportation projects can adversely affect the visual perception of environmental quality and require adequate visual impact assessment. In this study, we investigated the effects of the characteristics of the road project and the character of the existing landscape on the perceived visual impact of motorways, and developed a GIS-based prediction model based on the findings. An online survey using computer-visualised scenes of different motorway and landscape scenarios was carried out to obtain perception-based judgements on the visual impact. Motorway scenarios simulated included the baseline scenario without road, original motorway, motorways with timber noise barriers, transparent noise barriers andmore » tree screen; different landscape scenarios were created by changing land cover of buildings and trees in three distance zones. The landscape content of each scene was measured in GIS. The result shows that presence of a motorway especially with the timber barrier significantly decreases the visual quality of the view. The resulted visual impact tends to be lower where it is less visually pleasant with more buildings in the view, and can be slightly reduced by the visual absorption effect of the scattered trees between the motorway and the viewpoint. Based on the survey result, eleven predictors were identified for the visual impact prediction model which was applied in GIS to generate maps of visual impact of motorways in different scenarios. The proposed prediction model can be used to achieve efficient and reliable assessment of visual impact of motorways. - Highlights: • Motorways induce significant visual impact especially with timber noise barriers. • Visual impact is negatively correlated with amount of buildings in the view. • Visual impact is positively correlated with percentage of trees in the view. • Perception-based motorway visual impact prediction model using mapped predictors • Predicted visual impacts in different scenarios are mapped in GIS.« less

Optical devices in highly myopic eyes with low vision: a prospective study.

PubMed

Scassa, C; Cupo, G; Bruno, M; Iervolino, R; Capozzi, S; Tempesta, C; Giusti, C

2012-01-01

To compare, in relation to the cause of visual impairment, the possibility of rehabilitation, the corrective systems already in use and the finally prescribed optical devices in highly myopic patients with low vision. Some considerations about the rehabilitation of these subjects, especially in relation to their different pathologies, have also been made. 25 highly myopic subjects were enrolled. We evaluated both visual acuity and retinal sensitivity by Scanning Laser Ophthalmoscope (SLO) microperimetry. 20 patients (80%) were rehabilitated by means of monocular optical devices while five patients (20%) were rehabilitated binocularly. We found a good correlation between visual acuity and retinal sensitivity only when the macular pathology did not induce large areas of chorioretinal atrophy that cause lack of stabilization of the preferential retinal locus. In fact, the best results in reading and performing daily visual tasks were obtained by maximizing the residual vision in patients with retinal sensitivity greater than 10 dB. A well circumscribed area of absolute scotoma with a defined new retinal fixation locus could be considered as a positive predictive factor for the final rehabilitation process. A more careful evaluation of visual acuity, retinal sensitivity and preferential fixation locus is necessary in order to prescribe the best optical devices to patients with low vision, thus reducing the impact of the disability on their daily life.

Connecting Research on Retinitis Pigmentosa to the Practice of Orientation and Mobility.

ERIC Educational Resources Information Center

Geruschat, Duane R.; Turano, Kathleen A.

2002-01-01

Retinitis pigmentosa (RP) causes restriction of the visual field, progressive vision loss, and night blindness. This article presents an overview of the most common problems in orientation and mobility (O&M) for individuals with RP, appropriate interventions, vision science discoveries related to RP, and the impact of RP on functional visual…

Pest risk maps for invasive alien species: a roadmap for improvement

Treesearch

Robert C. Venette; Darren J. Kriticos; Roger D. Magarey; Frank H. Koch; Richard H.A. Baker; Susan P. Worner; Nadilia N. Gomez Raboteaux; Daniel W. McKenney; Erhard J. Dobesberger; Denys Yemshanov; Paul J. De Barro; William D. Hutchison; Glenn Fowler; Tom M. Kalaris; John Pedlar

2010-01-01

Pest risk maps are powerful visual communication tools to describe where invasive alien species might arrive, establish, spread, or cause harmful impacts. These maps inform strategic and tactical pest management decisions, such as potential restrictions on international trade or the design of pest surveys and domestic quarantines. Diverse methods are available to...

The impact of inverted text on visual word processing: An fMRI study.

PubMed

Sussman, Bethany L; Reddigari, Samir; Newman, Sharlene D

2018-06-01

Visual word recognition has been studied for decades. One question that has received limited attention is how different text presentation orientations disrupt word recognition. By examining how word recognition processes may be disrupted by different text orientations it is hoped that new insights can be gained concerning the process. Here, we examined the impact of rotating and inverting text on the neural network responsible for visual word recognition focusing primarily on a region of the occipto-temporal cortex referred to as the visual word form area (VWFA). A lexical decision task was employed in which words and pseudowords were presented in one of three orientations (upright, rotated or inverted). The results demonstrate that inversion caused the greatest disruption of visual word recognition processes. Both rotated and inverted text elicited increased activation in spatial attention regions within the right parietal cortex. However, inverted text recruited phonological and articulatory processing regions within the left inferior frontal and left inferior parietal cortices. Finally, the VWFA was found to not behave similarly to the fusiform face area in that unusual text orientations resulted in increased activation and not decreased activation. It is hypothesized here that the VWFA activation is modulated by feedback from linguistic processes. Copyright © 2018 Elsevier Inc. All rights reserved.

Mapping of interconnection of climate risks

NASA Astrophysics Data System (ADS)

Yokohata, Tokuta; Tanaka, Katsumasa; Nishina, Kazuya; Takanashi, Kiyoshi; Emori, Seita; Kiguchi, Masashi; Iseri, Yoshihiko; Honda, Yasushi; Okada, Masashi; Masaki, Yoshimitsu; Yamamoto, Akitomo; Shigemitsu, Masahito; Yoshimori, Masakazu; Sueyoshi, Tetsuo; Iwase, Kenta; Hanasaki, Naota; Ito, Akihiko; Sakurai, Gen; Iizumi, Toshichika; Oki, Taikan

2015-04-01

Anthropogenic climate change possibly causes various impacts on human society and ecosystem. Here, we call possible damages or benefits caused by the future climate change as "climate risks". Many climate risks are closely interconnected with each other by direct cause-effect relationship. In this study, the major climate risks are comprehensively summarized based on the survey of studies in the literature using IPCC AR5 etc, and their cause-effect relationship are visualized by a "network diagram". This research is conducted by the collaboration between the experts of various fields, such as water, energy, agriculture, health, society, and eco-system under the project called ICA-RUS (Integrated Climate Assessment - Risks, Uncertainties and Society). First, the climate risks are classified into 9 categories (water, energy, food, health, disaster, industry, society, ecosystem, and tipping elements). Second, researchers of these fields in our project survey the research articles, and pick up items of climate risks, and possible cause-effect relationship between the risk items. A long list of the climate risks is summarized into ~130, and that of possible cause-effect relationship between the risk items is summarized into ~300, because the network diagram would be illegible if the number of the risk items and cause-effect relationship is too large. Here, we only consider the risks that could occur if climate mitigation policies are not conducted. Finally, the chain of climate risks is visualized by creating a "network diagram" based on a network graph theory (Fruchtman & Reingold algorithm). Through the analysis of network diagram, we find that climate risks at various sectors are closely related. For example, the decrease in the precipitation under the global climate change possibly causes the decrease in river runoff and the decrease in soil moisture, which causes the changes in crop production. The changes in crop production can have an impact on society by changing the food price or food supply. Changes in river runoff can also make an impact on the hydropower efficiency. Comprehensive pictures of climate risks and their interconnections are clearly shown in a straightforward manner by the network diagram. We will have a discussion how our results can be helpful for our society to recognize the climate risk.

Visualization of Flow in Pressurizer Spray Line Piping and Estimation of Thermal Stress Fluctuation Caused by Swaying of Water Surface

NASA Astrophysics Data System (ADS)

Oumaya, Toru; Nakamura, Akira; Onojima, Daisuke; Takenaka, Nobuyuki

The pressurizer spray line of PWR plants cools reactor coolant by injecting water into pressurizer. Since the continuous spray flow rate during commercial operation of the plant is considered insufficient to fill the pipe completely, there is a concern that a water surface exists in the pipe and may periodically sway. In order to identify the flow regimes in spray line piping and assess their impact on pipe structure, a flow visualization experiment was conducted. In the experiment, air was used substituted for steam to simulate the gas phase of the pressurizer, and the flow instability causing swaying without condensation was investigated. With a full-scale mock-up made of acrylic, flow under room temperature and atmospheric pressure conditions was visualized, and possible flow regimes were identified based on the results of the experiment. Three representative patterns of swaying of water surface were assumed, and the range of thermal stress fluctuation, when the surface swayed instantaneously, was calculated. With the three patterns of swaying assumed based on the visualization experiment, it was confirmed that the thermal stress amplitude would not exceed the fatigue endurance limit prescribed in the Japanese Design and Construction Code.

Exploring the patient perspective of fatigue in adults with visual impairment: a qualitative study

PubMed Central

Bode, Christina; van der Aa, Hilde P A; Hulshof, Carel T J; Bosmans, Judith E; van Rens, Gerardus H M B; van Nispen, Ruth M A

2017-01-01

Objectives Fatigue is an often mentioned symptom by patients with irreversible visual impairment. This study explored the patient perspective of fatigue in visually impaired adults with a focus on symptoms of fatigue, causes, consequences and coping strategies. Setting Two large Dutch low vision multidisciplinary rehabilitation organisations. Participants 16 visually impaired adults with severe symptoms of fatigue selected by purposive sampling. Methods A qualitative study involving semistructured interviews. A total of four first-level codes were top–down predetermined in correspondence with the topics of the research question. Verbatim transcribed interviews were analysed with a combination of a deductive and inductive approach using open and axial coding. Results Participants often described the symptoms of fatigue as a mental, daily and physical experience. The most often mentioned causes of fatigue were a high cognitive load, the intensity and amount of activities, the high effort necessary to establish visual perception, difficulty with light intensity and negative cognitions. Fatigue had the greatest impact on the ability to carry out social roles and participation, emotional functioning and cognitive functioning. The most common coping strategies were relaxation, external support, socialising and physical exercise and the acceptance of fatigue. Conclusions Our results indicate that low vision-related fatigue is mainly caused by population specific determinants that seem different from the fatigue experience described in studies with other patient populations. Fatigue may be central to the way patients react, adapt and compensate to the consequences of vision loss. These findings indicate a need for future research aimed at interventions specifically tailored to the unique aspects of fatigue related to vision loss. PMID:28775181

The fibre orientation influence in cementitious composite against extreme load resistance

NASA Astrophysics Data System (ADS)

Lovichova, R.; Fornusek, J.; Mara, M.; Kocova, M.; Rihova, Z.

2018-02-01

This paper is focused on resistance of steel fibre-reinforced cement composite against impact of the deformable projectile shot from the 7.62 × 39 caliber. Different values of resistance against impact of the projectile are caused by different orientation of the fibres. The influence of formwork position, which is the main cause of the different orientation of the fibres, is investigated. The resistance was examined on thirty slabs made of ultra-high performance fibre-reinforced concrete (UHPFRC). Fifteen specimens with vertical orientation of formwork and fifteen with horizontal orientation of formwork was made. The resistance is classified according to the visual evaluation and local damage measurement on the front side and the rear side of the examined specimens. The experiment shown positive influence of vertically oriented formwork on the slabs according to their resistance against impact of the projectile.

Pest risk maps for invasive alien species: a roadmap for improvement

Treesearch

Robert C. Venette; Darren J. Kriticos; Roger D. Magarey; Frank H. Koch; Richard H. A. Baker; Susan P. Worner; Nadila N. Gomez Raboteaux; Daniel W. McKenney; Erhard J. Dobesberger; Denys Yemshanov; Paul J. De Barro; William D. Hutchinson; Glenn Fowler; Tom M. Kalaris; John Pedlar

2010-01-01

Pest risk maps are powerful visual communication tools to describe where invasive alien species might arrive, establish, spread, or cause harmful impacts. These maps inform strategic and tactical pest management decisions, such as potential restrictions on international trade or the design of pest surveys and domestic quarantines. Diverse methods are available to...

Disentangling How the Brain is “Wired” in Cortical/Cerebral Visual Impairment (CVI)

PubMed Central

Merabet, Lotfi B.; Mayer, D. Luisa; Bauer, Corinna M.; Wright, Darick; Kran, Barry S.

2017-01-01

Cortical/cerebral visual impairment (CVI) results from perinatal injury to visual processing structures and pathways of the brain and is the most common cause of severe visual impairment/blindness in children in developed countries. Children with CVI display a wide range of visual deficits including decreased visual acuity, impaired visual field function, as well as impairments in higher order visual processing and attention. Together, these visual impairments can dramatically impact upon a child’s development and well-being. Given the complex neurological underpinnings of this condition, CVI is often undiagnosed by eye care practitioners. Furthermore, the neurophysiological basis of CVI in relation to observed visual processing deficits remains poorly understood. Here, we present some of the challenges associated with the clinical assessment and management of individuals with CVI. We discuss how advances in brain imaging are likely to help uncover the underlying neurophysiology of this condition. In particular, we demonstrate how structural and functional neuroimaging approaches can help gain insight into abnormalities of white matter connectivity and cortical activation patterns respectively. Establishing a connection between how changes within the brain relate to visual impairments in CVI will be important for developing effective rehabilitative and education strategies for individuals living with this condition. PMID:28941531

Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality.

PubMed

Xu, Renfeng; Wang, Huachun; Thibos, Larry N; Bradley, Arthur

2017-04-01

Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1  cd/m², and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5  cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image quality remain throughout the photopic and mesopic ranges. However, restricting pupils to <2  mm will cause significant reductions in the best focus vision at low photopic and mesopic luminances.

Web Application for Coastal Area Planning through Analysis of Landslide and Soil Consumption

NASA Astrophysics Data System (ADS)

Panizzoni, Giulio; Debiasi, Alberto; Eccher, Matteo; De Amicis, Raffaele

2016-04-01

Global warming and rapid climatic changes are producing dramatic effects on coastal area of Mediterranean countries. Italian coastal areas are one of the most urbanized zones of the south western Europe and the extensive use of soil is causing a consistent impact on the hydrogeological context. Moreover, soil consumption combined with extreme meteorological events, facilitates the occurrence of hazardous landslide events. Environmental policy makers and data managers in territorial planning need to face such emergency situation with appropriate tools. We present an application service with the aim of advising user through environmental analysis of Landslide and Soil Consumption impact. This service wants also to improve the sharing of environmental harmonized datasets/metadata across different organizations and the creation of a collaborative environment where the stakeholders and environmental experts can share their data and work cooperatively. We developed a set of processing services providing functionalities to assess impact of landslide on territory and impact of land take and soil sealing. Among others, the service is able to evaluate environmental impacts of landslide events on Cultural Heritage sites. We have also designed a 3D WebGL client customized to execute the processing services and visualize their outputs. It provides high usability in terms of navigation and data visualization. In this way the service provides not only a Spatial Data Infrastructure to access and visualize data but a complete Decision Support Systems for a more effective environmental planning of coastal area.

The economic burden of visual impairment and blindness: a systematic review.

PubMed

Köberlein, Juliane; Beifus, Karolina; Schaffert, Corinna; Finger, Robert P

2013-11-07

Visual impairment and blindness (VI&B) cause a considerable and increasing economic burden in all high-income countries due to population ageing. Thus, we conducted a review of the literature to better understand all relevant costs associated with VI&B and to develop a multiperspective overview. Systematic review: Two independent reviewers searched the relevant literature and assessed the studies for inclusion and exclusion criteria as well as quality. Interventional, non-interventional and cost of illness studies, conducted prior to May 2012, investigating direct and indirect costs as well as intangible effects related to visual impairment and blindness were included. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement approach to identify the relevant studies. A meta-analysis was not performed due to the variability of the reported cost categories and varying definition of visual impairment. A total of 22 studies were included. Hospitalisation and use of medical services around diagnosis and treatment at the onset of VI&B were the largest contributor to direct medical costs. The mean annual expenses per patient were found to be US$ purchasing power parities (PPP) 12 175-14 029 for moderate visual impairment, US$ PPP 13 154-16 321 for severe visual impairment and US$ PPP 14 882-24 180 for blindness, almost twofold the costs for non-blind patients. Informal care was the major contributor to other direct costs, with the time spent by caregivers increasing from 5.8 h/week (or US$ PPP 263) for persons with vision >20/32 up to 94.1 h/week (or US$ PPP 55 062) for persons with vision ≤20/250. VI&B caused considerable indirect costs due to productivity losses, premature mortality and dead-weight losses. VI&B cause a considerable economic burden for affected persons, their caregivers and society at large, which increases with the degree of visual impairment. This review provides insight into the distribution of costs and the economic impact of VI&B.

Lunar Balance and Locomotion

NASA Technical Reports Server (NTRS)

Paloski, William H.

2008-01-01

Balance control and locomotor patterns were altered in Apollo crewmembers on the lunar surface, owing, presumably, to a combination of sensory-motor adaptation during transit and lunar surface operations, decreased environmental affordances associated with the reduced gravity, and restricted joint mobility as well as altered center-of-gravity caused by the EVA pressure suits. Dr. Paloski will discuss these factors, as well as the potential human and mission impacts of falls and malcoordination during planned lunar sortie and outpost missions. Learning objectives: What are the potential impacts of postural instabilities on the lunar surface? CME question: What factors affect balance control and gait stability on the moon? Answer: Sensory-motor adaptation to the lunar environment, reduced mechanical and visual affordances, and altered biomechanics caused by the EVA suit.

The Tehran Eye Study: research design and eye examination protocol

PubMed Central

Hashemi, Hassan; Fotouhi, Akbar; Mohammad, Kazem

2003-01-01

Background Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample. Methods Design Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described. Conclusion We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs. PMID:12859794

The Tehran Eye Study: research design and eye examination protocol.

PubMed

Hashemi, Hassan; Fotouhi, Akbar; Mohammad, Kazem

2003-07-15

Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample. Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described. We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs.

Impact damage resistance of carbon/epoxy composite tubes for the DC-XA liquid hydrogen feedline

NASA Technical Reports Server (NTRS)

Nettles, A. T.

1995-01-01

Low-velocity impacts were inflicted upon two elbow sections of carbon/epoxy feedline that are to be a part of the Delta Clipper-XA flight vehicle. A soap-based liquid leak detector solution was used to inspect the impact sites for leaks of pressurized gas that was pumped into the tube. Visual surface damage was noted and recorded for each impact site. After impact testing of each of the two sections of tubes was completed, the damage zones were disected from the tube and cross sectioned through the impact site. These specimens were polished after potting them in epoxy and were examined for microcracking using a fluorescent dye penetrant technique. The results showed that nonvisible damage could cause microcracking, thereby resulting in leaks through the tube wall.

Exploring the patient perspective of fatigue in adults with visual impairment: a qualitative study.

PubMed

Schakel, Wouter; Bode, Christina; van der Aa, Hilde P A; Hulshof, Carel T J; Bosmans, Judith E; van Rens, Gerardus H M B; van Nispen, Ruth M A

2017-08-03

Fatigue is an often mentioned symptom by patients with irreversible visual impairment. This study explored the patient perspective of fatigue in visually impaired adults with a focus on symptoms of fatigue, causes, consequences and coping strategies. Two large Dutch low vision multidisciplinary rehabilitation organisations. 16 visually impaired adults with severe symptoms of fatigue selected by purposive sampling. A qualitative study involving semistructured interviews. A total of four first-level codes were top-down predetermined in correspondence with the topics of the research question. Verbatim transcribed interviews were analysed with a combination of a deductive and inductive approach using open and axial coding. Participants often described the symptoms of fatigue as a mental, daily and physical experience. The most often mentioned causes of fatigue were a high cognitive load, the intensity and amount of activities, the high effort necessary to establish visual perception, difficulty with light intensity and negative cognitions. Fatigue had the greatest impact on the ability to carry out social roles and participation, emotional functioning and cognitive functioning. The most common coping strategies were relaxation, external support, socialising and physical exercise and the acceptance of fatigue. Our results indicate that low vision-related fatigue is mainly caused by population specific determinants that seem different from the fatigue experience described in studies with other patient populations. Fatigue may be central to the way patients react, adapt and compensate to the consequences of vision loss. These findings indicate a need for future research aimed at interventions specifically tailored to the unique aspects of fatigue related to vision loss. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Analysis of the Psychological Conflict of Contemporary Street Aesthetics in China from the Views of Media Communications

NASA Astrophysics Data System (ADS)

Feng, Chen; Xu, Hua Wei

2018-06-01

New media patterns generate more complicated and diversified space forms. Spatial experiences that are instant, fragmented, reality-virtuality interlaced are ubiquitous. Such interlacing brings an enormous impact on traditional Chinese streetscapes, increases the risks of the fragmentation of streetscapes, and leads to the disorder of visual aesthetics. Moreover, it necessarily imposes a great impact on traditional street aesthetics, and causes various psychological conflicts. This study aims to describe this phenomenon and try to explore the reason behind it in new view.

Prevalence of cataract surgery and visual outcomes in Indian immigrants in Singapore: the Singapore Indian eye study.

PubMed

Gupta, Preeti; Zheng, Yingfeng; Ting, Tay Wan; Lamoureux, Ecosse L; Cheng, Ching-Yu; Wong, Tien-Yin

2013-01-01

To determine the prevalence of cataract surgery and factors associated with post-surgical visual outcomes in migrant Indians living in Singapore. We conducted a population-based study in 3,400 Indian immigrants residing in Singapore-the Singapore Indian Eye Study (SINDI). All participants underwent comprehensive medical eye examination and a standardized interview. Post-operative visual impairment (VI) was defined as best-corrected or presenting visual acuity (BCVA or PVA) of 20/60 or worse. The age- and gender-standardized prevalence of cataract surgery was 9.7% (95% confidence interval [CI]: 8.9%, 10.7%) in Singapore resident Indians. Post-operative VI defined by BCVA occurred in 10.9% eyes (87/795). The main causes of post-operative VI were diabetic retinopathy (20.7%), posterior capsular opacification (18.4%), and age-related macular degeneration (12.6%). Undercorrected refractive error doubled the prevalence of post-operative VI when PVA was used. The rate of cataract surgery is about 10% in Indian residents in Singapore. Socioeconomic variables and migration had no significant impact on the prevalence of cataract surgery. Diabetic retinopathy was a major cause of post-operative VI in migrant Indians living in Singapore. Uncorrected postoperative refractive error remains an efficient way to improve vision.

Retinal Structures and Visual Cortex Activity are Impaired Prior to Clinical Vision Loss in Glaucoma.

PubMed

Murphy, Matthew C; Conner, Ian P; Teng, Cindy Y; Lawrence, Jesse D; Safiullah, Zaid; Wang, Bo; Bilonick, Richard A; Kim, Seong-Gi; Wollstein, Gadi; Schuman, Joel S; Chan, Kevin C

2016-08-11

Glaucoma is the second leading cause of blindness worldwide and its pathogenesis remains unclear. In this study, we measured the structure, metabolism and function of the visual system by optical coherence tomography and multi-modal magnetic resonance imaging in healthy subjects and glaucoma patients with different degrees of vision loss. We found that inner retinal layer thinning, optic nerve cupping and reduced visual cortex activity occurred before patients showed visual field impairment. The primary visual cortex also exhibited more severe functional deficits than higher-order visual brain areas in glaucoma. Within the visual cortex, choline metabolism was perturbed along with increasing disease severity in the eye, optic radiation and visual field. In summary, this study showed evidence that glaucoma deterioration is already present in the eye and the brain before substantial vision loss can be detected clinically using current testing methods. In addition, cortical cholinergic abnormalities are involved during trans-neuronal degeneration and can be detected non-invasively in glaucoma. The current results can be of impact for identifying early glaucoma mechanisms, detecting and monitoring pathophysiological events and eye-brain-behavior relationships, and guiding vision preservation strategies in the visual system, which may help reduce the burden of this irreversible but preventable neurodegenerative disease.

Retinal Structures and Visual Cortex Activity are Impaired Prior to Clinical Vision Loss in Glaucoma

PubMed Central

Murphy, Matthew C.; Conner, Ian P.; Teng, Cindy Y.; Lawrence, Jesse D.; Safiullah, Zaid; Wang, Bo; Bilonick, Richard A.; Kim, Seong-Gi; Wollstein, Gadi; Schuman, Joel S.; Chan, Kevin C.

2016-01-01

Glaucoma is the second leading cause of blindness worldwide and its pathogenesis remains unclear. In this study, we measured the structure, metabolism and function of the visual system by optical coherence tomography and multi-modal magnetic resonance imaging in healthy subjects and glaucoma patients with different degrees of vision loss. We found that inner retinal layer thinning, optic nerve cupping and reduced visual cortex activity occurred before patients showed visual field impairment. The primary visual cortex also exhibited more severe functional deficits than higher-order visual brain areas in glaucoma. Within the visual cortex, choline metabolism was perturbed along with increasing disease severity in the eye, optic radiation and visual field. In summary, this study showed evidence that glaucoma deterioration is already present in the eye and the brain before substantial vision loss can be detected clinically using current testing methods. In addition, cortical cholinergic abnormalities are involved during trans-neuronal degeneration and can be detected non-invasively in glaucoma. The current results can be of impact for identifying early glaucoma mechanisms, detecting and monitoring pathophysiological events and eye-brain-behavior relationships, and guiding vision preservation strategies in the visual system, which may help reduce the burden of this irreversible but preventable neurodegenerative disease. PMID:27510406

Online advertisement: how are visual strategies affected by the distance and the animation of banners?

PubMed

Pasqualotti, Léa; Baccino, Thierry

2014-01-01

Most of studies about online advertisements have indicated that they have a negative impact on users' cognitive processes, especially when they include colorful or animated banners and when they are close to the text to be read. In the present study we assessed the effects of two advertisements features-distance from the text and the animation-on visual strategies during a word-search task and a reading-for-comprehension task using Web-like pages. We hypothesized that the closer the advertisement was to the target text, the more cognitive processing difficulties it would cause. We also hypothesized that (1) animated banners would be more disruptive than static advertisements and (2) banners would have more effect on word-search performance than reading-for-comprehension performance. We used an automatic classifier to assess variations in use of Scanning and Reading visual strategies during task performance. The results showed that the effect of dynamic and static advertisements on visual strategies varies according to the task. Fixation duration indicated that the closest advertisements slowed down information processing but there was no difference between the intermediate (40 pixel) and far (80 pixel) distance conditions. Our findings suggest that advertisements have a negative impact on users' performance mostly when a lots of cognitive resources are required as for reading-for-comprehension.

Too little, too late: reduced visual span and speed characterize pure alexia.

PubMed

Starrfelt, Randi; Habekost, Thomas; Leff, Alexander P

2009-12-01

Whether normal word reading includes a stage of visual processing selectively dedicated to word or letter recognition is highly debated. Characterizing pure alexia, a seemingly selective disorder of reading, has been central to this debate. Two main theories claim either that 1) Pure alexia is caused by damage to a reading specific brain region in the left fusiform gyrus or 2) Pure alexia results from a general visual impairment that may particularly affect simultaneous processing of multiple items. We tested these competing theories in 4 patients with pure alexia using sensitive psychophysical measures and mathematical modeling. Recognition of single letters and digits in the central visual field was impaired in all patients. Visual apprehension span was also reduced for both letters and digits in all patients. The only cortical region lesioned across all 4 patients was the left fusiform gyrus, indicating that this region subserves a function broader than letter or word identification. We suggest that a seemingly pure disorder of reading can arise due to a general reduction of visual speed and span, and explain why this has a disproportionate impact on word reading while recognition of other visual stimuli are less obviously affected.

Too Little, Too Late: Reduced Visual Span and Speed Characterize Pure Alexia

PubMed Central

Habekost, Thomas; Leff, Alexander P.

2009-01-01

Whether normal word reading includes a stage of visual processing selectively dedicated to word or letter recognition is highly debated. Characterizing pure alexia, a seemingly selective disorder of reading, has been central to this debate. Two main theories claim either that 1) Pure alexia is caused by damage to a reading specific brain region in the left fusiform gyrus or 2) Pure alexia results from a general visual impairment that may particularly affect simultaneous processing of multiple items. We tested these competing theories in 4 patients with pure alexia using sensitive psychophysical measures and mathematical modeling. Recognition of single letters and digits in the central visual field was impaired in all patients. Visual apprehension span was also reduced for both letters and digits in all patients. The only cortical region lesioned across all 4 patients was the left fusiform gyrus, indicating that this region subserves a function broader than letter or word identification. We suggest that a seemingly pure disorder of reading can arise due to a general reduction of visual speed and span, and explain why this has a disproportionate impact on word reading while recognition of other visual stimuli are less obviously affected. PMID:19366870

Visual impact assessment in British oil and gas developments

Treesearch

Dennis F. Gillespie; Brian D. Clark

1979-01-01

Development of oil and gas resource in the North Sea has led to the application of visual impact assessment techniques to onshore oil and gas developments in the United Kingdom. Formal visual impact assessment methods are needed to supplement landscape evaluations and site selection studies. Three major orientations of British visual impact assessments are: the...

Impact of colour in the assessment of potential visual acuity in patients with age-related macular degeneration.

PubMed

Dorrepaal, Stephen J; Markowitz, Samuel N

2013-06-01

To compare chromatic and achromatic potential visual acuity (PVA) in patients with bilateral low vision caused by age-related macular degeneration (AMD). Prospective, nonrandomized, observational case series. Fifty-five patients, representing a consecutive series of patients all presenting with bilateral AMD. Best-corrected visual acuity of each eye was measured using an Early Treatment in Diabetic Retinopathy Study (ETDRS) chart with appropriate near correction. Included were cases with visual acuity of 0.4 logMAR (20/50) or worse in both eyes. Achromatic and chromatic PVA were measured in each eye using white on black and red on yellow flooding E charts at 50 cm in controlled lighting conditions. One hundred and seven eyes from 55 patients were included in the analysis. Mean achromatic and chromatic PVA were 0.69 ± 0.26 and 0.65 ± 0.22 logMAR, respectively. Overall, patients had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity worse than 0.9 logMAR also had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity between 0.4 and 0.9 logMAR had a trend toward a higher chromatic than achromatic visual acuity that was not significant, with a median difference of 0.1 logMAR (p = 0.8539). Patients with low vision caused by AMD can discern smaller targets when a red on yellow colour scheme is used than when using achromatic white on black charts. Copyright © 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Does Visual Performance Influence Head Impact Severity Among High School Football Athletes?

PubMed

Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W

2015-11-01

To compare the odds of sustaining moderate and severe head impacts, rather than mild, between high school football players with high and low visual performance. Prospective quasi-experimental. Clinical Research Center/On-field. Thirty-seven high school varsity football players. Athletes completed the Nike SPARQ Sensory Station visual assessment before the season. Head impact biomechanics were captured at all practices and games using the Head Impact Telemetry System. Each player was classified as either a high or low performer using a median split for each of the following visual performance measures: visual clarity, contrast sensitivity, depth perception, near-far quickness, target capture, perception span, eye-hand coordination, go/no go, and reaction time. We computed the odds of sustaining moderate and severe head impacts against the reference odds of sustaining mild head impacts across groups of high and low performers for each of the visual performance measures. Players with better near-far quickness had increased odds of sustaining moderate [odds ratios (ORs), 1.27; 95% confidence intervals (CIs), 1.04-1.56] and severe head impacts (OR, 1.45; 95% CI, 1.05-2.01) as measured by Head Impact Technology severity profile. High and low performers were at equal odds on all other measures. Better visual performance did not reduce the odds of sustaining higher magnitude head impacts. Visual performance may play less of a role than expected for protecting against higher magnitude head impacts among high school football players. Further research is needed to determine whether visual performance influences concussion risk. Based on our results, we do not recommend using visual training programs at the high school level for the purpose of reducing the odds of sustaining higher magnitude head impacts.

Potential future impacts on visual air quality for Class I areas

Treesearch

Gurule Nochumson; Mona J. Wecksung

1979-01-01

Visual air quality is most sensitive to degradation by air pollution in areas with good visibility. The protection of visual air quality in mandatory Class I Federal areas has been declared a national goal by Congress. Impacts on visual air quality are calculated for 154 Class I areas where visual air quality is considered an important value. These impacts are...

Visual impact of wind farms on cultural heritage: A Norwegian case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jerpasen, Gro B., E-mail: gro.jerpasen@niku.no; Larsen, Kari C., E-mail: kari.larsen@niku.n

2011-04-15

This paper discusses different approaches of how visual impact on cultural heritage can be methodologically improved within Environmental Impact Assessment (EIA). During the recent decade, visual impact on cultural heritage and heritage sites has become a more frequent but contentious issue in public and academic discussions. Yet, within EIA issues relating to heritage sites and visual impact are rarely debated or critically reflected upon. Today most methods and theories on visual impact and cultural heritage within EIA are transferred from disciplines such as landscape architecture, architecture and geography. The article suggests how working with the concepts and definitions of sitemore » and setting can be a methodological tool for delimiting and clarifying visual impact on cultural heritage sites. The article also presents ways of how public participation can be a tool to start exploring the field of what the visual impact on cultural heritage implies and how it effects upon our understanding and appreciation of heritage sites. Examples from a Norwegian case are taken as illustrations to highlight these issues.« less

Examining postconcussion symptoms of dizziness and imbalance on neurocognitive performance in collegiate football players.

PubMed

Honaker, Julie A; Lester, Houston F; Patterson, Jessie N; Jones, Sherri M

2014-07-01

This study examined the effects of symptom reports of dizziness and imbalance on cognitive function in concussed collegiate football players. Retrospective, descriptive. University athletic medicine facility. Twenty-seven collegiate football players were included in the final analysis: 16 with symptoms of dizziness/imbalance resulting from concussion and 11 without dizziness/imbalance resulting from concussion. Participants completed the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) at baseline, at 1 to 2 days postconcussion and 5 to 7 days postconcussion. The ImPACT neurocognitive assessment consists of 6 modules, yielding 4 composite scores: verbal memory, visual memory, visual-motor processing speed, and reaction time. In addition, it includes a postconcussion symptom scale total score. Results revealed that participants with reports of dizziness and imbalance had significantly lower scores on the ImPACT composite scores; however, these individuals also had an overall higher symptom inventory. When accounting for the additional postconcussion symptoms, time was the only significant effect. Dizziness and imbalance are common symptoms postconcussion; however, these symptoms did not predict performance on acute ImPACT scores. Further research is needed to understand the mechanisms causing postconcussion symptoms, including symptoms of dizziness and imbalance, and influence on outcomes postconcussion.

[Comparison of visual impairment caused by trachoma in China between 1978 and 2006].

PubMed

Hu, Ailian; Cai, Xiaogu; Qiao, Liya; Zhang, Ye; Zhang, Xu; Sun, Baochen; Wang, Ningli

2015-10-01

To understand the distribution of visual impairment caused by trachoma in China and provide evidences for evaluation of eliminating blinding trachoma in China in the mission of Vision 2020. Sampling study. The results from the first year 1987 and second (year 2006) national sampling surveys of disabled persons were analyzed. Chi-square test was performed using SAS 9.30 to analyze the rates of visual impairment caused by trachoma in different groups. Unifactor and multifactor analyses were applied to analyze the relevance between visual impairment caused by trachoma and risk factors, including gender and age. The rate of visual impairment caused by trachoma was 102.01 persons/100 000 in 1987 and 17.62 persons/100 000 in 2006. The percentage of trachoma in all kinds of visual impairment was 14.25% in 1987 and 1.87% in 2006, and the difference was significant (F = 1 382.6, P < 0.01). Spatial aggregation was obvious in visual impairment caused by trachoma. H-aggregation areas included Hubei, Sichuan, Anhui, Shannxi, Guizhou, Hunan provinces and Chongqing Municipality. Survival time without trachoma between 1987 and 2006 was significantly different (F = 2 745.9, P < 0.01). The rate and risk of visual impairment caused by trachoma increased with age. Except the group of > 85 years, the rate of visual impairment caused by trachoma in all age groups in 1987 was significantly higher than that in 2006. The risk of visual impairment caused by trachoma in 1987 was 5.8 times that in 2006. If the other risk factors were not involved, the risk in 1987 was 8.75 times that in 2006. The risk in females was twice that in males. Both, the rate and risk of visual impairment caused by trachoma were significantly reduced in China. Impressive progresses were achieved in trachoma prevention and control.

Visual Acuity Improvement of Amblyopia in an Adult With Levodopa/Carbidopa Treatment.

PubMed

Orge, Faruk H; Dar, Suhail A

2015-09-09

Amblyopia is the leading cause of visual loss in children, affecting 2% to 3% of the population. Occlusion of the dominant eye is the primary and best treatment, although efficacy decreases after 6 years of age. As a result, levodopa/carbidopa has been explored as an adjunct to conventional therapy and has been shown to have an immediate impact on visual acuity. Several studies to date have shown mixed results on the benefit of supplementing occlusion therapy with levodopa/carbidopa, although they have primarily studied children. The authors describe the oldest patient (46 years old) documented in the literature to have shown improvement in visual acuity using levodopa/carbidopa. He was given a 16-week course at a dose in line with previous studies while being effectively occluded full time due to a glaucomatous right eye with no light perception. On 3-month follow-up, his left eye improved two lines and stabilized at 6 months. Copyright 2015, SLACK Incorporated.

Traits and causes of environmental loss-related chemical accidents in China based on co-word analysis.

PubMed

Wu, Desheng; Song, Yu; Xie, Kefan; Zhang, Baofeng

2018-04-25

Chemical accidents are major causes of environmental losses and have been debated due to the potential threat to human beings and environment. Compared with the single statistical analysis, co-word analysis of chemical accidents illustrates significant traits at various levels and presents data into a visual network. This study utilizes a co-word analysis of the keywords extracted from the Web crawling texts of environmental loss-related chemical accidents and uses the Pearson's correlation coefficient to examine the internal attributes. To visualize the keywords of the accidents, this study carries out a multidimensional scaling analysis applying PROXSCAL and centrality identification. The research results show that an enormous environmental cost is exacted, especially given the expected environmental loss-related chemical accidents with geographical features. Meanwhile, each event often brings more than one environmental impact. Large number of chemical substances are released in the form of solid, liquid, and gas, leading to serious results. Eight clusters that represent the traits of these accidents are formed, including "leakage," "poisoning," "explosion," "pipeline crack," "river pollution," "dust pollution," "emission," and "industrial effluent." "Explosion" and "gas" possess a strong correlation with "poisoning," located at the center of visualization map.

Online advertisement: how are visual strategies affected by the distance and the animation of banners?

PubMed Central

Pasqualotti, Léa; Baccino, Thierry

2014-01-01

Most of studies about online advertisements have indicated that they have a negative impact on users' cognitive processes, especially when they include colorful or animated banners and when they are close to the text to be read. In the present study we assessed the effects of two advertisements features—distance from the text and the animation—on visual strategies during a word-search task and a reading-for-comprehension task using Web-like pages. We hypothesized that the closer the advertisement was to the target text, the more cognitive processing difficulties it would cause. We also hypothesized that (1) animated banners would be more disruptive than static advertisements and (2) banners would have more effect on word-search performance than reading-for-comprehension performance. We used an automatic classifier to assess variations in use of Scanning and Reading visual strategies during task performance. The results showed that the effect of dynamic and static advertisements on visual strategies varies according to the task. Fixation duration indicated that the closest advertisements slowed down information processing but there was no difference between the intermediate (40 pixel) and far (80 pixel) distance conditions. Our findings suggest that advertisements have a negative impact on users' performance mostly when a lots of cognitive resources are required as for reading-for-comprehension. PMID:24672501

Reorganization of Visual Callosal Connections Following Alterations of Retinal Input and Brain Damage

PubMed Central

Restani, Laura; Caleo, Matteo

2016-01-01

Vision is a very important sensory modality in humans. Visual disorders are numerous and arising from diverse and complex causes. Deficits in visual function are highly disabling from a social point of view and in addition cause a considerable economic burden. For all these reasons there is an intense effort by the scientific community to gather knowledge on visual deficit mechanisms and to find possible new strategies for recovery and treatment. In this review, we focus on an important and sometimes neglected player of the visual function, the corpus callosum (CC). The CC is the major white matter structure in the brain and is involved in information processing between the two hemispheres. In particular, visual callosal connections interconnect homologous areas of visual cortices, binding together the two halves of the visual field. This interhemispheric communication plays a significant role in visual cortical output. Here, we will first review the essential literature on the physiology of the callosal connections in normal vision. The available data support the view that the callosum contributes to both excitation and inhibition to the target hemisphere, with a dynamic adaptation to the strength of the incoming visual input. Next, we will focus on data showing how callosal connections may sense visual alterations and respond to the classical paradigm for the study of visual plasticity, i.e., monocular deprivation (MD). This is a prototypical example of a model for the study of callosal plasticity in pathological conditions (e.g., strabismus and amblyopia) characterized by unbalanced input from the two eyes. We will also discuss the findings of callosal alterations in blind subjects. Noteworthy, we will discuss data showing that inter-hemispheric transfer mediates recovery of visual responsiveness following cortical damage. Finally, we will provide an overview of how callosal projections dysfunction could contribute to pathologies such as neglect and occipital epilepsy. A particular focus will be on reviewing noninvasive brain stimulation techniques and optogenetic approaches that allow to selectively manipulate callosal function and to probe its involvement in cortical processing and plasticity. Overall, the data indicate that experience can potently impact on transcallosal connectivity, and that the callosum itself is crucial for plasticity and recovery in various disorders of the visual pathway. PMID:27895559

Cerebral Visual Impairment: Which Perceptive Visual Dysfunctions Can Be Expected in Children with Brain Damage? A Systematic Review

ERIC Educational Resources Information Center

Boot, F. H.; Pel, J. J. M.; van der Steen, J.; Evenhuis, H. M.

2010-01-01

The current definition of Cerebral Visual Impairment (CVI) includes all visual dysfunctions caused by damage to, or malfunctioning of, the retrochiasmatic visual pathways in the absence of damage to the anterior visual pathways or any major ocular disease. CVI is diagnosed by exclusion and the existence of many different causes and symptoms make…

Prevalence and causes of blindness and visual impairment among school children in south-western Nigeria.

PubMed

Ajaiyeoba, A I; Isawumi, M A; Adeoye, A O; Oluleye, T S

2005-01-01

The aim of the study was to assess the prevalence and identify the causes of blindness and visual impairment in school children of Ilesa-East Local Government Area of Osun State, Nigeria. A total of 1144 school children in primary and secondary schools were selected using a 2-stage random sampling method and examined to determine the prevalence and causes of blindness and visual impairment. A total of 17 (1.48%) children were blind or visually impaired. These comprised of 11 (0.96%) children who were visually impaired and 4 (0.3%) who were severely visually impaired. Only 2 (0.15%) school children were blind. The causes of visual impairment were refractive error 10 (0.87%) and immature cataract 1 (0.08%), causes of severe visual impairment included corneal opacities 2 (0.2%), amblyopia leading to squint 1 (0.08%) and 1 cataract 1 (0.08%). The causes of blindness in school children were corneal scars presumed to be due to vitamin A deficiency 1 (0.08%) and keratoconus 1 (0.08%). Causes of blindness and visual impairment in children attending regular schools in Nigeria were treatable. Prevention, early recognition and prompt treatment of these diseases by regular screening of school children would definitely reduce unnecessary visual handicap in Nigerian school children so that they can attain their full potential in the course of their education. Also, information from this study is relevant for the purpose of planning eye care programmes for the prevention of blindness in Nigerian school children. This will go a long way in the prevention of unnecessary blindness and visual impairment in school children.

Visual loss in Takayasu Arteritis - Look Beyond the Eye.

PubMed

Peter, Jayanthi; Joseph, George; Mathew, Vivek; Peter, John Victor

2014-08-01

Patients with Takayasu arteritis often present with reduced vision related either to the disease per se or due to complications of therapy. We report a patient with Takayasu arteritis who developed acute onset bilateral visual loss 6wks following percutaneous revascularization of occluded aortic arch branches. No ocular cause for the visual loss was evident. The reason for visual loss in this patient was an extraocular cause. Ocular and extraocular causes of visual loss in Takayasu arteritis are discussed.

Visualizing Internet routing changes.

PubMed

Lad, Mohit; Massey, Dan; Zhang, Lixia

2006-01-01

Today's Internet provides a global data delivery service to millions of end users and routing protocols play a critical role in this service. It is important to be able to identify and diagnose any problems occurring in Internet routing. However, the Internet's sheer size makes this task difficult. One cannot easily extract out the most important or relevant routing information from the large amounts of data collected from multiple routers. To tackle this problem, we have developed Link-Rank, a tool to visualize Internet routing changes at the global scale. Link-Rank weighs links in a topological graph by the number of routes carried over each link and visually captures changes in link weights in the form of a topological graph with adjustable size. Using Link-Rank, network operators can easily observe important routing changes from massive amounts of routing data, discover otherwise unnoticed routing problems, understand the impact of topological events, and infer root causes of observed routing changes.

Impact of visual and somatosensory deprivation on dynamic balance in adolescent idiopathic scoliosis.

PubMed

Kuo, Fang-Chuan; Wang, Nai-Hwei; Hong, Chang-Zern

2010-11-01

A cross-sectional study of balance control in adolescents with idiopathic scoliosis (AIS). To investigate the impact of visual and somatosensory deprivation on the dynamic balance in AIS patients and to discuss electromyographic (EMG) and posture sway findings. Most studies focus on posture sway in quiet standing controls with little effort on examining muscle-activated patterns in dynamic standing controls. Twenty-two AIS patients and 22 age-matched normal subjects were studied. To understand how visual and somatosensory information could modulate standing balance, balance tests with the Biodex stability system were performed on a moving platform under 3 conditions: visual feedback provided (VF), eyes closed (EC), and standing on a sponge pad with visual feedback provided (SV). Muscular activities of bilateral lumbar multifidi, gluteus medii, and gastrocnemii muscles were recorded with a telemetry EMG system. AIS patients had normal balance index and amplitude and duration of EMG similar to those of normal subjects in the balance test. However, the onset latency of right gastrocnemius was earlier in AIS patients than in normal subjects. In addition, body-side asymmetry was noted on muscle strength and onset latency in AIS subjects. Under EC condition, lumbar multifidi, and gluteus medii activities were higher than those under SV and VF conditions (P < 0.05). Under SV condition, the medial-lateral tilting angle was less than that under VF and EC conditions. In addition, the active duration of right gluteus medius was shorter under SV condition (P < 0.05). The dynamic balance control is particularly disruptive under visual deprivation with increasing lumbar multifidi and gluteus medii activities for compensation. Sponge pad can cause decrease in frontal plane tilting and gluteus medii effort. The asymmetric muscle strength and onset timing are attributed to anatomic deformation as opposed to neurologic etiological factors.

Causes of blindness and visual impairment in Pakistan. The Pakistan national blindness and visual impairment survey

PubMed Central

Dineen, B; Bourne, R R A; Jadoon, Z; Shah, S P; Khan, M A; Foster, A; Gilbert, C E; Khan, M D

2007-01-01

Objective To determine the causes of blindness and visual impairment in adults (⩾30 years old) in Pakistan, and to explore socio‐demographic variations in cause. Methods A multi‐stage, stratified, cluster random sampling survey was used to select a nationally representative sample of adults. Each subject was interviewed, had their visual acuity measured and underwent autorefraction and fundus/optic disc examination. Those with a visual acuity of <6/12 in either eye underwent a more detailed ophthalmic examination. Causes of visual impairment were classified according to the accepted World Health Organization (WHO) methodology. An exploration of demographic variables was conducted using regression modeling. Results A sample of 16 507 adults (95.5% of those enumerated) was examined. Cataract was the most common cause of blindness (51.5%; defined as <3/60 in the better eye on presentation) followed by corneal opacity (11.8%), uncorrected aphakia (8.6%) and glaucoma (7.1%). Posterior capsular opacification accounted for 3.6% of blindness. Among the moderately visually impaired (<6/18 to ⩾6/60), refractive error was the most common cause (43%), followed by cataract (42%). Refractive error as a cause of severe visual impairment/blindness was significantly higher in rural dwellers than in urban dwellers (odds ratio (OR) 3.5, 95% CI 1.1 to 11.7). Significant provincial differences were also identified. Overall we estimate that 85.5% of causes were avoidable and that 904 000 adults in Pakistan have cataract (<6/60) requiring surgical intervention. Conclusions This comprehensive survey provides reliable estimates of the causes of blindness and visual impairment in Pakistan. Despite expanded surgical services, cataract still accounts for over half of the cases of blindness in Pakistan. One in eight blind adults has visual loss from sequelae of cataract surgery. Services for refractive errors need to be further expanded and integrated into eye care services, particularly those serving rural populations. PMID:17229806

Stimulation of functional vision in children with perinatal brain damage.

PubMed

Alimović, Sonja; Mejaski-Bosnjak, Vlatka

2011-01-01

Cerebral visual impairment (CVI) is one of the most common causes of bilateral visual loss, which frequently occurs due to perinatal brain injury. Vision in early life has great impact on acquisition of basic comprehensions which are fundamental for further development. Therefore, early detection of visual problems and early intervention is necessary. The aim of the present study is to determine specific visual functioning of children with perinatal brain damage and the influence of visual stimulation on development of functional vision at early age of life. We initially assessed 30 children with perinatal brain damage up to 3 years of age, who were reffered to our pediatric low vision cabinet in "Little house" from child neurologists, ophthalmologists Type and degree of visual impairment was determined according to functional vision assessment of each child. On the bases of those assessments different kind of visual stimulations were carried out with children who have been identified to have a certain visual impairment. Through visual stimulation program some of the children were stimulated with light stimulus, some with different materials under the ultraviolet (UV) light, and some with bright color and high contrast materials. Children were also involved in program of early stimulation of overall sensory motor development. Goals and methods of therapy were determined individually, based on observation of child's possibilities and need. After one year of program, reassessment was done. Results for visual functions and functional vision were compared to evaluate the improvement of the vision development. These results have shown that there was significant improvement in functional vision, especially in visual attention and visual communication.

Epidemiological patterns of ocular trauma.

PubMed

Thylefors, B

1992-05-01

Ocular trauma is the cause of blindness in approximately half a million people worldwide, and many more have suffered partial loss of sight. Trauma is often the most important cause of unilateral loss of vision, particularly in developing countries. There is a cumulative risk of ocular trauma and visual loss during life, but the true incidence of accidents involving the eyes is not known. Males tend to have more eye trauma than females, and this is already apparent from childhood; lower socioeconomic classes are also more associated with ocular trauma. The setting for the occurrence of trauma is most commonly the workplace and, increasingly, road accidents. On the other hand, domestic accidents are probably under-reported. Of particular importance in some developing countries is the occurrence of superficial corneal trauma in agricultural work, often leading to rapidly progressing corneal ulceration and visual loss. The impact of ocular trauma, in terms of need for medical care, loss of income and cost of rehabilitation services when indicated, clearly makes the strengthening of preventive measures very worthwhile.

Impact of stimulus uncanniness on speeded response

PubMed Central

Takahashi, Kohske; Fukuda, Haruaki; Samejima, Kazuyuki; Watanabe, Katsumi; Ueda, Kazuhiro

2015-01-01

In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat. PMID:26052297

Cross-sectional study on prevalence, causes and avoidable causes of visual impairment in Maori children.

PubMed

Chong, Cheefoong; Dai, Shuan

2013-08-02

To provide information and comparison pertaining to visual impairment of Maori children with other children in New Zealand in particular: prevalence of blindness, causes of visual impairment, and avoidable causes of visual impairment. Retrospective data collection utilising the WHO/PBL eye examination record for children with blindness and low vision at Blind and Low Vision Education Network New Zealand (BLENNZ), Homai. Individuals not of Maori ethnicity or over the age of 16 were excluded from the study. 106 blind and 64 low-vision Maori children were studied. The main cause of blindness in Maori children is cortical visual impairment. Twenty-eight percent of causes of blindness in this population are potentially avoidable with non-accidental injury as the main cause. The prevalence of blindness and low vision in children amounts to 0.05% and 0.03%, respectively. The prevalence and causes of childhood blindness are comparable to the other ethnic groups in New Zealand. The main difference lies in avoidable causes of blindness, which appeared to be much higher in the Maori population. The leading cause of avoidable blindness in Maori children is caused by non-accidental injuries.

[Frequency and causes of blindness and visual impairment in schools for the blind in Yaoundé (Cameroon)].

PubMed

Noche, Christelle Domngang; Bella, Assumpta Lucienne

2010-01-01

To determine the causes of blindness and visual impairment in students attending schools for the blind in Yaounde (Cameroon) and to estimate their frequencies. This study examined all 56 students at three schools for the blind in Yaoundé from September 15 through October 15, 2006. We collected data about their age, sex, medical and surgical history. Visual acuity was measured to determine their vision status according to the World Health Organization categories for blindness and visual impairment. All subjects underwent an ocular examination. Epi Info 3.5.1. was used for the statistical analysis of age, sex, visual acuity, causes of blindness and visual impairment, and etiologies. Fifty six people were examined: 37 men (66.1%) and 19 women (33.9%). Their mean age was 21.57 ± 10.53 years (min-max: 5-49), and 48.2% were in the 10-19 years age group (n = 27). In all, 87.5% were blind, 7.14% severely visually impaired, and 1.78% moderately visually impaired. The main causes of blindness and visual impairment in our sample were corneal disease (32.14%), optic nerve lesions (26.78%), cataract and its surgical complications (19.64%), retinal disorders (10.71%), glaucoma (8.92%, and malformations of the eyeball (1.78%). Their etiologies included congenital cataracts (19.64%), meningitis/fever (8.92%), glaucoma (7.14%), measles (5.35%), ocular trauma (5.35%), albinism (3.57%), Lyell syndrome (1.8%), and alcohol ingestion (1.8%). Etiology was unknown in 46.42%. Fifty per cent of these causes of blindness and visual impairment were treatable and/or preventable. Corneal lesions were the main cause of blindness and visual impairment in our sample. Fifty per cent of the causes found were treatable and/or preventable. Thus, substantial efforts are required to ensure access to better quality specialist ocular care. Furthermore, local authorities should create more centers specialised in the rehabilitation of the visual handicapped.

Simulations and Visualizations of Hurricane Sandy (2012) as Revealed by the NASA CAMVis

NASA Technical Reports Server (NTRS)

Shen, Bo-Wen

2013-01-01

Storm Sandy first appeared as a tropical storm in the southern Caribbean Sea on Oct. 22, 2012, moved northeastward, turned northwestward, and made landfall near Brigantine, New Jersey in late October. Sandy devastated surrounding areas, caused an estimated damage of $50 billion, and became the second costliest tropical cyclone (TC) in U.S. History surpassed only by Hurricane Katrina (2005). To save lives and mitigate economic damage, a central question to be addressed is to what extent the lead time of severe storm prediction such as Sandy can be extended (e.g., Emanuel 2012; Kerr 2012). In this study, we present 10 numerical experiments initialized at 00 and 1200 UTC Oct. 22-26, 2012, with the NASA coupled advanced global modeling and visualization systems (CAMVis). All of the predictions realistically capture Sandy's movement with the northwestward turn prior to its landfall. However, three experiments (initialized at 0000 UTC Oct. 22 and 24 and 1200 UTC Oct. 22) produce larger errors. Among the 10 experiments, the control run initialized at 0000 UTC Oct. 23 produces a remarkable 7-day forecast. To illustrate the impact of environmental flows on the predictability of Sandy, we produce and discuss four-dimensional (4-D) visualizations with the control run. 4-D visualizations clearly demonstrate the following multiscale processes that led to the sinuous track of Sandy: the initial steering impact of an upper-level trough (appearing over the northwestern Caribbean Sea and Gulf of Mexico), the blocking impact of systems to the northeast of Sandy, and the binary interaction with a mid-latitude, upper-level trough that appeared at 130degrees west longitude on Oct. 23, moved to the East Coast and intensified during the period of Oct. 29-30 prior to Sandy's landfall.

Prevalence and causes of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China.

PubMed

He, Jiangnan; Lu, Lina; Zou, Haidong; He, Xiangui; Li, Qiangqiang; Wang, Weijie; Zhu, Jianfeng

2014-12-22

To assess the prevalence of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China. Children from grade 1 to 5 in schools for children of migrant workers were randomly chosen for ocular examinations. All children were screened for uncorrected visual acuity and presenting visual acuity. After screening, the children whose uncorrected visual acuity was 20/40 or less received ocular motility evaluation, cycloplegic refraction/non-cycloplegic refraction, and external eye, anterior segment, media, and fundus examinations. A total of 9673 children were enumerated and 9512 (98.34%) participated in this study. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye were 13.33%, 11.26%, and 0.63%, respectively. The rate of wearing spectacles of the children with visual impairment in one or both eyes was 15.50%. Of these, 26.05% were wearing spectacles with inaccurate prescriptions. Refractive error was a major cause of visual impairment, accounting for 89.48% of all the visual impairment causes. Other causes of visual impairment included amblyopia accounting for 10.12%; congenital cataract, 0.1%; congenital nystagmus, 0.1%; ocular prosthesis, 0.1%; macular degeneration, 0.05%; and opaque cornea, 0.05%. This is the first study of the prevalence and causes of visual impairment in schools for children of migrant workers in Shanghai, China. The visual impairment rate in schools for children of migrant workers in suburbs of Shanghai in the best eye before vision correction was lower than those of urban children in mainstream schools in Guangzhou in 2012, and higher than students in rural of Beijing in 1998 and in suburb of Chongqing in 2007. The refractive error was the principal cause of the visual impairment of the children of migrant workers. The rate of wearing spectacles was low and the percentage of inaccurate prescriptions, among those who wore spectacles, was high. Uncorrected refractive error was a significant cause of visual impairment in migrant children.

Bridging Theory with Practice: An Exploratory Study of Visualization Use and Design for Climate Model Comparison

DOE PAGES

Dasgupta, Aritra; Poco, Jorge; Wei, Yaxing; ...

2015-03-16

Evaluation methodologies in visualization have mostly focused on how well the tools and techniques cater to the analytical needs of the user. While this is important in determining the effectiveness of the tools and advancing the state-of-the-art in visualization research, a key area that has mostly been overlooked is how well established visualization theories and principles are instantiated in practice. This is especially relevant when domain experts, and not visualization researchers, design visualizations for analysis of their data or for broader dissemination of scientific knowledge. There is very little research on exploring the synergistic capabilities of cross-domain collaboration between domainmore » experts and visualization researchers. To fill this gap, in this paper we describe the results of an exploratory study of climate data visualizations conducted in tight collaboration with a pool of climate scientists. The study analyzes a large set of static climate data visualizations for identifying their shortcomings in terms of visualization design. The outcome of the study is a classification scheme that categorizes the design problems in the form of a descriptive taxonomy. The taxonomy is a first attempt for systematically categorizing the types, causes, and consequences of design problems in visualizations created by domain experts. We demonstrate the use of the taxonomy for a number of purposes, such as, improving the existing climate data visualizations, reflecting on the impact of the problems for enabling domain experts in designing better visualizations, and also learning about the gaps and opportunities for future visualization research. We demonstrate the applicability of our taxonomy through a number of examples and discuss the lessons learnt and implications of our findings.« less

Bridging Theory with Practice: An Exploratory Study of Visualization Use and Design for Climate Model Comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasgupta, Aritra; Poco, Jorge; Wei, Yaxing

Evaluation methodologies in visualization have mostly focused on how well the tools and techniques cater to the analytical needs of the user. While this is important in determining the effectiveness of the tools and advancing the state-of-the-art in visualization research, a key area that has mostly been overlooked is how well established visualization theories and principles are instantiated in practice. This is especially relevant when domain experts, and not visualization researchers, design visualizations for analysis of their data or for broader dissemination of scientific knowledge. There is very little research on exploring the synergistic capabilities of cross-domain collaboration between domainmore » experts and visualization researchers. To fill this gap, in this paper we describe the results of an exploratory study of climate data visualizations conducted in tight collaboration with a pool of climate scientists. The study analyzes a large set of static climate data visualizations for identifying their shortcomings in terms of visualization design. The outcome of the study is a classification scheme that categorizes the design problems in the form of a descriptive taxonomy. The taxonomy is a first attempt for systematically categorizing the types, causes, and consequences of design problems in visualizations created by domain experts. We demonstrate the use of the taxonomy for a number of purposes, such as, improving the existing climate data visualizations, reflecting on the impact of the problems for enabling domain experts in designing better visualizations, and also learning about the gaps and opportunities for future visualization research. We demonstrate the applicability of our taxonomy through a number of examples and discuss the lessons learnt and implications of our findings.« less

The consequence of spatial visual processing dysfunction caused by traumatic brain injury (TBI).

PubMed

Padula, William V; Capo-Aponte, Jose E; Padula, William V; Singman, Eric L; Jenness, Jonathan

2017-01-01

A bi-modal visual processing model is supported by research to affect dysfunction following a traumatic brain injury (TBI). TBI causes dysfunction of visual processing affecting binocularity, spatial orientation, posture and balance. Research demonstrates that prescription of prisms influence the plasticity between spatial visual processing and motor-sensory systems improving visual processing and reducing symptoms following a TBI. The rationale demonstrates that visual processing underlies the functional aspects of binocularity, balance and posture. The bi-modal visual process maintains plasticity for efficiency. Compromise causes Post Trauma Vision Syndrome (PTVS) and Visual Midline Shift Syndrome (VMSS). Rehabilitation through use of lenses, prisms and sectoral occlusion has inter-professional implications in rehabilitation affecting the plasticity of the bi-modal visual process, thereby improving binocularity, spatial orientation, posture and balance Main outcomes: This review provides an opportunity to create a new perspective of the consequences of TBI on visual processing and the symptoms that are often caused by trauma. It also serves to provide a perspective of visual processing dysfunction that has potential for developing new approaches of rehabilitation. Understanding vision as a bi-modal process facilitates a new perspective of visual processing and the potentials for rehabilitation following a concussion, brain injury or other neurological events.

Leading causes of certifiable visual loss in England and Wales during the year ending 31 March 2013.

PubMed

Quartilho, A; Simkiss, P; Zekite, A; Xing, W; Wormald, R; Bunce, C

2016-04-01

The last article on causes of sight impairment (SI) in England and Wales was for April 2007-March 2008. This report updates these figures for April 2012-March 2013. In England and Wales, registration for SI is initiated by completion of a certificate of vision impairment (CVI). The main cause of visual impairment was ascertained for certificates completed April 2012-March 2013. A proportional comparison against April 2007-March 2008 was made. We received 24 009 CVIs of which 10 410 were for severe sight impairment (SSI) and 13 129 were for SI. These numbers were slightly higher than those observed in April 2007-March 2008 (9823 SSI; 12 607 SI). The ratio SI:SSI has remained static with 55% of all certifications being SI. The proportion of certificates without a single main cause has fallen slightly (16.6 to 14%). The proportion of certificates with a main cause of degeneration of the macula and posterior pole (mostly age-related macular degeneration (AMD)) decreased from 58.6 to 50% SSI and from 57.2 to 52.5% SI. Glaucoma remains the second most common cause (11% SSI; 7.6% SI) but hereditary retinal disorders overtook diabetes as third leading cause of SSI. AMD is still by far the leading cause of certifications for sight impairment in England and Wales (both SI and SSI). Proportionate changes have been observed since 2008, but it is important to note that a proportionate increase in one condition will impact on others.

[Ventriloquism and audio-visual integration of voice and face].

PubMed

Yokosawa, Kazuhiko; Kanaya, Shoko

2012-07-01

Presenting synchronous auditory and visual stimuli in separate locations creates the illusion that the sound originates from the direction of the visual stimulus. Participants' auditory localization bias, called the ventriloquism effect, has revealed factors affecting the perceptual integration of audio-visual stimuli. However, many studies on audio-visual processes have focused on performance in simplified experimental situations, with a single stimulus in each sensory modality. These results cannot necessarily explain our perceptual behavior in natural scenes, where various signals exist within a single sensory modality. In the present study we report the contributions of a cognitive factor, that is, the audio-visual congruency of speech, although this factor has often been underestimated in previous ventriloquism research. Thus, we investigated the contribution of speech congruency on the ventriloquism effect using a spoken utterance and two videos of a talking face. The salience of facial movements was also manipulated. As a result, when bilateral visual stimuli are presented in synchrony with a single voice, cross-modal speech congruency was found to have a significant impact on the ventriloquism effect. This result also indicated that more salient visual utterances attracted participants' auditory localization. The congruent pairing of audio-visual utterances elicited greater localization bias than did incongruent pairing, whereas previous studies have reported little dependency on the reality of stimuli in ventriloquism. Moreover, audio-visual illusory congruency, owing to the McGurk effect, caused substantial visual interference to auditory localization. This suggests that a greater flexibility in responding to multi-sensory environments exists than has been previously considered.

Range management visual impacts

Treesearch

Bruce R. Brown; David Kissel

1979-01-01

Historical overgrazing of western public rangelands has resulted in the passage of the Public Rangeland Improvement Act of 1978. The main purpose of this Act is to improve unsatisfactory range conditions. A contributing factor to unfavorable range conditions is adverse visual impacts. These visual impacts can be identified in three categories of range management: range...

Special Problems of People with Diabetes and Visual Impairment.

ERIC Educational Resources Information Center

Rosenthal, J. L.

1993-01-01

This article addresses the types of visual impairment caused by diabetes and the unique problems that people with diabetes and visual impairment face. Diabetic retinopathy, cataracts, glaucoma, and diabetic optic neuropathy are discussed as causes of visual impairment, and specific problems in basic living are identified, including diet,…

SalHUD--A Graphical Interface to Public Health Data in Puerto Rico.

PubMed

Ortiz-Zuazaga, Humberto G; Arce-Corretjer, Roberto; Solá-Sloan, Juan M; Conde, José G

2015-12-22

This paper describes SalHUD, a prototype web-based application for visualizing health data from Puerto Rico. Our initial focus was to provide interactive maps displaying years of potential life lost (YPLL). The public-use mortality file for year 2008 was downloaded from the Puerto Rico Institute of Statistics website. Data was processed with R, Python and EpiInfo to calculate years of potential life lost for the leading causes of death on each of the 78 municipalities in the island. Death records were classified according to ICD-10 codes. YPLL for each municipality was integrated into AtlasPR, a D3 Javascript map library. Additional Javascript, HTML and CSS programing was required to display maps as a web-based interface. YPLL for all municipalities are displayed on a map of Puerto Rico for each of the ten leading causes of death and for all causes combined, so users may dynamically explore the impact of premature mortality. This work is the first step in providing the general public in Puerto Rico with user-friendly, interactive, visual access to public health data that is usually published in numerical, text-based media.

Re-learning to see in cortical blindness

PubMed Central

Melnick, Michael D.; Tadin, Duje; Huxlin, Krystel R.

2016-01-01

The incidence of cortically induced blindness (CB) is increasing as our population ages. The major cause of CB is stroke affecting the primary visual cortex. While the impact of this form of vision loss is devastating to quality of life, the development of principled, effective rehabilitation strategies for this condition lags far behind those used to treat motor stroke victims. Here we summarize recent developments in the still emerging field of visual restitution therapy, and compare the relative effectiveness of different approaches. We also draw insights into the properties of recovered vision, its limitations and likely neural substrates. We hope that these insights will guide future research and bring us closer to the goal of providing much-needed rehabilitation solutions for this patient population. PMID:26659828

Ramping and Uncertainty Prediction Tool - Analysis and Visualization of Wind Generation Impact on Electrical Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Etingov, Pavel; Makarov, PNNL Yuri; Subbarao, PNNL Kris

RUT software is designed for use by the Balancing Authorities to predict and display additional requirements caused by the variability and uncertainty in load and generation. The prediction is made for the next operating hours as well as for the next day. The tool predicts possible deficiencies in generation capability and ramping capability. This deficiency of balancing resources can cause serious risks to power system stability and also impact real-time market energy prices. The tool dynamically and adaptively correlates changing system conditions with the additional balancing needs triggered by the interplay between forecasted and actual load and output of variablemore » resources. The assessment is performed using a specially developed probabilistic algorithm incorporating multiple sources of uncertainty including wind, solar and load forecast errors. The tool evaluates required generation for a worst case scenario, with a user-specified confidence level.« less

Causes of severe visual impairment and blindness in children attending schools for the visually handicapped in the Czech Republic.

PubMed

Kocur, I; Kuchynka, P; Rodný, S; Baráková, D; Schwartz, E C

2001-10-01

To describe the causes of severe visual impairment and blindness in children in schools for the visually handicapped in the Czech Republic in 1998. Pupils attending all 10 primary schools for the visually handicapped were examined. A modified WHO/PBL eye examination record for children with blindness and low vision was used. 229 children (146 males and 83 females) aged 6-15 years were included in the study: 47 children had severe visual impairment (20.5%) (visual acuity in their better eye less than 6/60), and 159 were blind (69.5%) (visual acuity in their better eye less than 3/60). Anatomically, the most affected parts of the eye were the retina (124, 54.2%), optic nerve (35, 15.3%), whole globe (25, 10.9%), lens (20, 8.7%), and uvea (12, 5.2%). Aetiologically (timing of insult leading to visual loss), the major cause of visual impairment was retinopathy of prematurity (ROP) (96, 41.9 %), followed by abnormalities of unknown timing of insult (97, 42.4%), and hereditary disease (21, 9.2%). In 90 children (40%), additional disabilities were present: mental disability (36, 16%), physical handicap (16, 7%), and/or a combination of both (19, 8%). It was estimated that 127 children (56%) suffer from visual impairment caused by potentially preventable and/or treatable conditions (for example, ROP, cataract, glaucoma). Establishing a study group for comprehensive evaluation of causes of visual handicap in children in the Czech Republic, as well as for detailed analysis of present practice of screening for ROP was recommended.

The dark side of photovoltaic — 3D simulation of glare assessing risk and discomfort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, Thomas; Wollert, Alexander

2015-04-15

Photovoltaic (PV) systems form an important force in the implementation of renewable energies, but as we all know, the force has always its dark side. Besides efficiency considerations and discussions about architectures of power distribution networks, the increasing numbers of installations of PV systems for implementing renewable energies have secondary effects. PV systems can generate glare due to optical reflections and hence might be a serious concern. On the one hand, glare could affect safety, e.g. regarding traffic. On the other hand, glare is a constant source of discomfort in vicinities of PV systems. Hence, assessment of glare is decisivemore » for the success of renewable energies near municipalities and traffic zones for the success of solar power. Several courts decided on the change of PV systems and even on their de-installation because of glare effects. Thus, location-based assessments are required to limit potential reflections and to avoid risks for public infrastructure or discomfort of residents. The question arises on how to calculate reflections accurately according to the environment's topography. Our approach is founded in a 3D-based simulation methodology to calculate and visualize reflections based on the geometry of the environment of PV systems. This computational model is implemented by an interactive tool for simulation and visualization. Hence, project planners receive flexible assistance for adjusting the parameters of solar panels amid the planning process and in particular before the installation of a PV system. - Highlights: • Solar panels cause glare that impacts neighborhoods and traffic infrastructures. • Glare might cause disability and discomfort. • 3D environment for the calculation of glare • Interactive tool to simulate and visualize reflections • Impact assessment of solar power plant farms.« less

[Survey on avoidable blindness and visual impairment in Panama].

PubMed

López, Maritza; Brea, Ileana; Yee, Rita; Yi, Rodolfo; Carles, Víctor; Broce, Alberto; Limburg, Hans; Silva, Juan Carlos

2014-12-01

Determine prevalence of blindness and visual impairment in adults aged ≥ 50 years in Panama, identify their main causes, and characterize eye health services. Cross-sectional population study using standard Rapid Assessment of Avoidable Blindness methodology. Fifty people aged ≥ 50 years were selected from each of 84 clusters chosen through representative random sampling of the entire country. Visual acuity was assessed using a Snellen chart; lens and posterior pole status were assessed by direct ophthalmoscopy. Cataract surgery coverage was calculated and its quality assessed, along with causes of visual acuity < 20/60 and barriers to access to surgical treatment. A total of 4 125 people were examined (98.2% of the calculated sample). Age- and sex-adjusted prevalence of blindness was 3.0% (95% CI: 2.3-3.6). The main cause of blindness was cataract (66.4%), followed by glaucoma (10.2%). Cataract (69.2%) was the main cause of severe visual impairment and uncorrected refractive errors were the main cause of moderate visual impairment (60.7%). Surgical cataract coverage in individuals was 76.3%. Of all eyes operated for cataract, 58.0% achieved visual acuity ≤ 20/60 with available correction. Prevalence of blindness in Panama is in line with average prevalence found in other countries of the Region. This problem can be reduced, since 76.2% of cases of blindness and 85.0% of cases of severe visual impairment result from avoidable causes.

Impact of intravitreal pharmacotherapies including antivascular endothelial growth factor and corticosteroid agents on diabetic retinopathy.

PubMed

Wykoff, Charles C

2017-05-01

Diabetic retinopathy is common and increasing in prevalence. Pharmacologic management of diabetic macular edema (DME) has improved tremendously over the last decade with the use of two families of intravitreally administered medications: antivascular endothelial growth factor-specific agents and corticosteroids. Clinical evaluation of these pharmaceuticals has demonstrated that they can have a substantial impact on diabetic retinopathy severity levels and the underlying retinal vasculature itself. Phase 3 trials employing ranibizumab, aflibercept, and fluocinolone acetonide enrolling eyes with center-involving DME causing visual acuity loss have demonstrated impressive alteration of the natural history of progressive diabetic retinopathy worsening over time through blunted progression to proliferative diabetic retinopathy, improving diabetic retinopathy severity levels, and slowing progressive retinal nonperfusion, the underlying disease process central to diabetic retinopathy itself. Accumulating data indicate that the threshold to initiate ocular-specific pharmacologic treatment for diabetic retinopathy, previously predominately limited to eyes with visual loss because of center-involved DME or proliferative diabetic retinopathy, is being lowered to earlier stages of diabetic retinopathy. Ongoing clinical trials and secondary analyses continue to further explore the impact and durability of vascular endothelial growth factor blockade and corticosteroids on modification of diabetic retinopathy and the underlying retinal vasculature itself.

Ocean acidification and responses to predators: can sensory redundancy reduce the apparent impacts of elevated CO2 on fish?

PubMed

Lönnstedt, Oona M; Munday, Philip L; McCormick, Mark I; Ferrari, Maud C O; Chivers, Douglas P

2013-09-01

Carbon dioxide (CO2) levels in the atmosphere and surface ocean are rising at an unprecedented rate due to sustained and accelerating anthropogenic CO2 emissions. Previous studies have documented that exposure to elevated CO2 causes impaired antipredator behavior by coral reef fish in response to chemical cues associated with predation. However, whether ocean acidification will impair visual recognition of common predators is currently unknown. This study examined whether sensory compensation in the presence of multiple sensory cues could reduce the impacts of ocean acidification on antipredator responses. When exposed to seawater enriched with levels of CO2 predicted for the end of this century (880 μatm CO2), prey fish completely lost their response to conspecific alarm cues. While the visual response to a predator was also affected by high CO2, it was not entirely lost. Fish exposed to elevated CO2, spent less time in shelter than current-day controls and did not exhibit antipredator signaling behavior (bobbing) when multiple predator cues were present. They did, however, reduce feeding rate and activity levels to the same level as controls. The results suggest that the response of fish to visual cues may partially compensate for the lack of response to chemical cues. Fish subjected to elevated CO2 levels, and exposed to chemical and visual predation cues simultaneously, responded with the same intensity as controls exposed to visual cues alone. However, these responses were still less than control fish simultaneously exposed to chemical and visual predation cues. Consequently, visual cues improve antipredator behavior of CO2 exposed fish, but do not fully compensate for the loss of response to chemical cues. The reduced ability to correctly respond to a predator will have ramifications for survival in encounters with predators in the field, which could have repercussions for population replenishment in acidified oceans.

The Prevalence and Causes of Visual Impairment and Blindness Among Older Adults in the City of Lodz, Poland

PubMed Central

Nowak, Michal S.; Smigielski, Janusz

2015-01-01

Abstract To investigate the prevalence and causes of visual impairment and blindness in a sample of Polish older adults. The study was designed in a cross-sectional and observational manner. Data concerning the vision status were assessed in 2214 eyes from 1107 subjects of European Caucasian origin; most of whom live in the city of Lodz, in central Poland. Visual impairment was defined as distance visual acuity <20/40 in the worse-seeing eye. Low vision was defined as best-corrected visual acuity (BCVA) <20/40 but >20/200 in better-seeing eye, and blindness was defined as BCVA ≤20/200 in both eyes (United States criteria). Visual impairment was found in 27.5% subjects in the worse-seeing eye. Multiple regression analysis showed that increasing age (OR 0.98, 95% CI 0.97–0.99) and female gender (OR 1.47, 95% CI 1.11–1.93) were independent risk factors. No association was found between visual impairment and socioeconomic status of subjects. Noncorrectable visual impairment was found in 7.0% of subjects, including 5.2% of subjects with unilateral and 1.8% of subjects with bilateral visual impairment. Low vision and blindness accounted for 1.3% and 0.5%, respectively, and were only associated with older age (OR 1.05, 95% CI 1.02–1.10). Retinal diseases represented the major cause of noncorrectable visual impairment and accounted for more than half of causes of blindness. Provision of appropriate refractive correction improves visual acuity in 75% subjects presenting with visual impairment. Retinal diseases are a major cause of noncorrectable visual impairment and blindness in this older population. PMID:25654398

The prevalence and causes of visual impairment and blindness among older adults in the city of Lodz, Poland.

PubMed

Nowak, Michal S; Smigielski, Janusz

2015-02-01

To investigate the prevalence and causes of visual impairment and blindness in a sample of Polish older adults. The study was designed in a cross-sectional and observational manner. Data concerning the vision status were assessed in 2214 eyes from 1107 subjects of European Caucasian origin; most of whom live in the city of Lodz, in central Poland. Visual impairment was defined as distance visual acuity <20/40 in the worse-seeing eye. Low vision was defined as best-corrected visual acuity (BCVA) <20/40 but >20/200 in better-seeing eye, and blindness was defined as BCVA ≤20/200 in both eyes (United States criteria). Visual impairment was found in 27.5% subjects in the worse-seeing eye. Multiple regression analysis showed that increasing age (OR 0.98, 95% CI 0.97-0.99) and female gender (OR 1.47, 95% CI 1.11-1.93) were independent risk factors. No association was found between visual impairment and socioeconomic status of subjects. Noncorrectable visual impairment was found in 7.0% of subjects, including 5.2% of subjects with unilateral and 1.8% of subjects with bilateral visual impairment. Low vision and blindness accounted for 1.3% and 0.5%, respectively, and were only associated with older age (OR 1.05, 95% CI 1.02-1.10). Retinal diseases represented the major cause of noncorrectable visual impairment and accounted for more than half of causes of blindness. Provision of appropriate refractive correction improves visual acuity in 75% subjects presenting with visual impairment. Retinal diseases are a major cause of noncorrectable visual impairment and blindness in this older population.

Computer vision syndrome: a review of ocular causes and potential treatments.

PubMed

Rosenfield, Mark

2011-09-01

Computer vision syndrome (CVS) is the combination of eye and vision problems associated with the use of computers. In modern western society the use of computers for both vocational and avocational activities is almost universal. However, CVS may have a significant impact not only on visual comfort but also occupational productivity since between 64% and 90% of computer users experience visual symptoms which may include eyestrain, headaches, ocular discomfort, dry eye, diplopia and blurred vision either at near or when looking into the distance after prolonged computer use. This paper reviews the principal ocular causes for this condition, namely oculomotor anomalies and dry eye. Accommodation and vergence responses to electronic screens appear to be similar to those found when viewing printed materials, whereas the prevalence of dry eye symptoms is greater during computer operation. The latter is probably due to a decrease in blink rate and blink amplitude, as well as increased corneal exposure resulting from the monitor frequently being positioned in primary gaze. However, the efficacy of proposed treatments to reduce symptoms of CVS is unproven. A better understanding of the physiology underlying CVS is critical to allow more accurate diagnosis and treatment. This will enable practitioners to optimize visual comfort and efficiency during computer operation. Ophthalmic & Physiological Optics © 2011 The College of Optometrists.

The impact of interference on short-term memory for visual orientation.

PubMed

Rademaker, Rosanne L; Bloem, Ilona M; De Weerd, Peter; Sack, Alexander T

2015-12-01

Visual short-term memory serves as an efficient buffer for maintaining no longer directly accessible information. How robust are visual memories against interference? Memory for simple visual features has proven vulnerable to distractors containing conflicting information along the relevant stimulus dimension, leading to the idea that interacting feature-specific channels at an early stage of visual processing support memory for simple visual features. Here we showed that memory for a single randomly orientated grating was susceptible to interference from a to-be-ignored distractor grating presented midway through a 3-s delay period. Memory for the initially presented orientation became noisier when it differed from the distractor orientation, and response distributions were shifted toward the distractor orientation (by ∼3°). Interestingly, when the distractor was rendered task-relevant by making it a second memory target, memory for both retained orientations showed reduced reliability as a function of increased orientation differences between them. However, the degree to which responses to the first grating shifted toward the orientation of the task-relevant second grating was much reduced. Finally, using a dichoptic display, we demonstrated that these systematic biases caused by a consciously perceived distractor disappeared once the distractor was presented outside of participants' awareness. Together, our results show that visual short-term memory for orientation can be systematically biased by interfering information that is consciously perceived. (c) 2015 APA, all rights reserved).

The impact of macular surgery in different grades of epiretinal membrane.

PubMed

Batman, Cosar; Citirik, Mehmet

2017-01-01

To assess the impact of macular surgery on the functional and anatomic outcomes of the patients in different grades of epiretinal membrane (ERM). Seventy-one eyes of 71 patients who underwent 23-gauge transconjunctival sutureless pars plana vitrectomy for primary isolated ERM were evaluated in this study. There were 38 females (53.5%) and 33 males (46.5%). The average age of the patients was 68.1y (range 42-89y). Mean follow up period was 14mo (range 6-26mo). The cases were divided into two subgroups of cellophane maculopathy (CM) and macular pucker (MP). An improvement was observed in the postoperative best-corrected visual acuity (BCVA), as well as a decrement in central foveal thickness (CFT) in both groups (both of these being statistically significant; P =0.001). In comparison between two groups, it was found that there was a significant improvement on BCVA and CFT in CM group than MP group ( P =0.01). Furthermore, the postoperative fundus findings regarding RPE alterations and macular edema were significantly higher in MP group when compared to the CM group ( P =0.01). ERM and internal limiting membrane peeling surgery can lead to a significant reduction of CFT and visual improvements in idiopathic ERM. A long-term ERM persistence will cause unrecoverable retinal damage and visual loss.

The effects of age on crash risk associated with driver distraction.

PubMed

Guo, Feng; Klauer, Sheila G; Fang, Youjia; Hankey, Jonathan M; Antin, Jonathan F; Perez, Miguel A; Lee, Suzanne E; Dingus, Thomas A

2017-02-01

Driver distraction is a major contributing factor to crashes, which are the leading cause of death for the US population under 35 years of age. The prevalence of secondary-task engagement and its impacts on distraction and crashes may vary substantially by driver age. Driving performance and behaviour data were collected continuously using multiple cameras and sensors in situ for 3542 participant drivers recruited for up to 3 years for the Second Strategic Highway Research Program Naturalistic Driving Study. Secondary-task engagement at the onset of crashes and during normal driving segments was identified from videos. A case-cohort approach was used to estimate the crash odds ratios associated with, and the prevalence of, secondary tasks for four age groups: 16-20, 21-29, 30-64 and 65-98 years of age. Only severe crashes (property damage and higher severity) were included in the analysis. Secondary-task-induced distraction posed a consistently higher threat for drivers younger than 30 and above 65 when compared with middle-aged drivers, although senior drivers engaged in secondary tasks much less frequently than their younger counterparts. Secondary tasks with high visual-manual demand (e.g. visual-manual tasks performed on cell phones) affected drivers of all ages. Certain secondary tasks, such as operation of in-vehicle devices and talking/singing, increased the risk for only certain age groups. Teenaged, young adult drivers and senior drivers are more adversely impacted by secondary-task engagement than middle-aged drivers. Visual-manual distractions impact drivers of all ages, whereas cognitive distraction may have a larger impact on young drivers. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

Causes of severe visual impairment and blindness in children attending schools for the visually handicapped in the Czech Republic

PubMed Central

Kocur, I; Kuchynka, P; Rodny, S; Barakova, D; Schwartz, E

2001-01-01

AIMS—To describe the causes of severe visual impairment and blindness in children in schools for the visually handicapped in the Czech Republic in 1998.
METHODS—Pupils attending all 10 primary schools for the visually handicapped were examined. A modified WHO/PBL eye examination record for children with blindness and low vision was used.
RESULTS—229 children (146 males and 83 females) aged 6-15 years were included in the study: 47 children had severe visual impairment (20.5%) (visual acuity in their better eye less than 6/60), and 159 were blind (69.5%) (visual acuity in their better eye less than 3/60). Anatomically, the most affected parts of the eye were the retina (124, 54.2%), optic nerve (35, 15.3%), whole globe (25, 10.9%), lens (20, 8.7%), and uvea (12, 5.2%). Aetiologically (timing of insult leading to visual loss), the major cause of visual impairment was retinopathy of prematurity (ROP) (96, 41.9 %), followed by abnormalities of unknown timing of insult (97, 42.4%), and hereditary disease (21, 9.2%). In 90 children (40%), additional disabilities were present: mental disability (36, 16%), physical handicap (16, 7%), and/or a combination of both (19, 8%). It was estimated that 127 children (56%) suffer from visual impairment caused by potentially preventable and/or treatable conditions (for example, ROP, cataract, glaucoma).
CONCLUSIONS—Establishing a study group for comprehensive evaluation of causes of visual handicap in children in the Czech Republic, as well as for detailed analysis of present practice of screening for ROP was recommended.

 PMID:11567954

Prevalence and Causes of Visual Loss Among the Indigenous Peoples of the World: A Systematic Review.

PubMed

Foreman, Joshua; Keel, Stuart; van Wijngaarden, Peter; Bourne, Rupert A; Wormald, Richard; Crowston, Jonathan; Taylor, Hugh R; Dirani, Mohamed

2018-05-01

Studies have documented a higher disease burden in indigenous compared with nonindigenous populations, but no global data on the epidemiology of visual loss in indigenous peoples are available. A systematic review of literature on visual loss in the world's indigenous populations could identify major gaps and inform interventions to reduce their burden of visual loss. To conduct a systematic review on the prevalence and causes of visual loss among the world's indigenous populations. A search of databases and alternative sources identified literature on the prevalence and causes of visual loss (visual impairment and blindness) and eye diseases in indigenous populations. Studies from January 1, 1990, through August 1, 2017, that included clinical eye examinations of indigenous participants and, where possible, compared findings with those of nonindigenous populations were included. Methodologic quality of studies was evaluated to reveal gaps in the literature. Limited data were available worldwide. A total of 85 articles described 64 unique studies from 24 countries that examined 79 598 unique indigenous participants. Nineteen studies reported comparator data on 42 085 nonindigenous individuals. The prevalence of visual loss was reported in 13 countries, with visual impairment ranging from 0.6% in indigenous Australian children to 48.5% in native Tibetans 50 years or older. Uncorrected refractive error was the main cause of visual impairment (21.0%-65.1%) in 5 of 6 studies that measured presenting visual acuity. Cataract was the main cause of visual impairment in all 6 studies measuring best-corrected acuity (25.4%-72.2%). Cataract was the leading cause of blindness in 13 studies (32.0%-79.2%), followed by uncorrected refractive error in 2 studies (33.0% and 35.8%). Most countries with indigenous peoples do not have data on the burden of visual loss in these populations. Although existing studies vary in methodologic quality and reliability, they suggest that most visual loss in indigenous populations is avoidable. Improvements in quality and frequency of research into the eye health of indigenous communities appear to be required, and coordinated eye care programs should be implemented to specifically target the indigenous peoples of the world.

The prevalence and causes of visual impairment in seven-year-old children.

PubMed

Ghaderi, Soraya; Hashemi, Hassan; Jafarzadehpur, Ebrahim; Yekta, Abbasali; Ostadimoghaddam, Hadi; Mirzajani, Ali; Khabazkhoob, Mehdi

2018-05-01

To report the prevalence and causes of visual impairment in seven-year-old children in Iran and its relationship with socio-economic conditions. In a cross-sectional population-based study, first-grade students in the primary schools of eight cities in the country were randomly selected from different geographic locations using multistage cluster sampling. The examinations included visual acuity measurement, ocular motility evaluation, and cycloplegic and non-cycloplegic refraction. Using the definitions of the World Health Organization (presenting visual acuity less than or equal to 6/18 in the better eye) to estimate the prevalence of vision impairment, the present study reported presenting visual impairment in seven-year-old children. Of 4,614 selected students, 4,106 students participated in the study (response rate 89 per cent), of whom 2,127 (51.8 per cent) were male. The prevalence of visual impairment according to a visual acuity of 6/18 was 0.341 per cent (95 per cent confidence interval 0.187-0.571); 1.34 per cent (95 per cent confidence interval 1.011-1.74) of children had visual impairment according to a visual acuity of 6/18 in at least one eye. Sixty-six (1.6 per cent) and 23 (0.24 per cent) children had visual impairment according to a visual acuity of 6/12 in the worse and better eye, respectively. The most common causes of visual impairment were refractive errors (81.8 per cent) and amblyopia (14.5 per cent). Among different types of refractive errors, astigmatism was the main refractive error leading to visual impairment. According to the concentration index, the distribution of visual impairment in children from low-income families was higher. This study revealed a high prevalence of visual impairment in a representative sample of seven-year-old Iranian children. Astigmatism and amblyopia were the most common causes of visual impairment. The distribution of visual impairment was higher in children from low-income families. Cost-effective strategies are needed to address these easily treatable causes of visual impairment. © 2017 Optometry Australia.

Unilateral Amblyopia Affects Two Eyes: Fellow Eye Deficits in Amblyopia.

PubMed

Meier, Kimberly; Giaschi, Deborah

2017-03-01

Unilateral amblyopia is a visual disorder that arises after selective disruption of visual input to one eye during critical periods of development. In the clinic, amblyopia is understood as poor visual acuity in an eye that was deprived of pattern vision early in life. By its nature, however, amblyopia has an adverse effect on the development of a binocular visual system and the interactions between signals from two eyes. Visual functions aside from visual acuity are impacted, and many studies have indicated compromised sensitivity in the fellow eye even though it demonstrates normal visual acuity. While these fellow eye deficits have been noted, no overarching theory has been proposed to describe why and under what conditions the fellow eye is impacted by amblyopia. Here, we consider four explanations that may account for decreased fellow eye sensitivity: the fellow eye is adversely impacted by treatment for amblyopia; the maturation of the fellow eye is delayed by amblyopia; fellow eye sensitivity is impacted for visual functions that rely on binocular cortex; and fellow eye deficits reflect an adaptive mechanism that works to equalize the sensitivity of the two eyes. To evaluate these ideas, we describe five visual functions that are commonly reported to be deficient in the amblyopic eye (hyperacuity, contrast sensitivity, spatial integration, global motion, and motion-defined form), and unify the current evidence for fellow eye deficits. Further research targeted at exploring fellow eye deficits in amblyopia will provide us with a broader understanding of normal visual development and how amblyopia impacts the developing visual system.

Landscape control points: a procedure for predicting and monitoring visual impacts

Treesearch

R. Burton Litton

1973-01-01

The visual impacts of alterations to the landscape can be studied by setting up Landscape Control Points–a network of permanently established observation sites. Such observations enable the forest manager to anticipate visual impacts of management decision, select from a choice of alternative solutions, cover an area for comprehensive viewing, and establish a method to...

The Impact of Residual Vision in Spatial Skills of Individuals with Visual Impairments

ERIC Educational Resources Information Center

Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

2011-01-01

Loss of vision is believed to have a great impact on the acquisition of spatial knowledge. The aims of the present study are to examine the performance of individuals with visual impairments on spatial tasks and the impact of residual vision on processing these tasks. In all, 28 individuals with visual impairments--blindness or low…

Global data on visual impairment in the year 2002.

PubMed Central

Resnikoff, Serge; Pascolini, Donatella; Etya'ale, Daniel; Kocur, Ivo; Pararajasegaram, Ramachandra; Pokharel, Gopal P.; Mariotti, Silvio P.

2004-01-01

This paper presents estimates of the prevalence of visual impairment and its causes in 2002, based on the best available evidence derived from recent studies. Estimates were determined from data on low vision and blindness as defined in the International statistical classification of diseases, injuries and causes of death, 10th revision. The number of people with visual impairment worldwide in 2002 was in excess of 161 million, of whom about 37 million were blind. The burden of visual impairment is not distributed uniformly throughout the world: the least developed regions carry the largest share. Visual impairment is also unequally distributed across age groups, being largely confined to adults 50 years of age and older. A distribution imbalance is also found with regard to gender throughout the world: females have a significantly higher risk of having visual impairment than males. Notwithstanding the progress in surgical intervention that has been made in many countries over the last few decades, cataract remains the leading cause of visual impairment in all regions of the world, except in the most developed countries. Other major causes of visual impairment are, in order of importance, glaucoma, age-related macular degeneration, diabetic retinopathy and trachoma. PMID:15640920

Global data on visual impairment in the year 2002.

PubMed

Resnikoff, Serge; Pascolini, Donatella; Etya'ale, Daniel; Kocur, Ivo; Pararajasegaram, Ramachandra; Pokharel, Gopal P; Mariotti, Silvio P

2004-11-01

This paper presents estimates of the prevalence of visual impairment and its causes in 2002, based on the best available evidence derived from recent studies. Estimates were determined from data on low vision and blindness as defined in the International statistical classification of diseases, injuries and causes of death, 10th revision. The number of people with visual impairment worldwide in 2002 was in excess of 161 million, of whom about 37 million were blind. The burden of visual impairment is not distributed uniformly throughout the world: the least developed regions carry the largest share. Visual impairment is also unequally distributed across age groups, being largely confined to adults 50 years of age and older. A distribution imbalance is also found with regard to gender throughout the world: females have a significantly higher risk of having visual impairment than males. Notwithstanding the progress in surgical intervention that has been made in many countries over the last few decades, cataract remains the leading cause of visual impairment in all regions of the world, except in the most developed countries. Other major causes of visual impairment are, in order of importance, glaucoma, age-related macular degeneration, diabetic retinopathy and trachoma.

Vitrectomy for primary symptomatic vitreous opacities: an evidence-based review

PubMed Central

Ivanova, T; Jalil, A; Antoniou, Y; Bishop, P N; Vallejo-Garcia, J L; Patton, N

2016-01-01

Floaters are a common ocular condition which form as a consequence of aging changes in the vitreous. Although in most patients the symptoms are minimal, they can cause significant impairment in vision-related quality of life in a small population of patients. Recently there has been an increase in awareness of the visual disability caused by floaters, and the evidence-base for treatment of this condition using small-gauge vitrectomy has increased. In this review, we define the term ‘floaters' as symptomatic vitreous opacities (SVO). We suggest a classification dependent on the presence or absence of posterior vitreous detachment and discuss their pathogenesis and natural history. We review their impact on patients' quality of life related to visual function. We review the psychological factors that may have a role in some patients who appear to be affected by SVO to the extent that they pursue all options including surgery with all its attendant risks. We summarise the available evidence-base of treatment options available for SVO with special emphasis on the safety and efficacy of vitrectomy for this condition. PMID:26939559

Demographic and clinical characteristics of a paediatric low vision population in a low vision clinic in China.

PubMed

Gao, Guohong; Yu, Manrong; Dai, Jinhui; Xue, Feng; Wang, Xiaoying; Zou, Leilei; Chen, Minjie; Ma, Fei

2016-05-01

The aim was to describe the characteristics of the paediatric population attending the low vision clinic of the Eye and ENT Hospital, located in Shanghai, China. The clinical records of all the children attending the low vision clinic of Eye and ENT Hospital affiliated to Fudan University between January 1, 2009 and May 31, 2014 were retrospectively reviewed. The main data analysed were age, gender, education, visual demand, diagnosis, visual acuity and prescription of low vision aids. Of the 162 patients, 104 (64.20 per cent) were male. The age range of the study population was three to 20 years, with a mean of 10.73 ± 5.08 years. There were 43.21 per cent with moderate visual impairment, 26.54 per cent had severe visual impairment and 19.75 per cent were blind. The leading causes of visual impairment were congenital cataract (21.61 per cent), optic atrophy (14.20 per cent), macular dystrophy (11.73 per cent), nystagmus (9.88 per cent) and congenital glaucoma (9.26 per cent). The most frequently prescribed low vision devices for distant and near vision were binocular telescopes (23.57 per cent) and stand magnifiers (22.93 per cent), respectively. Young age (up to six years, 37.93 per cent), high cost (24.14 per cent), cosmetic reasons (17.24 per cent) and inconvenience (13.79 per cent) were the main reasons that children or parents refused to accept useful low vision aids. Congenital and hereditary diseases constituted the major causes of low vision in the study population. Strategies that make good-quality rehabilitation services available, affordable and accessible, especially in developing countries, will have the greatest impact on visual impairment. In China, both urban and rural, the coverage of low vision services should be strengthened. © 2016 The Authors. Clinical and Experimental Optometry © 2016 Optometry Australia.

Intracranial Aneurysms of Neuro-Ophthalmologic Relevance.

PubMed

Micieli, Jonathan A; Newman, Nancy J; Barrow, Daniel L; Biousse, Valérie

2017-12-01

Intracranial saccular aneurysms are acquired lesions that often present with neuro-ophthalmologic symptoms and signs. Recent advances in neurosurgical techniques, endovascular treatments, and neurocritical care have improved the optimal management of symptomatic unruptured aneurysms, but whether the chosen treatment has an impact on neuro-ophthalmologic outcomes remains debated. A review of the literature focused on neuro-ophthalmic manifestations and treatment of intracranial aneurysms with specific relevance to neuro-ophthalmologic outcomes was conducted using Ovid MEDLINE and EMBASE databases. Cavernous sinus aneurysms were not included in this review. Surgical clipping vs endovascular coiling for aneurysms causing third nerve palsies was compared in 13 retrospective studies representing 447 patients. Complete recovery was achieved in 78% of surgical patients compared with 44% of patients treated with endovascular coiling. However, the complication rate, hospital costs, and days spent in intensive care were reported as higher in surgically treated patients. Retrospective reviews of surgical clipping and endovascular coiling for all ocular motor nerve palsies (third, fourth, or sixth cranial nerves) revealed similar results of complete resolution in 76% and 49%, respectively. Improvement in visual deficits related to aneurysmal compression of the anterior visual pathways was also better among patients treated with clipping than with coiling. The time to treatment from onset of visual symptoms was a predictive factor of visual recovery in several studies. Few reports have specifically assessed the improvement of visual deficits after treatment with flow diverters. Decisions regarding the choice of therapy for intracranial aneurysms causing neuro-ophthalmologic signs ideally should be made at high-volume centers with access to both surgical and endovascular treatments. The status of the patient, location of the aneurysm, and experience of the treating physicians are important factors to consider. Although a higher rate of visual recovery was reported with neurosurgical clipping, this must be weighed against the potentially longer intensive care stays and increased early morbidity.

Effects of aging on audio-visual speech integration.

PubMed

Huyse, Aurélie; Leybaert, Jacqueline; Berthommier, Frédéric

2014-10-01

This study investigated the impact of aging on audio-visual speech integration. A syllable identification task was presented in auditory-only, visual-only, and audio-visual congruent and incongruent conditions. Visual cues were either degraded or unmodified. Stimuli were embedded in stationary noise alternating with modulated noise. Fifteen young adults and 15 older adults participated in this study. Results showed that older adults had preserved lipreading abilities when the visual input was clear but not when it was degraded. The impact of aging on audio-visual integration also depended on the quality of the visual cues. In the visual clear condition, the audio-visual gain was similar in both groups and analyses in the framework of the fuzzy-logical model of perception confirmed that older adults did not differ from younger adults in their audio-visual integration abilities. In the visual reduction condition, the audio-visual gain was reduced in the older group, but only when the noise was stationary, suggesting that older participants could compensate for the loss of lipreading abilities by using the auditory information available in the valleys of the noise. The fuzzy-logical model of perception confirmed the significant impact of aging on audio-visual integration by showing an increased weight of audition in the older group.

Risk factors affecting visual-motor coordination deficit among children residing near a petrochemical industrial estate.

PubMed

Aungudornpukdee, P; Vichit-Vadakan, N

2009-12-01

Thailand has been changed to rapid urbanization and industrialization since 1980s. During 1992 through 1996, the number of industrial factories in Rayong province increased very sharply. The major types of industries are petrol-chemical and plastic production. However, after the petrochemical industry boomed, the higher demand led to an industrial area expansion. The establishment of factories in this area leads to serious environmental and health impacts. The study aims to investigate the factors that affect visual-motor coordination deficit among children, 6-13 years of age, residing near the Petrochemical Industrial Estate, Map Ta Phut, Rayong province. A population-based cross-sectional study was employed for collecting data on neurobehavioral effects using the Digit Symbol Test. The study found one-third of 2,956 children presented with visual-motor coordination deficits. Three factors were identified that caused children to have a higher risk of visual-motor coordination deficits: gender (adjusted OR 1.934), monthly parental income (range of adjusted OR 1.977 - 2.612), and household environmental tobacco smoke (adjusted OR 1.284), while age (adjusted OR 0.874) and living period (adjusted OR 0.954) in study areas were reversed effects on visual-motor coordination deficit among children. The finding indicated that children with visual-motor coordination deficit were affected by gender, monthly parental income, age of children, length of living period, and household environmental tobacco smoke.

Front-Presented Looming Sound Selectively Alters the Perceived Size of a Visual Looming Object.

PubMed

Yamasaki, Daiki; Miyoshi, Kiyofumi; Altmann, Christian F; Ashida, Hiroshi

2018-07-01

In spite of accumulating evidence for the spatial rule governing cross-modal interaction according to the spatial consistency of stimuli, it is still unclear whether 3D spatial consistency (i.e., front/rear of the body) of stimuli also regulates audiovisual interaction. We investigated how sounds with increasing/decreasing intensity (looming/receding sound) presented from the front and rear space of the body impact the size perception of a dynamic visual object. Participants performed a size-matching task (Experiments 1 and 2) and a size adjustment task (Experiment 3) of visual stimuli with increasing/decreasing diameter, while being exposed to a front- or rear-presented sound with increasing/decreasing intensity. Throughout these experiments, we demonstrated that only the front-presented looming sound caused overestimation of the spatially consistent looming visual stimulus in size, but not of the spatially inconsistent and the receding visual stimulus. The receding sound had no significant effect on vision. Our results revealed that looming sound alters dynamic visual size perception depending on the consistency in the approaching quality and the front-rear spatial location of audiovisual stimuli, suggesting that the human brain differently processes audiovisual inputs based on their 3D spatial consistency. This selective interaction between looming signals should contribute to faster detection of approaching threats. Our findings extend the spatial rule governing audiovisual interaction into 3D space.

Elevated intracranial pressure causes optic nerve and retinal ganglion cell degeneration in mice.

PubMed

Nusbaum, Derek M; Wu, Samuel M; Frankfort, Benjamin J

2015-07-01

The purpose of this study was to develop a novel experimental system for the modulation and measurement of intracranial pressure (ICP), and to use this system to assess the impact of elevated ICP on the optic nerve and retinal ganglion cells (RGCs) in CD1 mice. This system involved surgical implantation of an infusion cannula and a radiowave based pressure monitoring probe through the skull and into the subarachnoid space. The infusion cannula was used to increase ICP, which was measured by the probe and transmitted to a nearby receiver. The system provided robust and consistent ICP waveforms, was well tolerated, and was stable over time. ICP was elevated to approximately 30 mmHg for one week, after which we assessed changes in optic nerve structure with transmission electron microscopy in cross section and RGC numbers with antibody staining in retinal flat mounts. ICP elevation resulted in optic nerve axonal loss and disorganization, as well as RGC soma loss. We conclude that the controlled manipulation of ICP in active, awake mice is possible, despite their small size. Furthermore, ICP elevation results in visual system phenotypes of optic nerve and RGC degeneration, suggesting that this model can be used to study the impact of ICP on the visual system. Potentially, this model can also be used to study the relationship between ICP and IOP, as well diseases impacted by ICP variation such as glaucoma, idiopathic intracranial hypertension, and the spaceflight-related visual impairment intracranial pressure syndrome. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Economic Burden of Visual Impairment and Comorbid Fatigue: A Cost-of-Illness Study (From a Societal Perspective).

PubMed

Schakel, Wouter; van der Aa, Hilde P A; Bode, Christina; Hulshof, Carel T J; van Rens, Ger H M B; van Nispen, Ruth M A

2018-04-01

To investigate the burden of visual impairment and comorbid fatigue in terms of impact on daily life, by estimating societal costs (direct medical costs and indirect non-health care costs) accrued by these conditions. This cost-of-illness study was performed from a societal perspective. Cross-sectional data of visually impaired adults and normally sighted adults were collected through structured telephone interviews and online surveys, respectively. Primary outcomes were fatigue severity (FAS), impact of fatigue on daily life (MFIS), and total societal costs. Cost differences between participants with and without vision loss, and between participants with and without fatigue, were examined by (adjusted) multivariate regression analyses, including bootstrapped confidence intervals. Severe fatigue (FAS ≥ 22) and high fatigue impact (MFIS ≥ 38) was present in 57% and 40% of participants with vision loss (n = 247), respectively, compared to 22% (adjusted odds ratio [OR] 4.6; 95% confidence interval [CI] [2.7, 7.6]) and 11% (adjusted OR 4.8; 95% CI [2.7, 8.7]) in those with normal sight (n = 233). A significant interaction was found between visual impairment and high fatigue impact for total societal costs (€449; 95% CI [33, 1017]). High fatigue impact was associated with significantly increased societal costs for participants with visual impairment (mean difference €461; 95% CI [126, 797]), but this effect was not observed for participants with normal sight (€12; 95% CI [-527, 550]). Visual impairment is associated with an increased prevalence of high fatigue impact that largely determines the economic burden of visual impairment. The substantial costs of visual impairment and comorbid fatigue emphasize the need for patient-centered interventions aimed at decreasing its impact.

Impact of a transposon insertion in phzF2 on the specialized metabolite production and interkingdom interactions of Pseudomonas aeruginosa.

PubMed

Phelan, Vanessa V; Moree, Wilna J; Aguilar, Julieta; Cornett, Dale S; Koumoutsi, Alexandra; Noble, Suzanne M; Pogliano, Kit; Guerrero, Carlos A; Dorrestein, Pieter C

2014-05-01

In microbiology, gene disruption and subsequent experiments often center on phenotypic changes caused by one class of specialized metabolites (quorum sensors, virulence factors, or natural products), disregarding global downstream metabolic effects. With the recent development of mass spectrometry-based methods and technologies for microbial metabolomics investigations, it is now possible to visualize global production of diverse classes of microbial specialized metabolites simultaneously. Using imaging mass spectrometry (IMS) applied to the analysis of microbiology experiments, we can observe the effects of mutations, knockouts, insertions, and complementation on the interactive metabolome. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the impact on specialized metabolite production of a transposon insertion into a Pseudomonas aeruginosa phenazine biosynthetic gene, phzF2. The disruption of phenazine biosynthesis led to broad changes in specialized metabolite production, including loss of pyoverdine production. This shift in specialized metabolite production significantly alters the metabolic outcome of an interaction with Aspergillus fumigatus by influencing triacetylfusarinine production.

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources.

PubMed

Klæboe, Ronny; Sundfør, Hanne Beate

2016-07-23

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors.

Impact of a Transposon Insertion in phzF2 on the Specialized Metabolite Production and Interkingdom Interactions of Pseudomonas aeruginosa

PubMed Central

Phelan, Vanessa V.; Moree, Wilna J.; Aguilar, Julieta; Cornett, Dale S.; Koumoutsi, Alexandra; Noble, Suzanne M.; Pogliano, Kit; Guerrero, Carlos A.

2014-01-01

In microbiology, gene disruption and subsequent experiments often center on phenotypic changes caused by one class of specialized metabolites (quorum sensors, virulence factors, or natural products), disregarding global downstream metabolic effects. With the recent development of mass spectrometry-based methods and technologies for microbial metabolomics investigations, it is now possible to visualize global production of diverse classes of microbial specialized metabolites simultaneously. Using imaging mass spectrometry (IMS) applied to the analysis of microbiology experiments, we can observe the effects of mutations, knockouts, insertions, and complementation on the interactive metabolome. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the impact on specialized metabolite production of a transposon insertion into a Pseudomonas aeruginosa phenazine biosynthetic gene, phzF2. The disruption of phenazine biosynthesis led to broad changes in specialized metabolite production, including loss of pyoverdine production. This shift in specialized metabolite production significantly alters the metabolic outcome of an interaction with Aspergillus fumigatus by influencing triacetylfusarinine production. PMID:24532776

Experience-dependent central vision deficits: Neurobiology and visual acuity.

PubMed

Williams, Kate; Balsor, Justin L; Beshara, Simon; Beston, Brett R; Jones, David G; Murphy, Kathryn M

2015-09-01

Abnormal visual experience during childhood often leads to amblyopia, with strong links to binocular dysfunction that can include poor acuity in both eyes, especially in central vision. In animal models of amblyopia, the non-deprived eye is often considered normal and what limits binocular acuity. This leaves open the question whether monocular deprivation (MD) induces binocular dysfunction similar to what is found in amblyopia. In previous studies of MD cats, we found a loss of excitatory receptors restricted to the central visual field representation in visual cortex (V1), including both eyes' columns. This led us to ask two questions about the effects of MD: how quickly are receptors lost in V1? and is there an impact on binocular acuity? We found that just a few hours of MD caused a rapid loss of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor proteins across all of V1. But after a few days of MD, there was recovery in the visual periphery, leaving a loss of AMPA receptors only in the central region of V1. We reared animals with early MD followed by a long period of binocular vision and found binocular acuity deficits that were greatest in the central visual field. Our results suggest that the greater binocular acuity deficits in the central visual field are driven in part by the long-term loss of AMPA receptors in the central region of V1. Copyright © 2014 Elsevier Ltd. All rights reserved.

Military target task performance after wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK)

NASA Astrophysics Data System (ADS)

Maurer, Tana; Deaver, Dawne; Howell, Christopher; Moyer, Steve; Nguyen, Oanh; Mueller, Greg; Ryan, Denise; Sia, Rose K.; Stutzman, Richard; Pasternak, Joseph; Bower, Kraig

2014-06-01

Major decisions regarding life and death are routinely made on the modern battlefield, where visual function of the individual soldier can be of critical importance in the decision-making process. Glasses in the combat environment have considerable disadvantages: degradation of short term visual performance can occur as dust and sweat accumulate on lenses during a mission or patrol; long term visual performance can diminish as lenses become increasingly scratched and pitted; during periods of intense physical trauma, glasses can be knocked off the soldier's face and lost or broken. Although refractive surgery offers certain benefits on the battlefield when compared to wearing glasses, it is not without potential disadvantages. As a byproduct of refractive surgery, elevated optical aberrations can be induced, causing decreases in contrast sensitivity and increases in the symptoms of glare, halos, and starbursts. Typically, these symptoms occur under low light level conditions, the same conditions under which most military operations are initiated. With the advent of wavefront aberrometry, we are now seeing correction not only of myopia and astigmatism but of other, smaller optical aberrations that can cause the above symptoms. In collaboration with the Warfighter Refractive Eye Surgery Program and Research Center (WRESP-RC) at Fort Belvoir and Walter Reed National Military Medical Center (WRNMMC), the overall objective of this study is to determine the impact of wavefront guided (WFG) versus wavefront-optimized (WFO) photorefractive keratectomy (PRK) on military task visual performance. Psychophysical perception testing was conducted before and after surgery to measure each participant's performance regarding target detection and identification using thermal imagery. The results are presented here.

The prevalence of visual impairment in school children of upper-middle socioeconomic status in Kathmandu.

PubMed

Sapkota, Yuddha D; Adhikari, Bishwa Nath; Pokharel, Gopal P; Poudyal, Bimal K; Ellwein, Leon B

2008-01-01

Assess visual impairment in school children of upper-middle socioeconomic status in Kathmandu for comparison with rural Jhapa District. Random selection of classes from secondary private schools in Kathmandu was used to identify the study sample. Children in 130 classes at 43 schools were enumerated using school records and examined between January-May 2006. Examinations included visual acuity testing, ocular motility evaluation, cycloplegic refraction, and examination of the external eye, anterior segment, media, and fundus. The principal cause was determined for eyes with uncorrected visual acuity < or = 20/40. A total of 4,501 children in grades 5-9 were enumerated; 4282 (95.1%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual impairment (< or = 20/40) in the better eye was 18.6%, 9.1%, and 0.86%, respectively. Refractive error was a cause in 93.3% of children with uncorrected visual impairment, amblyopia 1.8%, retinal disorders 1.3%, other causes 0.3%, and unexplained causes 4.4%. Among children correctable in at least one eye, 46.3% presented without the necessary spectacles. Visual impairment with myopia (-0.50 diopters) ranged from 10.9% in 10 year-olds to 27.3% in 15 year-olds, compared to 0.5%-3.0% in rural Jhapa District. Myopic visual impairment was associated with grade level, female gender, parental education, parental spectacle usage, and Mongol ethnicity. Visual impairment with myopia among upper-middle socioeconomic school children in Kathmandu is higher than that in rural Nepal, and a public health problem because nearly half are without corrective spectacles. Effective strategies are needed to eliminate this easily treatable cause of visual impairment.

Comparison on driving fatigue related hemodynamics activated by auditory and visual stimulus

NASA Astrophysics Data System (ADS)

Deng, Zishan; Gao, Yuan; Li, Ting

2018-02-01

As one of the main causes of traffic accidents, driving fatigue deserves researchers' attention and its detection and monitoring during long-term driving require a new technique to realize. Since functional near-infrared spectroscopy (fNIRS) can be applied to detect cerebral hemodynamic responses, we can promisingly expect its application in fatigue level detection. Here, we performed three different kinds of experiments on a driver and recorded his cerebral hemodynamic responses when driving for long hours utilizing our device based on fNIRS. Each experiment lasted for 7 hours and one of the three specific experimental tests, detecting the driver's response to sounds, traffic lights and direction signs respectively, was done every hour. The results showed that visual stimulus was easier to cause fatigue compared with auditory stimulus and visual stimulus induced by traffic lights scenes was easier to cause fatigue compared with visual stimulus induced by direction signs in the first few hours. We also found that fatigue related hemodynamics caused by auditory stimulus increased fastest, then traffic lights scenes, and direction signs scenes slowest. Our study successfully compared audio, visual color, and visual character stimulus in sensitivity to cause driving fatigue, which is meaningful for driving safety management.

Global magnitude of visual impairment caused by uncorrected refractive errors in 2004

PubMed Central

Pascolini, Donatella; Mariotti, Silvio P; Pokharel, Gopal P

2008-01-01

Abstract Estimates of the prevalence of visual impairment caused by uncorrected refractive errors in 2004 have been determined at regional and global levels for people aged 5 years and over from recent published and unpublished surveys. The estimates were based on the prevalence of visual acuity of less than 6/18 in the better eye with the currently available refractive correction that could be improved to equal to or better than 6/18 by refraction or pinhole. A total of 153 million people (range of uncertainty: 123 million to 184 million) are estimated to be visually impaired from uncorrected refractive errors, of whom eight million are blind. This cause of visual impairment has been overlooked in previous estimates that were based on best-corrected vision. Combined with the 161 million people visually impaired estimated in 2002 according to best-corrected vision, 314 million people are visually impaired from all causes: uncorrected refractive errors become the main cause of low vision and the second cause of blindness. Uncorrected refractive errors can hamper performance at school, reduce employability and productivity, and generally impair quality of life. Yet the correction of refractive errors with appropriate spectacles is among the most cost-effective interventions in eye health care. The results presented in this paper help to unearth a formerly hidden problem of public health dimensions and promote policy development and implementation, programmatic decision-making and corrective interventions, as well as stimulate research. PMID:18235892

Childhood blindness: a new form for recording causes of visual loss in children.

PubMed Central

Gilbert, C.; Foster, A.; Négrel, A. D.; Thylefors, B.

1993-01-01

The new standardized form for recording the causes of visual loss in children is accompanied by coding instructions and by a database for statistical analysis. The aim is to record the causes of childhood visual loss, with an emphasis on preventable and treatable causes, so that appropriate control measures can be planned. With this standardized methodology, it will be possible to monitor the changing patterns of childhood blindness over a period of time in response to changes in health care services, specific interventions, and socioeconomic development. PMID:8261552

Causes of blindness and visual impairment among students in integrated schools for the blind in Nepal.

PubMed

Shrestha, Jyoti Baba; Gnyawali, Subodh; Upadhyay, Madan Prasad

2012-12-01

To identify the causes of blindness and visual impairment among students in integrated schools for the blind in Nepal. A total of 778 students from all 67 integrated schools for the blind in Nepal were examined using the World Health Organization/Prevention of Blindness Eye Examination Record for Children with Blindness and Low Vision during the study period of 3 years. Among 831 students enrolled in the schools, 778 (93.6%) participated in the study. Mean age of students examined was 13.7 years, and the male to female ratio was 1.4:1. Among the students examined, 85.9% were blind, 10% had severe visual impairment and 4.1% were visually impaired. The cornea (22.8%) was the most common anatomical site of visual impairment, its most frequent cause being vitamin A deficiency, followed by the retina (18.4%) and lens (17.6%). Hereditary and childhood factors were responsible for visual loss in 27.9% and 22.0% of students, respectively. Etiology could not be determined in 46% of cases. Overall, 40.9% of students had avoidable causes of visual loss. Vision could be improved to a level better than 6/60 in 3.6% of students refracted. More than one third of students were visually impaired for potentially avoidable reasons, indicating lack of eye health awareness and eye care services in the community. The cause of visual impairment remained unknown in a large number of students, which indicates the need for introduction of modern diagnostic tools.

A Cross-sectional Study of Prevalence and Etiology of Childhood Visual Impairment in Auckland, New Zealand.

PubMed

Chong, Chee Foong; McGhee, Charles N J; Dai, Shuan

2014-01-01

Childhood visual impairment has significant individual and socioeconomic costs with global differences in etiology and prevalence. This study aimed to determine prevalence, etiology, and avoidable causes of childhood visual impairment in New Zealand. Retrospective data analysis from a national referral center, the Blind and Low Vision Education Network New Zealand, Auckland. The World Health Organization Program for Prevention of Blindness eye examination records for visually impaired children, 16 years or younger, registered with the Auckland Visual Resource Centre, were included. Data analyzed included demographics, etiology, visual acuity, visual fields, educational setting, and rehabilitation plan. Charts of 340 children were examined, of which 267 children (144 blind, 123 low vision) were included in the analysis, whereas the remaining 73 charts of children with no visual impairment were excluded. The calculated prevalence of blindness and low vision was 0.05% and 0.04%, respectively, in the Auckland region. Principal causes of blindness affecting 91 children (63.9%) were cerebral visual impairment in 61 children (42.4%), optic nerve atrophy in 18 children (12.5%), and retinal dystrophy in 13 children (9.0%). The main potentially avoidable causes of blindness in 27 children (19%) were neonatal trauma, asphyxia in 9 children (33%), and nonaccidental injury 6 children (22%). This first report of prevalence for childhood blindness and low vision in New Zealand is similar to data from Established Market Economy countries. The leading causes of blindness are also comparable to other high-income countries; however, proportions of avoidable causes differ significantly.

Face features and face configurations both contribute to visual crowding.

PubMed

Sun, Hsin-Mei; Balas, Benjamin

2015-02-01

Crowding refers to the inability to recognize an object in peripheral vision when other objects are presented nearby (Whitney & Levi Trends in Cognitive Sciences, 15, 160-168, 2011). A popular explanation of crowding is that features of the target and flankers are combined inappropriately when they are located within an integration field, thus impairing target recognition (Pelli, Palomares, & Majaj Journal of Vision, 4(12), 12:1136-1169, 2004). However, it remains unclear which features of the target and flankers are combined inappropriately to cause crowding (Levi Vision Research, 48, 635-654, 2008). For example, in a complex stimulus (e.g., a face), to what extent does crowding result from the integration of features at a part-based level or at the level of global processing of the configural appearance? In this study, we used a face categorization task and different types of flankers to examine how much the magnitude of visual crowding depends on the similarity of face parts or of global configurations. We created flankers with face-like features (e.g., the eyes, nose, and mouth) in typical and scrambled configurations to examine the impacts of part appearance and global configuration on the visual crowding of faces. Additionally, we used "electrical socket" flankers that mimicked first-order face configuration but had only schematic features, to examine the extent to which global face geometry impacted crowding. Our results indicated that both face parts and configurations contribute to visual crowding, suggesting that face similarity as realized under crowded conditions includes both aspects of facial appearance.

Statistics on Children with Visual Impairments.

ERIC Educational Resources Information Center

Viisola, Michelle

This report summarizes statistical data relating to children with visual impairments, including incidence, causes, and education. Data include: (1) prevalence estimates that indicate 1 percent of persons under the age of 18 in the United States have a visual impairment that cannot be corrected with glasses; (2) the leading cause of childhood…

Visual evoked potentials in the horse.

PubMed

Ström, L; Ekesten, B

2016-06-21

Electrical potentials generated in the central nervous system in response to brief visual stimuli, flash visual evoked potentials (FVEPs), can be recorded non-invasively over the occipital cortex. FVEPs are used clinically in human medicine and also experimentally in a number of animal species, but the method has not yet been evaluated in the horse. The method would potentially allow the ophthalmologist and equine clinician to evaluate visual impairment caused by disorders affecting post-retinal visual pathways. The aim was to establish a method for recording of FVEPs in horses in a clinical setting and to evaluate the waveform morphology in the normal horse. Ten horses were sedated with a continuous detomidine infusion. Responses were recorded from electrodes placed on the scalp. Several positions were evaluated to determine suitable electrode placement. Flash electroretinograms (FERGs) were recorded simultaneously. To evaluate potential contamination of the FVEP from retinal potentials, a retrobulbar nerve block was performed in two horses and transection of the optic nerve was performed in one horse as a terminal procedure. A series of positive (P) and negative (N) peaks in response to light stimuli was recorded in all horses. Reproducible wavelets with mean times-to-peaks of 26 (N1), 55 (P2), 141 (N2) and 216 ms (P4) were seen in all horses in all recordings. Reproducible results were obtained when the active electrode was placed in the midline rostral to the nuchal crest. Recording at lateral positions gave more variable results, possibly due to ear muscle artifacts. Averaging ≥100 responses reduced the impact of noise and artifacts. FVEPs were reproducible in the same horse during the same recording session and between sessions, but were more variable between horses. Retrobulbar nerve block caused a transient loss of the VEP whereas transection of the optic nerve caused an irreversible loss. We describe the waveform of the equine FVEP and our results show that it is possible to record FVEPs in sedated horses in a clinical setting. The potentials recorded were shown to be of post-retinal origin. Further studies are needed to provide normative data and assess potential clinical use.

Could visual neglect induce amblyopia?

PubMed

Bier, J C; Vokaer, M; Fery, P; Garbusinski, J; Van Campenhoudt, G; Blecic, S A; Bartholomé, E J

2004-12-01

Oculomotor nerve disease is a common cause of diplopia. When strabismus is present, absence of diplopia has to induce the research of either uncovering of visual fields or monocular suppression, amblyopia or blindness. We describe the case of a 41-year-old woman presenting with right oculomotor paresis and left object-centred visual neglect due to a right fronto-parietal haemorrhage expanding to the right peri-mesencephalic cisterna caused by the rupture of a right middle cerebral artery aneurysm. She never complained of diplopia despite binocular vision and progressive recovery of strabismus, excluding uncovering of visual fields. Since all other causes were excluded in this case, we hypothesise that the absence of diplopia was due to the object-centred visual neglect. Partial internal right oculomotor paresis causes an ocular deviation in abduction; the image being perceived deviated contralaterally to the left. Thus, in our case, the neglect of the left image is equivalent to a right monocular functional blindness. However, bell cancellation test clearly worsened when assessed in left monocular vision confirming that eye patching can worsen attentional visual neglect. In conclusion, our case argues for the possibility of a functional monocular blindness induced by visual neglect. We think that in presence of strabismus, absence of diplopia should induce the search for hemispatial visual neglect when supratentorial lesions are suspected.

Impact of healthcare strategies on patterns of paediatric sight impairment in a developed population: 1984-2011.

PubMed

Shirley, K; Chamney, S; Satkurunathan, P; McLoone, S; McLoone, E

2017-11-01

PurposeThe aim of our study was to analyse paediatric sight-impairment trends in Northern Ireland (NI) over a 28-year period to better understand the impact which changes in health-care provision may be having on childhood blindness and to enable us to assess our progress towards achieving the World Health Organisation (WHO) aims.MethodsA database of Certificates of Visual Impairment completed for NI children aged <16 years was used to determine the cause of sight impairment from 1984 to 2011. Causes were classified into preventable or treatable conditions and analysed for trends.ResultsFive hundred and ninety-eight children were registered as having impaired vision over the 28-year period. A total of 22% had preventable or treatable conditions. Optic atrophy was the most common cause responsible for 16% of registrations followed by albinism (12%), cerebral visual impairment (11%), congenital cataract (8%), retinopathy of prematurity (ROP) (8%), and congenital motor nystagmus (7%). The incident rate (per million population aged <16 years) for registerable vision loss due to congenital cataract decreased from 5.89 (CI 2.82-10.83) in 1984-1987 to 2.63 (CI 0.72-6.74) in 2008-2011. For ROP, the incident rate peaked during 2000-2003 at 8.87 (CI 4.85-14.88). Thereafter, there was a statistically significant reduction in incident rate to 1.98 (CI 0.41-5.77) in 2008-2011 (P=0.008).ConclusionsSight-impairment registrations due to preventable or treatable causes have decreased over the past 28 years. This is likely due to better surgical techniques and improved refractive care for conditions such as congenital cataract and ongoing research and treatment protocols for conditions such as ROP. Future advances in this area may help to further reduce the burden of childhood sight impairment and improve quality of life for these patients.

The impact of macular surgery in different grades of epiretinal membrane

PubMed Central

Batman, Cosar; Citirik, Mehmet

2017-01-01

AIM To assess the impact of macular surgery on the functional and anatomic outcomes of the patients in different grades of epiretinal membrane (ERM). METHODS Seventy-one eyes of 71 patients who underwent 23-gauge transconjunctival sutureless pars plana vitrectomy for primary isolated ERM were evaluated in this study. RESULTS There were 38 females (53.5%) and 33 males (46.5%). The average age of the patients was 68.1y (range 42-89y). Mean follow up period was 14mo (range 6-26mo). The cases were divided into two subgroups of cellophane maculopathy (CM) and macular pucker (MP). An improvement was observed in the postoperative best-corrected visual acuity (BCVA), as well as a decrement in central foveal thickness (CFT) in both groups (both of these being statistically significant; P=0.001). In comparison between two groups, it was found that there was a significant improvement on BCVA and CFT in CM group than MP group (P=0.01). Furthermore, the postoperative fundus findings regarding RPE alterations and macular edema were significantly higher in MP group when compared to the CM group (P=0.01). CONCLUSION ERM and internal limiting membrane peeling surgery can lead to a significant reduction of CFT and visual improvements in idiopathic ERM. A long-term ERM persistence will cause unrecoverable retinal damage and visual loss. PMID:29259907

The impact of online visual on users' motivation and behavioural intention - A comparison between persuasive and non-persuasive visuals

NASA Astrophysics Data System (ADS)

Ibrahim, Nurulhuda; Shiratuddin, Mohd Fairuz; Wong, Kok Wai

2016-08-01

Research related to the first impression has highlighted the importance of visual appeal in influencing the favourable attitude towards a website. In the perspective of impression formation, it is proposed that the users are actually attracted to certain characteristics or aspects of the visual properties of a website, while ignoring the rests. Therefore, this study aims to investigate which visual strongly appeals to the users by comparing the impact of common visuals with the persuasive visuals. The principles of social influence are proposed as the added value to the persuasiveness of the web visuals. An experimental study is conducted and the PLS-SEM method is employed to analyse the obtained data. The result of the exploratory analyses demonstrated that the structural model has better quality when tested with persuasive data sample compared to non-persuasive data sample, evident with stronger coefficient of determination and path coefficients. Thus, it is concluded that persuasive visual provides better impact towards users' attitude and behavioural intention of a website.

Prevalence and Causes of Visual Impairment and Blindness in Shanxi Province, China.

PubMed

Li, Tong; Du, Liping; Du, Lingzhen

2015-01-01

To estimate the prevalence and causes of visual impairment and blindness in Shanxi Province, China. Data were obtained from the Second National Sampling Survey of Disability conducted in 2006. Blindness and visual impairment were defined as best corrected visual acuity <3/60 and <6/18, respectively, in the better-seeing eye. Standardized ophthalmologic examinations were administered to participants aged 0-80 years in 2006. Visual acuity (VA) was measured using a Standard Logarithmic Visual Acuity E chart (Snellen) for subjects aged 7 years and older. Participants younger than 7 years were examined using special experiments or the Childhood Graphical Visual Chart. The prevalence of visual impairment and blindness in Shanxi was estimated to be 0.6% (466/75,016) among persons up to 80 years old. The prevalence in rural areas (0.7%; 351/48,137) was significantly higher than that in urban areas (0.4%; 115/26,879) and was higher in females (0.8%; 298/36,933) than in males (0.4%; 168/38,083). The most common cause of visual impairment and blindness was cataract (44.9%), followed by retinopathy and choroidopathy (12.5%), hereditary and developmental disorders (10.3%), corneal disease (5.2%), and refractive error (4.9%). Prevalences of visual impairment and blindness in women and in rural areas were higher than in men and urban areas, and increased with age. Cataract was the most prevalent cause of visual impairment and blindness. Based on the findings from this study, we suggest that provision of support and welfare services should be organized.

The Impact of Visual Impairment on Perceived School Climate

ERIC Educational Resources Information Center

Schade, Benjamin; Larwin, Karen H.

2015-01-01

The current investigation examines whether visual impairment has an impact on a student's perception of the school climate. Using a large national sample of high school students, perceptions were examined for students with vision impairment relative to students with no visual impairments. Three factors were examined: self-reported level of…

Clinical characteristics and causes of visual impairment in a low vision clinic in northern Jordan.

PubMed

Bakkar, May M; Alzghoul, Eman A; Haddad, Mera F

2018-01-01

The aim of the study was to identify causes of visual impairment among patients attending a low vision clinic in the north of Jordan and to study the relevant demographic characteristics of these patients. The retrospective study was conducted through a review of clinical records of 135 patients who attended a low vision clinic in Irbid. Clinical characteristics of the patients were collected, including age, gender, primary cause of low vision, best corrected visual acuity, and current prescribed low vision aids. Descriptive statistics analysis using numbers and percentages were calculated to summarize categorical and nominal data. A total of 135 patients (61 [45.2%] females and 74 [54.8%] males) were recruited in the study. Mean age ± standard deviation for the study population was 24.53 ± 16.245 years; age range was 5-90 years. Of the study population, 26 patients (19.3%) had mild visual impairment, 61 patients (45.2%) had moderate visual impairment, 27 patients (20.0%) had severe visual impairment, and 21 patients (15.6%) were blind. The leading causes of visual impairment across all age groups were albinism (31.9%) and retinitis pigmentosa (RP) (18.5%). Albinism also accounted for the leading cause of visual impairment among the pediatric age group (0-15 years) while albinism, RP, and keratoconus were the primary causes of visual impairment for older patients. A total of 59 patients (43.7%) were given low vision aids either for near or distance. The only prescribed low vision aids for distances were telescopes. For near, spectacle-type low vision aid was the most commonly prescribed low vision aids. Low vision services in Jordan are still very limited. A national strategy programme to increase awareness of low vision services should be implemented, and health care policies should be enforced to cover low vision aids through the national medical insurance.

Clinical characteristics and causes of visual impairment in a low vision clinic in northern Jordan

PubMed Central

Bakkar, May M; Alzghoul, Eman A; Haddad, Mera F

2018-01-01

Aim The aim of the study was to identify causes of visual impairment among patients attending a low vision clinic in the north of Jordan and to study the relevant demographic characteristics of these patients. Subjects and methods The retrospective study was conducted through a review of clinical records of 135 patients who attended a low vision clinic in Irbid. Clinical characteristics of the patients were collected, including age, gender, primary cause of low vision, best corrected visual acuity, and current prescribed low vision aids. Descriptive statistics analysis using numbers and percentages were calculated to summarize categorical and nominal data. Results A total of 135 patients (61 [45.2%] females and 74 [54.8%] males) were recruited in the study. Mean age ± standard deviation for the study population was 24.53 ± 16.245 years; age range was 5–90 years. Of the study population, 26 patients (19.3%) had mild visual impairment, 61 patients (45.2%) had moderate visual impairment, 27 patients (20.0%) had severe visual impairment, and 21 patients (15.6%) were blind. The leading causes of visual impairment across all age groups were albinism (31.9%) and retinitis pigmentosa (RP) (18.5%). Albinism also accounted for the leading cause of visual impairment among the pediatric age group (0–15 years) while albinism, RP, and keratoconus were the primary causes of visual impairment for older patients. A total of 59 patients (43.7%) were given low vision aids either for near or distance. The only prescribed low vision aids for distances were telescopes. For near, spectacle-type low vision aid was the most commonly prescribed low vision aids. Conclusion Low vision services in Jordan are still very limited. A national strategy programme to increase awareness of low vision services should be implemented, and health care policies should be enforced to cover low vision aids through the national medical insurance. PMID:29662299

Childhood blindness and severe visual impairment in Malaysia: a nationwide study

PubMed Central

Patel, D K; Tajunisah, I; Gilbert, C; Subrayan, V

2011-01-01

Aim To determine the causes of childhood blindness and severe visual impairment (BL/SVI) in schools for the blind in Malaysia. Methods All children ≤15years attending 24 schools for the blind throughout the country were examined using the WHO Prevention of Blindness Programme (WHO/PBL) eye examination record for children, and visual loss was classified according to the International Classification of Disease (ICD). Results In all, 469 children were examined, of whom 448 (95.6%) had BL/SVI. The major causes of visual loss were retinal disorders (n=148, 33% mainly retinopathy of prematurity (n=78, 17.4%)), cataract/pseudophakia/aphakia (n=77, 17.2%), and anomalies affecting the whole globe. (n=86, 19.2%). The major underlying etiology was undetermined (n=193, 43.1%), followed by hereditary factors, 21.7% (mainly retinal dystrophies), and perinatal factors, 20.5%. More than 34 (7.6%) cases were considered potentially preventable and 192 (42.9%) potentially treatable. Conclusion Diseases of the retina are the major cause of visual impairment, with retinopathy of prematurity being an important avoidable cause. This reflects expansion of neonatal services in Malaysia, and improved survival of very low birth weight and preterm babies. Lens-related causes of visual impairment reflect the need to further improve pediatric ophthalmology services in Malaysia. PMID:21350565

An historical ophthalmic study of Jane Austen.

PubMed

Wilson, Graham A

2012-11-01

Today, no other classic novelist has the popularity or power of Jane Austen, and in 2013 the world will celebrate 200 years of her comic masterpiece Pride and Prejudice. Her millions of fans have an abiding fascination with all aspects of her life, including her health and the cause of her death. This historical ophthalmic study of Jane Austen, based on very incomplete medical bibliographic data, finds that she had a mild ocular surface disorder from age 23. This disorder did not significantly impact on her visual performance for writing. There are many references to eyes in her novels, but Jane's eyes and those of her characters cannot contribute further to the debate around the cause of her death at age 41.

Adaptive Behavior of Primary School Students with Visual Impairments: The Impact of Educational Settings

ERIC Educational Resources Information Center

Metsiou, Katerina; Papadopoulos, Konstantinos; Agaliotis, Ioannis

2011-01-01

This study explored the adaptive behavior of primary school students with visual impairments, as well as the impact of educational setting on their adaptive behavior. Instrumentation included an informal questionnaire and the Vineland Adaptive Behavior Scales. Participants were 36 primary school students with visual impairments. The educational…

In-motion optical sensing for assessment of animal well-being

NASA Astrophysics Data System (ADS)

Atkins, Colton A.; Pond, Kevin R.; Madsen, Christi K.

2017-05-01

The application of in-motion optical sensor measurements was investigated for inspecting livestock soundness as a means of animal well-being. An optical sensor-based platform was used to collect in-motion, weight-related information. Eight steers, weighing between 680 and 1134 kg, were evaluated twice. Six of the 8 steers were used for further evaluation and analysis. Hoof impacts caused plate flexion that was optically sensed. Observed kinetic differences between animals' strides at a walking or running/trotting gait with significant force distributions of animals' hoof impacts allowed for observation of real-time, biometric patterns. Overall, optical sensor-based measurements identified hoof differences between and within animals in motion that may allow for diagnosis of musculoskeletal unsoundness without visual evaluation.

Is current eye-care-policy focus almost exclusively on cataract adequate to deal with blindness in India?

PubMed

Dandona, L; Dandona, R; Naduvilath, T J; McCarty, C A; Nanda, A; Srinivas, M; Mandal, P; Rao, G N

1998-05-02

India's National Programme for Control of Blindness focuses almost exclusively on cataract, based on a national survey done in the 1980s which reported that cataract caused 80% of the blindness in India. No current population-based data on the causes of blindness in India are available. We assessed the rate and causes of blindness in an urban population in southern India. We selected 2954 participants by stratified, random, cluster, systematic sampling from Hyderabad city. Eligible participants were interviewed and given a detailed ocular assessment, including visual acuity, refraction, slitlamp biomicroscopy, applanation intraocular pressure, gonioscopy, dilatation, grading of cataract, stereoscopic fundus assessment, and automated-threshold visual fields. 2522 participants, including 1399 aged 30 years or more, were assessed. 49 participants (all aged > or =30 years) were blind (presenting distance visual acuity <6/60 or central visual field <200 in the better eye). The rate of blindness among those aged 30 years or more, adjusted for age and sex, was 3.08% ([95% CI 1.95-4.21]). Causes included cataract (29.7%), retinal disease (17.1%), corneal disease (15.4%), refractive error (12.5%), glaucoma (12.1%), and optic atrophy (11.0%). 15.7% of the blindness caused by visual-field constriction would have been missed without visual-field examination. Also without visual-field and detailed dilated-fundus assessments, blindness attributed to cataract would have been overestimated by up to 75.8%. If the use of cataract surgery in this urban population was half that found in this study, which simulates the situation in rural India, cataract would have caused 51.8% (39.4-64.2) of blindness, significantly less than the 80% accepted by current policy. Much of the blindness in this Indian population was due to non-cataract causes. The previous national survey did not include detailed dilated-fundus assessment and visual-field examination which could have led to overestimation of cataract as a cause of blindness in India. Policy-makers in India should encourage well-designed population-based epidemiological studies from which to develop a comprehensive long-term policy on blindness in addition to dealing with cataract.

Refractive errors and cataract as causes of visual impairment in Brazil.

PubMed

Eduardo Leite Arieta, Carlos; Nicolini Delgado, Alzira Maria; José, Newton Kara; Temporini, Edméia Rita; Alves, Milton Ruiz; de Carvalho Moreira Filho, Djalma

2003-02-01

To identify the main causes of visual impairment (VA

Definition of blindness under National Programme for Control of Blindness: Do we need to revise it?

PubMed Central

Vashist, Praveen; Senjam, Suraj Singh; Gupta, Vivek; Gupta, Noopur; Kumar, Atul

2017-01-01

A review appropriateness of the current definition of blindness under National Programme for Control of Blindness (NPCB), Government of India. Online search of peer-reviewed scientific published literature and guidelines using PubMed, the World Health Organization (WHO) IRIS, and Google Scholar with keywords, namely blindness and visual impairment, along with offline examination of reports of national and international organizations, as well as their cross-references was done until December 2016, to identify relevant documents on the definition of blindness. The evidence for the historical and currently adopted definition of blindness under the NPCB, the WHO, and other countries was reviewed. Differences in the NPCB and WHO definitions were analyzed to assess the impact on the epidemiological status of blindness and visual impairment in India. The differences in the criteria for blindness under the NPCB and the WHO definitions cause an overestimation of the prevalence of blindness in India. These variations are also associated with an over-representation of refractive errors as a cause of blindness and an under-representation of other causes under the NPCB definition. The targets for achieving elimination of blindness also become much more difficult to achieve under the NPCB definition. Ignoring differences in definitions when comparing the global and Indian prevalence of blindness will cause erroneous interpretations. We recommend that the appropriate modifications should be made in the NPCB definition of blindness to make it consistent with the WHO definition. PMID:28345562

Definition of blindness under National Programme for Control of Blindness: Do we need to revise it?

PubMed

Vashist, Praveen; Senjam, Suraj Singh; Gupta, Vivek; Gupta, Noopur; Kumar, Atul

2017-02-01

A review appropriateness of the current definition of blindness under National Programme for Control of Blindness (NPCB), Government of India. Online search of peer-reviewed scientific published literature and guidelines using PubMed, the World Health Organization (WHO) IRIS, and Google Scholar with keywords, namely blindness and visual impairment, along with offline examination of reports of national and international organizations, as well as their cross-references was done until December 2016, to identify relevant documents on the definition of blindness. The evidence for the historical and currently adopted definition of blindness under the NPCB, the WHO, and other countries was reviewed. Differences in the NPCB and WHO definitions were analyzed to assess the impact on the epidemiological status of blindness and visual impairment in India. The differences in the criteria for blindness under the NPCB and the WHO definitions cause an overestimation of the prevalence of blindness in India. These variations are also associated with an over-representation of refractive errors as a cause of blindness and an under-representation of other causes under the NPCB definition. The targets for achieving elimination of blindness also become much more difficult to achieve under the NPCB definition. Ignoring differences in definitions when comparing the global and Indian prevalence of blindness will cause erroneous interpretations. We recommend that the appropriate modifications should be made in the NPCB definition of blindness to make it consistent with the WHO definition.

Prevalence and causes of visual impairment and blindness, cataract surgical coverage and outcomes of cataract surgery in Libya.

PubMed

Rabiu, Muhammad Mansur; Jenf, Mansour; Fituri, Suad; Choudhury, Abdulhanan; Agbabiaka, Idris; Mousa, Ahmed

2013-01-01

To assess the major causes of avoidable blindness, and outcomes and barriers to cataract services in Libya. A stratified multistage cluster random sample study was conducted in the four regions of Libya. Visual acuity and lens assessment were performed on all subjects. Those with presenting visual acuity <6/18 in either or both eyes were further investigated to determine cause(s) of impairment. Barriers to cataract surgery were investigated. Visual outcomes of subjects with surgery performed were assessed. A total of 8538 persons aged ≥50 years were examined across the four regions. The prevalence of blindness was 3.25% (3.15% with best correction), which varied across the regions (2.94-3.80%); after adjustment for age and sex, the prevalence was 2.66%. Major causes of blindness were cataract (29%), glaucoma (24%) and other corneal scars (14%). Causes were similar across all regions except in the south. Avoidable causes were responsible for 60.6% of blindness. Major causes of visual impairment were cataract (31.2%), diabetic retinopathy (16.6%) and posterior segment diseases (15.1%). Cataract surgical coverage among those with visual acuity <3/60 was 95.4%, with no sex differences. About 38% of cataract-operated eyes had poor outcome even after best correction (35%). There was poor outcome in 33% of pseudophakic eyes with best correction. The major barriers to service uptake were "waiting for maturity" (26%), "unaware of treatment" (24%) and "God's will/destiny" (17%). Libya needs to improve the quality of cataract surgery across all the regions. The southern region needs improvement in both quality and coverage of services.

Distance- and near-visual impairment in rural Chinese adults in Kailu, Inner Mongolia.

PubMed

Cheng, Fang; Shan, Li; Song, Wulian; Fan, Pan; Yuan, Huiping

2016-06-01

To investigate the prevalence and causes of distance-visual impairment and near-vision impairment in a rural Chinese population in Inner Mongolia. A population-based, cross-sectional study design was used to identify visual impairment in the Chinese aged 40 years and older living in Kailu County, Inner Mongolia. Low vision, blindness and near-visual impairment (NVI) were defined according to World Health Organization (WHO) criteria. The overall prevalence of blindness and visual impairment based on the presenting visual acuity (VA) was 2.2% (95% CI: 1.8-2.6) and 9.8% (95% CI: 8.9-10.6), respectively, and was adjusted to 0.9% (95% CI: 0.6-1.2) and 4.7% (95% CI: 4.1-5.3) using best-corrected visual acuity (BCVA), respectively. Taking the presenting VA into consideration, the leading cause of visual impairment and blindness was cataract (40.3%, 40.9%), followed by uncorrected refractive error (26.6%, 28.2%). According to the BCVA, the main cause of visual impairment and blindness was cataract (48.3%, 41.3%) followed by glaucoma (19.0%, 23.9%). Among the examined subjects, 80.3% had NVI, and 51.7% had presbyopia. Major barriers reported by NVI persons without near correction were lack of money to purchase prescription glasses and poor quality of the available ones (43.2%). Visual impairment is a serious public health problem, and the main causes leading to visual impairment are treatable and preventable in the rural Chinese population in Inner Mongolia. Presbyopia, together with the low rate of spectacles and lack of appropriate refractive and presbyopia spectacles, is highly prevalent in rural China. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Prevalence and Causes of Visual Impairment in Fundong District, North West Cameroon: Results of a Population-Based Survey.

PubMed

Oye, Joseph; Mactaggart, Islay; Polack, Sarah; Schmidt, Elena; Tamo, Violet; Okwen, Marvice; Kuper, Hannah

2017-12-01

To estimate the prevalence and causes of visual impairment in Fundong Health District, North West Cameroon. A total of 51 clusters of 80 people (all ages) were sampled with probability proportionate to size and compact segment sampling. Visual acuity (VA) was measured with a tumbling "E" chart. An ophthalmic nurse examined people with VA<6/18 in either eye. The presence of hearing and physical impairments were assessed using clinical examination, and self-reported visual problems using the Washington Group Short Set. In total, 4080 people were enumerated of whom 3567 were screened (response rate 87%). The overall prevalence of visual impairment was 2.3% (95% CI 1.8-3.0%) and blindness was 0.6% (0.3-1.0%). The prevalence of both blindness and visual impairment increased rapidly with age, so that the vast majority of cases of visual impairment (84%) and blindness (82%) were in people aged 50+. Posterior segment disease and cataract were the main causes of blindness and visual impairment, with refractive error also an important cause of visual impairment. Cataract surgical coverage (proportion of all cataracts that had received surgery) was relatively high (87% of people at VA<6/60). Post-surgery outcomes were poor, with 31% of operated eyes having VA<6/60. Among the 82 people with visual impairment, 22% had a physical impairment or epilepsy and 30% had a hearing impairment. Self-reported difficulties in vision were relatively closely related to clinical measures of visual impairment. Ophthalmic programmes in Cameroon need to incorporate control of posterior segment diseases while also working to improve outcomes after cataract surgery.

[Visual impairment and blindness in children in a Malawian school for the blind].

PubMed

Schulze Schwering, M; Nyrenda, M; Spitzer, M S; Kalua, K

2013-08-01

The aim of this study was to determine the anatomic sites of severe visual impairment and blindness in children in an integrated school for the blind in Malawi, and to compare the results with those of previous Malawian blind school studies. Children attending an integrated school for the blind in Malawi were examined in September 2011 using the standard WHO/PBL eye examination record for children with blindness and low vision. Visual acuity [VA] of the better eye was classified using the standardised WHO reporting form. Fifty-five pupils aged 6 to 19 years were examined, 39 (71 %) males, and 16 (29 %) females. Thirty eight (69%) were blind [BL], 8 (15 %) were severely visually impaired [SVI], 8 (15 %) visually impaired [VI], and 1 (1.8 %) was not visually impaired [NVI]. The major anatomic sites of visual loss were optic nerve (16 %) and retina (16 %), followed by lens/cataract (15 %), cornea (11 %) and lesions of the whole globe (11 %), uveal pathologies (6 %) and cortical blindness (2 %). The exact aetiology of VI or BL could not be determined in most children. Albinism accounted for 13 % (7/55) of the visual impairments. 24 % of the cases were considered to be potentially avoidable: refractive amblyopia among pseudophakic patients and corneal scaring. Optic atrophy, retinal diseases (mostly albinism) and cataracts were the major causes of severe visual impairment and blindness in children in an integrated school for the blind in Malawi. Corneal scarring was now the fourth cause of visual impairment, compared to being the commonest cause 35 years ago. Congenital cataract and its postoperative outcome were the commonest remedial causes of visual impairment. Georg Thieme Verlag KG Stuttgart · New York.

Causes of childhood blindness in the northeastern states of India.

PubMed

Bhattacharjee, Harsha; Das, Kalyan; Borah, Rishi Raj; Guha, Kamalesh; Gogate, Parikshit; Purukayastha, S; Gilbert, Clare

2008-01-01

The northeastern region (NER) of India is geographically isolated and ethno-culturally different from the rest of the country. There is lacuna regarding the data on causes of blindness and severe visual impairment in children from this region. To determine the causes of severe visual impairment and blindness amongst children from schools for the blind in the four states of NER of India. Survey of children attending special education schools for the blind in the NER. Blind and severely visually impaired children (best corrected visual acuity < 20/200 in the better eye, aged up to 16 years) underwent visual acuity estimation, external ocular examination, retinoscopy and fundoscopy. Refraction and low vision workup was done where indicated. World Health Organization's reporting form was used to code anatomical and etiological causes of visual loss. Microsoft Excel Windows software with SPSS. A total of 376 students were examined of whom 258 fulfilled the eligibility criteria. The major anatomical causes of visual loss amongst the 258 were congenital anomalies (anophthalmos, microphthalmos) 93 (36.1%); corneal conditions (scarring, vitamin A deficiency) 94 (36.7%); cataract or aphakia 28 (10.9%), retinal disorders 15 (5.8%) and optic atrophy 14 (5.3%). Nearly half of the children were blind from conditions which were either preventable or treatable (48.5%). Nearly half the childhood blindness in the NER states of India is avoidable and Vitamin A deficiency forms an important component unlike other Indian states. More research and multisectorial effort is needed to tackle congenital anomalies.

Prevalence and causes of severe visual impairment and blindness among children in the lorestan province of iran, using the key informant method.

PubMed

Razavi, Hessom; Kuper, Hannah; Rezvan, Farhad; Amelie, Khatere; Mahboobi-Pur, Hassan; Oladi, Mohammad Reza; Muhit, Mohammad; Hashemi, Hassan

2010-03-01

To estimate the prevalence and causes of severe visual impairment and blindness among children in Lorestan province of Iran, and to assess the feasibility of the Key Informant Method in this setting. Potential cases were identified using the Key Informant Method, in 3 counties of Lorestan province during June through August 2008, and referred for examination. Causes of severe visual impairment/blindness were determined and categorized using standard World Health Organization methods. Of 123 children referred for examination, 27 children were confirmed to have severe visual impairment/blindness or blindness. The median age was11 years (interquartile range 6-13), and 59% were girls. After adjusting for non-attenders, the estimated prevalence of severe visual impairment/blindness was 0.04% (0.03-0.05). The main site of abnormality was retina (44%), followed by disorders of the whole eye (33%). The majority of causes had a hereditary etiology (70%), which was associated with a family history of blindness (P = 0.002). Potentially avoidable causes of severe visual impairment/blindness were found in 14 children (52%). Almost all children with severe visual impairment/blindness had a history of parental consanguinity (93%). Our findings suggest a moderate prevalence of childhood blindness in the Lorestan province of Iran, a high proportion of which may be avoidable, given improved access to ophthalmic and genetic counselling services in rural areas. The Key Informant Method is feasible in Iran; future research is discussed.

Vision impairment and major causes of vision loss impacts on vision-specific functioning independent of socioeconomic factors.

PubMed

Chiang, Peggy P C; Zheng, Yingfeng; Wong, Tien Y; Lamoureux, Ecosse L

2013-02-01

To quantify the eye disease-specific impact of unilateral and bilateral vision impairment (VI) on vision-specific functioning (VF). The Singapore Indian Eye population-based study. Ethnic Indians older than 40 years of age living in Singapore. Participants underwent standardized ophthalmic assessments for VI and blindness, defined using presenting visual acuity (United States definition). Sociodemographic data were recorded using a standardized questionnaire. Rasch analysis was used to validate the Visual Function Index 11 and to determine its psychometric properties. The major causes of VI (i.e., cataract, refractive error, age-related macular degeneration, diabetic retinopathy [DR], and glaucoma) were determined by ophthalmologists on examination. Multivariate linear regression analysis was performed to assess the impact of VI on the overall VF Rasch score. Vision-specific functioning. Three thousand three hundred ninety-six persons were analyzed. Participants with VI had a systematic reduction in VF score compared with those with normal vision in both eyes, ranging from -11.2% normal vision in one eye and low vision in the other eye (95% confidence interval [CI], -12.2% to -10.3%; P<0.001), to -12.7% blindness in one eye and normal vision in the other eye (CI, -15.1% to -10.4%; P<0.001), to -19.4% low vision in both eyes (CI, -20.8% to -18.1%; P<0.001), to -52.9% blindness in one eye and low vision in other eye (CI, -55.3% to -50.4%; P<0.001), to -77.2% blindness in both eyes (CI, -82.4% to 72.0%; P<0.001). The impact of VI on VF score varied across different major causes of vision loss, regardless of socioeconomic factors. Vision impairment attributed to cataract in one or both eyes had a significant decrease in VF score by 17.7% and 22.3%, respectively, compared with those with normal vision in both eyes (P<0.001). The impact of unilateral and bilateral VI on VF score was greater in participants with glaucoma (32.2% in unilateral cases and 35.9% in bilateral cases; P<0.001) and DR (29.4% in unilateral cases and 33.3% in bilateral cases; P<0.001). Vision impairment and major age-related eye diseases such as cataract, DR, and glaucoma are associated significantly with worse deterioration in VF, regardless of education level, literacy adequacy, or immigration pattern. Glaucoma and DR seemed to have a greater negative impact on VF score compared with cataract. This study highlights the importance of disease-specific interventions in reducing the adverse impact of VI on daily activities. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Ocular cells and light: harmony or conflict?

PubMed

Jurja, Sanda; Hîncu, Mihaela; Dobrescu, Mihaela Amelia; Golu, Andreea Elena; Bălăşoiu, Andrei Theodor; Coman, Mălina

2014-01-01

Vision is based on the sensitivity of the eye to visible rays of the solar spectrum, which allows the recording and transfer of visual information by photoelectric reaction. Any electromagnetic radiation, if sufficiently intense, may cause damages in living tissues. In a changing environment, the aim of this paper is to point out the impact of light radiation on ocular cells, with its phototoxicity potential on eye tissues. In fact, faced with light and oxygen, the eye behaves like an ephemeral aggregate of unstable molecules, like a temporary crystallization threatened with entropia.

Visualization of Traffic Accidents

NASA Technical Reports Server (NTRS)

Wang, Jie; Shen, Yuzhong; Khattak, Asad

2010-01-01

Traffic accidents have tremendous impact on society. Annually approximately 6.4 million vehicle accidents are reported by police in the US and nearly half of them result in catastrophic injuries. Visualizations of traffic accidents using geographic information systems (GIS) greatly facilitate handling and analysis of traffic accidents in many aspects. Environmental Systems Research Institute (ESRI), Inc. is the world leader in GIS research and development. ArcGIS, a software package developed by ESRI, has the capabilities to display events associated with a road network, such as accident locations, and pavement quality. But when event locations related to a road network are processed, the existing algorithm used by ArcGIS does not utilize all the information related to the routes of the road network and produces erroneous visualization results of event locations. This software bug causes serious problems for applications in which accurate location information is critical for emergency responses, such as traffic accidents. This paper aims to address this problem and proposes an improved method that utilizes all relevant information of traffic accidents, namely, route number, direction, and mile post, and extracts correct event locations for accurate traffic accident visualization and analysis. The proposed method generates a new shape file for traffic accidents and displays them on top of the existing road network in ArcGIS. Visualization of traffic accidents along Hampton Roads Bridge Tunnel is included to demonstrate the effectiveness of the proposed method.

Visual impacts in the urban-wildland interface

Treesearch

Arthur W. Magill; Rowan A. Rowntree; Robert O. Brush

1979-01-01

The urban-wildland interface is treated as a place where extremes meet--where it is difficult to maintain a visually appealing transition from country to city. Problems are identified in relation to stable cities, urbanizing areas, and developing resorts in the wildlands. The visual problems of urbanization are also discussed in relation to physical impacts such as...

Visual Basic Programming Impact on Cognitive Style of College Students: Need for Prerequisites

ERIC Educational Resources Information Center

White, Garry L.

2012-01-01

This research investigated the impact learning a visual programming language, Visual Basic, has on hemispheric cognitive style, as measured by the Hemispheric Mode Indicator (HMI). The question to be answered is: will a computer programming course help students improve their cognitive abilities in order to perform well? The cognitive styles for…

The Impact of Baseline Trend Control on Visual Analysis of Single-Case Data

ERIC Educational Resources Information Center

Mercer, Sterett H.; Sterling, Heather E.

2012-01-01

The impact of baseline trend control on visual analyses of AB intervention graphs was examined with simulated data at various values of baseline trend, autocorrelation, and effect size. Participants included 202 undergraduate students with minimal training in visual analysis and 10 graduate students and faculty with more training and experience in…

Amplifying the helicopter drift in a conformal HMD

NASA Astrophysics Data System (ADS)

Schmerwitz, Sven; Knabl, Patrizia M.; Lueken, Thomas; Doehler, Hans-Ullrich

2016-05-01

Helicopter operations require a well-controlled and minimal lateral drift shortly before ground contact. Any lateral speed exceeding this small threshold can cause a dangerous momentum around the roll axis, which may cause a total roll over of the helicopter. As long as pilots can observe visual cues from the ground, they are able to easily control the helicopter drift. But whenever natural vision is reduced or even obscured, e.g. due to night, fog, or dust, this controllability diminishes. Therefore helicopter operators could benefit from some type of "drift indication" that mitigates the influence of a degraded visual environment. Generally humans derive ego motion by the perceived environmental object flow. The visual cues perceived are located close to the helicopter, therefore even small movements can be recognized. This fact was used to investigate a modified drift indication. To enhance the perception of ego motion in a conformal HMD symbol set the measured movement was used to generate a pattern motion in the forward field of view close or on the landing pad. The paper will discuss the method of amplified ego motion drift indication. Aspects concerning impact factors like visualization type, location, gain and more will be addressed. Further conclusions from previous studies, a high fidelity experiment and a part task experiment, will be provided. A part task study will be presented that compared different amplified drift indications against a predictor. 24 participants, 15 holding a fixed wing license and 4 helicopter pilots, had to perform a dual task on a virtual reality headset. A simplified control model was used to steer a "helicopter" down to a landing pad while acknowledging randomly placed characters.

Visual impairment and road traffic accidents among drivers in Jimma Town, Southwest Ethiopia.

PubMed

Biza, Mohamed; Mossie, Andualem; Woldemichael, Kifle; Gelaw, Yeshigeta

2013-04-01

Vision play a vital role in driving where good and efficient visual functioning of the driver is essential. Any significant loss of visual function will diminish a driver's ability to operate a motor vehicle safely and will thus contribute to road traffic injury. However, there is little evidence indicating that defects of vision alone cause road traffic accidents. To determine the impact of visual impairment and other factors on road traffic accident among vehicle drivers. A cross-sectional descriptive study was conducted on 249 sampled drivers in Southwest Ethiopia. A pretested interviewer led questionnaire was used for interview and vision tests were done using Snellen's acuity chart and Ishihara pseudo-isochromatic plates. Statistical analyses were performed using SPSS version 16.0. The mean age of drivers was 33.6 years (SD +/- 10.3). The relative frequency of self reported road traffic accident was 15.3%. The prevalence of uncorrected binocular visual impairment was 1.6% and there was a significant association between visual impairment and road traffic accident (P < 0.05). Uncorrected refractive error was seen in 7.6% and 8.8% of drivers in the right and left eyes respectively, and 3.2% of them had vision less than what is required to obtain driving license (visual acuity of 6/12). None of the drivers with refractive errors were wearing appropriate corrections. Color vision impairment was seen in 1.6% of the drivers. A significant proportion (9.6%) of the drivers did not have eye exam for their driving license. Uncorrected binocular visual impairment was strongly associated with road traffic accident. There is need for consistent inspection and screening, strict rules and regulations of licensing and health education for drivers to minimize road traffic accident.

Some effects of alcohol and eye movements on cross-race face learning.

PubMed

Harvey, Alistair J

2014-01-01

This study examines the impact of acute alcohol intoxication on visual scanning in cross-race face learning. The eye movements of a group of white British participants were recorded as they encoded a series of own-and different-race faces, under alcohol and placebo conditions. Intoxication reduced the rate and extent of visual scanning during face encoding, reorienting the focus of foveal attention away from the eyes and towards the nose. Differences in encoding eye movements also varied between own-and different-race face conditions as a function of alcohol. Fixations to both face types were less frequent and more lingering following intoxication, but in the placebo condition this was only the case for different-race faces. While reducing visual scanning, however, alcohol had no adverse effect on memory, only encoding restrictions associated with sober different-race face processing led to poorer recognition. These results support perceptual expertise accounts of own-race face processing, but suggest the adverse effects of alcohol on face learning published previously are not caused by foveal encoding restrictions. The implications of these findings for alcohol myopia theory are discussed.

Identifying and characterising cerebral visual impairment in children: a review.

PubMed

Philip, Swetha Sara; Dutton, Gordon N

2014-05-01

Cerebral visual impairment (CVI) comprises visual malfunction due to retro-chiasmal visual and visual association pathway pathology. This can be isolated or accompany anterior visual pathway dysfunction. It is a major cause of low vision in children in the developed and developing world due to increasing survival in paediatric and neonatal care. CVI can present in many combinations and degrees. There are multiple causes and it is common in children with cerebral palsy. CVI can be identified easily, if a structured approach to history-taking is employed. This review describes the features of CVI and describes practical management strategies aimed at helping affected children. A literature review was undertaken using 'Medline' and 'Pubmed'. Search terms included cerebral visual impairment, cortical visual impairment, dorsal stream dysfunction and visual function in cerebral palsy. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

The visual and functional impacts of astigmatism and its clinical management.

PubMed

Read, Scott A; Vincent, Stephen J; Collins, Michael J

2014-05-01

To provide a comprehensive overview of research examining the impact of astigmatism on clinical and functional measures of vision, the short and longer term adaptations to astigmatism that occur in the visual system, and the currently available clinical options for the management of patients with astigmatism. The presence of astigmatism can lead to substantial reductions in visual performance in a variety of clinical vision measures and functional visual tasks. Recent evidence demonstrates that astigmatic blur results in short-term adaptations in the visual system that appear to reduce the perceived impact of astigmatism on vision. In the longer term, uncorrected astigmatism in childhood can also significantly impact on visual development, resulting in amblyopia. Astigmatism is also associated with the development of spherical refractive errors. Although the clinical correction of small magnitudes of astigmatism is relatively straightforward, the precise, reliable correction of astigmatism (particularly high astigmatism) can be challenging. A wide variety of refractive corrections are now available for the patient with astigmatism, including spectacle, contact lens and surgical options. Astigmatism is one of the most common refractive errors managed in clinical ophthalmic practice. The significant visual and functional impacts of astigmatism emphasise the importance of its reliable clinical management. With continued improvements in ocular measurement techniques and developments in a range of different refractive correction technologies, the future promises the potential for more precise and comprehensive correction options for astigmatic patients. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

Considering Apical Scotomas, Confusion, and Diplopia When Prescribing Prisms for Homonymous Hemianopia

PubMed Central

Apfelbaum, Henry L.; Ross, Nicole C.; Bowers, Alex R.; Peli, Eli

2013-01-01

Purpose: While prisms are commonly prescribed for homonymous hemianopia to extend or expand the visual field, they cause potentially troubling visual side effects, including nonveridical location of perceived images, diplopia, and visual confusion. In addition, the field behind a prism at its apex is lost to an apical scotoma equal in magnitude to the amount of prism shift. The perceptual consequences of apical scotomas and the other effects of various designs were examined to consider parameters and designs that can mitigate the impact of these effects. Methods: Various configurations of sector and peripheral prisms were analyzed, in various directions of gaze, and their visual effects were illustrated using simulated perimetry. A novel “percept” diagram was developed that yielded insights into the patient's view through the prisms. The predictions were verified perimetrically with patients. Results: The diagrams distinguish between potentially beneficial field expansion via visual confusion and the pericentrally disturbing and useless effect of diplopia, and their relationship to prism power and gaze direction. They also illustrate the nonexpanding substitution of field segments of some popular prism designs. Conclusions: Yoked sector prisms have no effect at primary gaze or when gaze is directed toward the seeing hemifield, and they introduce pericentral field loss when gaze is shifted into them. When fitted unilaterally, sector prisms also have an effect only when the gaze is directed into the prism and may cause a pericentral scotoma and/or central diplopia. Peripheral prisms are effective at essentially all gaze angles. Since gaze is not directed into them, they avoid problematic pericentral effects. We derive useful recommendations for prism power and position parameters, including novel ways of fitting prisms asymmetrically. Translational Relevance: Clinicians will find these novel diagrams, diagramming techniques, and analyses valuable when prescribing prismatic aids for hemianopia and when designing new prism devices for patients with various types of field loss. PMID:24049719

[A cross-sectional study of moderate or severe visual impairment and blindness in residents with type 2 diabetes living in Xinjing Town, Shanghai].

PubMed

Bai, X L; Xu, X; Lu, M; He, J N; Xu, X; Du, X; Zhang, B; He, X G; Lu, L N; Zhu, J F; Zou, H D; Zhao, J L

2016-11-11

Objective: To investigate the prevalence, underlying causes and risk factors of moderate or severe visual impairment and blindness in a population with type 2 diabetes in Xinjing Town, Shanghai, China. Methods: A cross-sectional survey among local Han adult residents, who were previously diagnosed as type 2 diabetes, was conducted between October 2014 and January 2015. The survey was preceded by a pilot study; operational methods were refined and quality assurance evaluation was carried out. The best corrected visual acuity was recorded and classified following the modified World Health Organization grading system. Assigned ophthalmic doctors assured the leading causes of every blind or visually impaired eye. Binary logistic regression analysis was used to determine the related factors of blindness and moderate or severe visual impairment. Results: A total of 2 216 type 2 diabetic residents were enrolled, and 166 eyes (3.7%, 166/4 432) were blind. Cataract was the leading cause of blindness (39.8%); macular degeneration (18.0%) and eyeball atrophy (11.4%) were the second and third leading causes of blindness, respectively. Moderate or severe visual impairment was found in 376 eyes (8.5%, 376/4 432), and the most frequent cause was cataract (65.7%), followed by diabetic retinopathy (9.8%) and macular degeneration (9.4% ). Older age, female gender, earlier onset diabetes and a lower spherical equivalent in the better eye were associated with best corrected visual acuity<20/63 in the better eye. Conclusion: The prevalences of moderate or severe visual impairment and blindness in our population with type 2 diabetes were high. (Chin J Ophthalmol, 2016, 52: 825-830) .

ENVIRONMENTAL REVIEWS AND CASE STUDIES: The National Park Service Visual Resource Inventory: Capturing the Historic and Cultural Values of Scenic Views

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Robert G.; Meyer, Mark E.

Several United States (US) federal agencies have developed visual resource inventory (VRI) and management systems that reflect specific agency missions and visual resource management objectives. These programs have varied in the degree to which they incorporate historic and cultural elements and values into the scenic inventory process. The recent nationwide expansion of renewable energy and associated transmission development is causing an increase in visual impacts on both scenic and historic/cultural resources. This increase has highlighted the need for better integration of visual and historic/cultural resource assessment and management activities for land use planning purposes. The US Department of the Interiormore » National Park Service (NPS), in response to concerns arising from potential scenic impacts from renewable energy, electric transmission, and other types of development on lands and waters near NPS units, has developed a VRI process for high-value views both within and outside NPS unit boundaries. The NPS VRI incorporates historic and cultural elements and values into the scenic resource inventory process and provides practical guidance and metrics for successfully integrating historic and cultural concerns into the NPS’s scenic resource conservation efforts. This article describes the NPS VRI process and compares it with the VRI processes of the US Department of the Interior Bureau of Land Management and the US Department of Agriculture Forest Service, with respect to the incorporation of historic and cultural values. The article discusses why a scenic inventory approach that more robustly integrates the historic and cultural values of the landscape is essential for NPS landscapes, and for fulfillment of NPS’s mission. Inventories are underway at many NPS units, and the results indicate that the VRI process can be used successfully to capture important historic and cultural resource information and incorporate that information into the assessment of the scenic values of views within and outside NPS units. Environmental Practice 18: 166–179 (2016)« less

Examining the effect of state anxiety on compensatory and strategic adjustments in the planning of goal-directed aiming.

PubMed

Roberts, James W; Wilson, Mark R; Skultety, Jessica K; Lyons, James L

2018-04-01

The anxiety-perceptual-motor performance relationship may be enriched by investigations involving discrete manual responses due to the definitive demarcation of planning and control processes, which comprise the early and late portions of movement, respectively. To further examine the explanatory power of self-focus and distraction theories, we explored the potential of anxiety causing changes to movement planning that accommodate for anticipated negative effects in online control. As a result, we posed two hypotheses where anxiety causes performers to initially undershoot the target and enable more time to use visual feedback ("play-it-safe"), or fire a ballistic reach to cover a greater distance without later undertaking online control ("go-for-it"). Participants were tasked with an upper-limb movement to a single target under counter-balanced instructions to execute fast and accurate responses (low/normal anxiety) with non-contingent negative performance feedback (high anxiety). The results indicated that the previously identified negative impact of anxiety in online control was replicated. While anxiety caused a longer displacement to reach peak velocity and greater tendency to overshoot the target, there appeared to be no shift in the attempts to utilise online visual feedback. Thus, the tendency to initially overshoot may manifest from an inefficient auxiliary procedure that manages to uphold overall movement time and response accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources

PubMed Central

Klæboe, Ronny; Sundfør, Hanne Beate

2016-01-01

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors. PMID:27455301

Unsteady flow challenges tracking performance at vortex shedding frequencies without disrupting lift mechanisms

NASA Astrophysics Data System (ADS)

Matthews, Megan; Sponberg, Simon

2017-11-01

Birds, insects, and many animals use unsteady aerodynamic mechanisms to achieve stable hovering flight. Natural environments are often characterized by unsteady flows causing animals to dynamically respond to perturbations while performing complex tasks, such as foraging. Little is known about how unsteady flow around an animal interacts with already unsteady flow in the environment or how this impacts performance. We study how the environment impacts maneuverability to reveal any coupling between body dynamics and aerodynamics for hawkmoths, Manduca sexta,tracking a 3D-printed robotic flower in a wind tunnel. We also observe the leading-edge vortex (LEV), a known lift-generating mechanism for insect flight with smoke visualization. Moths in still and unsteady air exhibit near perfect tracking at low frequencies, but tracking in the flower wake results in larger overshoot at mid-range. Smoke visualization of the flower wake shows that the dominant vortex shedding corresponds to the same frequency band as the increased overshoot. Despite the large effect on flight dynamics, the LEV remains bound to the wing and thorax throughout the wingstroke. In general, unsteady wind seems to decrease maneuverability, but LEV stability seems decoupled from changes in flight dynamics.

Causes of severe visual impairment and blindness in children in schools for the blind in eastern Africa: changes in the last 14 years.

PubMed

Njuguna, Margaret; Msukwa, Gerald; Shilio, Bernadeth; Tumwesigye, Cillasy; Courtright, Paul; Lewallen, Susan

2009-01-01

To determine the causes of severe visual impairment and blindness in children attending schools for the blind in Kenya, Malawi, Uganda, and Tanzania and to compare the findings with those of a 1994 study. Children attending schools for the blind or annexes in 4 eastern African countries were examined. The major anatomical site of and underlying etiology of severe visual impairment and blindness was recorded using the standardized World Health Organization (WHO) reporting form. A total of 1062 children aged below 16 years were examined of whom 701 (65.2%) had severe visual impairment or blindness. The major anatomical sites of visual loss overall (% and 95% CI) were cornea scar/phthisis bulbi (19%,16.1-21.9), whole globe lesions (15.7%,13.0-18.4), retina (15.4 %, 12.7-18.1), lens related disorders (13.1%, 10.7-15.5), and optic nerve disorders (12.3%, 9.9-14.7). Corneal scar/phthisis was not distributed equally among the countries and was highest in Malawi, similar to findings in 1995. The major etiology of visual loss was childhood factors (29.9%) and an estimated 40% of severe visual impairment and blindness was due to potentially avoidable causes. The major causes of severe visual impairment and blindness overall have not changed appreciably since 1995. There are important differences among countries, however, and using overall estimates for planning may be misleading.

Visual Impairment Registry of Patients from North Kolkata, Eastern India: A Hospital-based Study.

PubMed

Bandyopadhyay, Sabyasachi; Bandyopadhyay, Samir Kumar; Biswas, Jaya; Saha Dutta Chowdhury, Mita; Dey, Asim Kumar; Chakrabarti, Asim

2018-01-01

To study the demographic profile, severity and causes of visual impairment among registered patients in a tertiary care hospital in north Kolkata, eastern India, and to assess the magnitude of under-registration in that population. This is a retrospective analytical study. A review of all visually impaired patients registered at our tertiary care hospital during a ten-year period from January 2005 to December 2014, which is entitled for certification of people of north Kolkata, eastern India (with a population denominator of 1.1 million), was performed. Overall, 2472 eyes of 1236 patients were analyzed in terms of demographic characteristics, cause of visual impairment, and percentage of visual disability as per the guidelines established by the government of India. Male patients (844, 68.28%; 95% confidence interval [CI], 65.69-70.87) registered more often than female patients (392; 31.72%, P = 0.0004). The registration rate for visual impairment was 11.24 per 100,000 per annum; this is not the true incidence rate, as both new patients and those visiting for renewal of certification were included in the study. Optic atrophy was the most common cause of visual impairment (384 eyes, 15.53%; 95% CI, 14.1-16.96). Commonest cause of visual impairment was optic atrophy followed by microphthalmos. Under-registration is a prevalent problem as the registration system is voluntary rather than mandatory, and female patients are more likely to be unregistered in this area.

A survey of visual impairment and blindness in children attending seven schools for the blind in Myanmar.

PubMed

Muecke, James; Hammerton, Michael; Aung, Yee Yee; Warrier, Sunil; Kong, Aimee; Morse, Anna; Holmes, Martin; Yapp, Michael; Hamilton, Carolyn; Selva, Dinesh

2009-01-01

To determine the causes of visual impairment and blindness amongst children in schools for the blind in Myanmar; to identify the avoidable causes of visual impairment and blindness; and to provide spectacles, low vision aids, orientation and mobility training and ophthalmic treatment where indicated. Two hundred and eight children under 16 years of age from all 7 schools for the blind in Myanmar were examined and the data entered into the World Health Organization Prevention of Blindness Examination Record for Childhood Blindness (WHO/PBL ERCB). One hundred and ninety nine children (95.7%) were blind (BL = Visual Acuity [VA] < 3/60 in the better eye) and 3 had severe visual impairment (SVI = VA < 6/60 to 3/60 in the better eye). Most children had corneal abnormalities as the major anatomical site of SVI/BL (100, 49.5%), however the cause of SVI/BL was unknown in the majority (88, 43.6%). Measles keratitis was the commonest identifiable cause (17.4%) and 88 children had avoidable causes of SVI/BL (43.6%). Nearly 16% of children required an optical device and 24.2% required medical attention, with a potential for visual improvement through intervention in 15.8%. Nearly half of the children in schools for the blind in Myanmar had potentially avoidable causes of SVI/BL. With measles being both the commonest identifiable and commonest avoidable cause, the data supports the need for a measles immunization campaign. There is also a need for a dedicated pediatric eye care center with regular ophthalmology visits to the schools, and improved optometric, low vision and orientation and mobility services in Myanmar.

Examining the Impact of Chess Instruction for the Visual Impairment on Mathematics

ERIC Educational Resources Information Center

Aydin, Mensure

2015-01-01

The purpose of the study is to explore the impact of chess instruction for visually impaired children on math achievement. The study group consists of a total of 26 visually impaired students from inclusion classes in inclusive secondary schools of MoNE (Ministry of National Education), 9 male and 5 female students in the experiment group and 8…

A simulated field trip: "The visual aspects of power plant sitings"

Treesearch

Bill Bottomly; Alex Young

1979-01-01

The growth of our economy is demanding construction of a variety of power plants to generate electricity which is having a significant impact on the visual environment. These power plants will consist of conventional thermal (fossil fuel and nuclear), geothermal, wind and solar power plants. There are several areas where solutions to the visual impacts of these power...

Smartphone serious games for vision and hearing assessment.

PubMed

Dias, Pedro; Aguiar, Bruno; Sousa, Filipe; Sousa, Augusto

2015-01-01

Falls are the second leading cause of accidental injury deaths worldwide. In this paper, it is intended to define methodologies that permit the evaluation of two potential factors which might have an impact on fall risk, these are: visual and hearing loss. The aim of the work developed is not to replace clinic visits, but to offer the user the means to continue the tracking of his vision and hearing at home, during the long time intervals between clinical tests. Tests conducted in a sample of our target users indicate a good ability to measure vision and hearing using an android smartphone and the proposed methodologies. While some tests require further validation, promising results were achieved in the most common tests for vision and hearing, presenting a good correlation between the system's results when compared to the traditional tests (for distance visual acuity) and the data gathered from the users (for hearing tests).

Causes of childhood blindness in the northeastern states of India

PubMed Central

Bhattacharjee, Harsha; Das, Kalyan; Borah, Rishi Raj; Guha, Kamalesh; Purukayastha, S; Gilbert, Clare

2008-01-01

Background: The northeastern region (NER) of India is geographically isolated and ethno-culturally different from the rest of the country. There is lacuna regarding the data on causes of blindness and severe visual impairment in children from this region. Aim: To determine the causes of severe visual impairment and blindness amongst children from schools for the blind in the four states of NER of India. Design and Setting: Survey of children attending special education schools for the blind in the NER. Materials and Methods: Blind and severely visually impaired children (best corrected visual acuity <20/200 in the better eye, aged up to 16 years) underwent visual acuity estimation, external ocular examination, retinoscopy and fundoscopy. Refraction and low vision workup was done where indicated. World Health Organization′s reporting form was used to code anatomical and etiological causes of visual loss. Statistical Analysis: Microsoft Excel Windows software with SPSS. Results: A total of 376 students were examined of whom 258 fulfilled the eligibility criteria. The major anatomical causes of visual loss amongst the 258 were congenital anomalies (anophthalmos, microphthalmos) 93 (36.1%); corneal conditions (scarring, vitamin A deficiency) 94 (36.7%); cataract or aphakia 28 (10.9%), retinal disorders 15 (5.8%) and optic atrophy 14 (5.3%). Nearly half of the children were blind from conditions which were either preventable or treatable (48.5%). Conclusion: Nearly half the childhood blindness in the NER states of India is avoidable and Vitamin A deficiency forms an important component unlike other Indian states. More research and multisectorial effort is needed to tackle congenital anomalies. PMID:18974521

Prevalence and Causes of Visual Impairment and Blindness among Cocoa Farmers in Ghana.

PubMed

Boadi-Kusi, Samuel Bert; Hansraj, Rekha; Mashige, Khathutshelo Percy; Osafo-Kwaako, Alfred; Ilechie, Alex Azuka; Abokyi, Samuel

2017-02-01

To determine the prevalence and causes of visual impairment and blindness among cocoa farmers in Ghana in order to formulate early intervention strategies. A cross-sectional study using multistage random sampling from four cocoa growing districts in Ghana was conducted from November 2013 to April 2014. A total of 512 cocoa farmers aged 40 years and older were interviewed and examined. The brief interview questionnaire was administered to elicit information on the demographics and socioeconomic details of participants. The examination included assessment of visual acuity (VA), retinoscopy, subjective refraction, direct ophthalmoscopy, slit-lamp biomicroscopy and intraocular pressure (IOP). For quality assurance, a random sample of cocoa farmers were selected and re-examined independently. Moderate to severe visual impairment (VA <6/18 to 3/60 in the better-seeing eye) was present in 89 participants (17.4%) and 27 (5.3%) were blind (presenting VA <3/60 in the better eye) defined using presenting VA. The main causes of visual impairment were cataract (45, 38.8%), uncorrected refractive error (42, 36.2%), posterior segment disorders (15, 12.9%), and corneal opacity (11, 9.5%). The prevalence of visual impairment and blindness among cocoa farmers in Ghana is relatively high. The major causes of visual impairment and blindness are largely preventable or treatable, indicating the need for early eye care service interventions.

Blindness and Visual Impairment Profile and Rapid Assessment of Avoidable Blindness in South East Asia: Analysis of New Data. 2017 APAO Holmes Lecture.

PubMed

Das, Taraprasad

2018-03-13

The International Agency for Prevention of Blindness (IAPB) South East Asia region (SEAR) that consists of 11 countries contains 26% of the world's population (1,761,000,000). In this region 12 million are blind and 78.5 million are visually impaired. This amounts to 30% of global blindness and 32% of global visual impairment. Rapid assessment of avoidable blindness (RAAB) survey analysis. RAAB, either a repeat or a first time survey, was completed in 8 countries in this decade (2010 onwards). These include Bangladesh, Bhutan, India, Indonesia, Maldives, Sri Lanka, Thailand, and Timor Leste. Cataract is the principal cause of blindness and severe visual impairment in all countries. Refractive error is the principal cause of moderate visual impairment in 4 countries: Bangladesh, India, Maldives, and Sri Lanka; cataract continues to be the principal cause of moderate visual impairment in 4 other countries: Bhutan, Indonesia, Thailand, and Timor Leste. Outcome of cataract surgery is suboptimal in the Maldives and Timor Leste. Rigorous focus is necessary to improve cataract surgery outcomes and correction of refractive error without neglecting the quality of care. At the same time allowances must be made for care of the emerging causes of visual impairment and blindness such as glaucoma and posterior segment disorders, particularly diabetic retinopathy. Copyright 2018 Asia-Pacific Academy of Ophthalmology.

A comparison of two-coloured filter systems for treating visual reading difficulties.

PubMed

Hall, Roger; Ray, Nicola; Harries, Priscilla; Stein, John

2013-01-01

Visual disturbances that make it difficult to read text are often termed "visual stress". Coloured filters in spectacles may help some children overcome reading problems that are often caused by visual stress. It has been suggested that for optimal effect each child requires an individually prescribed colour for each eye, as determined in systems such as the "Harris Foundation" coloured filters. Alternatively, it has been argued that only blue or yellow filters, as used in the "Dyslexia Research Trust" (DRT) filter system, are necessary to affect the underlying physiology. A randomised, double blind trial with 73 delayed readers, was undertaken to compare changes in reading and spelling as well as irregular and non-word reading skills after 3 months of wearing either the Harris or the DRT filters. Reading improved significantly after wearing either type of filter (t = -8.4, p < 0.01), with 40% of the children improving their reading age by 6 months or more during the 3 month trial. However, spelling ability (t = 2.1, p = 0.05) and non-word reading (f = 4.7, p < 0.05) improved significantly more with the DRT than with the Harris filters. Education and rehabilitation professionals should therefore, consider coloured filters as an effective intervention for delayed readers experiencing visual stress. Any disability that impacts on a child's capacity to read has serious implications for academic development as well as the ability to participate independently in activities of daily living. One reading disability, generally termed "visual stress", is related to visual disturbances that make it difficult to read text. This research demonstrates the beneficial use of coloured filters for promoting visual reading capacity for children with visual stress. Professionals who are involved in the needs of children with reading delay, may like to consider the benefits that coloured filters can afford children with visual reading problems.

A comparison of two-coloured filter systems for treating visual reading difficulties

PubMed Central

Hall, Roger; Ray, Nicola; Harries, Priscilla

2013-01-01

Purpose Visual disturbances that make it difficult to read text are often termed “visual stress”. Coloured filters in spectacles may help some children overcome reading problems that are often caused by visual stress. It has been suggested that for optimal effect each child requires an individually prescribed colour for each eye, as determined in systems such as the “Harris Foundation” coloured filters. Alternatively, it has been argued that only blue or yellow filters, as used in the “Dyslexia Research Trust” (DRT) filter system, are necessary to affect the underlying physiology. Method A randomised, double blind trial with 73 delayed readers, was undertaken to compare changes in reading and spelling as well as irregular and non-word reading skills after 3 months of wearing either the Harris or the DRT filters. Results Reading improved significantly after wearing either type of filter (t = −8.4, p < 0.01), with 40% of the children improving their reading age by 6 months or more during the 3 month trial. However, spelling ability (t = 2.1, p = 0.05) and non-word reading (f = 4.7, p < 0.05) improved significantly more with the DRT than with the Harris filters. Conclusion Education and rehabilitation professionals should therefore, consider coloured filters as an effective intervention for delayed readers experiencing visual stress. Implications for Rehabilitation Any disability that impacts on a child’s capacity to read has serious implications for academic development as well as the ability to participate independently in activities of daily living. One reading disability, generally termed “visual stress”, is related to visual disturbances that make it difficult to read text. This research demonstrates the beneficial use of coloured filters for promoting visual reading capacity for children with visual stress. Professionals who are involved in the needs of children with reading delay, may like to consider the benefits that coloured filters can afford children with visual reading problems. PMID:23627538

[Treatment of macular hematoma complicating AMD by vitrectomy, subretinal r-TPA injection, intravitreal injection of bevacizumab combined with gas tamponade: Report of 4 cases].

PubMed

Abboud, M; Benzerroug, M; Milazzo, S

2017-02-01

The occurrence of a subretinal hematoma in age-related macular degeneration (AMD) is a serious complication that can impact the visual prognosis with a poor functional recovery. The management of this complication remains controversial. Several therapeutic methods have been described. We report the results of four patients treated with a protocol combining: vitrectomy, subretinal injection of r-TPA 0.025mg/0.3ml, intravitreal injection of 0.05ml of bevacizumab and retinal tamponade with 20% SF6 gas. Our series consists of four patients with a submacular hematoma complicating AMD, included in succession between October 2013 and October 2014 and treated with the same treatment protocol and by the same surgeon. All patients underwent surgery within eight days after the onset of the macular hematoma. Patients with a consultation period longer than eight days did not undergo this treatment. Face down postoperative positioning was then carried out for seven days by the patients. We observed a shift in the macular hematoma in the four patients, which allowed the identification of secondary neovascularization responsible for the bleeding. The visual acuity improved in three patients from hand motion (HM) preoperatively to 2/10 at one month postoperatively. One patient maintained visual acuity 1/20 during the entire follow-up despite almost complete resorption of the subretinal hematoma. These visual acuities were stable at 6 months postoperatively. Macular subretinal hematoma can cause severe visual loss by several mechanisms. The blood accumulates between the neurosensory retina and the retinal pigment epithelium, which causes a toxic effect on the surrounding tissues, thus resulting in a loss of photoreceptors and cellular destruction in the pigment epithelium and choriocapillaris, evolving into a fibroglial scar. The therapeutic evaluation of this protocol in our series of four patients gives a favorable result. We observed an improvement in visual acuity in 3/4 of cases. This surgical technique appears to be effective in the treatment of this complication of AMD. However, a study on a larger scale is needed to confirm these results. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Changes in White Matter Microstructure Impact Cognition by Disrupting the Ability of Neural Assemblies to Synchronize.

PubMed

Bells, Sonya; Lefebvre, Jérémie; Prescott, Steven A; Dockstader, Colleen; Bouffet, Eric; Skocic, Jovanka; Laughlin, Suzanne; Mabbott, Donald J

2017-08-23

Cognition is compromised by white matter (WM) injury but the neurophysiological alterations linking them remain unclear. We hypothesized that reduced neural synchronization caused by disruption of neural signal propagation is involved. To test this, we evaluated group differences in: diffusion tensor WM microstructure measures within the optic radiations, primary visual area (V1), and cuneus; neural phase synchrony to a visual attention cue during visual-motor task; and reaction time to a response cue during the same task between 26 pediatric patients (17/9: male/female) treated with cranial radiation treatment for a brain tumor (12.67 ± 2.76 years), and 26 healthy children (16/10: male/female; 12.01 ± 3.9 years). We corroborated our findings using a corticocortical computational model representing perturbed signal conduction from myelin. Patients show delayed reaction time, WM compromise, and reduced phase synchrony during visual attention compared with healthy children. Notably, using partial least-squares-path modeling we found that WM insult within the optic radiations, V1, and cuneus is a strong predictor of the slower reaction times via disruption of neural synchrony in visual cortex. Observed changes in synchronization were reproduced in a computational model of WM injury. These findings provide new evidence linking cognition with WM via the reliance of neural synchronization on propagation of neural signals. SIGNIFICANCE STATEMENT By comparing brain tumor patients to healthy children, we establish that changes in the microstructure of the optic radiations and neural synchrony during visual attention predict reaction time. Furthermore, by testing the directionality of these links through statistical modeling and verifying our findings with computational modeling, we infer a causal relationship, namely that changes in white matter microstructure impact cognition in part by disturbing the ability of neural assemblies to synchronize. Together, our human imaging data and computer simulations show a fundamental connection between WM microstructure and neural synchronization that is critical for cognitive processing. Copyright © 2017 the authors 0270-6474/17/378227-12$15.00/0.

Impact of the Alexander technique on well-being: a randomised controlled trial involving older adults with visual impairment.

PubMed

Gleeson, Michael; Sherrington, Catherine; Lo, Serigne; Auld, Robin; Keay, Lisa

2017-11-01

Older adults with visual loss have high rates of depression, restricted participation and reduced quality of life. We sought to measure the impact of lessons in the Alexander technique on vision-related emotional and social well-being, as secondary outcomes to a study on improving physical functioning in this population. This is a single-blind randomised controlled trial. One hundred and twenty community-dwelling adults aged 50 to 90 years with visual impairments were randomised to either 12 Alexander lessons over 12 weeks and usual care or usual care. The Perceived Visual Ability Scale, the Keele Assessment of Participation, the emotional subscale of the Impact of Vision Impairment Profile, the Positive and Negative Affect Scale and the five-item Geriatric Depression Scale were administered at baseline and three and 12 months. Participants were receiving services from Guide Dogs NSW/ACT. None of the validated questionnaires found statistically significant improvements after adjustment for baseline at three or 12 months, although the emotional subscale of the Impact of Vision Impairment approached significance in favour of the intervention group (4.54 points, 95 per cent CI: -0.14 to 9.21, p = 0.06). Depressive symptoms were prevalent and associated with greater impact of visual impairment on emotional well-being (odds ratio: 1.12, 95 per cent CI: 1.07 to 1.17, p < 0.0001). Faster gait, an indicator of general mobility, was associated with less depressive symptoms (odds ratio: 1.27, 95 per cent CI: 1.06 to 1.54, p = 0.01). On average, there was no significant impact of weekly lessons in the Alexander technique on social and emotional well-being, although the emotional impact of visual impairment showed a trend toward less distress in the intervention group. Our data found that emotional distress associated with visual impairment influences depressive symptoms but contrary to expectations, the level of social support received was not significant. Additionally, gait speed is a significant predictor of depressive symptoms, suggesting that general mobility is of importance to the well-being of older adults with visual impairments. © 2017 Optometry Australia.

ICT integration in mathematics initial teacher training and its impact on visualization: the case of GeoGebra

NASA Astrophysics Data System (ADS)

Dockendorff, Monika; Solar, Horacio

2018-01-01

This case study investigates the impact of the integration of information and communications technology (ICT) in mathematics visualization skills and initial teacher education programmes. It reports on the influence GeoGebra dynamic software use has on promoting mathematical learning at secondary school and on its impact on teachers' conceptions about teaching and learning mathematics. This paper describes how GeoGebra-based dynamic applets - designed and used in an exploratory manner - promote mathematical processes such as conjectures. It also refers to the changes prospective teachers experience regarding the relevance visual dynamic representations acquire in teaching mathematics. This study observes a shift in school routines when incorporating technology into the mathematics classroom. Visualization appears as a basic competence associated to key mathematical processes. Implications of an early integration of ICT in mathematics initial teacher training and its impact on developing technological pedagogical content knowledge (TPCK) are drawn.

Evolution of a visual impact model to evaluate nuclear plant siting and design option

Treesearch

Brian A. Gray; John Ady; Grant R. Jones

1979-01-01

The development of a visual impact method- elegy is reviewed from first concepts (1973) to application.3/ The method can be used to train evaluators to use explicit criteria (vividness, intactness and unity) to assess change in a setting's visual quality as the result of construction of a nuclear facility, or any other visible alteration. Slides of "before...

Visual Analysis as a design and decision-making tool in the development of a quarry

Treesearch

Randall Boyd Fitzgerald

1979-01-01

In order to obtain local and state government approvals, an environmental impact analysis of the mining and reclamation of a proposed hard rock quarry was required. High visibility of the proposed mining area from the adjacent community required a visual impact analysis in the planning and design of the project. The Visual Analysis defined design criteria for the...

ICT Integration in Mathematics Initial Teacher Training and Its Impact on Visualization: The Case of GeoGebra

ERIC Educational Resources Information Center

Dockendorff, Monika; Solar, Horacio

2018-01-01

This case study investigates the impact of the integration of information and communications technology (ICT) in mathematics visualization skills and initial teacher education programmes. It reports on the influence GeoGebra dynamic software use has on promoting mathematical learning at secondary school and on its impact on teachers' conceptions…

Visual Confirmation (VICON) of Takeoff Clearance Signal System Impact Study

DOT National Transportation Integrated Search

1980-11-01

A study was performed to evaluate the impact on airport capacity and voice communications of the Visual Confirmation of Takeoff Clearance (VICON) Signal System. Befoe-and-after test data collection and analysis were conducted at Bradley International...

The correlation between visual acuity and color vision as an indicator of the cause of visual loss.

PubMed

Almog, Yehoshua; Nemet, Arie

2010-06-01

To explore the correlation between visual acuity (VA) and color vision and to establish a guide for the diagnosis of the cause of visual loss based on this correlation. Retrospective comparative evaluation of a diagnostic test. A total of 259 patients with visual impairment caused by 1 of 4 possible disease categories were included. Patients were divided into 4 groups according to the etiology of visual loss: 1) optic neuropathies, 2) macular diseases, 3) media opacities, and 4) amblyopia. The best-corrected VA was established and a standard Ishihara 15 color plates was tested and correlated to the VA in every group separately. Correlation between the VA and the color vision along the different etiologies was evaluated. Frequency of each combination of color vision and VA in every disease category was established. VA is correlated with color vision in all 4 disease categories. For the same degree of VA loss, patients with optic neuropathy are most likely and patients with amblyopia are the least expected to have a significant color vision loss. Patients with optic neuropathy had considerably worse average color vision (6.7/15) compared to patients in the other 3 disease categories: 11.1/15 (macular diseases), 13.2/15 (media opacities), and 13.4/15 (amblyopia). Diseases of the optic nerve affect color vision earlier and more profoundly than other diseases. When the cause of visual loss is uncertain, the correlation between the severity of color vision and VA loss can imply the possible etiology of the visual loss. Copyright 2010 Elsevier Inc. All rights reserved.

Causes and anatomical site of blindness and severe visual loss in Isfahan, Islamic Republic of Iran.

PubMed

Dehghan, A; Kianersi, F; Moazam, E; Ghanbari, H

2010-02-01

This study in 2005 evaluated the causes and major anatomical site of blindness and severe visual loss at a school for blind children in Isfahan province, Islamic Republic of Iran. All 211 students were examined according to the modified WHO/PBL eye examination record: 70.4% were blind, 24.3% had severe visual loss and 5.3% were visually impaired. The major causes of abnormality were hereditary factors (42.7%), prenatal/neonatal (18.5%) and unknown etiology (35.5%). The main sites of abnormality were the retina (62.6%), whole globe (17.5%), lens (7.1%) and optic nerve (7.1%). A high proportion of parents were in a consanguineous marriage (49.2%). The pattern of blindness in Isfahan encompasses characteristics of both developed and developing countries.

Substantial adverse association of visual and vascular comorbidities on visual disability in multiple sclerosis.

PubMed

Marrie, Ruth Ann; Cutter, Gary; Tyry, Tuula

2011-12-01

Visual comorbidities are common in multiple sclerosis (MS) but the impact of visual comorbidities on visual disability is unknown. We assessed the impact of visual and vascular comorbidities on severity of visual disability in MS. In 2006, we queried participants of the North American Research Committee on Multiple Sclerosis (NARCOMS) about cataracts, glaucoma, uveitis, hypertension, hypercholesterolemia, heart disease, diabetes and peripheral vascular disease. We assessed visual disability using the Vision subscale of Performance Scales. Using Cox regression, we investigated whether visual or vascular comorbidities affected the time between MS symptom onset and the development of mild, moderate and severe visual disability. Of 8983 respondents, 1415 (15.9%) reported a visual comorbidity while 4745 (52.8%) reported a vascular comorbidity. The median (interquartile range) visual score was 1 (0-2). In a multivariable Cox model the risk of mild visual disability was higher among participants with vascular (hazard ratio [HR] 1.45; 95% confidence interval [CI]: 1.39-1.51) and visual comorbidities (HR 1.47; 95% CI: 1.37-1.59). Vascular and visual comorbidities were similarly associated with increased risks of moderate and severe visual disability. Visual and vascular comorbidities are associated with progression of visual disability in MS. Clinicians hearing reports of worsening visual symptoms in MS patients should consider visual comorbidities as contributing factors. Further study of these issues using objective, systematic neuro-ophthalmologic evaluations is warranted.

The Status of Childhood Blindness and Functional Low Vision in the Eastern Mediterranean Region in 2012

PubMed Central

Khandekar, Rajiv; Kishore, H.; Mansu, Rabiu M.; Awan, Haroon

2014-01-01

Childhood blindness and visual impairment (CBVI) are major disabilities that compromise the normal development of children. Health resources and practices to prevent CBVI are suboptimal in most countries in the Eastern Mediterranean Region (EMR). We reviewed the magnitude and the etiologies of childhood visual disabilities based on the estimates using socioeconomic proxy indicators such as gross domestic product (GDP) per capita and <5-year mortality rates. The result of these findings will facilitate novel concepts in addressing and developing services to effectively reduce CBVI in this region. The current study determined the rates of bilateral blindness (defined as  Best corrected visual acuity(BCVA)) less than 3/60 in the better eye or a visual field of 10° surrounding central fixation) and functional low vision (FLV) (visual impairment for which no treatment or refractive correction can improve the vision up to >6/18 in a better eye) in children <15 years old. We used the 2011 population projections, <5-year mortality rates and GDP per capita of 23 countries (collectively grouped as EMR). Based on the GDP, we divided the countries into three groups; high, middle- and low-income nations. By applying the bilateral blindness and FLV rates to high, middle- and low-income countries from the global literature to the population of children <15 years, we estimated that there could be 238,500 children with bilateral blindness (rate 1.2/1,000) in the region. In addition, there could be approximately 417,725 children with FLV (rate of 2.1/1,000) in the region. The causes of visual disability in the three groups are also discussed based on the available data. As our estimates are based on hospital and blind school studies in the past, they could have serious limitations for projecting the present magnitude and causes of visual disabilities in children of EMR. An effective approach to eye health care and screening for children within primary health care and with the available resources are discussed. The objectives, strategies, and operating procedures for child eye-care are presented. Variables impacting proper screening are discussed. To reach the targets, we recommend urgent implementation of new approaches to low vision and rehabilitation of children. PMID:25371641

The status of childhood blindness and functional low vision in the Eastern Mediterranean region in 2012.

PubMed

Khandekar, Rajiv; Kishore, H; Mansu, Rabiu M; Awan, Haroon

2014-01-01

Childhood blindness and visual impairment (CBVI) are major disabilities that compromise the normal development of children. Health resources and practices to prevent CBVI are suboptimal in most countries in the Eastern Mediterranean Region (EMR). We reviewed the magnitude and the etiologies of childhood visual disabilities based on the estimates using socioeconomic proxy indicators such as gross domestic product (GDP) per capita and <5-year mortality rates. The result of these findings will facilitate novel concepts in addressing and developing services to effectively reduce CBVI in this region. The current study determined the rates of bilateral blindness (defined as  Best corrected visual acuity(BCVA)) less than 3/60 in the better eye or a visual field of 10° surrounding central fixation) and functional low vision (FLV) (visual impairment for which no treatment or refractive correction can improve the vision up to >6/18 in a better eye) in children <15 years old. We used the 2011 population projections, <5-year mortality rates and GDP per capita of 23 countries (collectively grouped as EMR). Based on the GDP, we divided the countries into three groups; high, middle- and low-income nations. By applying the bilateral blindness and FLV rates to high, middle- and low-income countries from the global literature to the population of children <15 years, we estimated that there could be 238,500 children with bilateral blindness (rate 1.2/1,000) in the region. In addition, there could be approximately 417,725 children with FLV (rate of 2.1/1,000) in the region. The causes of visual disability in the three groups are also discussed based on the available data. As our estimates are based on hospital and blind school studies in the past, they could have serious limitations for projecting the present magnitude and causes of visual disabilities in children of EMR. An effective approach to eye health care and screening for children within primary health care and with the available resources are discussed. The objectives, strategies, and operating procedures for child eye-care are presented. Variables impacting proper screening are discussed. To reach the targets, we recommend urgent implementation of new approaches to low vision and rehabilitation of children.

Patient-reported utilities in bilateral visual impairment from amblyopia and age-related macular degeneration.

PubMed

van de Graaf, Elizabeth S; Despriet, Dominiek D G; Klaver, Caroline C W; Simonsz, Huibert J

2016-05-17

Utility of visual impairment caused by amblyopia is important for the cost-effectiveness of screening for amblyopia (lazy eye, prevalence 3-3.5 %). We previously measured decrease of utility in 35-year-old persons with unilateral persistent amblyopia. The current observational case-control study aimed to measure loss of utility in patients with amblyopia with recent decrease of vision in their better eye. As these patients are rare, the sample was supplemented by patients with bilateral age-related macular degeneration with similar decrease of vision. From our out-patient department, two groups of patients with recent deterioration to bilateral visual acuity less than Snellen 0.5 (bilateral visual impairment, BVI) were recruited, with either persistent amblyopia and age-related macular degeneration (AMB + AMD), or with bilateral age-related macular degeneration (BAMD). To measure utility, the time trade-off method and the standard gamble method were applied through interviews. Correlations were sought between utility values and visual acuity, age and Visual Function Questionnaire-25 scores. Seventeen AMB + AMD patients (mean age 72.9 years), and 63 BAMD patients (mean age 79.6 years) were included in the study. Among AMB + AMD, 80 % were willing to trade lifetime in exchange for cure. The overall mean time trade-off utility was 0.925. Among BAMD, 75 % were willing to trade, utility was 0.917. Among AMB + AMD, 38 % accepted risk of death in exchange for cure, overall mean standard gamble utility was 0.999. Among BAMD, 49 % accepted risk of death, utility was 0.998. Utility was not related to visual acuity but it was to age (p = 0.02). Elderly patients with BVI, caused by persistent amblyopia and age-related macular degeneration (AMD) or by bilateral AMD, had an approximately 8 % loss of TTO utility. Notably, the 8 % loss in elderly with BVI differs little from the 3.7 % loss we found previously in 35-year-old persons with unilateral amblyopia with good vision in the other eye. The moderate impact of BVI in senescence could be explained by adaptation, comorbidity, avoidance of risk and a changed percept of cure.

[Epidemiological survey of visual impairment in Funing County, Jiangsu].

PubMed

Yang, M; Zhang, J F; Zhu, R R; Kang, L H; Qin, B; Guan, H J

2017-07-11

Objective: To investigate the prevalence of visual impairment and factors associated with visual impairment among people aged 50 years and above in Funing County, Jiangsu Province. Methods: Cross-sectional study. Random cluster sampling was used in selecting individuals aged ≥50 years in 30 clusters, and 5 947 individuals received visual acuity testing and eye examination. Stata 13.0 software was used to analyze the data. Multivariate logistic regression was used to detect possible factors of visual impairment such as age, gender and education. Statistical significance was defined as P< 0.05. Results: A total of 6 145 persons aged 50 years and above were enumerated, and 5 947 (96.8%) participants were examined. Based on the criteria of World Health Organization (WHO) visual impairment classification and presenting visual acuity, 138 persons were diagnosed as blindness, and 1 405 persons were diagnosed as low vision. The prevalence of blindness and low vision was 2.32% and 23.63%, respectively. And the prevalence of visual impairment was 25.95%. Based on the criteria of WHO visual impairment classification and best-corrected visual acuity, 92 persons were diagnosed as blindness, and 383 persons were diagnosed as low vision. The prevalence of blindness and low vision was 1.55% and 6.44%, respectively. And the prevalence of visual impairment was 7.99%. Concerning presenting visual acuity and best-corrected visual acuity, the prevalence of blindness and low vision was higher in old people, females and less educated persons. Cataract (46.63%) was the leading cause of blindness. Uncorrected refractive error (36.51%) was also a main cause of visual impairment. Conclusion: The prevalence of visual impairment is higher in old people, females and less educated persons in Funing County, Jiangsu Province. Cataract is still the leading cause of visual impairment. (Chin J Ophthalmol, 2017, 53: 502-508) .

Perception and Attention for Visualization

ERIC Educational Resources Information Center

Haroz, Steve

2013-01-01

This work examines how a better understanding of visual perception and attention can impact visualization design. In a collection of studies, I explore how different levels of the visual system can measurably affect a variety of visualization metrics. The results show that expert preference, user performance, and even computational performance are…

The Impact of Visual Communication on the Intersubjective Development of Early Parent?Child Interaction with 18- to 24-Month-Old Deaf Toddlers

ERIC Educational Resources Information Center

Loots, Gerrit; Devise, Isabel; Jacquet, Wolfgang

2005-01-01

This article presents a study that examined the impact of visual communication on the quality of the early interaction between deaf and hearing mothers and fathers and their deaf children aged between 18 and 24 months. Three communication mode groups of parent?deaf child dyads that differed by the use of signing and visual?tactile communication…

Spatial vision in older adults: perceptual changes and neural bases.

PubMed

McKendrick, Allison M; Chan, Yu Man; Nguyen, Bao N

2018-05-17

The number of older adults is rapidly increasing internationally, leading to a significant increase in research on how healthy ageing impacts vision. Most clinical assessments of spatial vision involve simple detection (letter acuity, grating contrast sensitivity, perimetry). However, most natural visual environments are more spatially complicated, requiring contrast discrimination, and the delineation of object boundaries and contours, which are typically present on non-uniform backgrounds. In this review we discuss recent research that reports on the effects of normal ageing on these more complex visual functions, specifically in the context of recent neurophysiological studies. Recent research has concentrated on understanding the effects of healthy ageing on neural responses within the visual pathway in animal models. Such neurophysiological research has led to numerous, subsequently tested, hypotheses regarding the likely impact of healthy human ageing on specific aspects of spatial vision. Healthy normal ageing impacts significantly on spatial visual information processing from the retina through to visual cortex. Some human data validates that obtained from studies of animal physiology, however some findings indicate that rethinking of presumed neural substrates is required. Notably, not all spatial visual processes are altered by age. Healthy normal ageing impacts significantly on some spatial visual processes (in particular centre-surround tasks), but leaves contrast discrimination, contrast adaptation, and orientation discrimination relatively intact. The study of older adult vision contributes to knowledge of the brain mechanisms altered by the ageing process, can provide practical information regarding visual environments that older adults may find challenging, and may lead to new methods of assessing visual performance in clinical environments. © 2018 The Authors Ophthalmic & Physiological Optics © 2018 The College of Optometrists.

Retinopathy of prematurity as a major cause of severe visual impairment and blindness in children in schools for the blind in Guadalajara city, Mexico.

PubMed

Zepeda-Romero, L C; Barrera-de-Leon, J C; Camacho-Choza, C; Gonzalez Bernal, C; Camarena-Garcia, E; Diaz-Alatorre, C; Gutierrez-Padilla, J A; Gilbert, C

2011-11-01

To determine the causes of blindness in students attending schools for the blind in Guadalajara city, Mexico and to assess the availability of screening for retinopathy of prematurity (ROP) in local neonatal intensive care units. Information on causes of blindness was obtained by interview with parents and teachers, review of records and examination. Causes of visual loss in children with a distance visual acuity of <6/60 (ie, severely visually impaired or blind) were determined and classified according to the WHO's classification system for children. Of 153 children in the two participating schools, 144 were severely visual impaired or blind. Their ages ranged from 4 months to 15 years and 58% were female. ROP was the most common cause of visual loss (34.7%), followed by optic nerve lesions (17.4%) and glaucoma (14.6%). 25/59 (42.3%) children aged 0-4 years were blind from ROP compared with 6/32 (18.8%) children aged 10-15 years. 78% of children blind from ROP had psychomotor delay and less than half (46%) had not received treatment for ROP. All five privately funded neonatal intensive care units in the city regularly screen for ROP compared with only four of the 12 units in the public sector. ROP is the leading cause of blindness in children in Mexico despite national guidelines being in place. Health policies promoting primary prevention through improved neonatal care need to be implemented. Advocacy is required so that the time ophthalmologists spend screening and treating ROP is included in their job description and hence salaried.

Visual impairment and blindness in Hungary.

PubMed

Szabó, Dorottya; Sándor, Gábor László; Tóth, Gábor; Pék, Anita; Lukács, Regina; Szalai, Irén; Tóth, Georgina Zsófia; Papp, András; Nagy, Zoltán Zsolt; Limburg, Hans; Németh, János

2018-03-01

The aim of this study was to estimate the prevalence and causes of blindness, severe visual impairment (SVI), moderate visual impairment (MVI), and early visual impairment (EVI) and its causes in an established market economy of Europe. A cross-sectional population-based survey. A sample size of 3675 was calculated using the standard Rapid Assessment of Avoidable Blindness (RAAB) software in Hungary. A total of 105 clusters of 35 people aged 50 years or older were randomly selected with probability proportionate to size by the Hungarian Central Statistical Office. Households within the clusters were selected using compact segment sampling. Visual acuity (VA) was assessed with a Snellen tumbling E-chart with or without a pinhole in the households. The adjusted prevalences of bilateral blindness, SVI, MVI and EVI were 0.9% (95% CI: 0.6-1.2), 0.5% (95% CI: 0.2-0.7), 5.1% (95% CI: 4.3-5.9) and 6.9% (95% CI: 5.9-7.9), respectively. The major causes of blindness in Hungary were age-related macular degeneration (AMD; 27.3%) and other posterior segment diseases (27.3%), cataract (21.2%) and glaucoma (12.1%). Cataract was the main cause of SVI, MVI and EVI. Cataract surgical coverage (CSC) was 90.7%. Of all bilateral blindness in Hungary, 45.5% was considered avoidable. This study proved that RAAB methodology can be successfully conducted in industrialized countries, which often lack reliable epidemiologic data. The prevalence of blindness was relatively low, with AMD and other posterior segment diseases being the leading causes, and cataract is still a significant cause of visual impairment. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Prevalence and causes of blindness in children in Vietnam.

PubMed

Limburg, Hans; Gilbert, Clare; Hon, Do Nhu; Dung, Nguyen Chi; Hoang, Tran Huy

2012-02-01

To estimate the prevalence of blindness in children in Vietnam and to assess the major causes. A population-based study sampled children from 16 provinces across Vietnam. The second study examined children attending all blind schools in Vietnam. In 16 provinces, 28 800 children aged 0-15 were sampled. In 28 blind schools, 569 children aged 0-15 were examined. In children not seeing well according to the parents, presenting visual acuity (PVA) was assessed. If PVA was <3/60 in one or both eyes, the child was examined by an ophthalmologist. All children in blind schools were examined by a pediatric ophthalmologist. Blindness was defined as PVA <3/60 in the better eye. Causes of visual loss were classified using the World Health Organization classification. In the population-based study, 22 children had a PVA <3/60 in the better eye, a prevalence of 7.6/10 000 children (95% confidence interval [CI], 4.9-11.8/10 000). Fourteen children had a pinhole visual acuity <3/60 in the better eye, a prevalence of 4.9/10 000 (95% CI, 2.8-8.4/10 000). An estimated 16 400 (95% CI, 10 500-25 300), children were blind from all causes, with 36.4% from uncorrected refractive errors. In the blind schools, 411 children had a PVA <3/60 in the better eye and 55.5% were male. Conditions of the retina (24.6%) and cornea (24.0%) predominated. Retinopathy of prematurity (ROP) caused blindness in 32.6% of children younger than 10 years, but in only 6% of older children. The converse was true for corneal scarring and phthisis (14.0% and 27.3%, respectively). All other causes were similar between age groups (53.5% and 66.7%, respectively). More than half of all causes were avoidable. Vietnam is developing very rapidly, and this is impacting health indices. The mortality rate of those younger than 5 years declined from 65/100 live births in 1980 to 14/100 in 2008. The findings of this study show these changes, because the childhood blindness prevalence was relatively low, and the causes show improved control of measles and vitamin A deficiency, as well as increased services for premature babies. Eye care services for children should now focus on refractive errors, cataract, and control of ROP. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

On relative distortion in fingerprint comparison.

PubMed

Kalka, Nathan D; Hicklin, R Austin

2014-11-01

When fingerprints are deposited, non-uniform pressure in conjunction with the inherent elasticity of friction ridge skin often causes linear and non-linear distortions in the ridge and valley structure. The effects of these distortions must be considered during analysis of fingerprint images. Even when individual prints are not notably distorted, relative distortion between two prints can have a serious impact on comparison. In this paper we discuss several metrics for quantifying and visualizing linear and non-linear fingerprint deformations, and software tools to assist examiners in accounting for distortion in fingerprint comparisons. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Adult Visual Experience Promotes Recovery of Primary Visual Cortex from Long-Term Monocular Deprivation

ERIC Educational Resources Information Center

Fischer, Quentin S.; Aleem, Salman; Zhou, Hongyi; Pham, Tony A.

2007-01-01

Prolonged visual deprivation from early childhood to maturity is believed to cause permanent visual impairment. However, there have been case reports of substantial improvement of binocular vision in human adults following lifelong visual impairment or deprivation. These observations, together with recent findings of adult ocular dominance…

34 CFR 396.4 - What definitions apply?

Code of Federal Regulations, 2013 CFR

2013-07-01

... primarily upon visual modes, such as sign language, lip reading, and gestures, or reading and writing to... impairments described in paragraphs (1)(i) and (ii) of this definition causes extreme difficulty in attaining... and visual disabilities that cause extreme difficulty in attaining independence in daily life...

34 CFR 396.4 - What definitions apply?

Code of Federal Regulations, 2011 CFR

2011-07-01

... primarily upon visual modes, such as sign language, lip reading, and gestures, or reading and writing to... impairments described in paragraphs (1)(i) and (ii) of this definition causes extreme difficulty in attaining... and visual disabilities that cause extreme difficulty in attaining independence in daily life...

34 CFR 396.4 - What definitions apply?

Code of Federal Regulations, 2014 CFR

2014-07-01

... primarily upon visual modes, such as sign language, lip reading, and gestures, or reading and writing to... impairments described in paragraphs (1)(i) and (ii) of this definition causes extreme difficulty in attaining... and visual disabilities that cause extreme difficulty in attaining independence in daily life...

Comparable mechanisms of working memory interference by auditory and visual motion in youth and aging

PubMed Central

Mishra, Jyoti; Zanto, Theodore; Nilakantan, Aneesha; Gazzaley, Adam

2013-01-01

Intrasensory interference during visual working memory (WM) maintenance by object stimuli (such as faces and scenes), has been shown to negatively impact WM performance, with greater detrimental impacts of interference observed in aging. Here we assessed age-related impacts by intrasensory WM interference from lower-level stimulus features such as visual and auditory motion stimuli. We consistently found that interference in the form of ignored distractions and secondary task i nterruptions presented during a WM maintenance period, degraded memory accuracy in both the visual and auditory domain. However, in contrast to prior studies assessing WM for visual object stimuli, feature-based interference effects were not observed to be significantly greater in older adults. Analyses of neural oscillations in the alpha frequency band further revealed preserved mechanisms of interference processing in terms of post-stimulus alpha suppression, which was observed maximally for secondary task interruptions in visual and auditory modalities in both younger and older adults. These results suggest that age-related sensitivity of WM to interference may be limited to complex object stimuli, at least at low WM loads. PMID:23791629

Evolutionary relevance facilitates visual information processing.

PubMed

Jackson, Russell E; Calvillo, Dusti P

2013-11-03

Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

Cognitive load effects on early visual perceptual processing.

PubMed

Liu, Ping; Forte, Jason; Sewell, David; Carter, Olivia

2018-05-01

Contrast-based early visual processing has largely been considered to involve autonomous processes that do not need the support of cognitive resources. However, as spatial attention is known to modulate early visual perceptual processing, we explored whether cognitive load could similarly impact contrast-based perception. We used a dual-task paradigm to assess the impact of a concurrent working memory task on the performance of three different early visual tasks. The results from Experiment 1 suggest that cognitive load can modulate early visual processing. No effects of cognitive load were seen in Experiments 2 or 3. Together, the findings provide evidence that under some circumstances cognitive load effects can penetrate the early stages of visual processing and that higher cognitive function and early perceptual processing may not be as independent as was once thought.

Laser Optometric Assessment Of Visual Display Viewability

NASA Astrophysics Data System (ADS)

Murch, Gerald M.

1983-08-01

Through the technique of laser optometry, measurements of a display user's visual accommodation and binocular convergence were used to assess the visual impact of display color, technology, contrast, and work time. The studies reported here indicate the potential of visual-function measurements as an objective means of improving the design of visual displays.

Reducing Visual Discomfort with HMDs Using Dynamic Depth of Field.

PubMed

Carnegie, Kieran; Rhee, Taehyun

2015-01-01

Although head-mounted displays (HMDs) are ideal devices for personal viewing of immersive stereoscopic content, exposure to VR applications on them results in significant discomfort for the majority of people, with symptoms including eye fatigue, headaches, nausea, and sweating. A conflict between accommodation and vergence depth cues on stereoscopic displays is a significant cause of visual discomfort. This article describes the results of an evaluation used to judge the effectiveness of dynamic depth-of-field (DoF) blur in an effort to reduce discomfort caused by exposure to stereoscopic content on HMDs. Using a commercial game engine implementation, study participants report a reduction of visual discomfort on a simulator sickness questionnaire when DoF blurring is enabled. The study participants reported a decrease in symptom severity caused by HMD exposure, indicating that dynamic DoF can effectively reduce visual discomfort.

Comparing the Impact of Refractive and Nonrefractive Vision Loss on Functioning and Disability: The Salisbury Eye Evaluation.

PubMed

Zebardast, Nazlee; Swenor, Bonnielin K; van Landingham, Suzanne W; Massof, Robert W; Munoz, Beatriz; West, Sheila K; Ramulu, Pradeep Y

2015-06-01

To compare the effects of uncorrected refractive error (URE) and nonrefractive visual impairment (VI) on performance and disability measures. Cross-sectional, population-based study. A total of 2469 individuals with binocular presenting visual acuity (PVA) of ≥ 20/80 who participated in the first round of the Salisbury Eye Evaluation study. The URE was defined as binocular PVA of ≤ 20/30, improving to >20/30 with subjective refraction. The VI was defined as post-refraction binocular best-corrected visual acuity (BCVA) of ≤ 20/30. The visual acuity decrement due to VI was calculated as the difference between BCVA and 20/30, whereas visual acuity due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of (1) vision status (VI, URE, or normal vision) using the group with normal vision as reference and (2) a 1-line decrement in acuity due to VI or URE. Objective measures of visual function were obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual difficulty measured by the Activities of Daily Vision (ADV) scale. The ADV responses were analyzed using Rasch analysis to determine visual ability. Compared with individuals with normal vision, subjects with VI (n = 191) had significantly poorer objective and subjective visual functioning in all metrics examined (P < 0.05), whereas subjects with URE (n = 132) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation, and lower ADV scores (P < 0.05), but did not demonstrate slower stair climbing or descent speed. For all functional metrics evaluated, the impact of VI was greater than the impact of URE. The impact of a 1-line VA decrement due to VI was associated with greater deficits in mobility measures and driving cessation when compared with a 1-line VA decrement due to URE. Visual impairment is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and nonrefractive vision loss should be distinguished in studies evaluating visual disability and be understood to have differing consequences. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Five-year study of ocular injuries due to fireworks in India.

PubMed

Malik, Archana; Bhala, Soniya; Arya, Sudesh K; Sood, Sunandan; Narang, Subina

2013-08-01

To study the demographic profile, cause, type and severity of ocular injuries, their complications and final visual outcome following fireworks around the time of Deepawali in India. Case records of patients who presented with firework-related injuries during 2005-2009 at the time of Deepawali were reviewed. Data with respect to demographic profile of patients, cause and time of injury, time of presentation and types of intervention were analyzed. Visual acuity at presentation and final follow-up, anterior and posterior segment findings, and any diagnostic and surgical interventions carried out were noted. One hundred and one patients presented with firework-related ocular injuries, of which 77.5 % were male. The mean age was 17.60 ± 11.9 years, with 54 % being ≤14 years of age. The mean time of presentation was 8.9 h. Seventeen patients had open globe injury (OGI) and 84 had closed globe injury (CGI). Fountains were the most common cause of CGI and bullet bombs were the most common cause of OGI. Mean log MAR visual acuity at presentation was 0.64 and 1.22 and at last follow-up was 0.09 and 0.58 for CGI and OGI, respectively (p < 0.05). Patients with CGI had a better visual outcome. Three patients with OGI developed permanent blindness. Factors associated with poor visual outcome included poor initial visual acuity, OGI, intraocular foreign body (IOFB), retinal detachment and development of endophthalmitis. Firework injuries were seen mostly in males and children. Poor visual outcome was associated with poor initial visual acuity, OGI, IOFB, retinal detachment and development of endophthalmitis, while most patients with CGI regained good vision.

Migraine with Aura

MedlinePlus

... processes visual signals (visual cortex) and causes these visual hallucinations. Many of the same factors that trigger migraine can also trigger migraine with aura, including stress, bright lights, some foods and medications, too much or too little sleep, ...

Population-based survey of prevalence, causes, and risk factors for blindness and visual impairment in an aging Chinese metropolitan population

PubMed Central

Hu, Jian-Yan; Yan, Liang; Chen, Yong-Dong; Du, Xin-Hua; Li, Ting-Ting; Liu, De-An; Xu, Dong-Hong; Huang, Yi-Min; Wu, Qiang

2017-01-01

AIM To assess the prevalence, causes, and risk factors for blindness and visual impairment among elderly (≥60 years of age) Chinese people in a metropolitan area of Shanghai, China. METHODS Random cluster sampling was conducted to identify participants among residents ≥60 years of age living in the Xietu Block, Xuhui District, Shanghai, China. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were checked by the Early Treatment Diabetic Retinopathy Study (ETDRS) visual chart. All eligible participants underwent a comprehensive eye examination. Blindness and visual impairment were defined according to World Health Organization (WHO) criteria. RESULTS A total of 4190 persons (1688 men and 2502 women) participated in the study, and the response rate was 91.1%. Based on PVA, the prevalence of blindness was 1.1% and that of visual impairment was 7.6%. Based on BCVA, the prevalence of blindness and visual impairment decreased to 0.9% and 3.9%, respectively. Older (≥80 years of age) women, with low educational levels and smoking habits, exhibited a significantly greater chance for blindness and visual impairment than did those with high educational levels and no smoking habits (P<0.05). Based on PVA and BCVA, the main causes of blindness were cataract, myopic maculopathy, and age-related macular degeneration (AMD). CONCLUSION Our findings help to identify the population in need of intervention, to highlight the need for additional eye healthcare services in urban China. PMID:28149791

Population-based survey of prevalence, causes, and risk factors for blindness and visual impairment in an aging Chinese metropolitan population.

PubMed

Hu, Jian-Yan; Yan, Liang; Chen, Yong-Dong; Du, Xin-Hua; Li, Ting-Ting; Liu, De-An; Xu, Dong-Hong; Huang, Yi-Min; Wu, Qiang

2017-01-01

To assess the prevalence, causes, and risk factors for blindness and visual impairment among elderly (≥60 years of age) Chinese people in a metropolitan area of Shanghai, China. Random cluster sampling was conducted to identify participants among residents ≥60 years of age living in the Xietu Block, Xuhui District, Shanghai, China. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were checked by the Early Treatment Diabetic Retinopathy Study (ETDRS) visual chart. All eligible participants underwent a comprehensive eye examination. Blindness and visual impairment were defined according to World Health Organization (WHO) criteria. A total of 4190 persons (1688 men and 2502 women) participated in the study, and the response rate was 91.1%. Based on PVA, the prevalence of blindness was 1.1% and that of visual impairment was 7.6%. Based on BCVA, the prevalence of blindness and visual impairment decreased to 0.9% and 3.9%, respectively. Older (≥80 years of age) women, with low educational levels and smoking habits, exhibited a significantly greater chance for blindness and visual impairment than did those with high educational levels and no smoking habits ( P <0.05). Based on PVA and BCVA, the main causes of blindness were cataract, myopic maculopathy, and age-related macular degeneration (AMD). Our findings help to identify the population in need of intervention, to highlight the need for additional eye healthcare services in urban China.

Are Hemianopic Reading and Visual Exploration Impairments Visually Elicited? New Insights from Eye Movements in Simulated Hemianopia

ERIC Educational Resources Information Center

Schuett, Susanne; Kentridge, Robert W.; Zihl, Josef; Heywood, Charles A.

2009-01-01

Hemianopic reading and visual exploration impairments are well-known clinical phenomena. Yet, it is unclear whether they are primarily caused by the hemianopic visual field defect itself or by additional brain injury preventing efficient spontaneous oculomotor adaptation. To establish the extent to which these impairments are visually elicited we…

Syllable Transposition Effects in Korean Word Recognition

ERIC Educational Resources Information Center

Lee, Chang H.; Kwon, Youan; Kim, Kyungil; Rastle, Kathleen

2015-01-01

Research on the impact of letter transpositions in visual word recognition has yielded important clues about the nature of orthographic representations. This study investigated the impact of syllable transpositions on the recognition of Korean multisyllabic words. Results showed that rejection latencies in visual lexical decision for…

Surfing-related ocular injuries.

PubMed

Kim, J W; McDonald, H R; Rubsamen, P E; Luttrull, J K; Drouilhet, J H; Frambach, D A; Boyer, D S; Lambrou, F H; Hendrick, A; Weiss, J N; Engstrom, R E; Ing, M

1998-01-01

This report evaluates the clinical characteristics of surfing-related ocular trauma to learn the nature of such injuries and propose possible preventive measures. The authors reviewed 11 cases of surfing-related eye injuries caused by direct trauma from the surfboard, studying their mechanism of injury, the associated ocular complications, and the anatomic and visual outcomes of surgical repair. Surfing-related ocular injuries occurred exclusively in young males (mean age, 24.8 years; range, 14-37 years). The mechanism of injury most frequently responsible was impact with the sharp nose of the surfboard following a fall. Serious posterior segment complications were observed in all 11 patients, with nine patients suffering ruptured globes. Despite immediate medical attention, five patients did not recover ambulatory levels of visual acuity (>5/200). Surfing-related ocular trauma presenting to the retinal specialist typically leaves the patient with a permanent visual disability. Important factors contributing to these high-velocity injuries include the sharply pointed nose of the surfboard and the leash keeping the surfer in close proximity to the board following a fall. A simple modification in surfboard design such as blunting the sharp nose of the surfboard, or appropriate protective guards fitted over the surfboard nose, should lessen the severity of such injuries.

The Impact of Ocular Pressures, Material Properties and Geometry on Optic Nerve Head Deformation

NASA Technical Reports Server (NTRS)

Feola, Andrew J.; Myers, Jerry G.; Raykin, Julia; Nelson, Emily S.; Samuels, Brian C.; Ethier C. Ross

2017-01-01

Alteration in intracranial pressure (ICP) has been associated with various diseases that cause visual impairment, including glaucoma, idiopathic intracranial hypertension and Visual Impairment and Intracranial Pressure (VIIP) syndrome. However, how changes in ICP lead to vision loss is unclear, although it is hypothesized to involve deformations of the tissues in the optic nerve head (ONH). Recently, understanding the effect of ICP alterations on ocular tissues has become a major concern for NASA, where 42 of astronauts that partake in long duration space missions suffer from VIIP syndrome. Astronauts with VIIP syndrome suffer from visual impairment and changes in ocular anatomy that persist after returning to earth (1). It is hypothesized that the cephalad fluid shift that occurs upon entering microgravity increases ICP, which leads to an altered biomechanical environment in the posterior globe and optic nerve sheath, and subsequently VIIP syndrome. Our goal was to develop a finite element (FE) model to simulate the acute effects of elevated ICP on the posterior eye. Here, we simulated how inter-individual differences affect the deformation of ONH tissues. Further, we examined how several different geometries influenced deformations when exposed to elevated ICP.

The impact of visual impairment on the ability to perform activities of daily living for persons with severe/profound intellectual disability.

PubMed

Dijkhuizen, Annemarie; Hilgenkamp, Thessa I M; Krijnen, Wim P; van der Schans, Cees P; Waninge, Aly

2016-01-01

The ability to perform activities of daily living (ADL) as a component of participation is one of the factors that contribute to quality of life. The ability to perform ADL for persons experiencing severe/profound intellectual disability (ID) may be reduced due to their cognitive and physical capacities. However, until recently, the impact of the significantly prevalent visual impairments on the performance of activities of daily living has not yet been revealed within this group. The purpose of this prospective cross-sectional study was to investigate the impact of visual impairment on the performance of activities of daily living for persons with a severe/profound intellectual disability. The Barthel Index (BI) and Comfortable Walking Speed (CWS) were used to measure the ability of performing activities of daily living (ADL) in 240 persons with severe/profound ID and having Gross Motor Functioning Classification System (GMFCS) levels I, II or III; this included 120 persons with visual impairment. The impact of visual impairment on ADL was analyzed with linear regression. The results of the study demonstrated that visual impairment slightly affects the ability of performing activities of daily living (BI) for persons experiencing a severe/profound intellectual disability. GMFCS Levels II or III, profound ID level, and visual impairment each have the effect of lowering BI scores. GMFCS Levels II or III, and profound ID level each have the effect of increasing CWS scores, which indicates a lower walking speed. A main effect of visual impairment is present on CWS, but our results do show a substantive interaction effect between GMFCS level III and visual impairment on Comfortable Walking Speed in persons with a severe/profound intellectual disability. Visual impairment has a slight effect on ability to perform ADL in persons experiencing severe/profound ID. Copyright © 2015 Elsevier Ltd. All rights reserved.

Causes of visual impairment in children with low vision.

PubMed

Shah, Mufarriq; Khan, Mirzaman; Khan, Muhammad Tariq; Khan, Mohammad Younas; Saeed, Nasir

2011-02-01

To determine the main causes of visual impairment in children with low vision. To assess the need of spectacles and low vision devices (LVDs) in children and to evaluate visual outcome after using their LVDs for far and near distance. Observational study. Khyber Institute of Ophthalmic Medical Sciences, Peshawar, Pakistan, from June 2006 to December 2007. The clinical record of 270 children with low vision age 4-16 years attending the Low Vision Clinic were included. All those children, aged 4-16 years, who had corrected visual acuity (VA) less than 6/18 in the better eye after medical or surgical treatment, were included in the study. WHO low vision criteria were used to classify into visually impaired, severe visually impaired and blind. Results were described as percentage frequencies. One hundred and eighty nine (70%) were males and 81 (30%) were females. The male to female ratio was 2.3:1. The main causes of visual impairment included nystagmus (15%), Stargardt's disease (14%), maculopathies (13%), myopic macular degeneration (11%) and oculocutaneous albinism (7%). The percentages of visually impaired, severe visually impaired and blind were 33.8%, 27.2% and 39.0% respectively. Spectacles were prescribed to 146 patients and telescopes were prescribed to 75 patients. Spectacles and telescope both were prescribed to 179 patients while Ocutech telescope was prescribed to 4 patients. Retinal diseases nystagmus and macular conditions were mainly responsible for low vision in children. Visually impaired children especially with hereditary/congenital ocular anomalies benefit from refraction and low vision services which facilitate vision enhancement and inclusive education.

The Impact of Visual Disability on the Quality of Life of Older Persons in Rural Northeast Thailand

ERIC Educational Resources Information Center

La Grow, Steven; Sudnongbua, Supaporn; Boddy, Julie

2011-01-01

A high rate of self-reported visual disability was found among a sample of persons aged 60 and older in the course of a study that assessed the impact of feelings of abandonment among older persons in a remote rural area in northeast Thailand (Sudnongbua, La Grow, & Boddy, 2010). This study assessed the impact of self-reported visual…

AFRICOM: An Effective Organization or a Military Hurdle?

DTIC Science & Technology

2010-12-01

challenges that impact their effectiveness and therefore success. These challenges are not easy to visualize, thus making it more difficult to derive and...BLANK v ABSTRACT Many organizations face challenges that impact their effectiveness and therefore success. These challenges are not easy to visualize...examination of the variables that have the potential to adversely impact AFRICOM’s effectiveness. First, throughout the literature there are no specific

Using Flow Charts to Visualize the Decision-Making Process in Space Weather Forecasting

NASA Astrophysics Data System (ADS)

Aung, M. T. Y.; Myat, T.; Zheng, Y.; Mays, M. L.; Ngwira, C.; Damas, M. C.

2016-12-01

Our society today relies heavily on technological systems such as satellites, navigation systems, power grids and aviation. These systems are very sensitive to space weather disturbances. When Earth-directed space weather driven by the Sun arrives at the Earth, it causes changes to the Earth's radiation environment and the magnetosphere. Strong disturbances in the magnetosphere of the Earth are responsible for geomagnetic storms that can last from hours to days depending on strength of storms. Geomagnetic storms can severely impact critical infrastructure on Earth, such as the electric power grid, and Solar Energetic Particles that can endanger life in outer space. How can we lessen these adverse effects? They can be lessened through the early warning signals sent by space weather forecasters before CME or high-speed stream arrives. A space weather forecaster's duty is to send predicted notifications to high-tech industries and NASA missions so that they could take extra measures for protection. NASA space weather forecasters make prediction decisions by following certain steps and processes from the time an event occurs at the sun all the way to the impact locations. However, there has never been a tool that helps these forecasters visualize the decision process until now. A flow chart is created to help forecasters visualize the decision process. This flow chart provides basic knowledge of space weather and can be used to train future space weather forecasters. It also helps to cut down the training period and increase consistency in forecasting. The flow chart is also a great reference for people who are already familiar with space weather.

The Prevalence and Causes of Visaual Impairment and Blindness in a Rural Population in the North of Iran

PubMed Central

HASHEMI, Hassan; REZVAN, Farhad; YEKTA, AbbasAli; OSTADIMOGHADDAM, Hadi; SOROUSH, Sara; DADBIN, Nooshin; KHABAZKHOOB, Mehdi

2015-01-01

Background: Visual impairment is a very important public health problem. In Iran, reports of visual impairment and blindness have been published from the urban population while the prevalence of visual impairment in the rural population has not been reported. The purpose of this study to determine the prevalence and causes of visual impairment, in a rural population in district of based on age and sex Methods: In a cross-sectional population-based study, using random cluster sampling, 13 of the 83 villages of Khaf County in the north east of Iran were selected. Eye examinations were performed in a Mobile Eye Clinic (Nooravaran Salamat, 2011) and included optometric examinations such as measuring uncorrected and corrected visual acuity along with non-cycloplegic refraction. Results: The prevalence of visual impairment, low vision, and blindness was 6.3% (95% CI 5.3–7.3), 3.4% (95% CI 2.6–4.1), and 3.0% (95% CI 2.3–3.6), respectively. The prevalence of visual impairment ranged from 1.8% in the participant younger than 20 years of age to 28% in the subjects aged 60 and over (P<0.001). After matching for age, the prevalence of visual impairment and low vision was significantly higher in women. The most prevalent causes of visual impairment were uncorrected refractory error (54.5%) and cataract (17.6%). Conclusion: The prevalence of visual impairment was significantly higher in the rural population of this study when compared to previous reports from Iran. It seems that provision of therapeutic facilities like cataract surgery and availability of eyeglasses in villages can considerably reduce the prevalence of visual impairment. PMID:26258099

The Prevalence and Causes of Visaual Impairment and Blindness in a Rural Population in the North of Iran.

PubMed

Hashemi, Hassan; Rezvan, Farhad; Yekta, AbbasAli; Ostadimoghaddam, Hadi; Soroush, Sara; Dadbin, Nooshin; Khabazkhoob, Mehdi

2015-06-01

Visual impairment is a very important public health problem. In Iran, reports of visual impairment and blindness have been published from the urban population while the prevalence of visual impairment in the rural population has not been reported. The purpose of this study to determine the prevalence and causes of visual impairment, in a rural population in district of based on age and sex. In a cross-sectional population-based study, using random cluster sampling, 13 of the 83 villages of Khaf County in the north east of Iran were selected. Eye examinations were performed in a Mobile Eye Clinic (Nooravaran Salamat, 2011) and included optometric examinations such as measuring uncorrected and corrected visual acuity along with non-cycloplegic refraction. The prevalence of visual impairment, low vision, and blindness was 6.3% (95% CI 5.3-7.3), 3.4% (95% CI 2.6-4.1), and 3.0% (95% CI 2.3-3.6), respectively. The prevalence of visual impairment ranged from 1.8% in the participant younger than 20 years of age to 28% in the subjects aged 60 and over (P<0.001). After matching for age, the prevalence of visual impairment and low vision was significantly higher in women. The most prevalent causes of visual impairment were uncorrected refractory error (54.5%) and cataract (17.6%). The prevalence of visual impairment was significantly higher in the rural population of this study when compared to previous reports from Iran. It seems that provision of therapeutic facilities like cataract surgery and availability of eyeglasses in villages can considerably reduce the prevalence of visual impairment.

SPATIAL HETEROGENEITY OF PHOTOSYNTHETIC ACTIVITY WITHIN DISEASED CORALS FROM THE GREAT BARRIER REEF(1).

PubMed

Roff, George; Ulstrup, Karin E; Fine, Maoz; Ralph, Peter J; Hoegh-Guldberg, Ove

2008-04-01

Morphological diagnosis and descriptions of seven disease-like syndromes affecting scleractinian corals were characterized from the southern Great Barrier Reef (GBR). Chl a fluorescence of PSII was measured using an Imaging-PAM (pulse amplitude modulated) fluorometer, enabling visualization of the two-dimensional variability in the photophysiology of endosymbiotic dinoflagellates (zooxanthellae) by measuring rapid light curves. Three of four syndromes associated with active tissue loss (type a) were spatially homogenous (white syndrome, brown band, and skeletal eroding band), with no impact on the photochemical function of zooxanthellae populations at or behind the lesion borders. However, a decline in maximum quantum yield (Fv /Fm ) and elevated levels of maximum nonphotochemical quenching (NPQmax ) occurred in visually healthy tissue of black band disease adjacent to the lesion borders, possibly due to hypoxic conditions caused by the black band cyanobacterial mat. Two out of three syndromes associated with pathological change of intact tissue with no active tissue loss (type b) showed variable photophysiological responses (neoplasia and pigmentation response). Only the bleached foci associated with white patch syndrome appeared to impact primarily on the symbiotic dinoflagellates, as evidenced by declines in minimum fluorescence (F0 ) and maximum quantum yield (Fv /Fm ), with no indication of degeneration in the host tissues. Our results suggest that for the majority of coral syndromes from the GBR, pathogenesis occurs in the host tissue, while the impact on the zooxanthellae populations residing in affected corals is minimal. © 2008 Phycological Society of America.

Exploring the functional nature of synaesthetic colour: Dissociations from colour perception and imagery.

PubMed

Chiou, Rocco; Rich, Anina N; Rogers, Sebastian; Pearson, Joel

2018-08-01

Individuals with grapheme-colour synaesthesia experience anomalous colours when reading achromatic text. These unusual experiences have been said to resemble 'normal' colour perception or colour imagery, but studying the nature of synaesthesia remains difficult. In the present study, we report novel evidence that synaesthetic colour impacts conscious vision in a way that is different from both colour perception and imagery. Presenting 'normal' colour prior to binocular rivalry induces a location-dependent suppressive bias reflecting local habituation. By contrast, a grapheme that evokes synaesthetic colour induces a facilitatory bias reflecting priming that is not constrained to the inducing grapheme's location. This priming does not occur in non-synaesthetes and does not result from response bias. It is sensitive to diversion of visual attention away from the grapheme, but resistant to sensory perturbation, reflecting a reliance on cognitive rather than sensory mechanisms. Whereas colour imagery in non-synaesthetes causes local priming that relies on the locus of imagined colour, imagery in synaesthetes caused global priming not dependent on the locus of imagery. These data suggest a unique psychophysical profile of high-level colour processing in synaesthetes. Our novel findings and method will be critical to testing theories of synaesthesia and visual awareness. Copyright © 2018 Elsevier B.V. All rights reserved.

Refractive index and its impact on pseudophakic dysphotopsia.

PubMed

Radmall, Bryce R; Floyd, Anne; Oakey, Zack; Olson, Randall J

2015-01-01

It has been shown that the biggest dissatisfier for uncomplicated cataract surgery patients is pseudophakic dysphotopsia (PD). While edge design of an intraocular lens (IOL) impacts this problem, refractive index is still controversial as to its impact. This retrospective cohort study was designed to determine the role of increasing refractive index in PD. This study was conducted at the John A. Moran Eye Center, University of Utah, USA. A retrospective chart review identified patients who received one of two hydrophobic acrylic single piece IOLs (AcrySof WF SP [SN60WF] or Tecnis SP [ZCB00]), which differed mainly by refractive index (1.55 versus 1.47). Eighty-seven patients who had received implantation of a one-piece hydrophobic acrylic IOL were enrolled. Patients were included if the surgery had been uncomplicated and took place at least a year before study participation. All eligible patients had 20/20 best corrected vision, without any disease known to impact visual quality. In addition to conducting a record review, the enrolled patients were surveyed for PD, using a modified National Eye Institute Visual Function questionnaire, as well as for overall satisfaction with visual quality. Statistical analysis demonstrated no difference between the two cohorts regarding PD, general visual function, and overall visual satisfaction. The study suggests that with the two IOLs assessed, increasing the refractive index does not increase incidence of PD or decrease overall visual satisfaction.

The impact of the luminance, size and location of LED billboards on drivers' visual performance-Laboratory tests.

PubMed

Zalesinska, Malgorzata

2018-08-01

A proper visual performance by drivers can be ensured by, among else, a correct distribution of luminance in their field of view. At night, when the driver's sight is adapted to low luminance levels, high luminance level objects located near the road may be a source of glare, which is not only a nuisance, but it may also blind the driver. For many years, LED billboards (light-emitting diode billboards) have been installed near roads. Such billboards are usually large, have high luminance and show dynamically changing images. These parameters have a significant impact on the drivers' visual performance and, in turn, on road traffic safety. The study on the impact of the luminance, size and location of LED billboards on the drivers' visual performance was conducted on a volunteer group. Testing the impact of LED billboards on the visual performance of drivers in real-life conditions is very difficult. Therefore, the tests have been conducted in laboratory conditions, using a car driving simulator. The paper describes the testing procedure and tests results. The permissible luminance and areas of LED screens in two locations near the road, which significantly reduce the drivers' visual performance in municipal traffic at night, were determined by conducting an analysis of the results. Recommendations on the permissible luminance and areas of LED billboards were formulated. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prevalence and causes of low vision and blindness in Baotou

PubMed Central

Zhang, Guisen; Li, Yan; Teng, Xuelong; Wu, Qiang; Gong, Hui; Ren, Fengmei; Guo, Yuxia; Liu, Lei; Zhang, Han

2016-01-01

Abstract The aim of this study was to investigate the prevalence and causes of low vision and blindness in Baotou, Inner Mongolia. A cross-sectional study was carried out. Multistage sampling was used to select samples. The visual acuity was estimated using LogMAR and corrected by pinhole as best-corrected visual acuity. There were 7000 samples selected and 5770 subjects included in this investigation. The overall bilateral prevalence rates of low vision and blindness were 3.66% (95% CI: 3.17–4.14) and 0.99% (95% CI: 0.73–1.24), respectively. The prevalence of bilateral low vision, blindness, and visual impairment increased with age and decreased with education level. The main leading cause of low vision and blindness was cataract. Diabetic retinopathy and age-related macular degeneration were found to be the second leading causes of blindness in Baotou. The low vision and blindness were more prevalent in elderly people and subjects with low education level in Baotou. Cataract was the main cause for visual impairment and more attention should be paid to fundus diseases. In order to prevent blindness, much more eye care programs should be established. PMID:27631267

Prevalence and causes of low vision and blindness in Baotou: A cross-sectional study.

PubMed

Zhang, Guisen; Li, Yan; Teng, Xuelong; Wu, Qiang; Gong, Hui; Ren, Fengmei; Guo, Yuxia; Liu, Lei; Zhang, Han

2016-09-01

The aim of this study was to investigate the prevalence and causes of low vision and blindness in Baotou, Inner Mongolia.A cross-sectional study was carried out. Multistage sampling was used to select samples. The visual acuity was estimated using LogMAR and corrected by pinhole as best-corrected visual acuity.There were 7000 samples selected and 5770 subjects included in this investigation. The overall bilateral prevalence rates of low vision and blindness were 3.66% (95% CI: 3.17-4.14) and 0.99% (95% CI: 0.73-1.24), respectively. The prevalence of bilateral low vision, blindness, and visual impairment increased with age and decreased with education level. The main leading cause of low vision and blindness was cataract. Diabetic retinopathy and age-related macular degeneration were found to be the second leading causes of blindness in Baotou.The low vision and blindness were more prevalent in elderly people and subjects with low education level in Baotou. Cataract was the main cause for visual impairment and more attention should be paid to fundus diseases. In order to prevent blindness, much more eye care programs should be established.

Postoperative magnetic resonance imaging artifact with cobalt-chromium versus titanium spinal instrumentation: presented at the 2013 Joint Spine Section Meeting. Clinical article.

PubMed

Ahmad, Faiz U; Sidani, Charif; Fourzali, Roberto; Wang, Michael Y

2013-11-01

Cobalt-chromium alloy (CoCr) rods haves some preferred biomechanical properties over titanium rods for spinal fixation. The use of CoCr rods in spinal fusion is relatively new, and there is no study in the existing world literature assessing the artifact caused by these rods in patients undergoing postoperative MRI. The purpose of this study is to compare the amount of imaging artifact caused by these implants and to assess its impact on the visualization of neighboring neural structures. This study investigated MR images in patients who underwent implantation of thoracolumbar instrumentation using 5.5-mm-diameter CoCr rods between November 2009 and March 2011 and images obtained in a comparison group of patients who had 5.5-mm titanium rods implanted during the same time period. Axial measurements of the artifact created by the rods between the screw heads were compared between the groups. Two blinded board-certified radiologists performed the measurements independently. They scored the visualization of the spinal canal using a subjective scoring system of 1-3, with 1 representing very good visualization and 2 and 3 representing reduced (good or suboptimal, respectively) visualization as a result of rod-related artifact. All measurements and scores were independently provided for T1-weighted and T2-weighted fast spin echo sequences (1.5-T magnet, 5-mm slice thickness). A total of 40 levels from the CoCr group (6 patients) and 30 levels from the titanium group (9 patients) were included in the analysis. Visualization of the canal at all levels was rated a score of 1 (very good) by both evaluators for both the CoCr and titanium groups. The average artifact on T1-weighted images measured 11.8 ± 1.8 mm for the CoCr group and 8.5 ± 1.2 mm for the titanium group (p < 0.01). The corresponding measurements on T2-weighted images were 11.0 ± 2.3 mm and 8.3 ± 1.7 mm (p < 0.01), respectively. In a mixed regression model, the mean artifact measurement for the CoCr group was, on average, 3.5 mm larger than for the control group. There was no significant difference between the measurements of the 2 evaluators (p = 0.99). The artifact caused by CoCr rods is approximately 3.5 mm larger than that caused by titanium rods on axial T1- and T2-weighted MRI. However, artifact from either CoCr or titanium was not found to interfere with the evaluation of the spinal canal and surrounding neural elements.

Improving Dorsal Stream Function in Dyslexics by Training Figure/Ground Motion Discrimination Improves Attention, Reading Fluency, and Working Memory.

PubMed

Lawton, Teri

2016-01-01

There is an ongoing debate about whether the cause of dyslexia is based on linguistic, auditory, or visual timing deficits. To investigate this issue three interventions were compared in 58 dyslexics in second grade (7 years on average), two targeting the temporal dynamics (timing) of either the auditory or visual pathways with a third reading intervention (control group) targeting linguistic word building. Visual pathway training in dyslexics to improve direction-discrimination of moving test patterns relative to a stationary background (figure/ground discrimination) significantly improved attention, reading fluency, both speed and comprehension, phonological processing, and both auditory and visual working memory relative to controls, whereas auditory training to improve phonological processing did not improve these academic skills significantly more than found for controls. This study supports the hypothesis that faulty timing in synchronizing the activity of magnocellular with parvocellular visual pathways is a fundamental cause of dyslexia, and argues against the assumption that reading deficiencies in dyslexia are caused by phonological deficits. This study demonstrates that visual movement direction-discrimination can be used to not only detect dyslexia early, but also for its successful treatment, so that reading problems do not prevent children from readily learning.

Cross-modal perceptual load: the impact of modality and individual differences.

PubMed

Sandhu, Rajwant; Dyson, Benjamin James

2016-05-01

Visual distractor processing tends to be more pronounced when the perceptual load (PL) of a task is low compared to when it is high [perpetual load theory (PLT); Lavie in J Exp Psychol Hum Percept Perform 21(3):451-468, 1995]. While PLT is well established in the visual domain, application to cross-modal processing has produced mixed results, and the current study was designed in an attempt to improve previous methodologies. First, we assessed PLT using response competition, a typical metric from the uni-modal domain. Second, we looked at the impact of auditory load on visual distractors, and of visual load on auditory distractors, within the same individual. Third, we compared individual uni- and cross-modal selective attention abilities, by correlating performance with the visual Attentional Network Test (ANT). Fourth, we obtained a measure of the relative processing efficiency between vision and audition, to investigate whether processing ease influences the extent of distractor processing. Although distractor processing was evident during both attend auditory and attend visual conditions, we found that PL did not modulate processing of either visual or auditory distractors. We also found support for a correlation between the uni-modal (visual) ANT and our cross-modal task but only when the distractors were visual. Finally, although auditory processing was more impacted by visual distractors, our measure of processing efficiency only accounted for this asymmetry in the auditory high-load condition. The results are discussed with respect to the continued debate regarding the shared or separate nature of processing resources across modalities.

Communicating Emerging Issues in Ocean Hypoxia (or Suffocating in Your Own Home)

NASA Astrophysics Data System (ADS)

Whitney, F. A.; Tunnicliffe, V.; Diaz, R. J.

2009-12-01

Some large regions of our interior oceans are losing oxygen both from the impacts of human uses of coastal margins and the impacts that climate change is having on ocean circulation. As oxygen minimum zones expand, impacts are especially noticed along the edges of continents. Ecosystems are being affected in ways that result in habitat compression or forced migrations. Looking into the future, we foresee large scale disruptions to habitat that, in some cases, will dramatically impact fish productivity. As waters become more hypoxic, energy fixed by marine plants will be less available to support higher trophic levels (e.g. fish and marine mammals). Communicating concern about hypoxia has its challenges: the word itself is poorly know to those on land who live in an oxygen-rich world. Thus, crucial factors in effective communication include illustrating: i) how many ocean animals live “on the edge”, ii) how ocean organisms respond to hypoxia iii) the long-term effects on ocean ecosystems and iv) causes and mitigation. For media that respond to visual stimulation, good graphics, evocative analogies and focussed examples are important.

Perceptual visual dysfunction, physical impairment and quality of life in Bangladeshi children with cerebral palsy.

PubMed

Mitry, D; Williams, C; Northstone, K; Akter, A; Jewel, J; Khan, N; Muhit, M; Gilbert, C E; Bowman, R

2016-09-01

Cerebral palsy (CP) is the most common cause of motor disability in children and is often accompanied by sensory and/or cognitive impairment. The aim of this study was to characterise visual acuity impairment, perceptual visual dysfunction (PVD) and physical disability in a community-based sample of Bangladeshi children with CP and to assess the impact of these factors on the quality of life of the children. A key informant study was used to recruit children with CP from Sirajganj district. Gross Motor Function Classification System (GMFCS) levels and visual impairment were assessed by a physiotherapist and an optometrist, respectively. Assessments of visual perception were performed and standardised questionnaires were administered to each child's main carer to elicit indicators of PVD and parent-reported health-related quality of life. A generalised linear regression analysis was conducted to assess the determinants of the quality of life scores. 180 children were recruited. The median age was 8 years (IQR: 6-11 years); 112 (62%) were male; 57 (32%) had visual acuity impairment and 95 (53%) had some parent-reported PVD. In analyses adjusted for age, sex, GMFCS and acuity impairment, visual attention (p<0.001) and recognition/navigation (p<0.001) were associated with total health-related quality of life, and there were similar trends for total PVD score (p=0.006) and visual search (p=0.020). PVD is an important contributor in reducing quality of life in children with CP, independent of motor disability and acuity impairment. Better characterisation of PVD is important to help design interventions for affected children, which may improve their quality of life. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Visibility and Visual Characteristics of the Ivanpah Solar Electric Generating System Power Tower Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Robert; Abplanalp, Jennifer M.

2015-03-01

This report presents the results of a study conducted to document the visibility and visual characteristics of the Ivanpah Solar Electric Generating System (ISEGS), a utility-scale solar power tower facility located on land administered by the U.S. Department of the Interior Bureau of Land Management in southern California. Study activities consisted of field observations of the ISEGS facility and comparison of the observations made in the field with the visual contrast assessments and visual simulations in the ISEGS Final Environmental Impact Statement (Final EIS) and supporting documents created prior to ISEGS construction. Field observations of ISEGS were made from 19more » locations within 35 mi (56 km) of the facility in the course of one week in September 2014. The study results established that reflected sunlight from the receivers was the primary source of visual contrast from the operating ISEGS facility. The ISEGS facility was found to be a major source of visual contrast for all observations up to 20 mi (32 km), and was easily visible at 35 mi. Glare from individual heliostats was frequently visible, and often brighter than the reflected light from the receivers. Heliostat glare caused discomfort for one or more viewers at distances up to 20 mi. The ISEGS power blocks were brightly lit at night, and were conspicuous at the observation distance of approximately 6 mi (10 km). The facility is substantially brighter and is seen more clearly in the field than in photographs of the facility or in the prepared simulations, which were based on photographs. The simulations of the ISEGS facility in the Final EIS, which were evaluated as part of this study, sometimes lacked spatial accuracy and realism. The evaluated simulations generally under-represented the actual visual contrast from the project, and some of the contrast ratings in the Final EIS predicted substantially lower levels of visual contrast than were actually observed for the operating facility.« less

'I didn't see that coming': simulated visual fields and driving hazard perception test performance.

PubMed

Glen, Fiona C; Smith, Nicholas D; Jones, Lee; Crabb, David P

2016-09-01

Evidence is limited regarding specific types of visual field loss associated with unsafe driving. We use novel gaze-contingent software to examine the effect of simulated visual field loss on computer-based driving hazard detection with the specific aim of testing the impact of scotomata located to the right and left of fixation. The 'hazard perception test' is a component of the UK driving licence examination, which measures speed of detecting 15 different hazards in a series of real-life driving films. We have developed a novel eye-tracking and computer set up capable of generating a realistic gaze-contingent scotoma simulation (GazeSS) overlaid on film content. Thirty drivers with healthy vision completed three versions of the hazard perception test in a repeated measures experiment. In two versions, GazeSS simulated a scotoma in the binocular field of view to the left or right of fixation. A third version was unmodified to establish baseline performance. Participants' mean baseline hazard perception test score was 51 ± 7 (out of 75). This reduced to 46 ± 9 and 46 ± 11 when completing the task with a binocular visual field defect located to the left and right of fixation, respectively. While the main effect of simulated visual field loss on performance was statistically significant (p = 0.007), there were no average differences in the experimental conditions where a scotoma was located in the binocular visual field to the right or left of fixation. Simulated visual field loss impairs driving hazard detection on a computer-based test. There was no statistically significant difference in average performance when the simulated scotoma was located to the right or left of fixation of the binocular visual field, but certain types of hazard caused more difficulties than others. © 2016 Optometry Australia.

Visual body size norms and the under‐detection of overweight and obesity

PubMed Central

Robinson, E.

2017-01-01

Summary Objectives The weight status of men with overweight and obesity tends to be visually underestimated, but visual recognition of female overweight and obesity has not been formally examined. The aims of the present studies were to test whether people can accurately recognize both male and female overweight and obesity and to examine a visual norm‐based explanation for why weight status is underestimated. Methods The present studies examine whether both male and female overweight and obesity are visually underestimated (Study 1), whether body size norms predict when underestimation of weight status occurs (Study 2) and whether visual exposure to heavier body weights adjusts visual body size norms and results in underestimation of weight status (Study 3). Results The weight status of men and women with overweight and obesity was consistently visually underestimated (Study 1). Body size norms predicted underestimation of weight status (Study 2) and in part explained why visual exposure to heavier body weights caused underestimation of overweight (Study 3). Conclusions The under‐detection of overweight and obesity may have been in part caused by exposure to larger body sizes resulting in an upwards shift in the range of body sizes that are perceived as being visually ‘normal’. PMID:29479462

Techniques for Fault Detection and Visualization of Telemetry Dependence Relationships for Root Cause Fault Analysis in Complex Systems

NASA Astrophysics Data System (ADS)

Guy, Nathaniel

This thesis explores new ways of looking at telemetry data, from a time-correlative perspective, in order to see patterns within the data that may suggest root causes of system faults. It was thought initially that visualizing an animated Pearson Correlation Coefficient (PCC) matrix for telemetry channels would be sufficient to give new understanding; however, testing showed that the high dimensionality and inability to easily look at change over time in this approach impeded understanding. Different correlative techniques, combined with the time curve visualization proposed by Bach et al (2015), were adapted to visualize both raw telemetry and telemetry data correlations. Review revealed that these new techniques give insights into the data, and an intuitive grasp of data families, which show the effectiveness of this approach for enhancing system understanding and assisting with root cause analysis for complex aerospace systems.

Association of Visual Impairment and All-Cause 10-Year Mortality Among Indigenous Australian Individuals Within Central Australia: The Central Australian Ocular Health Study.

PubMed

Ng, Soo Khai; Kahawita, Shyalle; Andrew, Nicholas Howard; Henderson, Tim; Craig, Jamie Evan; Landers, John

2018-05-01

It is well established from different population-based studies that visual impairment is associated with increased mortality rate. However, to our knowledge, the association of visual impairment with increased mortality rate has not been reported among indigenous Australian individuals. To assess the association between visual impairment and 10-year mortality risk among the remote indigenous Australian population. Prospective cohort study recruiting indigenous Australian individuals from 30 remote communities located within the central Australian statistical local area over a 36-month period between July 2005 and June 2008. The data were analyzed in January 2017. Visual acuity, slitlamp biomicroscopy, and fundus examination were performed on all patients at recruitment. Visual impairment was defined as a visual acuity of less than 6/12 in the better eye. Mortality rate and mortality cause were obtained at 10 years, and statistical analyses were performed. Hazard ratios for 10-year mortality with 95% confidence intervals are presented. One thousand three hundred forty-seven patients were recruited from a total target population number of 2014. The mean (SD) age was 56 (11) years, and 62% were women. The total all-cause mortality was found to be 29.3% at 10 years. This varied from 21.1% among those without visual impairment to 48.5% among those with visual impairment. After adjustment for age, sex, and the presence of diabetes and hypertension, those with visual impairment were 40% more likely to die (hazard ratio, 1.40; 95% CI, 1.16-1.70; P = .001) during the 10-year follow-up period compared with those with normal vision. Bilateral visual impairment among remote indigenous Australian individuals was associated with 40% higher 10-year mortality risk compared with those who were not visually impaired. Resource allocation toward improving visual acuity may therefore aid in closing the gap in mortality outcomes between indigenous and nonindigenous Australian individuals.

The effect of amblyopia on fine motor skills in children.

PubMed

Webber, Ann L; Wood, Joanne M; Gole, Glen A; Brown, Brian

2008-02-01

In an investigation of the functional impact of amblyopia in children, the fine motor skills of amblyopes and age-matched control subjects were compared. The influence of visual factors that might predict any decrement in fine motor skills was also explored. Vision and fine motor skills were tested in a group of children (n = 82; mean age, 8.2 +/- 1.7 [SD] years) with amblyopia of different causes (infantile esotropia, n = 17; acquired strabismus, n = 28; anisometropia, n = 15; mixed, n = 13; and deprivation n = 9), and age-matched control children (n = 37; age 8.3 +/- 1.3 years). Visual motor control (VMC) and upper limb speed and dexterity (ULSD) items of the Bruininks-Oseretsky Test of Motor Proficiency were assessed, and logMAR visual acuity (VA) and Randot stereopsis were measured. Multiple regression models were used to identify the visual determinants of fine motor skills performance. Amblyopes performed significantly poorer than control subjects on 9 of 16 fine motor skills subitems and for the overall age-standardized scores for both VMC and ULSD items (P < 0.05). The effects were most evident on timed tasks. The etiology of amblyopia and level of binocular function significantly affected fine motor skill performance on both items; however, when examined in a multiple regression model that took into account the intercorrelation between visual characteristics, poorer fine motor skills performance was associated with strabismus (F(1,75) = 5.428; P = 0.022), but not with the level of binocular function, refractive error, or visual acuity in either eye. Fine motor skills were reduced in children with amblyopia, particularly those with strabismus, compared with control subjects. The deficits in motor performance were greatest on manual dexterity tasks requiring speed and accuracy.

A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

PubMed Central

Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

2007-01-01

The case of a 23‐year‐old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was set to a drug‐induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise recovered largely. Neuropsychological tests revealed deficits in fast visual detection tasks and non‐verbal learning, and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. Four months after the accident, she developed a psychological reaction consisting of nightmares with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning flash were retrospectively retraced. PMID:17369595

A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

PubMed Central

Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

2009-01-01

The case of a 23-year-old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was sent into a drug-induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise largely recovered. Neuropsychological tests revealed deficits in fast visual detection tasks and non-verbal learning and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. At 4 months after the accident, she developed a psychological reaction consisting of nightmares, with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning strike were retrospectively retraced PMID:21734915

Comparison of the efficacy and safety of 2% lidocaine HCl with different epinephrine concentration for local anesthesia in participants undergoing surgical extraction of impacted mandibular third molars: A multicenter, randomized, double-blind, crossover, phase IV trial.

PubMed

Karm, Myong-Hwan; Park, Fiona Daye; Kang, Moonkyu; Kim, Hyun Jeong; Kang, Jeong Wan; Kim, Seungoh; Kim, Yong-Deok; Kim, Cheul-Hong; Seo, Kwang-Suk; Kwon, Kyung-Hwan; Kim, Chul-Hwan; Lee, Jung-Woo; Hong, Sung-Woon; Lim, Mi Hyoung; Nam, Seung Kwan; Cho, Jae Min

2017-05-01

The most commonly impacted tooth is the third molar. An impacted third molar can ultimately cause acute pain, infection, tumors, cysts, caries, periodontal disease, and loss of adjacent teeth. Local anesthesia is employed for removing the third molar. This study aimed to evaluate the efficacy and safety of 2% lidocaine with 1:80,000 or 1:200,000 epinephrine for surgical extraction of bilateral impacted mandibular third molars. Sixty-five healthy participants underwent surgical extraction of bilateral impacted mandibular third molars in 2 separate visits while under local anesthesia with 2% lidocaine with different epinephrine concentration (1:80,000 or 1:200,000) in a double-blind, randomized, crossover trial. Visual analog scale pain scores obtained immediately after surgical extraction were primarily evaluated for the 2 groups receiving different epinephrine concentrations. Visual analog scale pain scores were obtained 2, 4, and 6 hours after administering an anesthetic. Onset and duration of analgesia, onset of pain, intraoperative bleeding, operator's and participant's overall satisfaction, drug dosage, and hemodynamic parameters were evaluated for the 2 groups. There were no statistically significant differences between the 2 groups in any measurements except hemodynamic factors (P >.05). Changes in systolic blood pressure and heart rate following anesthetic administration were significantly greater in the group receiving 1:80,000 epinephrine than in that receiving 1:200,000 epinephrine (P ≤.01). The difference in epinephrine concentration between 1:80,000 and 1:200,000 in 2% lidocaine liquid does not affect the medical efficacy of the anesthetic. Furthermore, 2% lidocaine with 1:200,000 epinephrine has better safety with regard to hemodynamic parameters than 2% lidocaine with 1:80,000 epinephrine. Therefore, we suggest using 2% lidocaine with 1:200,000 epinephrine rather than 2% lidocaine with 1:80,000 epinephrine for surgical extraction of impacted mandibular third molars in hemodynamically unstable patients.

Comparison of the efficacy and safety of 2% lidocaine HCl with different epinephrine concentration for local anesthesia in participants undergoing surgical extraction of impacted mandibular third molars

PubMed Central

Karm, Myong-Hwan; Park, Fiona Daye; Kang, Moonkyu; Kim, Hyun Jeong; Kang, Jeong Wan; Kim, Seungoh; Kim, Yong-Deok; Kim, Cheul-Hong; Seo, Kwang-Suk; Kwon, Kyung-Hwan; Kim, Chul-Hwan; Lee, Jung-Woo; Hong, Sung-Woon; Lim, Mi Hyoung; Nam, Seung Kwan; Cho, Jae Min

2017-01-01

Abstract Background: The most commonly impacted tooth is the third molar. An impacted third molar can ultimately cause acute pain, infection, tumors, cysts, caries, periodontal disease, and loss of adjacent teeth. Local anesthesia is employed for removing the third molar. This study aimed to evaluate the efficacy and safety of 2% lidocaine with 1:80,000 or 1:200,000 epinephrine for surgical extraction of bilateral impacted mandibular third molars. Methods: Sixty-five healthy participants underwent surgical extraction of bilateral impacted mandibular third molars in 2 separate visits while under local anesthesia with 2% lidocaine with different epinephrine concentration (1:80,000 or 1:200,000) in a double-blind, randomized, crossover trial. Visual analog scale pain scores obtained immediately after surgical extraction were primarily evaluated for the 2 groups receiving different epinephrine concentrations. Visual analog scale pain scores were obtained 2, 4, and 6 hours after administering an anesthetic. Onset and duration of analgesia, onset of pain, intraoperative bleeding, operator's and participant's overall satisfaction, drug dosage, and hemodynamic parameters were evaluated for the 2 groups. Results: There were no statistically significant differences between the 2 groups in any measurements except hemodynamic factors (P >.05). Changes in systolic blood pressure and heart rate following anesthetic administration were significantly greater in the group receiving 1:80,000 epinephrine than in that receiving 1:200,000 epinephrine (P ≤.01). Conclusion: The difference in epinephrine concentration between 1:80,000 and 1:200,000 in 2% lidocaine liquid does not affect the medical efficacy of the anesthetic. Furthermore, 2% lidocaine with 1:200,000 epinephrine has better safety with regard to hemodynamic parameters than 2% lidocaine with 1:80,000 epinephrine. Therefore, we suggest using 2% lidocaine with 1:200,000 epinephrine rather than 2% lidocaine with 1:80,000 epinephrine for surgical extraction of impacted mandibular third molars in hemodynamically unstable patients. PMID:28538371

Direct and indirect effects of attention and visual function on gait impairment in Parkinson's disease: influence of task and turning.

PubMed

Stuart, Samuel; Galna, Brook; Delicato, Louise S; Lord, Sue; Rochester, Lynn

2017-07-01

Gait impairment is a core feature of Parkinson's disease (PD) which has been linked to cognitive and visual deficits, but interactions between these features are poorly understood. Monitoring saccades allows investigation of real-time cognitive and visual processes and their impact on gait when walking. This study explored: (i) saccade frequency when walking under different attentional manipulations of turning and dual-task; and (ii) direct and indirect relationships between saccades, gait impairment, vision and attention. Saccade frequency (number of fast eye movements per-second) was measured during gait in 60 PD and 40 age-matched control participants using a mobile eye-tracker. Saccade frequency was significantly reduced in PD compared to controls during all conditions. However, saccade frequency increased with a turn and decreased under dual-task for both groups. Poorer attention directly related to saccade frequency, visual function and gait impairment in PD, but not controls. Saccade frequency did not directly relate to gait in PD, but did in controls. Instead, saccade frequency and visual function deficit indirectly impacted gait impairment in PD, which was underpinned by their relationship with attention. In conclusion, our results suggest a vital role for attention with direct and indirect influences on gait impairment in PD. Attention directly impacted saccade frequency, visual function and gait impairment in PD, with connotations for falls. It also underpinned indirect impact of visual and saccadic impairment on gait. Attention therefore represents a key therapeutic target that should be considered in future research. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Rain-induced ejection of pathogens from leaves: revisiting the hypothesis of splash-on-film using high-speed visualization.

PubMed

Gilet, Tristan; Bourouiba, Lydia

2014-12-01

Plant diseases are a major cause of losses of crops worldwide. Although rainfalls and foliar disease outbreaks are correlated, the detailed mechanism explaining their link remains poorly understood. The common assumption from phytopathology for such link is that a splash is generated upon impact of raindrops on contaminated liquid films coating sick leaves. We examine this assumption using direct high-speed visualizations of the interactions of raindrops and leaves over a range of plants. We show that films are seldom found on the surface of common leaves. We quantify the leaf-surface's wetting properties, showing that sessile droplets instead of films are predominant on the surfaces of leaves. We find that the presence of sessile drops rather than that of films has important implications when coupled with the compliance of a leaf: it leads to a new physical picture consisting of two dominant rain-induced mechanisms of ejection of pathogens. The first involves a direct interaction between the fluids of the raindrop and the sessile drops via an off-centered splash. The second involves the indirect action of the raindrop that leads to the inertial detachment of the sessile drop via the leaf's motion imparted by the impact of the raindrop. Both mechanisms are distinct from the commonly assumed scenario of splash-on-film in terms of outcome: they result in different fragmentation processes induced by surface tension, and, thus, different size-distributions of droplets ejected. This is the first time that modern direct high-speed visualizations of impacts on leaves are used to examine rain-induced ejection of pathogens at the level of a leaf and identify the inertial detachment and off-center splash ejections as alternatives to the classically assumed splash-on-film ejections of foliar pathogens. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey.

PubMed

Abokyi, Samuel; Ilechie, Alex; Nsiah, Peter; Darko-Takyi, Charles; Abu, Emmanuel Kwasi; Osei-Akoto, Yaw Jnr; Youfegan-Baanam, Mathurin

2016-01-01

To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population. A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16-39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss. The mean age of participants was 21.86 years (95% CI: 21.72-21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56-3.72) and 0.79% (95% CI: 0.54-1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden. Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey

PubMed Central

Abokyi, Samuel; Ilechie, Alex; Nsiah, Peter; Darko-Takyi, Charles; Abu, Emmanuel Kwasi; Osei-Akoto, Yaw Jnr; Youfegan-Baanam, Mathurin

2015-01-01

Purpose To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population. Methods A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16–39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA ≤ 6/12 in one or both eyes to determine the principal cause of the vision loss. Results The mean age of participants was 21.86 years (95% CI: 21.72–21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56–3.72) and 0.79% (95% CI: 0.54–1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden. Conclusion Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment. PMID:26025809

[National survey of blindness and avoidable visual impairment in Argentina, 2013].

PubMed

Barrenechea, Rosario; de la Fuente, Inés; Plaza, Roberto Gustavo; Flores, Nadia; Segovia, Lía; Villagómez, Zaida; Camarero, Esteban Elián; Zepeda-Romero, Luz Consuelo; Lansingh, Van C; Limburg, Hans; Silva, Juan Carlos

2015-01-01

Determine the prevalence of blindness and avoidable visual impairment in Argentina, its causes, the coverage of cataract surgery, and the barriers that hinder access to these services. Cross-sectional population study conducted between May and November 2013 using the standard methodology for rapid assessment of avoidable blindness (RAAB), with a random cluster sampling of 50 people aged 50 years or more, -representative of the entire country. Participants' visual acuity (VA) was measured and the lens and posterior pole were examined by direct ophthalmoscopy. An assessment was made of the causes of having VA < 20/60, the coverage and quality of cataract surgery, and the barriers to accessing treatment. 3 770 people were assessed (92.0% of the projected number). The prevalence of blindness was 0.7% (confidence interval of 95%: 0.4-1.0%). Unoperated cataract was the main cause of blindness and severe visual impairment (44.0% and 71.1%, respectively), while the main cause of moderate visual impairment was uncorrected refractive errors (77.8%). Coverage of cataract surgery was of 97.1%, and 82.0% of operated eyes achieved VA ≥ 20/60. The main barriers to receiving this treatment were fear of the surgical procedure or of a poor result (34.9%), the cost (30.2%), and not having access to the treatment (16.3%). There is a low prevalence of blindness in the studied population and cataract is the main cause of blindness and severe visual impairment. Efforts should continue to extend coverage of cataract surgery, enhance preoperative evaluation, improve calculations of the intraocular lenses that patients need, and correct post-operative refractive errors with greater precision.

Blindness and visual impairment in the Americas and the Caribbean

PubMed Central

Muñoz, B; West, S K

2002-01-01

Aim: To summarise available data on the prevalence and causes of visual impairment and blindness in the Americas and the Caribbean. Methods: The published literature was searched in Medline and LILACS using the following key words: blindness, visual impairment, prevalence. Articles were reviewed, and the references of the articles were also searched for relevant articles, which were also reviewed. Results: Using the mortality in children under the age of 5 as an indicator, the overall prevalence of childhood blindness (in the under age 15 group) for the region was estimated at 0.45/1000, with the majority (67%) living in countries with mortality of children under age 5 above 30/1000 live births. Corneal opacities were more common in countries where the under 5 year mortality are above 30/1000 live births and retinopathy of prematurity (ROP) was an important cause in countries with intermediate death rates. For adults, overall blindness rates were not estimated because of the social, economic, and ethnic diversity in the region. The primary causes of visual loss in adults in the Americas were age related eye diseases, notably cataract and glaucoma in the African-American and Hispanic populations, and age related macular degeneration in the white population. Uncorrected refractive error was a significant cause of decreased vision across ages, ethnic groups, and countries. Conclusion: More data are needed on the magnitude and causes of visual loss for the Caribbean and Latin American countries. Rates of blindness and visual loss from available data within these countries are widely disparate. Prevention and control of avoidable blindness needs to be an ongoing focus in this region. PMID:11973241

Resolution of Spatial and Temporal Visual Attention in Infants with Fragile X Syndrome

ERIC Educational Resources Information Center

Farzin, Faraz; Rivera, Susan M.; Whitney, David

2011-01-01

Fragile X syndrome is the most common cause of inherited intellectual impairment and the most common single-gene cause of autism. Individuals with fragile X syndrome present with a neurobehavioural phenotype that includes selective deficits in spatiotemporal visual perception associated with neural processing in frontal-parietal networks of the…

Seeing the Invisible with Schlieren Imaging

ERIC Educational Resources Information Center

Lekholm, Ville; Ramme, Goran; Thornell, Greger

2011-01-01

Schlieren imaging is a method for visualizing differences in refractive index as caused by pressure or temperature non-uniformities within a medium, or as caused by the mixing of two fluids. It is an inexpensive yet powerful and straightforward tool for sensitive and high-resolution visualization of otherwise invisible phenomena. In this article,…

Characteristics of visual fatigue under the effect of 3D animation.

PubMed

Chang, Yu-Shuo; Hsueh, Ya-Hsin; Tung, Kwong-Chung; Jhou, Fong-Yi; Lin, David Pei-Cheng

2015-01-01

Visual fatigue is commonly encountered in modern life. Clinical visual fatigue characteristics caused by 2-D and 3-D animations may be different, but have not been characterized in detail. This study tried to distinguish the differential effects on visual fatigue caused by 2-D and 3-D animations. A total of 23 volunteers were subjected to accommodation and vergence assessments, followed by a 40-min video game program designed to aggravate their asthenopic symptoms. The volunteers were then assessed for accommodation and vergence parameters again and directed to watch a 5-min 3-D video program, and then assessed again for the parameters. The results support that the 3-D animations caused similar characteristics in vision fatigue parameters in some specific aspects as compared to that caused by 2-D animations. Furthermore, 3-D animations may lead to more exhaustion in both ciliary and extra-ocular muscles, and such differential effects were more evident in the high demand of near vision work. The current results indicated that an arbitrary set of indexes may be promoted in the design of 3-D display or equipments.

Blindness and visual impairment in Remo, Ogun State, Nigeria: a hospital-based study.

PubMed

Otulana, T O

2012-09-01

This study was conducted to determine the magnitude and causes of blindness and visual impairment in Remo, Ogun State, Nigeria. A retrospective clinic based study to analyse the cases of patients with blindness in general hospitals of Iperu and Isara areas of Ogun state between May 2005 and December 2005. The data of demographic characteristics and diagnosis were retrieved from the outpatient cards. Three hundred and sixty-nine cases registered in the eye clinic during the period of the study and were examined. 177 were males and 190 were females. The age range of patients seen was between 17 days and 89years with a mean age of 43.3 years, ± 23.62(SD). 116 patients were aged 70years and above while 13 patients were less than 10years. 29.5% of the clinic attendance were uniocularly blind, 21.1% were bilaterally blind while 25 2% were visually impaired. 55.1% of the bilateral blindness was in males. 30.8% cases of the bilaterally blind were from age related cataract, 23.1% from glaucoma, 6 cases were due to Retinitis Pigmentosa and 3 from pterygium, Cataract followed by glaucoma was the leading cause of uniocular blindness. Cataract was responsible for 66.7% of visually impairment. Blindness and visual impairment is a public health problem in Remo Ogun State, Nigeria; cataract, glaucoma and pterygium were the important causes of blindness and visual impairment. The major causes of blindness in this part of Ogun state are preventable.

Blindness and Severe Visual Impairment in Pupils at Schools for the Blind in Burundi

PubMed Central

Ruhagaze, Patrick; Njuguna, Kahaki Kimani Margaret; Kandeke, Lévi; Courtright, Paul

2013-01-01

Purpose: To determine the causes of childhood blindness and severe visual impairment in pupils attending schools for the blind in Burundi in order to assist planning for services in the country. Materials and Methods: All pupils attending three schools for the blind in Burundi were examined. A modified WHO/PBL eye examination record form for children with blindness and low vision was used to record the findings. Data was analyzed for those who became blind or severely visually impaired before the age of 16 years. Results: Overall, 117 pupils who became visually impaired before 16 years of age were examined. Of these, 109 (93.2%) were blind or severely visually impaired. The major anatomical cause of blindness or severe visual impairment was cornea pathology/phthisis (23.9%), followed by lens pathology (18.3%), uveal lesions (14.7%) and optic nerve lesions (11.9%). In the majority of pupils with blindness or severe visual impairment, the underlying etiology of visual loss was unknown (74.3%). More than half of the pupils with lens related blindness had not had surgery; among those who had surgery, outcomes were generally poor. Conclusion: The causes identified indicate the importance of continuing preventive public health strategies, as well as the development of specialist pediatric ophthalmic services in the management of childhood blindness in Burundi. The geographic distribution of pupils at the schools for the blind indicates a need for community-based programs to identify and refer children in need of services. PMID:23580854

Blindness and severe visual impairment in pupils at schools for the blind in Burundi.

PubMed

Ruhagaze, Patrick; Njuguna, Kahaki Kimani Margaret; Kandeke, Lévi; Courtright, Paul

2013-01-01

To determine the causes of childhood blindness and severe visual impairment in pupils attending schools for the blind in Burundi in order to assist planning for services in the country. All pupils attending three schools for the blind in Burundi were examined. A modified WHO/PBL eye examination record form for children with blindness and low vision was used to record the findings. Data was analyzed for those who became blind or severely visually impaired before the age of 16 years. Overall, 117 pupils who became visually impaired before 16 years of age were examined. Of these, 109 (93.2%) were blind or severely visually impaired. The major anatomical cause of blindness or severe visual impairment was cornea pathology/phthisis (23.9%), followed by lens pathology (18.3%), uveal lesions (14.7%) and optic nerve lesions (11.9%). In the majority of pupils with blindness or severe visual impairment, the underlying etiology of visual loss was unknown (74.3%). More than half of the pupils with lens related blindness had not had surgery; among those who had surgery, outcomes were generally poor. The causes identified indicate the importance of continuing preventive public health strategies, as well as the development of specialist pediatric ophthalmic services in the management of childhood blindness in Burundi. The geographic distribution of pupils at the schools for the blind indicates a need for community-based programs to identify and refer children in need of services.

Blindness and visual impairment in opera.

PubMed

Aydin, Pinar; Ritch, Robert; O'Dwyer, John

2018-01-01

The performing arts mirror the human condition. This study sought to analyze the reasons for inclusion of visually impaired characters in opera, the cause of the blindness or near blindness, and the dramatic purpose of the blindness in the storyline. We reviewed operas from the 18 th century to 2010 and included all characters with ocular problems. We classified the cause of each character's ocular problem (organic, nonorganic, and other) in relation to the thematic setting of the opera: biblical and mythical, blind beggars or blind musicians, historical (real or fictional characters), and contemporary or futuristic. Cases of blindness in 55 characters (2 as a choir) from 38 operas were detected over 3 centuries of repertoire: 11 had trauma-related visual impairment, 5 had congenital blindness, 18 had visual impairment of unknown cause, 9 had psychogenic or malingering blindness, and 12 were symbolic or miracle-related. One opera featured an ophthalmologist curing a patient. The research illustrates that visual impairment was frequently used as an artistic device to enhance the intent and situate an opera in its time.

Prevalence of refractive error and visual impairment among rural school-age children of Goro District, Gurage Zone, Ethiopia.

PubMed

Kedir, Jafer; Girma, Abonesh

2014-10-01

Refractive error is one of the major causes of blindness and visual impairment in children; but community based studies are scarce especially in rural parts of Ethiopia. So, this study aims to assess the prevalence of refractive error and its magnitude as a cause of visual impairment among school-age children of rural community. This community-based cross-sectional descriptive study was conducted from March 1 to April 30, 2009 in rural villages of Goro district of Gurage Zone, found south west of Addis Ababa, the capital of Ethiopia. A multistage cluster sampling method was used with simple random selection of representative villages in the district. Chi-Square and t-tests were used in the data analysis. A total of 570 school-age children (age 7-15) were evaluated, 54% boys and 46% girls. The prevalence of refractive error was 3.5% (myopia 2.6% and hyperopia 0.9%). Refractive error was the major cause of visual impairment accounting for 54% of all causes in the study group. No child was found wearing corrective spectacles during the study period. Refractive error was the commonest cause of visual impairment in children of the district, but no measures were taken to reduce the burden in the community. So, large scale community level screening for refractive error should be conducted and integrated with regular school eye screening programs. Effective strategies need to be devised to provide low cost corrective spectacles in the rural community.

Awareness of blindness and other smoking-related diseases and its impact on motivation for smoking cessation in eye patients.

PubMed

Handa, S; Woo, J H; Wagle, A M; Htoon, H M; Au Eong, K G

2011-09-01

Cigarette smoking is a major cause of morbidity and mortality. The association between smoking and eye diseases is less widely recognised relative to other better-known smoking-related conditions. This study aims to assess the awareness and fear of known smoking-related diseases among current smokers attending an ophthalmology outpatient clinic and to evaluate their relative impact on the likelihood of smoking cessation. A cross-sectional survey using a structured interview of randomly selected current smokers attending an eye clinic was conducted. The knowledge of six smoking-related diseases (lung cancer, heart attack, stroke, blindness, other cancers, and other lung diseases) was assessed. The fear of smoking-related conditions and the relative impact of each smoking-related condition on the smoker's motivation to quit smoking were evaluated. Out of 200 current smokers aged from 14 to 83 years, only 42.5% (85 patients) were aware that smoking causes blindness. Smokers' perception of harm caused by smoking was 6.53±3.21 (mean±SD) on a visual analogue scale of 0 to 10. Patients placed blindness as the second most important motivating factor to quit smoking immediately, within 1 year and 5 years, after lung cancer. The awareness of the risk of blindness from smoking was lowest compared with five other smoking-related diseases among eye patients who smoke. However, blindness remains a key motivational factor in smoking cessation and hence should be emphasised as an important negative health consequence of smoking in public health education and anti-smoking campaigns.

An Optimized Centrifugal Method for Separation of Semen from Superabsorbent Polymers for Forensic Analysis.

PubMed

Camarena, Lucy R; Glasscock, Bailey K; Daniels, Demi; Ackley, Nicolle; Sciarretta, Marybeth; Seashols-Williams, Sarah J

2017-03-01

Connection of a perpetrator to a sexual assault is best performed through the confirmed presence of semen, thereby proving sexual contact. Evidentiary items can include sanitary napkins or diapers containing superabsorbent polymers (SAPs), complicating spermatozoa visualization and DNA analysis. In this report, we evaluated the impact of SAPS on the current forensic DNA workflow, developing an efficient centrifugal protocol for separating spermatozoa from SAP material. The optimized filtration method was compared to common practices of excising the top layer only, resulting in significantly higher sperm yields when a core sample of the substrate was taken. Direct isolation of the SAP-containing materials without filtering resulted in 20% sample failure; additionally, SAP material was observed in the final eluted DNA samples, causing physical interference. Thus, use of the described centrifugal-filtering method is a simple preliminary step that improves spermatozoa visualization and enables more consistent DNA yields, while also avoiding SAP interference. © 2016 American Academy of Forensic Sciences.

Unusual phenotypic expression of an XLRS1 mutation in X-linked juvenile retinoschisis.

PubMed

Dodds, Jodi A; Srivastava, Anand K; Holden, Kenton R

2006-04-01

X-linked juvenile retinoschisis is a rare progressive vitreoretinal degenerative process that appears in early childhood, results in decreased visual acuity and blindness (if severe), and is caused by various mutations within the XLRS1 gene at Xp22.2. We report an affected family of Western European ancestry with X-linked juvenile retinoschisis. The family was found to carry a 304C-->T substitution in exon 4 of the XLRS1 gene, resulting in an Arg102Trp amino acid substitution. Two of the four available clinical cases in this family were found to carry the mutation. All available mothers of affected males were found to be unaffected carriers of the mutation, a typical feature of X-linked diseases. Two new female carriers, sisters of affected males, were identified and counseled accordingly. Questionnaires on visual functioning were given to the affected family members to examine the psychologic and sociologic impact of X-linked juvenile retinoschisis, which documented an associated stigma even when affected with a "mild" phenotype.

Prevalence of visual impairment and outcomes of cataract surgery in Chaonan, South China

PubMed Central

Zhang, Xiujuan; Li, Emmy Y.; Leung, Christopher Kai-Shun; Musch, David C.; Tang, Xin; Zheng, Chongren; He, Mingguang; Chang, David F.

2017-01-01

Purpose To estimate the prevalence and causes of blindness and visual impairment (VI), and report the outcomes of cataract surgery in Chaonan Region, Guangdong Province, southern China Design Cross-sectional population-based survey Participants A total of 3484 participants including 1397 men (40.1%) and 2087 women (59.9%) aged ≥50 years were examined (94.2% response rate). Method A two-stage cluster sampling procedure was used to select 3700 participants aged ≥50 years from 74 clusters of Chaonan Region. Participants were examined according to the Rapid Assessment of Avoidable Blindness (RAAB) method. Blindness and visual impairment (VI) were defined by the World Health Organization criteria. Participants with visual acuity (VA) < 6/18 in either eye were examined by ophthalmologists. The primary causes of blindness and VI were reported with reference to the participant’s better eye. Main outcome measures Prevalence and main causes of blindness, severe visual impairment (SVI), VI and the outcomes of cataract surgery Results The standardized prevalence rates of blindness, SVI, and VI were 2.4% (95% confidence interval [CI], 1.9–2.9%), 1.0% (95% CI, 0.7–1.4%), and 6.4% (95% CI, 5.6%– 7.1%), respectively. The principal cause of blindness and SVI was cataract, accounting for 67.1% and 67.6% respectively, and the principal cause of VI was refractive error (46.9%). One hundred and fifty five out of 3484 (4.4%) people (211 eyes) had cataract surgery. Of the 211 eyes that had cataract surgery, 96.7% were pseudophakic. 67.2% of the 211 operated eyes had a presenting visual acuity (PVA) of 6/18 or better. Conclusions The prevalence of blindness, SVI, and VI was high among rural residents in Chaonan. Cataract remained the leading cause of avoidable blindness. Outcomes of cataract surgery performed in rural private clinics were suboptimal. Quality-control initiatives such as hands-on training program should be introduced to improve cataract surgery outcomes. PMID:28797099

The Tribal Odisha Eye Disease Study (TOES) 1: prevalence and causes of visual impairment among tribal children in an urban school in Eastern India.

PubMed

Warkad, Vivekanand U; Panda, Lapam; Behera, Pradeep; Das, Taraprasad; Mohanta, Bikash C; Khanna, Rohit

2018-04-01

To estimate the prevalence and causes of visual impairment and other ocular comorbidities among tribal children in an urban school population in eastern India. In this cross-sectional study, vision screening tests were administered to tribal school children. Demographic data, including name, age, sex, home district, height, and weight of each child, and examination data, including unaided and pinhole visual acuity, external eye examination with a flashlight, slit-lamp examination, intraocular pressure (IOP) measurement, and undilated fundus photography, were collected. Children with visual acuity of less than 20/20, abnormal anterior or posterior segment findings, and IOP of >21 mm Hg were referred for further evaluation. Of 10,038 children (5,840 males [58.2%]) screened, 335 (median age, 9 years; range, 6-17 years) were referred. Refractive error was the most common cause of visual impairment (59.52%; 95% CI, 51.97-66.65) followed by amblyopia (17.2%; 95% CI, 12.3-23.6) and posterior segment anomaly (14.88%; 95% CI, 10.2-21.0). The prevalence of best-corrected visual acuity of 20/40 was 0.13%. The prevalence of blindness was 0.03%. Visual impairment among tribal children in this residential school is an uncommon but important disability. Copyright © 2018 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Prevalence of blindness and cataract surgical outcomes in Takeo Province, Cambodia.

PubMed

Mörchen, Manfred; Langdon, Toby; Ormsby, Gail M; Meng, Ngy; Seiha, Do; Piseth, Kong; Keeffe, Jill E

2015-01-01

To estimate the prevalence of blindness and cataract surgical outcomes in persons 50 years or older above in Takeo Province, Cambodia. A population based survey. A total of 93 villages were selected through probability proportionate to size using the Rapid Assessment of Avoidable Blindness methodology. Households from 93 villages were selected using compact segment sampling. Visual acuity (VA) of 4650 people 50 years or older was tested and lens status and cause of visual impairment were assessed. The response rate was 96.2%. The age- and sex-adjusted prevalence of bilateral blindness [presenting visual acuity (PVA) <3/60 in the better eye] was 3.4% (95% confidence interval, 2.8%-4.0%), resulting in an estimated 4187 people blind in Takeo Province. The age- and sex-adjusted prevalence of low vision (PVA <6/18 to 3/60) was 21.1%, an estimated 25,900 people. Cataract surgical coverage in the bilaterally blind was 64.7% (female 59.5%, male 78.1%). Cataract surgical outcome was poor (best-corrected visual acuity <6/60) in only 7.7% and good in 88.7% (best-corrected visual acuity ≥6/18) of eyes operated in the last 5 years before the survey. The cataract surgical coverage for women is less than that for men. The increased life expectancy in Cambodia and the fact that women constitute 60.6% of the population (aged ≥50 years) at Takeo Province could have had an impact on cataract workload and high prevalence of blindness. A repeated survey using the same methodology after 8-12 years might be helpful in proving genuine change over time.

A randomized trial of Rapid Rhino Riemann and Telfa nasal packs following endoscopic sinus surgery.

PubMed

Cruise, A S; Amonoo-Kuofi, K; Srouji, I; Kanagalingam, J; Georgalas, C; Patel, N N; Badia, L; Lund, V J

2006-02-01

To compare Telfa with the Rapid Rhino Riemann nasal pack for use following endoscopic sinus surgery. Prospective, randomized, double-blind, paired trial. Tertiary otolaryngology hospital. Forty-five adult patients undergoing bilateral endoscopic sinus surgery for either chronic rhinosinusitis or nasal polyps. A visual analogue scale was used to assess discomfort caused by the presence of the packs in the nose and by their removal. The amount of bleeding was noted with the packs in place and following their removal. Crusting and adhesions were assessed 2 and 6 weeks following surgery. Both packs performed well giving good haemostasis and causing little bleeding on removal. Both packs caused only mild discomfort while in the nose. On the visual analogue scale of 0-10 cm the mean visual analogue score for Rapid Rhino Riemann pack was 1.7 and for Telfa 2.0 (P = 0.371). The Rapid Rhino Riemann pack caused significantly less pain on removal compared with the Telfa pack with a mean visual analogue score of 2.0 in comparison with 3.7 for Telfa (P = 0.001). There were less adhesions with the Rapid Rhino Riemann than Telfa pack but this was not statistically significant (P = 0.102). Both Telfa and Rapid Rhino Riemann packs can be recommended as packs that control postoperative haemorrhage, do not cause bleeding on removal and cause little discomfort while in the nose. The Rapid Rhino Riemann pack has the advantage of causing significantly less pain on removal.

Finite Element Modeling Techniques for Analysis of VIIP

NASA Technical Reports Server (NTRS)

Feola, Andrew J.; Raykin, J.; Gleason, R.; Mulugeta, Lealem; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.; Ethier, C. Ross

2015-01-01

Visual Impairment and Intracranial Pressure (VIIP) syndrome is a major health concern for long-duration space missions. Currently, it is thought that a cephalad fluid shift in microgravity causes elevated intracranial pressure (ICP) that is transmitted along the optic nerve sheath (ONS). We hypothesize that this in turn leads to alteration and remodeling of connective tissue in the posterior eye which impacts vision. Finite element (FE) analysis is a powerful tool for examining the effects of mechanical loads in complex geometries. Our goal is to build a FE analysis framework to understand the response of the lamina cribrosa and optic nerve head to elevations in ICP in VIIP.

Impact of low vision rehabilitation on functional vision performance of children with visual impairment.

PubMed

Ganesh, Suma; Sethi, Sumita; Srivastav, Sonia; Chaudhary, Amrita; Arora, Priyanka

2013-09-01

To evaluate the impact of low vision rehabilitation on functional vision of children with visual impairment. The LV Prasad-Functional Vision Questionnaire, designed specifically to measure functional performance of visually impaired children of developing countries, was used to assess the level of difficulty in performing various tasks pre and post visual rehabilitation in children with documented visual impairment. Chi-square test was used to assess the impact of rehabilitation intervention on functional vision performance; a P < 0.05 was considered significant. LogMAR visual acuity prior to the introduction of low vision devices (LVDs) was 0.90 ± 0.05 for distance and for near it was 0.61 ± 0.05. After the intervention, the acuities improved significantly for distance (0.2 ± 0.27; P < 0.0001) and near (0.42 ± 0.17; P = 0.001). The most common reported difficulties were related to their academic activities like copying from the blackboard (80%), reading textbook at arm's length (77.2%), and writing along a straight line (77.2%). Absolute raw score of disability pre-LVD was 15.05 which improved to 7.58 post-LVD. An improvement in functional vision post visual rehabilitation was especially found in those activities related to their studying lifestyle like copying from the blackboard (P < 0.0001), reading textbook at arm's length (P < 0.0001), and writing along a straight line (P = 0.003). In our study group, there was a significant improvement in functional vision post visual rehabilitation, especially with those activities which are related to their academic output. It is important for these children to have an early visual rehabilitation to decrease the impairment associated with these decreased visual output and to enhance their learning abilities.

Visual Search in ASD: Instructed versus Spontaneous Local and Global Processing

ERIC Educational Resources Information Center

Van der Hallen, Ruth; Evers, Kris; Boets, Bart; Steyaert, Jean; Noens, Ilse; Wagemans, Johan

2016-01-01

Visual search has been used extensively to investigate differences in mid-level visual processing between individuals with ASD and TD individuals. The current study employed two visual search paradigms with Gaborized stimuli to assess the impact of task distractors (Experiment 1) and task instruction (Experiment 2) on local-global visual…

Timing the impact of literacy on visual processing

PubMed Central

Pegado, Felipe; Comerlato, Enio; Ventura, Fabricio; Jobert, Antoinette; Nakamura, Kimihiro; Buiatti, Marco; Ventura, Paulo; Dehaene-Lambertz, Ghislaine; Kolinsky, Régine; Morais, José; Braga, Lucia W.; Cohen, Laurent; Dehaene, Stanislas

2014-01-01

Learning to read requires the acquisition of an efficient visual procedure for quickly recognizing fine print. Thus, reading practice could induce a perceptual learning effect in early vision. Using functional magnetic resonance imaging (fMRI) in literate and illiterate adults, we previously demonstrated an impact of reading acquisition on both high- and low-level occipitotemporal visual areas, but could not resolve the time course of these effects. To clarify whether literacy affects early vs. late stages of visual processing, we measured event-related potentials to various categories of visual stimuli in healthy adults with variable levels of literacy, including completely illiterate subjects, early-schooled literate subjects, and subjects who learned to read in adulthood (ex-illiterates). The stimuli included written letter strings forming pseudowords, on which literacy is expected to have a major impact, as well as faces, houses, tools, checkerboards, and false fonts. To evaluate the precision with which these stimuli were encoded, we studied repetition effects by presenting the stimuli in pairs composed of repeated, mirrored, or unrelated pictures from the same category. The results indicate that reading ability is correlated with a broad enhancement of early visual processing, including increased repetition suppression, suggesting better exemplar discrimination, and increased mirror discrimination, as early as ∼100–150 ms in the left occipitotemporal region. These effects were found with letter strings and false fonts, but also were partially generalized to other visual categories. Thus, learning to read affects the magnitude, precision, and invariance of early visual processing. PMID:25422460

Timing the impact of literacy on visual processing.

PubMed

Pegado, Felipe; Comerlato, Enio; Ventura, Fabricio; Jobert, Antoinette; Nakamura, Kimihiro; Buiatti, Marco; Ventura, Paulo; Dehaene-Lambertz, Ghislaine; Kolinsky, Régine; Morais, José; Braga, Lucia W; Cohen, Laurent; Dehaene, Stanislas

2014-12-09

Learning to read requires the acquisition of an efficient visual procedure for quickly recognizing fine print. Thus, reading practice could induce a perceptual learning effect in early vision. Using functional magnetic resonance imaging (fMRI) in literate and illiterate adults, we previously demonstrated an impact of reading acquisition on both high- and low-level occipitotemporal visual areas, but could not resolve the time course of these effects. To clarify whether literacy affects early vs. late stages of visual processing, we measured event-related potentials to various categories of visual stimuli in healthy adults with variable levels of literacy, including completely illiterate subjects, early-schooled literate subjects, and subjects who learned to read in adulthood (ex-illiterates). The stimuli included written letter strings forming pseudowords, on which literacy is expected to have a major impact, as well as faces, houses, tools, checkerboards, and false fonts. To evaluate the precision with which these stimuli were encoded, we studied repetition effects by presenting the stimuli in pairs composed of repeated, mirrored, or unrelated pictures from the same category. The results indicate that reading ability is correlated with a broad enhancement of early visual processing, including increased repetition suppression, suggesting better exemplar discrimination, and increased mirror discrimination, as early as ∼ 100-150 ms in the left occipitotemporal region. These effects were found with letter strings and false fonts, but also were partially generalized to other visual categories. Thus, learning to read affects the magnitude, precision, and invariance of early visual processing.

[Visual development and amblyopia prophylaxis in pediatric glaucoma].

PubMed

Steffen, H

2011-07-01

In children with congenital glaucoma the functional long-term result is often disappointing even if the intraocular pressure is well controlled. The reason for this discrepancy is attributed to amblyogenic factors responsible for interfering with normal visual development. These amblyogenic factors are corneal edema, irregular astigmatism and non-corrected ametropia as monocular causes. Binocular causes are anisometropia-induced suppression and strabismus. Full ametropic correction and a very early prophylaxis and treatment of amblyopia with a close follow-up are mandatory to reduce amblyogenic visual impairment in children with congenital glaucoma.

Prevelence and causes of visual impairment and blindness in older adults in an area of India with a high cataract surgical rate.

PubMed

Murthy, Gudlavalleti V S; Vashist, Praveen; John, Neena; Pokharel, Gopal; Ellwein, Leon B

2010-08-01

The cataract surgical rate (CSR) in Gujarat, India is reported to be above 10,000 per million population. This study was conducted to investigate the prevalence and causes of vision impairment/blindness among older adults in a high CSR area. Geographically defined cluster sampling was used in randomly selecting persons >or= 50 years of age in Navsari district. Subjects in 35 study clusters were enumerated and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity < 20/32. A total of 5158 eligible persons were enumerated and 4738 (91.9%) examined. Prevalence of presenting visual impairment < 20/63 to 20/200 in the better eye was 29.3% (95% confidence interval [CI]: 27.5-31.2) and 13.5% (95% CI: 12.0-14.9) with best correction. The prevalence of presenting bilateral blindness (< 20/200) was 6.9% (95% CI: 5.7-8.1), and 3.1% (95% CI: 2.5-3.7) with best correction. Presenting and best-corrected blindness were both associated with older age and illiteracy; gender and rural/urban residence were not significant. Cataract in one or both eyes was the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%). Cataract (50.3%) and refractive error (35.4%) were the main causes in eyes with vision acuity < 20/63 to 20/200, and refractive error (86.6%) in eyes with acuity < 20/32 to 20/63. Visual impairment and blindness is a significant problem among the elderly in Gujarat. Despite a reportedly high CSR, cataract remains the predominant cause of blindness.

A survey of visual impairment and blindness in children attending four schools for the blind in Cambodia.

PubMed

Sia, David I T; Muecke, James; Hammerton, Michael; Ngy, Meng; Kong, Aimee; Morse, Anna; Holmes, Martin; Piseth, Horm; Hamilton, Carolyn; Selva, Dinesh

2010-08-01

To identify the causes of blindness and severe visual impairment (BL/SVI) in children attending four schools for the blind in Cambodia and to provide spectacles, low vision aids, orientation and mobility training and ophthalmic treatment. Children < 16 years of age were recruited from all 4 schools for the blind in Cambodia. Causes of visual impairment and blindness were determined and categorized using World Health Organization methods. Of the 95 children examined, 54.7% were blind (BL) and 10.5% were severely visually impaired (SVI). The major anatomical site of BL/SVI was the lens in 27.4%, cornea in 25.8%, retina in 21% and whole globe in 17.7%. The major underlying etiologies of BL/SVI were hereditary factors (mainly cataract and retinal dystrophies) in 45.2%, undetermined/unknown (mainly microphthalmia and anterior segment dysgenesis) in 38.7% and childhood factors in 11.3%. Avoidable causes of BL/SVI accounted for 50% of the cases; 12.9% of the total were preventable with measles being the commonest cause (8.1% of the total); 37.1% were treatable with cataracts and glaucoma being the commonest causes (22.6% and 4.8% respectively). More than 35% of children required an optical device and 27.4% had potential for visual improvement with intervention. Half of the BL/SVI causes were potentially avoidable. The data support the need for increased coverage of measles immunization. There is also a need to develop specialized pediatric ophthalmic services for the management of surgically remediable conditions, to provide optometric, low vision and orientation and mobility services. Genetic risk counseling services also may be considered.

Causes of blindness in children attending four schools for the blind in Thailand and the Philippines. A comparison between urban and rural blind school populations.

PubMed

Gilbert, C; Foster, A

1993-08-01

Using WHO definitions of visual loss and a standardised methodology, 256 children were examined in schools for the blind in Thailand (1 school) and the Philippines (3 schools). 244 (95%) were blind (BL) or severely visually impaired (SVI). Causes of SVI and blindness were classified anatomically and aetiologically, and avoidable causes identified. Causes of visual loss in Khon Kaen, Thailand (n = 65) and Manila, Philippines, (n = 113) were similar, with conditions of the whole globe accounting for 27.7 and 27.4% of SVI/BL; retinal disease 29.2 and 23.0%; cataract 16.9 and 16.8%; corneal disease 12.3 and 13.4%; and optic nerve disease and glaucoma 6.2 and 8.8%. Perinatal factors accounted for 20.0 and 23.0% of SVI/BL; hereditary disease 13.8 and 17.7%; and 12.3 and 15.0% was due to events occurring during childhood. The underlying aetiology could not be determined in 50.8 and 41.6% of cases, respectively. In the two schools together twenty six children (15%) were blind from retinopathy of prematurity (ROP) and 16 (9%) from corneal scarring attributed to Vitamin A deficiency. 103 of 178 (58%) children had avoidable causes of visual loss. In the Filipino towns of Baguio and Davao (n = 66), the causes of visual loss were different from those in Khon Kaen and Manila, with 54.8 and 42.9% of SVI/BL being due to corneal disease, and only 3.2 and 8.5% to retinal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten-year all-cause mortality and its association with vision among Indigenous Australians within Central Australia: the Central Australian Ocular Health Study.

PubMed

Liu, Ebony; Ng, Soo K; Kahawita, Shyalle; Andrew, Nicholas H; Henderson, Tim; Craig, Jamie E; Landers, John

2017-05-01

No studies to date have explored the association of vision with mortality in Indigenous Australians. We aimed to determine the 10-year all-cause mortality and its associations among Indigenous Australians living in Central Australia. Prospective observational cohort study. A total of 1257 (93.0%) of 1347 patients from The Central Australian Ocular Health Study, over the age of 40 years, were available for follow-up during a 10-year period. All-cause mortality and its associations with visual acuity, age and gender were analysed. All-cause mortality. All-cause mortality was 29.3% at the end of 10 years. Mortality increased as age of recruitment increased: 14.2% (40-49 years), 22.6% (50-59 years), 50.3% (60 years or older) (χ = 59.15; P < 0.00001). Gender was not associated with mortality as an unadjusted variable, but after adjustment with age and visual acuity, women were 17.0% less likely to die (t = 2.09; P = 0.037). Reduced visual acuity was associated with increased mortality rate (5% increased mortality per one line of reduced visual acuity; t = 4.74; P < 0.0001) after adjustment for age, sex, diabetes and hypertension. The 10-year all-cause mortality rate of Indigenous Australians over the age of 40 years and living in remote communities of Central Australia was 29.3%. This is more than double that of the Australian population as a whole. Mortality was significantly associated with visual acuity at recruitment. Further work designed to better understand this association is warranted and may help to reduce this disparity in the future. © 2016 Royal Australian and New Zealand College of Ophthalmologists.

Fluorescence Aggregation-Caused Quenching versus Aggregation-Induced Emission: A Visual Teaching Technology for Undergraduate Chemistry Students

ERIC Educational Resources Information Center

Ma, Xiaofeng; Sun, Rui; Cheng, Jinghui; Liu, Jiaoyan; Gou, Fei; Xiang, Haifeng; Zhou, Xiangge

2016-01-01

A laboratory experiment visually exploring two opposite basic principles of fluorescence of aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) is demonstrated. The students would prepared two salicylaldehyde-based Schiff bases through a simple one-pot condensation reaction of one equiv of 1,2-diamine with 2 equiv of…

A Discussion of Commercially Available Intra-ocular Telescopic Implants for Patients with Age-Related Macular Degeneration.

PubMed

Dunbar, Hannah M P; Dhawahir-Scala, Felipe E

2018-06-01

Age-related macular degeneration (AMD) is the leading cause of visual impairment in the western world, causing significant reduction in quality of life. Despite treatment advances, the burden of visual impairment caused by AMD continues to rise. In addition to traditional low vision rehabilitation and support, optical and electronic aids, and strategies to enhance the use of peripheral vision, implantable telescopic devices have been indicated as a surgical means of enhancing vision. Here we examine the literature on commercially available telescopic devices discussing their design, mode of action, surgical procedure and published outcomes on visual acuity, quality of life, surgical complication rates and cost effectiveness data where available.Funding Article processing charges were funded by VisionCare Inc.

Impact of Buffer, Protein Concentration and Sucrose Addition on the Aggregation and Particle Formation during Freezing and Thawing.

PubMed

Hauptmann, Astrid; Podgoršek, Katja; Kuzman, Drago; Srčič, Stanko; Hoelzl, Georg; Loerting, Thomas

2018-03-19

This study addresses the effect of freezing and thawing on a therapeutic monoclonal antibody (mAb) solution and the corresponding buffer formulation. Particle formation, crystallization behaviour, morphology changes and cryo-concentration effects were studied after varying the freezing and thawing rates, buffer formulation and protein concentration. The impact of undergoing multiple freeze/thaw (FT)-cycles at controlled and uncontrolled temperature rates on mAb solutions was investigated in terms of particle formation. Physicochemical characteristics were analysed by Differential Scanning Calorimetry whereas morphology changes are visualized by cryomicroscopy measurements. Micro Flow Imaging, Archimedes and Dynamic Light Scattering were used to investigate particle formation. Data retrieved in the present study emphasizes the damage caused by multiple FT-cyles and the need for sucrose as a cryoprotectant preventing cold-crystallization specifically at high protein concentrations. Low protein concentrations cause an increase of micron particle formation. Low freezing rates lead to a decreased particle number with increased particle diameter. The overall goal of this research is to gain a better understanding of the freezing and thawing behaviour of mAb solutions with the ultimate aim to optimize this process step by reducing the unwanted particle formation, which also includes protein aggregates.

Improving Dorsal Stream Function in Dyslexics by Training Figure/Ground Motion Discrimination Improves Attention, Reading Fluency, and Working Memory

PubMed Central

Lawton, Teri

2016-01-01

There is an ongoing debate about whether the cause of dyslexia is based on linguistic, auditory, or visual timing deficits. To investigate this issue three interventions were compared in 58 dyslexics in second grade (7 years on average), two targeting the temporal dynamics (timing) of either the auditory or visual pathways with a third reading intervention (control group) targeting linguistic word building. Visual pathway training in dyslexics to improve direction-discrimination of moving test patterns relative to a stationary background (figure/ground discrimination) significantly improved attention, reading fluency, both speed and comprehension, phonological processing, and both auditory and visual working memory relative to controls, whereas auditory training to improve phonological processing did not improve these academic skills significantly more than found for controls. This study supports the hypothesis that faulty timing in synchronizing the activity of magnocellular with parvocellular visual pathways is a fundamental cause of dyslexia, and argues against the assumption that reading deficiencies in dyslexia are caused by phonological deficits. This study demonstrates that visual movement direction-discrimination can be used to not only detect dyslexia early, but also for its successful treatment, so that reading problems do not prevent children from readily learning. PMID:27551263

Annual incidences of visual impairment during 10-year period in Mie prefecture, Japan.

PubMed

Ikesugi, Kengo; Ichio, Takako; Tsukitome, Hideyuki; Kondo, Mineo

2017-07-01

To determine the annual incidence of visual impairment in a Japanese population during a 10-year period. We examined the physical disability certificates issued yearly between 2004 and 2013 in Mie prefecture, Japan. During this period 2468 visually impaired people were registered under the newly defined Act on Welfare of the Physically Disabled Persons' criteria. The age, sex distribution, and causes of visual impairment were determined from the certificates. The major causes of visual impairment during the ten-year period were glaucoma (23.3%), diabetic retinopathy (17.3%), retinitis pigmentosa (12.2%), macular degeneration (9.0%), chorioretinal degeneration or high myopia (7.4%), optic atrophy (5.8%), stroke or brain tumor (5.4%) and cataracts (3.7%). The incidence of glaucoma was significantly higher throughout the period (2004-2013), and that of diabetic retinopathy was lower between 2007 and 2013. The incidence of retinitis pigmentosa did not change significantly during the 10-year period. The incidence of macular degeneration tended to increase between 2004 and 2007, but it decreased significantly between 2007 and 2013. The results indicate that in Japan, the rates of the major causes of visual impairment altered in the most recent 10-year period reflecting the recent changes in the social background and advances in ocular and systemic treatment.

Color impact in visual attention deployment considering emotional images

NASA Astrophysics Data System (ADS)

Chamaret, C.

2012-03-01

Color is a predominant factor in the human visual attention system. Even if it cannot be sufficient to the global or complete understanding of a scene, it may impact the visual attention deployment. We propose to study the color impact as well as the emotion aspect of pictures regarding the visual attention deployment. An eye-tracking campaign has been conducted involving twenty people watching half pictures of database in full color and the other half of database in grey color. The eye fixations of color and black and white images were highly correlated leading to the question of the integration of such cues in the design of visual attention model. Indeed, the prediction of two state-of-the-art computational models shows similar results for the two color categories. Similarly, the study of saccade amplitude and fixation duration versus time viewing did not bring any significant differences between the two mentioned categories. In addition, spatial coordinates of eye fixations reveal an interesting indicator for investigating the differences of visual attention deployment over time and fixation number. The second factor related to emotion categories shows evidences of emotional inter-categories differences between color and grey eye fixations for passive and positive emotion. The particular aspect associated to this category induces a specific behavior, rather based on high frequencies, where the color components influence the visual attention deployment.

Phonological Skills, Visual Attention Span, and Visual Stress in Developmental Dyslexia

ERIC Educational Resources Information Center

Saksida, Amanda; Iannuzzi, Stéphanie; Bogliotti, Caroline; Chaix, Yves; Démonet, Jean-François; Bricout, Laure; Billard, Catherine; Nguyen-Morel, Marie-Ange; Le Heuzey, Marie-France; Soares-Boucaud, Isabelle; George, Florence; Ziegler, Johannes C.; Ramus, Franck

2016-01-01

In this study, we concurrently investigated 3 possible causes of dyslexia--a phonological deficit, visual stress, and a reduced visual attention span--in a large population of 164 dyslexic and 118 control French children, aged between 8 and 13 years old. We found that most dyslexic children showed a phonological deficit, either in terms of…

Do Dyslexic Individuals Present a Reduced Visual Attention Span? Evidence from Visual Recognition Tasks of Non-Verbal Multi-Character Arrays

ERIC Educational Resources Information Center

Yeari, Menahem; Isser, Michal; Schiff, Rachel

2017-01-01

A controversy has recently developed regarding the hypothesis that developmental dyslexia may be caused, in some cases, by a reduced visual attention span (VAS). To examine this hypothesis, independent of phonological abilities, researchers tested the ability of dyslexic participants to recognize arrays of unfamiliar visual characters. Employing…

'When is VISION asked too much'?

PubMed

van der Wildt, G J; den Brinker, B P; Wertheim, A H

1995-01-01

The last two decades a shift took place from substitutional/compensatory training to utilisation of residual vision regarding rehabilitation of the visually impaired. Some of the visually impaired are able to use their visual perception nearly as complete as normal seeing people in spite of a severe visual disability. On the other hand, people with nearly normal functions can be severely visually handicapped. To illustrate this, two cases are presented. The first case is a man, aged 47 years, with a juvenile macular degeneration on both eyes. In spite of a very low visual acuity of less then 0.05, he finished an university education and he is able to maintain himself very well in a leading position in a scientific environment, by using adequate low vision devices. Also for his leisure activities, as photography and speed skating, he relies upon visual perception. The second case is a woman, aged 30 years, with nearly normal visual functions, who is not able to read for longer periods caused by conflicting information from the body- and eye movements, and the visual input. This causes sickness during reading. She is unable to use books for her study and is working with recordings on tape. The results of a comprehensive visual assessment will be related to the specific low vision devices and its use.

Effect of rising atmospheric carbon dioxide concentration on the protein composition of cereal grain.

PubMed

Wroblewitz, Stefanie; Hüther, Liane; Manderscheid, Remy; Weigel, Hans-Joachim; Wätzig, Hermann; Dänicke, Sven

2014-07-16

The present study investigates effects of rising atmospheric CO2 concentration on protein composition of maize, wheat, and barley grain, especially on the fractions prolamins and glutelins. Cereals were grown at different atmospheric CO2 concentrations to simulate future climate conditions. Influences of two nitrogen fertilization levels were studied for wheat and barley. Enriched CO2 caused an increase of globulin and B-hordein of barley. In maize, the content of globulin, α-zein, and LMW polymers decreased, whereas total glutelin, zein, δ-zein, and HMW polymers rose. Different N supplies resulted in variations of barley subfractions and wheat globulin. Other environmental influences showed effects on the content of nearly all fractions and subfractions. Variations in starch-protein bodies caused by different CO2 treatments could be visualized by scanning electron microscopy. In conclusion, climate change would have impacts on structural composition of proteins and, consequently, on the nutritional value of cereals.

A high-quality high-fidelity visualization of the September 11 attack on the World Trade Center.

PubMed

Rosen, Paul; Popescu, Voicu; Hoffmann, Christoph; Irfanoglu, Ayhan

2008-01-01

In this application paper, we describe the efforts of a multidisciplinary team towards producing a visualization of the September 11 Attack on the North Tower of New York's World Trade Center. The visualization was designed to meet two requirements. First, the visualization had to depict the impact with high fidelity, by closely following the laws of physics. Second, the visualization had to be eloquent to a nonexpert user. This was achieved by first designing and computing a finite-element analysis (FEA) simulation of the impact between the aircraft and the top 20 stories of the building, and then by visualizing the FEA results with a state-of-the-art commercial animation system. The visualization was enabled by an automatic translator that converts the simulation data into an animation system 3D scene. We built upon a previously developed translator. The translator was substantially extended to enable and control visualization of fire and of disintegrating elements, to better scale with the number of nodes and number of states, to handle beam elements with complex profiles, and to handle smoothed particle hydrodynamics liquid representation. The resulting translator is a powerful automatic and scalable tool for high-quality visualization of FEA results.

Advanced X-Ray Inspection of Reinforced Carbon Composite Materials on the Orbiter Leading Edge Structural Subsystem (LESS)

NASA Technical Reports Server (NTRS)

Hernandez, Jose M.; Berry, Robert F.; Osborn, Robin; Bueno, Clifford; Osterlitz, Mark; Mills, Richard; Morris, Philip; Phalen, Robert; McNab, Jim; Thibodeaux, Tahanie;

[Self-relaxation techniques for glaucoma patients. Significance of autogenic training, hypnosis and music therapy].

PubMed

Bertelmann, T; Strempel, I

2016-02-01

Glaucoma is currently the second most common cause of severe visual impairment and blindness worldwide. Standard pharmaceutical and surgical interventions often fail to prevent progression of glaucomatous optic neuropathy. To evaluate whether adjuvantly applied self-relaxation techniques can significantly impact intraocular pressure, ocular perfusion and the overall mental state of affected patients. A search of the literature was carried out and a comprehensive overview of currently available data is presented. Autogenic training, hypnosis and music therapy can significantly impact intraocular pressure, ocular perfusion and overall mental state of patients suffering from glaucoma. As all of these adjuvant therapeutic options are cost-effective, available almost everywhere and at anytime as well as without any known side effects, they can be useful additional techniques in the overall concept for treating glaucoma patients. Regular ocular examinations by an ophthalmologist are, however, mandatory.

Cyber threat impact assessment and analysis for space vehicle architectures

NASA Astrophysics Data System (ADS)

McGraw, Robert M.; Fowler, Mark J.; Umphress, David; MacDonald, Richard A.

2014-06-01

This paper covers research into an assessment of potential impacts and techniques to detect and mitigate cyber attacks that affect the networks and control systems of space vehicles. Such systems, if subverted by malicious insiders, external hackers and/or supply chain threats, can be controlled in a manner to cause physical damage to the space platforms. Similar attacks on Earth-borne cyber physical systems include the Shamoon, Duqu, Flame and Stuxnet exploits. These have been used to bring down foreign power generation and refining systems. This paper discusses the potential impacts of similar cyber attacks on space-based platforms through the use of simulation models, including custom models developed in Python using SimPy and commercial SATCOM analysis tools, as an example STK/SOLIS. The paper discusses the architecture and fidelity of the simulation model that has been developed for performing the impact assessment. The paper walks through the application of an attack vector at the subsystem level and how it affects the control and orientation of the space vehicle. SimPy is used to model and extract raw impact data at the bus level, while STK/SOLIS is used to extract raw impact data at the subsystem level and to visually display the effect on the physical plant of the space vehicle.

Spatial Disorientation in Military Vehicles: Causes, Consequences and Cures (Desorientation spaiale dans les vehicules militaires: causes, consequences et remedes)

DTIC Science & Technology

2003-02-01

servcice warfighters (Training devices and protocols, Onboard equipment, Cognitive and sensorimotor aids, Visual and auditory symbology, Peripheral visual...vestibular stimulation causing a decrease in cerebral blood pressure with the consequent reduction in G-tolerance and increased likelihood of ALOC or GLOC...tactile stimulators (e.g. one providing a sensation of movement) or of displays with a more complex coding (e.g. by increase in the number of tactors, or

Comparing the Impact of Refractive and Non-Refractive Vision Loss on Functioning and Disability: The Salisbury Eye Evaluation

PubMed Central

Zebardast, Nazlee; Swenor, Bonnielin K.; van Landingham, Suzanne W.; Massof, Robert W.; Munoz, Beatriz; West, Sheila K.; Ramulu, Pradeep Y.

2015-01-01

Purpose To compare the effects of uncorrected refractive error (URE) and non-refractive visual impairment (VI) on performance and disability measures. Design Cross-sectional population-based study. Participants 2469 individuals with binocular presenting visual acuity (PVA) of 20/80 or better who participated in the first round of the Salisbury Eye Evaluation study. Methods URE was defined as binocular PVA of 20/30 or worse, improving to better than 20/30 with subjective refraction. VI was defined as post-refraction binocular best corrected visual acuity (BCVA) of 20/30 or worse. The visual acuity decrement attributable to VI was calculated as the difference between BCVA and 20/30 while that due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of 1) vision status (VI, URE, or normal vision) using the group with normal vision as reference, and 2) a one-line decrement in acuity due to VI or URE. Main Outcome Measures Objective measures of visual function were obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual difficulty measured by the Activities of Daily Vision (ADV) scale. ADV responses were analyzed using Rasch analysis to determine visual ability. Results Compared to individuals with normal vision, subjects with VI (n=191) had significantly poorer objective and subjective visual functioning in all metrics examined (p<0.05) while subjects with URE (n=132) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation and lower ADV scores (p<0.05), but did not demonstrate slower stair climbing or descent speed. For all functional metrics evaluated, the impact of VI was greater than the impact of URE. The impact of a one-line VA decrement due to VI was associated with greater deficits in mobility measures and driving cessation when compared to a one-line VA decrement due to URE. Conclusions VI is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and non-refractive vision loss should be distinguished in studies evaluating visual disability, and should be understood to have differing consequences. PMID:25813453

Flashes and Floaters.

PubMed

Sharma, Priya; Sridhar, Jayanth; Mehta, Sonia

2015-09-01

Flashes and floaters are common ocular complaints. Flashes refer to aberrations of light that are seen in a patient's field of gaze. The flashes can be of varying sizes, colors, frequency, and durations, depending on the cause. Floaters are another common visual phenomenon caused by particles or debris in the vitreous gel of the eye that cause shadows and thus visual changes, especially against bright backgrounds and in brightly lit environments. Flashes and floaters can occur individually or together. This article discusses common causes of flashes and floaters to help with the triaging and management of these patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion

PubMed Central

Smith, Ross T.; Hunter, Estin V.; Davis, Miles G.; Sterling, Michele; Moseley, G. Lorimer

2017-01-01

Background Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can’t be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. Method In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%–200%—the Motor Offset Visual Illusion (MoOVi)—thus simulating more or less movement than that actually occurring. At 50o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360o immersive virtual reality with and without three-dimensional properties, was also investigated. Results Perception of head movement was dependent on visual-kinaesthetic feedback (p = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Discussion Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and therapy of people with spinal pain. PMID:28243537

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion.

PubMed

Harvie, Daniel S; Smith, Ross T; Hunter, Estin V; Davis, Miles G; Sterling, Michele; Moseley, G Lorimer

2017-01-01

Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can't be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50 o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%-200%-the Motor Offset Visual Illusion (MoOVi)-thus simulating more or less movement than that actually occurring. At 50 o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360 o immersive virtual reality with and without three-dimensional properties, was also investigated. Perception of head movement was dependent on visual-kinaesthetic feedback ( p  = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and therapy of people with spinal pain.

Comparison of visual status of Iranian military and commercial drivers.

PubMed

Ghasemi, Mohammad; Hoseini Yazdi, Seyed Hosein; Heravian, Javad; Jafarzadehpur, Ebrahim; Rezaee, Maryam

2015-04-01

There is no legal requirement for Iranian military truck drivers to undergo regular visual checkups as compared to commercial truck drivers. This study aimed to evaluate the impact of drivers' visual checkups by comparing the visual function of Iranian military and commercial truck drivers. In this comparative cross-sectional study, two hundred military and 200 commercial truck drivers were recruited and their Visual Acuity (VA), Visual Field (VF), color vision and Contrast Sensitivity (CS) were assessed and compared using the Snellen chart, confrontation screening method, D15 test and Pelli-Robson letter chart, respectively. A questionnaire regarding driving exposure and history of motor-vehicle crashes (MVCs) was also filled by drivers. Results were analyzed using an independent samples t-test, one-way ANOVA (assessing difference in number of MVCs across different age groups), chi-square test and Pearson correlation at statistical significance level of P < 0.05. Mean age was 41.6 ± 9.2 for the military truck drivers and 43.4 ± 10.9 for commercial truck drivers (P > 0.05). No significant difference between military and commercial drivers was found in terms of driving experience, number of MVCs, binocular VA, frequency of color vision defects and CS scores. In contrast, the last ocular examination was significantly earlier in military drivers than commercial drivers (P < 0.001). In addition, 4% of military drivers did not meet the national standards to drive as opposed to 2% of commercial drivers. There was a significant but weak correlation between binocular VA and age (r = 0.175, P < 0.001). However, CS showed a significantly moderate correlation with age (r = -0.488, P < 0.001). The absence of legal requirement for regular eye examination in military drivers caused the incompetent drivers to be missed in contrast to commercial drivers. The need for scientific revision of VA standard for Iranian drivers is also discussed. The CS measurement in visual checkups of older drivers deserves to be investigated more thoroughly.

Visual quality assessment of alternative silvicultural practices in upland hardwood management

Treesearch

Tim McDonald; Bryce Stokes

1997-01-01

Visual impacts of forest operations are of increasing concern to forest managers. Tools are available for evaluating, and potentially avoiding, problems in visual quality resulting from poorly designed harvest unit boundaries. One of these visualization tools is applied in comparing various harvest unit shape alternatives in an upland hardwood stand on steeply sloping...

Long-Term Impact of Improving Visualization Abilities of Minority Engineering and Technology Students: Preliminary Results

ERIC Educational Resources Information Center

Study, Nancy E.

2011-01-01

Previous studies found that students enrolled in introductory engineering graphics courses at a historically black university (HBCU) had significantly lower than average test scores on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT) when it was administered during the first week of class. Since the ability to visualize is…

Visual, Motor, and Visual-Motor Integration Difficulties in Students with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Oliver, Kimberly

2013-01-01

Autism spectrum disorders (ASDs) affect 1 in every 88 U.S. children. ASDs have been described as neurological and developmental disorders impacting visual, motor, and visual-motor integration (VMI) abilities that affect academic achievement (CDC, 2010). Forty-five participants (22 ASD and 23 Typically Developing [TD]) 8 to 14 years old completed…

Phonological-orthographic consistency for Japanese words and its impact on visual and auditory word recognition.

PubMed

Hino, Yasushi; Kusunose, Yuu; Miyamura, Shinobu; Lupker, Stephen J

2017-01-01

In most models of word processing, the degrees of consistency in the mappings between orthographic, phonological, and semantic representations are hypothesized to affect reading time. Following Hino, Miyamura, and Lupker's (2011) examination of the orthographic-phonological (O-P) and orthographic-semantic (O-S) consistency for 1,114 Japanese words (339 katakana and 775 kanji words), in the present research, we initially attempted to measure the phonological-orthographic (P-O) consistency for those same words. In contrast to the O-P and O-S consistencies, which were equivalent for kanji and katakana words, the P-O relationships were much more inconsistent for the kanji words than for the katakana words. The impact of kanji words' P-O consistency was then examined in both visual and auditory word recognition tasks. Although there was no effect of P-O consistency in the standard visual lexical-decision task, significant effects were detected in a lexical-decision task with auditory stimuli, in a perceptual identification task using masked visual stimuli, and in a lexical-decision task with degraded visual stimuli. The implications of these results are discussed in terms of the impact of P-O consistency in auditory and visual word recognition. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Stereopsis and amblyopia: A mini-review

PubMed Central

Levi, Dennis M.; Knill, David C.; Bavelier, Daphne

2015-01-01

Amblyopia is a neuro-developmental disorder of the visual cortex that arises from abnormal visual experience early in life. Amblyopia is clinically important because it is a major cause of vision loss in infants and young children. Amblyopia is also of basic interest because it reflects the neural impairment that occurs when normal visual development is disrupted. Amblyopia provides an ideal model for understanding when and how brain plasticity may be harnessed for recovery of function. Over the past two decades there has been a rekindling of interest in developing more effective methods for treating amblyopia, and for extending the treatment beyond the critical period, as exemplified by new clinical trials and new basic research studies. The focus of this review is on stereopsis and its potential for recovery. Impaired stereoscopic depth perception is the most common deficit associated with amblyopia under ordinary (binocular) viewing conditions (Webber & Wood, 2005). Our review of the extant literature suggests that this impairment may have a substantial impact on visuomotor tasks, difficulties in playing sports in children and locomoting safely in older adults. Furthermore, impaired stereopsis may also limit career options for amblyopes. Finally, stereopsis is more impacted in strabismic than in anisometropic amblyopia. Our review of the various approaches to treating amblyopia (patching, perceptual learning, videogames) suggests that there are several promising new approaches to recovering stereopsis in both anisometropic and strabismic amblyopes. However, recovery of stereoacuity may require more active treatment in strabismic than in anisometropic amblyopia. Individuals with strabismic amblyopia have a very low probability of improvement with monocular training; however they fare better with dichoptic training than with monocular training, and even better with direct stereo training. PMID:25637854

Stereopsis and amblyopia: A mini-review.

PubMed

Levi, Dennis M; Knill, David C; Bavelier, Daphne

2015-09-01

Amblyopia is a neuro-developmental disorder of the visual cortex that arises from abnormal visual experience early in life. Amblyopia is clinically important because it is a major cause of vision loss in infants and young children. Amblyopia is also of basic interest because it reflects the neural impairment that occurs when normal visual development is disrupted. Amblyopia provides an ideal model for understanding when and how brain plasticity may be harnessed for recovery of function. Over the past two decades there has been a rekindling of interest in developing more effective methods for treating amblyopia, and for extending the treatment beyond the critical period, as exemplified by new clinical trials and new basic research studies. The focus of this review is on stereopsis and its potential for recovery. Impaired stereoscopic depth perception is the most common deficit associated with amblyopia under ordinary (binocular) viewing conditions (Webber & Wood, 2005). Our review of the extant literature suggests that this impairment may have a substantial impact on visuomotor tasks, difficulties in playing sports in children and locomoting safely in older adults. Furthermore, impaired stereopsis may also limit career options for amblyopes. Finally, stereopsis is more impacted in strabismic than in anisometropic amblyopia. Our review of the various approaches to treating amblyopia (patching, perceptual learning, videogames) suggests that there are several promising new approaches to recovering stereopsis in both anisometropic and strabismic amblyopes. However, recovery of stereoacuity may require more active treatment in strabismic than in anisometropic amblyopia. Individuals with strabismic amblyopia have a very low probability of improvement with monocular training; however they fare better with dichoptic training than with monocular training, and even better with direct stereo training. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Impact of Rope Jumping Exercise on Physical Fitness of Visually Impaired Students

ERIC Educational Resources Information Center

Chen, Chao-Chien; Lin, Shih-Yen

2011-01-01

The main purpose of this study was to investigate the impact of rope jumping exercise on the health-related physical fitness of visually impaired students. The participants' physical fitness was examined before and after the training. The exercise intensity of the experimental group was controlled with Rating of Perceived Exertion (RPE) (values…

The off-road recreation vehicle—visual impacts

Treesearch

Stephen F. McCool

1979-01-01

The off-road recreation vehicle (ORV) has become a major influence on the character of wild landscapes. Visual impacts resulting from ORV use are shaped not only by site-environmental variables, but also by the nature of the recreation experience users seek, The problem is further compounded by conflicts between ORV?s and other recreational uses. Solutions to ORV-...

Harvesting costs and environmental impacts associated with skyline yarding shelterwood harvests and thinning in Appalachian hardwoods

Treesearch

J. E. Baumgras; C. B. LeDoux; J. R. Sherar

1993-01-01

To evaluate the potential for moderating the visual impact and soil disturbance associated with timber harvesting on steep-slope hardwood sites, thinning and shelterwood harvests were conducted with a skyline yarding system. Operations were monitored to document harvesting production, residual stand damage, soil disturbance, and visual quality. Yarding costs for...

Appraising the reliability of visual impact assessment methods

Treesearch

Nickolaus R. Feimer; Kenneth H. Craik; Richard C. Smardon; Stephen R.J. Sheppard

1979-01-01

This paper presents the research approach and selected results of an empirical investigation aimed at the evaluation of selected observer-based visual impact assessment (VIA) methods. The VIA methods under examination were chosen to cover a range of VIA methods currently in use in both applied and research settings. Variation in three facets of VIA methods were...

Hippocampal Modulation of Associative Learning

DTIC Science & Technology

1992-01-01

Improvement of Visual Communication and Its Impact on Spatial Learning. Third Annual Argonne Symposium for Undergraduates in Science, Engineering and...baseline for these observations. PUBLICATIONS: Goldbogen, G., Lerman, Z., Morton, D. and Wallisky, M. An Investigation of the Improvement of Visual ... Communication and Its Impact on Spatial Learning. Third Annual Argonne Symposium for Undergraduates in Science, Engineering and Mathematics (Submitted

Training in Mental Rotation and Spatial Visualization and Its Impact on Orthographic Drawing Performance

ERIC Educational Resources Information Center

Samsudin, Khairulanuar; Rafi, Ahmad; Hanif, Abd Samad

2011-01-01

This paper reports the findings from an experimental study based on the pretest posttest research design that studied mental rotation (MR) and spatial visualization (SV) training outcomes and their impact on orthographic drawing performance. The sample of the study comprised 98 secondary school students (36 girls, 62 boys, Mage = 15.5 years, age…

Potential Visual Impacts of Utility-Scale Solar Energy Development within Solar Energy Zones on Selected Viewpoints in Death Valley and Joshua Tree National Parks, and El Camino Real De Tierra Adentro National Historic Trail

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Robert G.; Abplanalp, Jennifer M.; Cantwell, Brian L.

In connection with the Bureau of Land Management’s (BLM’s) Solar Programmatic Environmental Impact Statement (Solar PEIS), Argonne National Laboratory (Argonne) has conducted an extended visual impact analysis for selected key observation points (KOPs) within three National Park Service (NPS) units located within the 25-mi (40-km) viewshed of four solar energy zones (SEZs) identified in the Solar PEIS. The analysis includes only those NPS units that the Solar PEIS identified as potentially subject to moderate or strong visual contrasts associated with solar development within the SEZs. The NPS units included in the analysis are Death Valley and Joshua Tree National Parksmore » and El Camino Real De Tierra Adentro National Historic Trail. The analysis showed that certain KOPs in each of these NPS units could potentially be subject to major visual contrast and impacts from solar development within the SEZs, but many of the KOPs would likely be subject to moderate, minor, or negligible contrasts and impacts, generally because they were relatively distant from the relevant SEZ, had views of the SEZ partially blocked by intervening terrain, and/or had very low vertical angles of view toward the SEZ. For all three NPS units, power tower facilities were found to be major contributors to potential visual contrasts, primarily because of the long-distance visibility of intensely bright reflection of light from the receivers on the central towers, but also because of the height and strong vertical line of the tower structures and the potential for night-sky impacts from FAA-mandated hazard navigation lighting.« less

The cannabinoid system and visual processing: a review on experimental findings and clinical presumptions.

PubMed

Schwitzer, Thomas; Schwan, Raymund; Angioi-Duprez, Karine; Ingster-Moati, Isabelle; Lalanne, Laurence; Giersch, Anne; Laprevote, Vincent

2015-01-01

Cannabis is one of the most prevalent drugs used worldwide. Regular cannabis use is associated with impairments in highly integrative cognitive functions such as memory, attention and executive functions. To date, the cerebral mechanisms of these deficits are still poorly understood. Studying the processing of visual information may offer an innovative and relevant approach to evaluate the cerebral impact of exogenous cannabinoids on the human brain. Furthermore, this knowledge is required to understand the impact of cannabis intake in everyday life, and especially in car drivers. Here we review the role of the endocannabinoids in the functioning of the visual system and the potential involvement of cannabis use in visual dysfunctions. This review describes the presence of the endocannabinoids in the critical stages of visual information processing, and their role in the modulation of visual neurotransmission and visual synaptic plasticity, thereby enabling them to alter the transmission of the visual signal. We also review several induced visual changes, together with experimental dysfunctions reported in cannabis users. In the discussion, we consider these results in relation to the existing literature. We argue for more involvement of public health research in the study of visual function in cannabis users, especially because cannabis use is implicated in driving impairments. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

Cerebral visual impairment in children: Causes and associated ophthalmological problems.

PubMed

Pehere, Niranjan; Chougule, Pratik; Dutton, Gordon N

2018-06-01

The aim of this study is to identify common causes, associated ophthalmological abnormalities, and systemic comorbidities in children in Andhra Pradesh, India, with cerebral visual impairment (CVI). A retrospective review of case records of all children aged <16 years with diagnosis of CVI seen between January 2016 and December 2016 was carried out. Data were collected for their age, gender, cause of CVI, refraction, accommodation, anterior and posterior segment examination findings, and systemic problems. A total of 124 patients were identified and studied (80 boys and 44 girls, mean age 5.23 years, 44.8% aged <2 years). The most common causes of CVI were hypoxic-ischemic encephalopathy (HIE) (34.4%), undetermined etiology (32.8%), neonatal seizures, and infantile spasms (16% each). The most common presenting complaints were poor vision (76%) and squint (11.2%). Profound visual impairment was seen in 88.8%, and 11.2% had high functioning CVI. Fifty-eight (46.4%) patients had significant refractive errors, 40 (32.25%) had strabismus, 4 (3.2%) had visually significant cataract, and 40 (32%) had optic atrophy. Motor delay was observed in 39.5%, speech delay was evident in 22.4%, and cognitive delay in 16%. HIE is the most common cause (one-third) of CVI in our population, and the majority of them presented at age <2 years (44.8%) with profound visual impairment (88.8%). A significant number of them have treatable ophthalmic conditions such as refractive errors (46.4%), accommodative insufficiency (12.1%), and cataract (3.2%), and more than one-third of them also have delay in other areas of development.

Presumed topiramate retinopathy: a case report.

PubMed

Yeung, Tiffany L M; Li, Patrick S H; Li, Kenneth K W

2016-08-01

We report a case of peripheral pigmentary retinopathy and visual field loss following topiramate use for uncontrolled seizures. Such side effects have not been well documented despite the increasing use of topiramate in the past 10 years. A thorough search of available English literature revealed only a small number of reports of topiramate-induced retinopathy or visual field defects in humans. One similar case has been described. We are concerned about the possible rare instances of this occurrence in future patients and hence would like to propose a presumed correlation. A 48-year-old Chinese woman developed blurred vision after 9 months of topiramate use. Her visual acuity dropped from 1.2 to 0.7 in both eyes, with bilateral diffuse pigmentary retinopathy and a constricted visual field. Despite an improvement in visual acuity after cessation of the drug, the other clinical findings remained. The temporal relationship between the initiation of topiramate and the visual disturbance suggests that topiramate could be the cause of such signs and symptoms. Topiramate potentially causes pigmentary retinopathy and constricted visual field.

Delayed visual attention caused by high myopic refractive error.

PubMed

Winges, Kimberly M; Zarpellon, Ursula; Hou, Chuan; Good, William V

2005-06-01

Delayed visual maturation (DVM) is usually a retrospective diagnosis given to infants who are born with no or poor visually-directed behavior, despite normal acuity on objective testing, but who recover months later. This condition can be organized into several types based on associated neurodevelopmental or ocular findings, but the etiology of DVM is probably complex and involves multiple possible origins. Here we report two infants who presented with delayed visual maturation (attention). They were visually unresponsive at birth but were later found to have high myopic errors. Patient 1 had -4 D right eye, -5 D left eye. Patient 2 had -9 D o.u. Upon spectacle correction at 5 and 4 months, respectively, both infants immediately displayed visually-directed behavior, suggesting that a high refractive error was the cause of inattention in these patients. These findings could add to knowledge surrounding DVM and the diagnosis of apparently blind infants. Findings presented here also indicate the importance of prompt refractive error measurement in such cases.

Intense illumination in the morning hours improved mood and alertness but not mental performance.

PubMed

Leichtfried, Veronika; Mair-Raggautz, Maria; Schaeffer, Viktoria; Hammerer-Lercher, Angelika; Mair, Gerald; Bartenbach, Christian; Canazei, Markus; Schobersberger, Wolfgang

2015-01-01

Cognitive performance and alertness are two determinants for work efficiency, varying throughout the day and depending on bright light. We conducted a prospective crossover study evaluating the impacts of exposure to an intense, early morning illumination on sustained attention, alertness, mood, and serum melatonin levels in 33 healthy individuals. Compared with a dim illumination, the intense illumination negatively impacted performance requiring sustained attention; however, it positively impacted subjective alertness and mood and had no impact on serum melatonin levels. These results suggest that brief exposure to bright light in the morning hours can improve subjective measures of mood and alertness, but can also have detrimental effects on mental performance as a result of visual distraction. Therefore, it is important that adequate lighting should correspond to both non-visual and visual demands. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The economic impact of poor sample quality in clinical chemistry laboratories: results from a global survey.

PubMed

Erdal, Erik P; Mitra, Debanjali; Khangulov, Victor S; Church, Stephen; Plokhoy, Elizabeth

2017-03-01

Background Despite advances in clinical chemistry testing, poor blood sample quality continues to impact laboratory operations and the quality of results. While previous studies have identified the preanalytical causes of lower sample quality, few studies have examined the economic impact of poor sample quality on the laboratory. Specifically, the costs associated with workarounds related to fibrin and gel contaminants remain largely unexplored. Methods A quantitative survey of clinical chemistry laboratory stakeholders across 10 international regions, including countries in North America, Europe and Oceania, was conducted to examine current blood sample testing practices, sample quality issues and practices to remediate poor sample quality. Survey data were used to estimate costs incurred by laboratories to mitigate sample quality issues. Results Responses from 164 participants were included in the analysis, which was focused on three specific issues: fibrin strands, fibrin masses and gel globules. Fibrin strands were the most commonly reported issue, with an overall incidence rate of ∼3%. Further, 65% of respondents indicated that these issues contribute to analyzer probe clogging, and the majority of laboratories had visual inspection and manual remediation practices in place to address fibrin- and gel-related quality problems (55% and 70%, respectively). Probe maintenance/replacement, visual inspection and manual remediation were estimated to carry significant costs for the laboratories surveyed. Annual cost associated with lower sample quality and remediation related to fibrin and/or gel globules for an average US laboratory was estimated to be $100,247. Conclusions Measures to improve blood sample quality present an important step towards improved laboratory operations.

Beyond Our Fears: Conversations with Veteran Artists about Their Dedication to Visual Art Making

ERIC Educational Resources Information Center

Puffer, Kristine Widmer

2011-01-01

This study examines the reactions of veteran artists to some issues associated with the process of creating visual art that can cause fear, fear significant enough to derail many professional artists and cause them to quit making art altogether. Based on the writings of Bayles and Orland and enhanced by J. M. Erikson, this study provides insight…

Characteristics, Causes, and Evaluation of Helicopter Particulate Visual Obstruction

DTIC Science & Technology

2012-09-10

future full-scale testing. The thrust sources examined were a 1 in. diameter nozzle , a 4 in. diameter nozzle , and a 16 in. ducted fan. The sources...Hiller also evaluated inclining the thrust vector , and determined there was little reduction in dynamic pressure at the point of ground interaction...CHARACTERISTICS, CAUSES, AND EVALUATION OF HELICOPTER PARTICULATE VISUAL OBSTRUCTION THESIS

Sleep Disturbances among Persons Who Are Visually Impaired: Survey of Dog Guide Users.

ERIC Educational Resources Information Center

Fouladi, Massoud K.; Moseley, Merrick J.; Jones, Helen S.; Tobin, Michael J.

1998-01-01

A survey completed by 1237 adults with severe visual impairments found that 20% described the quality of their sleep as poor or very poor. Exercise was associated with better sleep and depression with poorer sleep. However, visual acuity did not predict sleep quality, casting doubt on the idea that restricted visual input (light) causes sleep…

Neuro-Ophthalmological Disorders in Cerebral Palsy: Ophthalmological, Oculomotor, and Visual Aspects

ERIC Educational Resources Information Center

Fazzi, Elisa; Signorini, Sabrina G.; La Piana, Roberta; Bertone, Chiara; Misefari, Walter; Galli, Jessica; Balottin, Umberto; Bianchi, Paolo Emilio

2012-01-01

Aim: Cerebral visual impairment (CVI) is a disorder caused by damage to the retrogeniculate visual pathways. Cerebral palsy (CP) and CVI share a common origin: 60 to 70% of children with CP also have CVI. We set out to describe visual dysfunction in children with CP. A further aim was to establish whether different types of CP are associated with…

Ageing vision and falls: a review.

PubMed

Saftari, Liana Nafisa; Kwon, Oh-Sang

2018-04-23

Falls are the leading cause of accidental injury and death among older adults. One of three adults over the age of 65 years falls annually. As the size of elderly population increases, falls become a major concern for public health and there is a pressing need to understand the causes of falls thoroughly. While it is well documented that visual functions such as visual acuity, contrast sensitivity, and stereo acuity are correlated with fall risks, little attention has been paid to the relationship between falls and the ability of the visual system to perceive motion in the environment. The omission of visual motion perception in the literature is a critical gap because it is an essential function in maintaining balance. In the present article, we first review existing studies regarding visual risk factors for falls and the effect of ageing vision on falls. We then present a group of phenomena such as vection and sensory reweighting that provide information on how visual motion signals are used to maintain balance. We suggest that the current list of visual risk factors for falls should be elaborated by taking into account the relationship between visual motion perception and balance control.

[Prevalence of low visual acuity and ophthalmological disorders in six-year-old children from Santa Fe city].

PubMed

Verrone, Pablo J; Simi, Marcelo R

2008-08-01

Changes in children visual acuity that are not treated carry a high risk of irreversible consequences. To determine the prevalence of low visual acuity and to diagnose the ophthalmologic diseases that cause it in six-year-old children from Santa Fe City, Argentina. Observational, descriptive and transversal design. Visual acuity is defined as the eye's capacity to distinguish separate points and to recognize shapes. It was determined using the Snellen table for farsighted vision on 177 six-year-old children who attended four elementary schools in Santa Fe City. An ophthalmologic examination was performed on those who had low visual acuity and their mothers were interviewed to ascertain the pathological background of their children. The prevalence of low visual acuity was 10.7% (n= 19). The prevalence of amblyopia was 3.9%. Refraction errors were the only cause of low visual acuity. Astigmatism was predominantly frequent. The most frequent pathological backgrounds were: ocular infections, premature birth, history of malnutrition and maternal use of tobacco. The prevalence of low visual acuity found in this study is lower than the one informed in most other studies. This data require confirmation by further studies.

Conservation implications of anthropogenic impacts on visual communication and camouflage.

PubMed

Delhey, Kaspar; Peters, Anne

2017-02-01

Anthropogenic environmental impacts can disrupt the sensory environment of animals and affect important processes from mate choice to predator avoidance. Currently, these effects are best understood for auditory and chemosensory modalities, and recent reviews highlight their importance for conservation. We examined how anthropogenic changes to the visual environment (ambient light, transmission, and backgrounds) affect visual communication and camouflage and considered the implications of these effects for conservation. Human changes to the visual environment can increase predation risk by affecting camouflage effectiveness, lead to maladaptive patterns of mate choice, and disrupt mutualistic interactions between pollinators and plants. Implications for conservation are particularly evident for disrupted camouflage due to its tight links with survival. The conservation importance of impaired visual communication is less documented. The effects of anthropogenic changes on visual communication and camouflage may be severe when they affect critical processes such as pollination or species recognition. However, when impaired mate choice does not lead to hybridization, the conservation consequences are less clear. We suggest that the demographic effects of human impacts on visual communication and camouflage will be particularly strong when human-induced modifications to the visual environment are evolutionarily novel (i.e., very different from natural variation); affected species and populations have low levels of intraspecific (genotypic and phenotypic) variation and behavioral, sensory, or physiological plasticity; and the processes affected are directly related to survival (camouflage), species recognition, or number of offspring produced, rather than offspring quality or attractiveness. Our findings suggest that anthropogenic effects on the visual environment may be of similar importance relative to conservation as anthropogenic effects on other sensory modalities. © 2016 Society for Conservation Biology.

Contingency Analysis Post-Processing With Advanced Computing and Visualization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yousu; Glaesemann, Kurt; Fitzhenry, Erin

Contingency analysis is a critical function widely used in energy management systems to assess the impact of power system component failures. Its outputs are important for power system operation for improved situational awareness, power system planning studies, and power market operations. With the increased complexity of power system modeling and simulation caused by increased energy production and demand, the penetration of renewable energy and fast deployment of smart grid devices, and the trend of operating grids closer to their capacity for better efficiency, more and more contingencies must be executed and analyzed quickly in order to ensure grid reliability andmore » accuracy for the power market. Currently, many researchers have proposed different techniques to accelerate the computational speed of contingency analysis, but not much work has been published on how to post-process the large amount of contingency outputs quickly. This paper proposes a parallel post-processing function that can analyze contingency analysis outputs faster and display them in a web-based visualization tool to help power engineers improve their work efficiency by fast information digestion. Case studies using an ESCA-60 bus system and a WECC planning system are presented to demonstrate the functionality of the parallel post-processing technique and the web-based visualization tool.« less

Quality of life and visual function in Nigeria: findings from the National Survey of Blindness and Visual Impairment.

PubMed

Tran, Hang My; Mahdi, Abdull M; Sivasubramaniam, Selvaraj; Gudlavalleti, Murthy V S; Gilbert, Clare E; Shah, Shaheen P; Ezelum, C C; Abubakar, Tafida; Bankole, Olufunmilayo O

2011-12-01

To assess associations of visual function (VF) and quality of life (QOL) by visual acuity (VA), causes of blindness and types of cataract procedures in Nigeria. Multi-stage stratified cluster random sampling was used to identify a nationally representative sample of persons aged ≥ 40 years. VF/QOL questionnaires were administered to participants with VA <6/60 in one or both eyes and/or Mehra-Minassian cataract grade 2B or 3 in one or both eyes and a random sample of those with bilateral VA ≥ 6/12. VF/QOL questionnaires were administered to 2076 participants. Spearman's rank correlation showed a strong correlation between decreasing VA and VF/QOL scores (p<0.0001) with greatest impact on social (p<0.0001) and mobility-related activities (p<0.0001). People who were blind due to glaucoma had lower VF and QOL scores than those who were blind due to cataract. Mean VF and QOL scores were lower after couching compared with conventional cataract surgery (mean VF score=51.0 vs 63.0 and mean QOL score=71.3 vs 79.3). Finally, VF and QOL scores were lower among populations with specific characteristics. Populations with the following characteristics should be targeted to improve VF and QOL: people who are blind, older people, women, manual labourers, people living in rural areas, those living in the northern geopolitical zones, those practising Islamic and Traditionalism faith, those not currently married and those who have undergone couching.

[Methods for estimating personal costs of disease using retinal diseases as an example].

PubMed

Porz, G; Scholl, H P N; Holz, F G; Finger, R P

2010-03-01

Age-related macular degeneration (AMD) and other retinal diseases, such as diabetic retinopathy (DRP) and hereditary retinal dystrophy can not only lead to a loss of visual function but also to a higher psychological and financial burden for the affected persons. Against this background a quantification of personal cost and vision-related quality of life was performed. A total of 66 patients (mean age 69 years, SD 13 years) with clinically confirmed diagnoses of AMD, DRP or retinal dystrophy were interviewed regarding costs for medicines, aids and equipment, support in everyday life and social benefits. Vision-related quality of life was recorded using the Impact of Vision Impairment profile (IVI). The average total annual cost was 751 per patient, out of which the largest amount was cost of support in everyday life (506). Costs as well as dependence on other persons or social services increased with decreasing visual acuity (p=0.013). Vision-related quality of life decreased with increasing visual disability especially in the IVI subscales mobility and independence as well as reading and accessing information (p=0.002). Prevention or delay of visual disability and blindness caused by AMD or other retinal diseases and thus ensuring independence is not only relevant from a medical perspective but also from a health economic perspective. Against the background of a relative shortage of resources, costs should be reduced regardless of whether they are personal or societal costs.

Lawn mower injuries as a cause of serious visual acuity impairment - Case reports.

PubMed

Jasielska, Monika; Winiarczyk, Mateusz; Bieliński, Paweł; Mackiewicz, Jerzy

2017-05-11

[b]Abstract Objective.[/b] The aim of the study is to present four cases of lawn mowers injuries as a cause of serious visual acuity impairment. [b]Materials and Method[/b]. A retrospective study of four patients admitted in 2013-2015 to the Department of Vitreoretinal Surgery in Lublin with severe open or closed globe injury, one with an intraocular foreign body (IOFB). The presence of eye protective equipment was assessed, as well as visual acuity, eye tissue condition before and after treatment, and applied therapy. In all cases an improvement was achieved in local conditions. The intraocular foreign body was removed, wounds sutured and damaged tissues placed in position. All eyeballs were saved. In three cases, visual acuity was improved to a usable level. Three patients underwent pars plana vitrectomy, one with IOFB removal from the vitreous cavity. [b]Conclusions[/b]. Lawn mower induced eye injuries are a significant cause of serious visual acuity impairment or blindness. The presented study shows that lawn mower eye injuries are still a therapeutic, social and economic problem, yet are very preventable with proper eye protection and patients' education. Current prevention strategies are inadequate, and therefore should be updated.

Visualizing interconnections among climate risks

NASA Astrophysics Data System (ADS)

Tanaka, K.; Yokohata, T.; Nishina, K.; Takahashi, K.; Emori, S.; Kiguchi, M.; Iseri, Y.; Honda, Y.; Okada, M.; Masaki, Y.; Yamamoto, A.; Shigemitsu, M.; Yoshimori, M.; Sueyoshi, T.; Hanasaki, N.; Ito, A.; Sakurai, G.; Iizumi, T.; Nishimori, M.; Lim, W. H.; Miyazaki, C.; Kanae, S.; Oki, T.

2015-12-01

It is now widely recognized that climate change is affecting various sectors of the world. Climate change impact on one sector may spread out to other sectors including those seemingly remote, which we call "interconnections of climate risks". While a number of climate risks have been identified in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5), there has been no attempt to explore their interconnections comprehensively. Here we present a first and most exhaustive visualization of climate risks drawn based on a systematic literature survey. Our risk network diagrams depict that changes in the climate system impact natural capitals (terrestrial water, crop, and agricultural land) as well as social infrastructures, influencing the socio-economic system and ultimately our access to food, water, and energy. Our findings suggest the importance of incorporating climate risk interconnections into impact and vulnerability assessments and call into question the widely used damage function approaches, which address a limited number of climate change impacts in isolation. Furthermore, the diagram is useful to educate decision makers, stakeholders, and general public about cascading risks that can be triggered by the climate change. Socio-economic activities today are becoming increasingly more inter-dependent because of the rapid technological progress, urbanization, and the globalization among others. Equally complex is the ecosystem that is susceptible to climate change, which comprises interwoven processes affecting one another. In the context of climate change, a number of climate risks have been identified and classified according to regions and sectors. These reports, however, did not fully address the inter-relations among risks because of the complexity inherent in this issue. Climate risks may ripple through sectors in the present inter-dependent world, posing a challenge ahead of us to maintain the resilience of the system. It is therefore imperative to improve our understanding on how climate change may induce a chain of impacts. Our study is a first step toward this goal by mapping out climate risks and their cause-effect relationships based on current literature.

Clinical approach to optic neuropathies

PubMed Central

Behbehani, Raed

2007-01-01

Optic neuropathy is a frequent cause of vision loss encountered by ophthalmologist. The diagnosis is made on clinical grounds. The history often points to the possible etiology of the optic neuropathy. A rapid onset is typical of demyelinating, inflammatory, ischemic and traumatic causes. A gradual course points to compressive, toxic/nutritional and hereditary causes. The classic clinical signs of optic neuropathy are visual field defect, dyschromatopsia, and abnormal papillary response. There are ancillary investigations that can support the diagnosis of optic neuropathy. Visual field testing by either manual kinetic or automated static perimetry is critical in the diagnosis. Neuro-imaging of the brain and orbit is essential in many optic neuropathies including demyelinating and compressive. Newer technologies in the evaluation of optic neuropathies include multifocal visual evoked potentials and optic coherence tomography. PMID:19668477

Prevalence, Causes and Social Factors of Visual Impairment among Chinese Adults: Based on a National Survey.

PubMed

Guo, Chao; Wang, Zhenjie; He, Ping; Chen, Gong; Zheng, Xiaoying

2017-09-08

Visual impairment has become a global challenge, especially for developing countries. This study aims to estimate the prevalence, causes and social factors of visual impairment among Chinese adults. Data were from a nationally representative population-based cross-sectional study. The study population were 1,909,199 non-institutionalized adults aged 18 years and older in mainland China. In the survey, low vision and blindness were checked by ophthalmologists according to the WHO best-corrected visual acuity (BCVA) criteria. Population weighted numbers and prevalence of low vision and blindness with 95% confidence intervals (CIs) were estimated where appropriate. Multivariable logistic regression analysis was used to identify the social factors of visual impairment. The weighted prevalence of visual impairment was 17.17 (95% CI, 16.84-17.50) per 1000 Chinese adults aged 18 years and older. Cataract (57.35%), disorders of choroid and retina (9.80%), and disorders of cornea (6.49%) contributed more than 70 percent to the visual impairment in Chinese adults. Older age groups, young or middle-aged male adults, female elders, illiterate, rural dwellers, non-eastern residents, singles, unemployment, and from family with lower income were associated with visual impairment. More efforts are warranted to enhance treatment and rehabilitation among people with eye disorders to prevent visual impairment.

Prevalence, Causes and Social Factors of Visual Impairment among Chinese Adults: Based on a National Survey

PubMed Central

Wang, Zhenjie; He, Ping; Chen, Gong; Zheng, Xiaoying

2017-01-01

Visual impairment has become a global challenge, especially for developing countries. This study aims to estimate the prevalence, causes and social factors of visual impairment among Chinese adults. Data were from a nationally representative population-based cross-sectional study. The study population were 1,909,199 non-institutionalized adults aged 18 years and older in mainland China. In the survey, low vision and blindness were checked by ophthalmologists according to the WHO best-corrected visual acuity (BCVA) criteria. Population weighted numbers and prevalence of low vision and blindness with 95% confidence intervals (CIs) were estimated where appropriate. Multivariable logistic regression analysis was used to identify the social factors of visual impairment. The weighted prevalence of visual impairment was 17.17 (95% CI, 16.84–17.50) per 1000 Chinese adults aged 18 years and older. Cataract (57.35%), disorders of choroid and retina (9.80%), and disorders of cornea (6.49%) contributed more than 70 percent to the visual impairment in Chinese adults. Older age groups, young or middle-aged male adults, female elders, illiterate, rural dwellers, non-eastern residents, singles, unemployment, and from family with lower income were associated with visual impairment. More efforts are warranted to enhance treatment and rehabilitation among people with eye disorders to prevent visual impairment. PMID:28885571

The Visual Syntax of Algebra.

ERIC Educational Resources Information Center

Kirshner, David

1989-01-01

A structured system of visual features is seen to parallel the propositional hierarchy of operations usually associated with the parsing of algebraic expressions. Women more than men were found to depend on these visual cues. Possible causes and consequences are discussed. Subjects were secondary and college students. (Author/DC)

Auditory Emotional Cues Enhance Visual Perception

ERIC Educational Resources Information Center

Zeelenberg, Rene; Bocanegra, Bruno R.

2010-01-01

Recent studies show that emotional stimuli impair performance to subsequently presented neutral stimuli. Here we show a cross-modal perceptual enhancement caused by emotional cues. Auditory cue words were followed by a visually presented neutral target word. Two-alternative forced-choice identification of the visual target was improved by…

Visual Arts and Academic Achievement

ERIC Educational Resources Information Center

Gibson, Marcia A.; Larson, Meredith A.

2007-01-01

The focus on academic performance testing in elementary schools has caused a decrease in student experience in the arts. Visual arts (drawing, painting, sculpture, and collage) have been minimized in elementary schools. Without exposure to the special avenues of cognitive development and personal expression nurtured by visual arts, students are…

Scaffolding Learning from Molecular Visualizations

ERIC Educational Resources Information Center

Chang, Hsin-Yi; Linn, Marcia C.

2013-01-01

Powerful online visualizations can make unobservable scientific phenomena visible and improve student understanding. Instead, they often confuse or mislead students. To clarify the impact of molecular visualizations for middle school students we explored three design variations implemented in a Web-based Inquiry Science Environment (WISE) unit on…

Effect of Conus Eccentricity on Visual Outcomes After Intracorneal Ring Segments Implantation in Keratoconus.

PubMed

Gatzioufas, Zisis; Panos, Georgios D; Elalfy, Mohamed; Khine, Aye; Hamada, Samer; Lake, Damian; Kozeis, Nikos; Balidis, Miltos

2018-03-01

To investigate the potential impact of cone eccentricity on visual outcomes after Keraring (Mediphacos, Belo Horizonte, Brazil) implantation for keratoconus. Nineteen eyes from 19 patients with keratoconus who underwent femtosecond laser-assisted Keraring implantation for keratoconus were included in this retrospective study. Uncorrected visual acuity (UDVA), corrected visual acuity (CDVA), keratometric readings, central corneal thickness, maximum keratometric distance from corneal apex (DKmax), corneal thinnest point from corneal apex (DTh), and coma were evaluated preoperatively and 6 months after the Keraring implantation. DKmax and DTh were used as metrics reflecting the eccentricity of the cone. UDVA, CDVA, keratometric readings, and coma improved at 6 months postoperatively. However, there was no correlation between DKmax or DTh and visual outcomes at 6 months postoperatively. The data did not show any impact of the cone eccentricity on visual outcomes after Keraring implantation for keratoconus at 6 months postoperatively. [J Refract Surg. 2018;34(3):196-200.]. Copyright 2018, SLACK Incorporated.

The Critical Role of Cyberinfrastructure in Global Observations of Natural Hazards

NASA Astrophysics Data System (ADS)

Orcutt, J. A.

2005-12-01

This past year has brought grave lessons about the critical risks posed by natural hazards. The Sumatra earthquake and resultant tsunami causing as many as 300,000 deaths, and Hurricane Katrina and its destruction of the Gulf Coast in Louisiana and Mississippi with an unknown loss of life and infrastructure damage that may approach $100,000,000,000 in rebuilding costs, have been shattering experiences. The Sumatra earthquake reminds us of the tsunami threat we face in Cascadia and news about the avian flu in the orient and its potential transmission to and between humans threatens to bring a natural disaster that can dwarf either of this year's disasters. All of these phenomena have their roots in the geosciences. While the threats of terrorism have dominated political discussions globally for the past few years, the growing impact of natural hazards, including the long-term impact of a potentially changing climate, require that geoscientists develop globally distributed observing systems critically important in mitigating the societal impacts of these hazards. This is particularly important for the AGU, the largest professional geosciences organization in the world today. One of the lessons learned during the past year, however, is that accessing the data and information needed to predict and subsequently understand the impact of hazards is difficult requiring more time than can generally be afforded. For the AGU, the new Focus Group on Earth and Space Science Informatics has an important role in bringing modern methods in information technology, computer sciences, and cyberinfrastructure to the problem of providing coherent access to near-real-time data from the growing suite of Earth observations, the use of the data in model assimilation, the transformation of data to knowledge, and the visualization of the results for use by those responsible for managing the damage caused by these natural hazards. While the challenge is enormous, there is considerable promise in a number of new approaches from the Global Earth Observing System of Systems (GEOSS) to the Ocean Observatories Initiative (OOI) and a powerful suite of Earth observations from space. New grid technologies in the computer sciences, the ability to link globally distributed sites at bandwidths of 10-40 Gbps, couple sensor networks across vast spatial scales, and visualize data at 100Megapixel resolutions make the use of data and information for mitigating growing natural hazards practical.

Negative Correlations in Visual Cortical Networks

PubMed Central

Chelaru, Mircea I.; Dragoi, Valentin

2016-01-01

The amount of information encoded by cortical circuits depends critically on the capacity of nearby neurons to exhibit trial-to-trial (noise) correlations in their responses. Depending on their sign and relationship to signal correlations, noise correlations can either increase or decrease the population code accuracy relative to uncorrelated neuronal firing. Whereas positive noise correlations have been extensively studied using experimental and theoretical tools, the functional role of negative correlations in cortical circuits has remained elusive. We addressed this issue by performing multiple-electrode recording in the superficial layers of the primary visual cortex (V1) of alert monkey. Despite the fact that positive noise correlations decayed exponentially with the difference in the orientation preference between cells, negative correlations were uniformly distributed across the population. Using a statistical model for Fisher Information estimation, we found that a mild increase in negative correlations causes a sharp increase in network accuracy even when mean correlations were held constant. To examine the variables controlling the strength of negative correlations, we implemented a recurrent spiking network model of V1. We found that increasing local inhibition and reducing excitation causes a decrease in the firing rates of neurons while increasing the negative noise correlations, which in turn increase the population signal-to-noise ratio and network accuracy. Altogether, these results contribute to our understanding of the neuronal mechanism involved in the generation of negative correlations and their beneficial impact on cortical circuit function. PMID:25217468

Developing Local Scale, High Resolution, Data to Interface with Numerical Hurricane Models

NASA Astrophysics Data System (ADS)

Witkop, R.; Becker, A.

2017-12-01

In 2017, the University of Rhode Island's (URI's) Graduate School of Oceanography (GSO) developed hurricane models that specify wind speed, inundation, and erosion around Rhode Island with enough precision to incorporate impacts on individual facilities. At the same time, URI's Marine Affairs Visualization Lab (MAVL) developed a way to realistically visualize these impacts in 3-D. Since climate change visualizations and water resource simulations have been shown to promote resiliency action (Sheppard, 2015) and increase credibility (White et al., 2010) when local knowledge is incorporated, URI's hurricane models and visualizations may also more effectively enable hurricane resilience actions if they include Facility Manager (FM) and Emergency Manager (EM) perceived hurricane impacts. This study determines how FM's and EM's perceive their assets as being vulnerable to quantifiable hurricane-related forces at the individual facility scale while exploring methods to elicit this information from FMs and EMs in a format usable for incorporation into URI GSO's hurricane models.

[Prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in Shuangcheng City of Heilongjiang Province: the China Nine-Province Survey].

PubMed

Zhang, Liqiong; Cui, Hao; Zhao, Jialiang; Ellwein, Leon B; Li, Zhijian; Li, Mingsheng; Yu, Nannan; Wang, Yu; Gao, Xuecheng

2014-03-01

To investigate the prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in Shuangcheng City of Heilongjiang Province, China. It was a population-based cross-section study. Geographically defined cluster sampling was used in randomly selecting 5 841 individuals aged 50 years or above in 28 basic sample units in Shuangcheng City from September to December 2006. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated through village registers followed door-to-door visits.Eligible individuals were invited to receive visual acuity measurement and eye examination. Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity. Five thousands four hundreds and eighty-one individuals were enumerated and 5 047 persons were examined, the response rate was 92.08%. Based on the criteria of World Health Organization visual impairment classification in 1973, the prevalence of blindness and moderate and severe visual impairment defined as best corrected visual acuity was 1.72% (87/5 047) and 4.69% (237/5 047) respectively. The prevalence of blindness and moderate and severe visual impairment defined as presenting visual acuity was 1.90% (96/5 047) and 7.23% (365/5 047) respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (trend χ(2)=674.44, P < 0.01), female (χ(2)=39.61, P < 0.01) and illiterate (trend χ(2)=142.82, P < 0.01) persons. Cataract (52.70%) was still the first leading cause of blindness and visual impairment. The percentage of the retinal diseases, including age-related macular degeneration, high myopic retinopathy and diabetic retinopathy was 11.31% among the eyes with blindness and moderate and severe visual impairment. Un-corrected refractive error(13.38%) also was the main cause of visual impairment. The prevalence of blindness and moderate and severe visual impairment in Shuangcheng City is relatively higher in China Nine Province Survey. Cataract, retinal diseases and un-corrected refractive error are the main causes of the blindness and moderate and severe visual impairment.

How to Make a Good Animation: A Grounded Cognition Model of How Visual Representation Design Affects the Construction of Abstract Physics Knowledge

ERIC Educational Resources Information Center

Chen, Zhongzhou; Gladding, Gary

2014-01-01

Visual representations play a critical role in teaching physics. However, since we do not have a satisfactory understanding of how visual perception impacts the construction of abstract knowledge, most visual representations used in instructions are either created based on existing conventions or designed according to the instructor's intuition,…

Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals.

PubMed

van Boxtel, M P; ten Tusscher, M P; Metsemakers, J F; Willems, B; Jolles, J

2001-10-01

It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

Processing of microencapsulated dyes for the visual inspection of fibre reinforced plastics

NASA Astrophysics Data System (ADS)

Hopmann, Ch.; Kerschbaum, M.; Küsters, K.

2014-05-01

The evaluation of damages caused during processing, assembly or usage of fibre reinforced plastics is still a challenge. The use of inspection technology like ultrasonic scanning enables a detailed damage analysis but requires high investments and trained staff. Therefore, the visual inspection method is widely used. A drawback of this method is the difficult identification of barely visible damages, which can already be detrimental for the structural integrity. Therefore an approach is undertaken to integrate microencapsulated dyes into the laminates of fibre reinforced plastic parts to highlight damages on the surface. In case of a damage, the microcapsules rupture which leads to a release of the dye and a visible bruise on the part surface. To enable a wide application spectrum for this technology the microcapsules must be processable without rupturing with established manufacturing processes for fibre reinforced plastics. Therefore the incorporation of microcapsules in the filament winding, prepreg autoclave and resin transfer moulding (RTM) process is investigated. The results show that the use of a carrier medium is a feasible way to incorporate the microcapsules into the laminate for all investigated manufacturing processes. Impact testing of these laminates shows a bruise formation on the specimen surface which correlates with the impact energy level. This indicates a microcapsule survival during processing and shows the potential of this technology for damage detection and characterization.

Interfering Neighbours: The Impact of Novel Word Learning on the Identification of Visually Similar Words

ERIC Educational Resources Information Center

Bowers, Jeffrey S.; Davis, Colin J.; Hanley, Derek A.

2005-01-01

We assessed the impact of visual similarity on written word identification by having participants learn new words (e.g. BANARA) that were neighbours of familiar words that previously had no neighbours (e.g. BANANA). Repeated exposure to these new words made it more difficult to semantically categorize the familiar words. There was some evidence of…

The Impact of Semantic Relevance and Heterogeneity of Pictorial Stimuli on Individual Brainstorming: An Extension of the SIAM Model

ERIC Educational Resources Information Center

Guo, Jing; McLeod, Poppy Lauretta

2014-01-01

Drawing upon the Search for Ideas in Associative Memory (SIAM) model as the theoretical framework, the impact of heterogeneity and topic relevance of visual stimuli on ideation performance was examined. Results from a laboratory experiment showed that visual stimuli increased productivity and diversity of idea generation, that relevance to the…

Visual Impacts of Prescribed Burning on Mixed Conifer and Giant Sequoia Forests

Treesearch

Lin Cotton; Joe R. McBride

1987-01-01

Prescribed burning programs have evolved with little concern for the visual impact of burning and the potential prescribed burning can have in managing the forest scene. Recent criticisms by the public of the prescribed burning program at Sequoia National Park resulted in an outside review of the National Park fire management programs in Sequoia, Kings Canyon, and...

Creating Visual Aids with Graphic Organisers on an Infinite Canvas--The Impact on the Presenter

ERIC Educational Resources Information Center

Casteleyn, Jordi; Mottart, Andre; Valcke, Martin

2015-01-01

Instead of the traditional set of slides, the visual aids of a presentation can now be graphic organisers (concept maps, knowledge maps, mind maps) on an infinite canvas. Constructing graphic organisers has a beneficial impact on learning, but this topic has not been studied in the context of giving a presentation. The present study examined this…

Patterns and comparisons of human-induced changes in river flood impacts in cities

NASA Astrophysics Data System (ADS)

Clark, Stephanie; Sharma, Ashish; Sisson, Scott A.

2018-03-01

In this study, information extracted from the first global urban fluvial flood risk data set (Aqueduct) is investigated and visualized to explore current and projected city-level flood impacts driven by urbanization and climate change. We use a novel adaption of the self-organizing map (SOM) method, an artificial neural network proficient at clustering, pattern extraction, and visualization of large, multi-dimensional data sets. Prevalent patterns of current relationships and anticipated changes over time in the nonlinearly-related environmental and social variables are presented, relating urban river flood impacts to socioeconomic development and changing hydrologic conditions. Comparisons are provided between 98 individual cities. Output visualizations compare baseline and changing trends of city-specific exposures of population and property to river flooding, revealing relationships between the cities based on their relative map placements. Cities experiencing high (or low) baseline flood impacts on population and/or property that are expected to improve (or worsen), as a result of anticipated climate change and development, are identified and compared. This paper condenses and conveys large amounts of information through visual communication to accelerate the understanding of relationships between local urban conditions and global processes.

Influence of uncorrected refractive error and unmet refractive error on visual impairment in a Brazilian population.

PubMed

Ferraz, Fabio H; Corrente, José E; Opromolla, Paula; Schellini, Silvana A

2014-06-25

The World Health Organization (WHO) definitions of blindness and visual impairment are widely based on best-corrected visual acuity excluding uncorrected refractive errors (URE) as a visual impairment cause. Recently, URE was included as a cause of visual impairment, thus emphasizing the burden of visual impairment due to refractive error (RE) worldwide is substantially higher. The purpose of the present study is to determine the reversal of visual impairment and blindness in the population correcting RE and possible associations between RE and individual characteristics. A cross-sectional study was conducted in nine counties of the western region of state of São Paulo, using systematic and random sampling of households between March 2004 and July 2005. Individuals aged more than 1 year old were included and were evaluated for demographic data, eye complaints, history, and eye exam, including no corrected visual acuity (NCVA), best corrected vision acuity (BCVA), automatic and manual refractive examination. The definition adopted for URE was applied to individuals with NCVA > 0.15 logMAR and BCVA ≤ 0.15 logMAR after refractive correction and unmet refractive error (UREN), individuals who had visual impairment or blindness (NCVA > 0.5 logMAR) and BCVA ≤ 0.5 logMAR after optical correction. A total of 70.2% of subjects had normal NCVA. URE was detected in 13.8%. Prevalence of 4.6% of optically reversible low vision and 1.8% of blindness reversible by optical correction were found. UREN was detected in 6.5% of individuals, more frequently observed in women over the age of 50 and in higher RE carriers. Visual impairment related to eye diseases is not reversible with spectacles. Using multivariate analysis, associations between URE and UREN with regard to sex, age and RE was observed. RE is an important cause of reversible blindness and low vision in the Brazilian population.

Influence of uncorrected refractive error and unmet refractive error on visual impairment in a Brazilian population

PubMed Central

2014-01-01

Background The World Health Organization (WHO) definitions of blindness and visual impairment are widely based on best-corrected visual acuity excluding uncorrected refractive errors (URE) as a visual impairment cause. Recently, URE was included as a cause of visual impairment, thus emphasizing the burden of visual impairment due to refractive error (RE) worldwide is substantially higher. The purpose of the present study is to determine the reversal of visual impairment and blindness in the population correcting RE and possible associations between RE and individual characteristics. Methods A cross-sectional study was conducted in nine counties of the western region of state of São Paulo, using systematic and random sampling of households between March 2004 and July 2005. Individuals aged more than 1 year old were included and were evaluated for demographic data, eye complaints, history, and eye exam, including no corrected visual acuity (NCVA), best corrected vision acuity (BCVA), automatic and manual refractive examination. The definition adopted for URE was applied to individuals with NCVA > 0.15 logMAR and BCVA ≤ 0.15 logMAR after refractive correction and unmet refractive error (UREN), individuals who had visual impairment or blindness (NCVA > 0.5 logMAR) and BCVA ≤ 0.5 logMAR after optical correction. Results A total of 70.2% of subjects had normal NCVA. URE was detected in 13.8%. Prevalence of 4.6% of optically reversible low vision and 1.8% of blindness reversible by optical correction were found. UREN was detected in 6.5% of individuals, more frequently observed in women over the age of 50 and in higher RE carriers. Visual impairment related to eye diseases is not reversible with spectacles. Using multivariate analysis, associations between URE and UREN with regard to sex, age and RE was observed. Conclusion RE is an important cause of reversible blindness and low vision in the Brazilian population. PMID:24965318

Attentional asymmetry between visual hemifields is related to habitual direction of reading and its implications for debate on cause and effects of dyslexia.

PubMed

Kermani, Mojtaba; Verghese, Ashika; Vidyasagar, Trichur R

2018-02-01

A major controversy regarding dyslexia is whether any of the many visual and phonological deficits found to be correlated with reading difficulty cause the impairment or result from the reduced amount of reading done by dyslexics. We studied this question by comparing a visual capacity in the left and right visual hemifields in people habitually reading scripts written right-to-left or left-to-right. Selective visual attention is necessary for efficient visual search and also for the sequential recognition of letters in words. Because such attentional allocation during reading depends on the direction in which one is reading, asymmetries in search efficiency may reflect biases arising from the habitual direction of reading. We studied this by examining search performance in three cohorts: (a) left-to-right readers who read English fluently; (b) right-to-left readers fluent in reading Farsi but not any left-to-right script; and (c) bilingual readers fluent in English and in Farsi, Arabic, or Hebrew. Left-to-right readers showed better search performance in the right hemifield and right-to-left readers in the left hemifield, but bilingual readers showed no such asymmetries. Thus, reading experience biases search performance in the direction of reading, which has implications for the cause and effect relationships between reading and cognitive functions. Copyright © 2017 John Wiley & Sons, Ltd.

Activity Sculptures: Exploring the Impact of Physical Visualizations on Running Activity.

PubMed

Stusak, Simon; Tabard, Aurélien; Sauka, Franziska; Khot, Rohit Ashok; Butz, Andreas

2014-12-01

Data sculptures are a promising type of visualizations in which data is given a physical form. In the past, they have mostly been used for artistic, communicative or educational purposes, and designers of data sculptures argue that in such situations, physical visualizations can be more enriching than pixel-based visualizations. We present the design of Activity Sculptures: data sculptures of running activity. In a three-week field study we investigated the impact of the sculptures on 14 participants' running activity, the personal and social behaviors generated by the sculptures, as well as participants' experiences when receiving these individual physical tokens generated from the specific data of their runs. The physical rewards generated curiosity and personal experimentation but also social dynamics such as discussion on runs or envy/competition. We argue that such passive (or calm) visualizations can complement nudging and other mechanisms of persuasion with a more playful and reflective look at ones' activity.

Dual Coding in Children.

ERIC Educational Resources Information Center

Burton, John K.; Wildman, Terry M.

The purpose of this study was to test the applicability of the dual coding hypothesis to children's recall performance. The hypothesis predicts that visual interference will have a small effect on the recall of visually presented words or pictures, but that acoustic interference will cause a decline in recall of visually presented words and…

Causes of Childhood Vision Impairment in the School for the Blind in Eritrea.

PubMed

Gyawali, Rajendra; Moodley, Vanessa R

2017-12-01

Our study provides the much-needed evidence on causes of childhood blindness in Eritrea. This will assist authorities to plan appropriate strategies and implement preventive, curative, and rehabilitative services to address these causes of vision loss in children in this resource-limited country. This study aims to identify the causes of severe vision impairment and blindness in children attending the only school for the blind in Eritrea. All children enrolled in the school were examined, and the World Health Organization form for the examination of visually impaired children was used to record the data. Examination included visual acuity, refraction, anterior segment, and fundus assessment. Causes of vision loss for children with severe vision impairment (visual acuity <6/60 to 3/60) and blindness (visual acuity <3/60) are reported. Causes were classified by the anatomical site affected and by underlying etiology based on the timing of the insult and causal factor. A total of 92 children were examined, and 71 (77.2%) of them had severe vision impairment and blindness. The major causes of vision loss were corneal scars (16.9%), cataract (12.7%), phthisis bulbi (11.3%), congenital eye deformities (11.3%), optic atrophy (9.3%), and presumed chorioretinal Toxoplasma scars (7.0%). Hereditary factors were the major known etiological category (15.5%) followed by the sequel of eye injuries (12.7%). Blindness due to vitamin A deficiency was not found, whereas infectious causes such as measles and ophthalmia neonatorum were relatively absent (one case each). Potentially avoidable causes of vision impairment were accounted for in 47.9% of children. This study provides the first direct evidence on childhood vision impairment in Eritrea. Despite the limitations, it is clearly shown that nearly half of the vision loss is due to avoidable causes. Thus, preventive public health strategies, specialist pediatric eye care, and rehabilitative services are recommended to address childhood vision impairment in Eritrea.

Spatial Visualization--A Gateway to Computer-Based Technology.

ERIC Educational Resources Information Center

Norman, Kent L.

1994-01-01

A model is proposed for the influence of individual differences on performance when computer-based technology is introduced. The primary cognitive factor driving differences in performance is spatial visualization ability. Four techniques for mitigating the negative impact of low spatial visualization are discussed: spatial metaphors, graphical…

Visual Impairment in Infants and Young Children.

ERIC Educational Resources Information Center

Teplin, Stuart W.

1995-01-01

This article reviews the structure, development, function, and assessment of the visual system and then considers: common eye problems of young children with visual impairment; impacts of severe impairment on child development; and the roles of early intervention professionals, ophthalmologists, and pediatricians in working with these children and…

Monitoring operational data production applying Big Data tooling

NASA Astrophysics Data System (ADS)

Som de Cerff, Wim; de Jong, Hotze; van den Berg, Roy; Bos, Jeroen; Oosterhoff, Rijk; Klein Ikkink, Henk Jan; Haga, Femke; Elsten, Tom; Verhoef, Hans; Koutek, Michal; van de Vegte, John

2015-04-01

Within the KNMI Deltaplan programme for improving the KNMI operational infrastructure an new fully automated system for monitoring the KNMI operational data production systems is being developed: PRISMA (PRocessflow Infrastructure Surveillance and Monitoring Application). Currently the KNMI operational (24/7) production systems consist of over 60 applications, running on different hardware systems and platforms. They are interlinked for the production of numerous data products, which are delivered to internal and external customers. All applications are individually monitored by different applications, complicating root cause and impact analysis. Also, the underlying hardware and network is monitored separately using Zabbix. Goal of the new system is to enable production chain monitoring, which enables root cause analysis (what is the root cause of the disruption) and impact analysis (what other products will be effected). The PRISMA system will make it possible to dispose all the existing monitoring applications, providing one interface for monitoring the data production. For modeling the production chain, the Neo4j Graph database is used to store and query the model. The model can be edited through the PRISMA web interface, but is mainly automatically provided by the applications and systems which are to be monitored. The graph enables us to do root case and impact analysis. The graph can be visualized in the PRISMA web interface on different levels. Each 'monitored object' in the model will have a status (OK, error, warning, unknown). This status is derived by combing all log information available. For collecting and querying the log information Splunk is used. The system is developed using Scrum, by a multi-disciplinary team consisting of analysts, developers, a tester and interaction designer. In the presentation we will focus on the lessons learned working with the 'Big data' tooling Splunk and Neo4J.

Visualizing Human Migration Trhough Space and Time

NASA Astrophysics Data System (ADS)

Zambotti, G.; Guan, W.; Gest, J.

2015-07-01

Human migration has been an important activity in human societies since antiquity. Since 1890, approximately three percent of the world's population has lived outside of their country of origin. As globalization intensifies in the modern era, human migration persists even as governments seek to more stringently regulate flows. Understanding this phenomenon, its causes, processes and impacts often starts from measuring and visualizing its spatiotemporal patterns. This study builds a generic online platform for users to interactively visualize human migration through space and time. This entails quickly ingesting human migration data in plain text or tabular format; matching the records with pre-established geographic features such as administrative polygons; symbolizing the migration flow by circular arcs of varying color and weight based on the flow attributes; connecting the centroids of the origin and destination polygons; and allowing the user to select either an origin or a destination feature to display all flows in or out of that feature through time. The method was first developed using ArcGIS Server for world-wide cross-country migration, and later applied to visualizing domestic migration patterns within China between provinces, and between states in the United States, all through multiple years. The technical challenges of this study include simplifying the shapes of features to enhance user interaction, rendering performance and application scalability; enabling the temporal renderers to provide time-based rendering of features and the flow among them; and developing a responsive web design (RWD) application to provide an optimal viewing experience. The platform is available online for the public to use, and the methodology is easily adoptable to visualizing any flow, not only human migration but also the flow of goods, capital, disease, ideology, etc., between multiple origins and destinations across space and time.

Retinitis pigmentosa.

PubMed

Hamel, Christian

2006-10-11

Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and characterized by retinal pigment deposits visible on fundus examination. Prevalence of non syndromic RP is approximately 1/4,000. The most common form of RP is a rod-cone dystrophy, in which the first symptom is night blindness, followed by the progressive loss in the peripheral visual field in daylight, and eventually leading to blindness after several decades. Some extreme cases may have a rapid evolution over two decades or a slow progression that never leads to blindness. In some cases, the clinical presentation is a cone-rod dystrophy, in which the decrease in visual acuity predominates over the visual field loss. RP is usually non syndromic but there are also many syndromic forms, the most frequent being Usher syndrome. To date, 45 causative genes/loci have been identified in non syndromic RP (for the autosomal dominant, autosomal recessive, X-linked, and digenic forms). Clinical diagnosis is based on the presence of night blindness and peripheral visual field defects, lesions in the fundus, hypovolted electroretinogram traces, and progressive worsening of these signs. Molecular diagnosis can be made for some genes, but is not usually performed due to the tremendous genetic heterogeneity of the disease. Genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, so the visual prognosis is poor. The therapeutic approach is restricted to slowing down the degenerative process by sunlight protection and vitaminotherapy, treating the complications (cataract and macular edema), and helping patients to cope with the social and psychological impact of blindness. However, new therapeutic strategies are emerging from intensive research (gene therapy, neuroprotection, retinal prosthesis).

Retinitis pigmentosa

PubMed Central

Hamel, Christian

2006-01-01

Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and characterized by retinal pigment deposits visible on fundus examination. Prevalence of non syndromic RP is approximately 1/4,000. The most common form of RP is a rod-cone dystrophy, in which the first symptom is night blindness, followed by the progressive loss in the peripheral visual field in daylight, and eventually leading to blindness after several decades. Some extreme cases may have a rapid evolution over two decades or a slow progression that never leads to blindness. In some cases, the clinical presentation is a cone-rod dystrophy, in which the decrease in visual acuity predominates over the visual field loss. RP is usually non syndromic but there are also many syndromic forms, the most frequent being Usher syndrome. To date, 45 causative genes/loci have been identified in non syndromic RP (for the autosomal dominant, autosomal recessive, X-linked, and digenic forms). Clinical diagnosis is based on the presence of night blindness and peripheral visual field defects, lesions in the fundus, hypovolted electroretinogram traces, and progressive worsening of these signs. Molecular diagnosis can be made for some genes, but is not usually performed due to the tremendous genetic heterogeneity of the disease. Genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, so the visual prognosis is poor. The therapeutic approach is restricted to slowing down the degenerative process by sunlight protection and vitaminotherapy, treating the complications (cataract and macular edema), and helping patients to cope with the social and psychological impact of blindness. However, new therapeutic strategies are emerging from intensive research (gene therapy, neuroprotection, retinal prosthesis). PMID:17032466

Five-Year Incidence of Visual Impairment in Middle-Aged Iranians: The Shahroud Eye Cohort Study.

PubMed

Hashemi, Hassan; Mehravaran, Shiva; Emamian, Mohammad Hassan; Fotouhi, Akbar

2017-02-01

To study the 5-year incidence of visual impairment and its causes and risk factors, in the middle-aged Iranian sample of the Shahroud Eye Cohort Study (ShECS). Data from subjects who had participated in both phases of the ShECS were used to determine age- and sex-specific incidence rates of visual impairment using the World Health Organization (WHO) definitions for bilateral low vision (visual acuity, VA, >0.5 and ≤1.3 LogMAR in the better eye) and blindness (VA worse than 1.3 LogMAR in the better eye). Risk ratios (RR) and 95% confidence intervals (CIs) were calculated using multivariable log-binomial regression. Of the 5079 ShECS I survivors, 4737 (93.3%) completed the 5-year follow-up. Their mean age at baseline was 50.9 ± 6.2 years, and 58.9% were female. The incidence of visual impairment was 1.12% (95% CI 0.82-1.42%) by presenting VA and 0.19% (95% CI 0.07-0.32%) by best-corrected VA; leading causes of the former were uncorrected refractive error (81.3%) and diabetic retinopathy (15.1%). In the multivariable model, risk factors for incident visual impairment by presenting VA were older age (RR 1.05, p = 0.044), lower education (RR 0.89, p = 0.002), and diabetes (RR 3.74, p < 0.001). This is the first incidence study of visual impairment in a middle-aged Iranian population. Since age is a major risk factor, the number of visually impaired is expected to increase as the population ages, and less treatable causes such as diabetic retinopathy begin to surface. Measures for tackling uncorrected refractive error and enhancing diabetes screening and preventive programs are recommended.

A population-based study of visual impairment among pre-school children in Beijing: the Beijing study of visual impairment in children.

PubMed

Lu, Qing; Zheng, Yuanyuan; Sun, Baochen; Cui, Tongtong; Congdon, Nathan; Hu, Ailian; Chen, Jianhua; Shi, Jiliang

2009-06-01

To evaluate the prevalence and causes of visual impairment among Chinese children aged 3 to 6 years in Beijing. Population-based prevalence survey. Presenting and pinhole visual acuity were tested using picture optotypes or, in children with pinhole vision < 6/18, a Snellen tumbling E chart. Comprehensive eye examinations and cycloplegic refraction were carried out for children with pinhole vision < 6/18 in the better-seeing eye. All examinations were completed on 17,699 children aged 3 to 6 years (95.3% of sample). Subjects with bilateral correctable low vision (presenting vision < 6/18 correctable to >or= 6/18) numbered 57 (0.322%; 95% confidence interval [CI], 0.237% to 0.403%), while 14 (0.079%; 95% CI, 0.038% to 0.120%) had bilateral uncorrectable low vision (best-corrected vision of < 6/18 and >or= 3/60), and 5 subjects (0.028%; 95% CI, 0.004% to 0.054%) were bilaterally blind (best-corrected acuity < 3/60). The etiology of 76 cases of visual impairment included: refractive error in 57 children (75%), hereditary factors (microphthalmos, congenital cataract, congenital motor nystagmus, albinism, and optic nerve disease) in 13 children (17.1 %), amblyopia in 3 children (3.95%), and cortical blindness in 1 child (1.3%). The cause of visual impairment could not be established in 2 (2.63%) children. The prevalence of visual impairment did not differ by gender, but correctable low vision was significantly (P < .0001) more common among urban as compared with rural children. The leading causes of visual impairment among Chinese preschool-aged children are refractive error and hereditary eye diseases. A higher prevalence of refractive error is already present among urban as compared with rural children in this preschool population.

Characteristics of childhood uveitis leading to visual impairment and blindness in the Netherlands.

PubMed

Hettinga, Ymkje M; Verhagen, Fleurieke H; van Genderen, Maria; de Boer, Joke H

2014-12-01

To investigate the clinical characteristics of childhood uveitis leading to visual impairment or blindness. In this descriptive study, we reviewed data from the medical records of 58 children with visual impairment or blindness due to childhood uveitis, which were seen at an institute for visually impaired patients (Bartiméus) between January 1981 and December 2012, in a retrospective, cross-sectional manner. Thirty-two of the 58 children (55%) were visually impaired and 26 (45%) were legally blind. Uveitis was posterior in 76% of all cases. Infectious uveitis represented 74% of all cases, of which 86% was congenital. Five patients (9%) had uveitis related to a systemic disease, and ten patients (17%) had idiopathic uveitis. There was a decrease in infectious causes over the last decades (p = 0.04) and an increase in idiopathic uveitis (p < 0.01), but the rate of children with posterior uveitis remained constant. There was an overall decrease in the number of children with uveitis referred to Bartiméus. The number of ocular complications at the time of intake was higher in children with acquired disease compared with congenital diseases (p < 0.01), as it was in children with non-infectious uveitis compared with infectious uveitis (p = 0.04). Most comorbidities that were noted were seen in children with infectious uveitis. Most patients suffering from visual impairment or blindness due to childhood uveitis had posterior and/or infectious uveitis, mostly congenital. There is a shift in causes which shows a decrease in infectious causes and an increase in idiopathic causes. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

[Refractive errors as causes of visual impairment in children from public schools of the Botucatu region - SP].

PubMed

Oliveira, Claudia Akemi Shiratori de; Hisatomi, Kenia Scrocaro; Leite, Cristiano Pinheiro; Schellini, Silvana Artioli; Padovani, Carlos Roberto; Padovani, Carlos Roberto Pereira

2009-01-01

To evaluate the refractive errors as cause of visual impairment in school children from the Botucatu region. A sectional study was conducted evaluating preschool and elementary school students, according to gender, refractive error, visual acuity and treatment. Four thousand six hundred and twenty-three (4,623) children were submitted to visual acuity evaluation and 8.1% of them were submitted to complete ocular examination. There were 63.2% hyperopic astigmatism, 15.7% myopic astigmatism, 12.5% astigmatism, 4.9% hyperopia and 3.7% myopia. Corrective lenses were prescribed for 48.7% of the evaluated children. The most frequent refractive error was hyperopic astigmatism and 50% of the children received treatment. The frequency of refractive errors was 3.9% of the studied population.

Neck/shoulder discomfort due to visually demanding experimental near work is influenced by previous neck pain, task duration, astigmatism, internal eye discomfort and accommodation

PubMed Central

Forsman, Mikael; Richter, Hans O.

2017-01-01

Visually demanding near work can cause eye discomfort, and eye and neck/shoulder discomfort during, e.g., computer work are associated. To investigate direct effects of experimental near work on eye and neck/shoulder discomfort, 33 individuals with chronic neck pain and 33 healthy control subjects performed a visual task four times using four different trial lenses (referred to as four different viewing conditions), and they rated eye and neck/shoulder discomfort at baseline and after each task. Since symptoms of eye discomfort may differ depending on the underlying cause, two categories were used; internal eye discomfort, such as ache and strain, that may be caused by accommodative or vergence stress; and external eye discomfort, such as burning and smarting, that may be caused by dry-eye disorders. The cumulative performance time (reflected in the temporal order of the tasks), astigmatism, accommodation response and concurrent symptoms of internal eye discomfort all aggravated neck/shoulder discomfort, but there was no significant effect of external eye discomfort. There was also an interaction effect between the temporal order and internal eye discomfort: participants with a greater mean increase in internal eye discomfort also developed more neck/shoulder discomfort with time. Since moderate musculoskeletal symptoms are a risk factor for more severe symptoms, it is important to ensure a good visual environment in occupations involving visually demanding near work. PMID:28832612

Neck/shoulder discomfort due to visually demanding experimental near work is influenced by previous neck pain, task duration, astigmatism, internal eye discomfort and accommodation.

PubMed

Zetterberg, Camilla; Forsman, Mikael; Richter, Hans O

2017-01-01

Visually demanding near work can cause eye discomfort, and eye and neck/shoulder discomfort during, e.g., computer work are associated. To investigate direct effects of experimental near work on eye and neck/shoulder discomfort, 33 individuals with chronic neck pain and 33 healthy control subjects performed a visual task four times using four different trial lenses (referred to as four different viewing conditions), and they rated eye and neck/shoulder discomfort at baseline and after each task. Since symptoms of eye discomfort may differ depending on the underlying cause, two categories were used; internal eye discomfort, such as ache and strain, that may be caused by accommodative or vergence stress; and external eye discomfort, such as burning and smarting, that may be caused by dry-eye disorders. The cumulative performance time (reflected in the temporal order of the tasks), astigmatism, accommodation response and concurrent symptoms of internal eye discomfort all aggravated neck/shoulder discomfort, but there was no significant effect of external eye discomfort. There was also an interaction effect between the temporal order and internal eye discomfort: participants with a greater mean increase in internal eye discomfort also developed more neck/shoulder discomfort with time. Since moderate musculoskeletal symptoms are a risk factor for more severe symptoms, it is important to ensure a good visual environment in occupations involving visually demanding near work.

7 Key Challenges for Visualization in Cyber Network Defense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Best, Daniel M.; Endert, Alexander; Kidwell, Dan

In this paper we present seven challenges, informed by two user studies, to be considered when developing a visualization for cyber security purposes. Cyber security visualizations must go beyond isolated solutions and “pretty picture” visualizations in order to make impact to users. We provide an example prototype that addresses the challenges with a description of how they are met. Our aim is to assist in increasing utility and adoption rates for visualization capabilities in cyber security.

Interoceptive signals impact visual processing: Cardiac modulation of visual body perception.

PubMed

Ronchi, Roberta; Bernasconi, Fosco; Pfeiffer, Christian; Bello-Ruiz, Javier; Kaliuzhna, Mariia; Blanke, Olaf

2017-09-01

Multisensory perception research has largely focused on exteroceptive signals, but recent evidence has revealed the integration of interoceptive signals with exteroceptive information. Such research revealed that heartbeat signals affect sensory (e.g., visual) processing: however, it is unknown how they impact the perception of body images. Here we linked our participants' heartbeat to visual stimuli and investigated the spatio-temporal brain dynamics of cardio-visual stimulation on the processing of human body images. We recorded visual evoked potentials with 64-channel electroencephalography while showing a body or a scrambled-body (control) that appeared at the frequency of the on-line recorded participants' heartbeat or not (not-synchronous, control). Extending earlier studies, we found a body-independent effect, with cardiac signals enhancing visual processing during two time periods (77-130 ms and 145-246 ms). Within the second (later) time-window we detected a second effect characterised by enhanced activity in parietal, temporo-occipital, inferior frontal, and right basal ganglia-insula regions, but only when non-scrambled body images were flashed synchronously with the heartbeat (208-224 ms). In conclusion, our results highlight the role of interoceptive information for the visual processing of human body pictures within a network integrating cardio-visual signals of relevance for perceptual and cognitive aspects of visual body processing. Copyright © 2017 Elsevier Inc. All rights reserved.

Causes of severe visual impairment and blindness in children in the Republic of Suriname.

PubMed

Heijthuijsen, Astrid Anna Maria; Beunders, Victoria Apollonia Annemarie; Jiawan, Dinesh; de Mesquita-Voigt, Anne-Marie Bueno; Pawiroredjo, Jerrel; Mourits, Maarten; Tanck, Michael; Verhoeff, Joost; Saeed, Peerooz

2013-07-01

To determine the causes of severe visual impairment and blindness (SVI/BL) in children in Suriname (Dutch Guyana) and to identify preventable and treatable causes. 4643 children under 16 years of age were recruited from two locations: 33 children attending the only school for the blind were examined and 4610 medical records were analysed at an eye clinic. Data have been collected using the WHO Prevention of Blindness Programme eye examination record for children. 65 children were identified with SVI/BL, 58.5% were blind and 41.5% were severely visually impaired (SVI). The major anatomical site of SVI/BL was the retina in 33.8%, lens in 15.4% and normal appearing globe in 15.4%. The major underlying aetiology of SVI/BL was undetermined in 56.9% (mainly cataract and abnormality since birth) and perinatal factors 21.5% (mainly retinopathy of prematurity (ROP)). Avoidable causes of SVI/BL accounted for 40% of cases; 7.7% were preventable and 32.3% were treatable with cataracts and ROP the most common causes (15.4% and 12.3%, respectively). More than a third of the SVI/BL causes are potentially avoidable, with childhood cataract and ROP the leading causes. Corneal scarring from vitamin A deficiency does not seem to be a continuing issue in Suriname.

Detecting Damage in Composite Material Using Nonlinear Elastic Wave Spectroscopy Methods

NASA Astrophysics Data System (ADS)

Meo, Michele; Polimeno, Umberto; Zumpano, Giuseppe

2008-05-01

Modern aerospace structures make increasing use of fibre reinforced plastic composites, due to their high specific mechanical properties. However, due to their brittleness, low velocity impact can cause delaminations beneath the surface, while the surface may appear to be undamaged upon visual inspection. Such damage is called barely visible impact damage (BVID). Such internal damages lead to significant reduction in local strengths and ultimately could lead to catastrophic failures. It is therefore important to detect and monitor damages in high loaded composite components to receive an early warning for a well timed maintenance of the aircraft. Non-linear ultrasonic spectroscopy methods are promising damage detection and material characterization tools. In this paper, two different non-linear elastic wave spectroscopy (NEWS) methods are presented: single mode nonlinear resonance ultrasound (NRUS) and nonlinear wave modulation technique (NWMS). The NEWS methods were applied to detect delamination damage due to low velocity impact (<12 J) on various composite plates. The results showed that the proposed methodology appear to be highly sensitive to the presence of damage with very promising future NDT and structural health monitoring applications.

Evidence for potential impacts of ozone on Pinus cembra L. at mountain sites in Europe: an overview.

PubMed

Wieser, G; Manning, W J; Tausz, M; Bytnerowicz, A

2006-01-01

We summarize what is known about the impact of ozone (O(3)) on Pinus cembra in the timberline ecotone of the central European Alps and the Carpathian Mountains. In the central European Alps exposure to ambient and two-fold ambient O(3) throughout one growing season did neither cause any visible injury nor affect the photosynthetic machinery and biochemical parameters in current to 1-year-old needles. By contrast, in the southern French Alps and in the Carpathians 1-year-old needles of Pinus cembra trees showed visual symptoms similar to those observed in O(3) stressed pine stands in southern California. For the southern French Alps the observed symptoms could clearly be attributed O(3) and differences in O(3) uptake seems to be the likely key factor for explaining the observed decline. For the Carpathians however, other reasons such as drought may not be excluded in eliciting the observed symptoms. Thus, the action of O(3) has always to be evaluated in concert with other environmental impacts, determining the tree's sensitivity to stress.

Visual Environments for CFD Research

NASA Technical Reports Server (NTRS)

Watson, Val; George, Michael W. (Technical Monitor)

1994-01-01

This viewgraph presentation gives an overview of the visual environments for computational fluid dynamics (CFD) research. It includes details on critical needs from the future computer environment, features needed to attain this environment, prospects for changes in and the impact of the visualization revolution on the human-computer interface, human processing capabilities, limits of personal environment and the extension of that environment with computers. Information is given on the need for more 'visual' thinking (including instances of visual thinking), an evaluation of the alternate approaches for and levels of interactive computer graphics, a visual analysis of computational fluid dynamics, and an analysis of visualization software.

Causes of vision impairment and assessment of need for low vision services for students of blind schools in Nepal.

PubMed

Kansakar, I; Thapa, H B; Salma, K C; Ganguly, S; Kandel, R P; Rajasekaran, S

The present study is first of its kind to evaluate causes of visual impairment of blind students in Nepal and assess their need for low vision rehabilitation services. To evaluate causes of vision impairment of students enrolled in blind schools in Nepal and assess the need for low vision rehabilitation services in these students. A survey was conducted in 12 blind schools in Nepal, which were registered with Nepal Association for Welfare of Blindness (NAWB).It was conducted by a team of an ophthalmologist and an optometrist, by using standard eye examination protocols of the World Health Organization Prevention of Blindness Program (WHO/PBL). Of the 345 students enrolled in 12 schools, 285 students were examined (response rate of 82.61%). The students were in the 5 - 29 years age group. Nearly three-fourth of the children had become blind within one year of age and 52.3% visually impaired at birth and 20.7% developed vision impairment within one year of age. After refraction, 26 students (9.12%) had mild visual impairment, 21 students (7.37%) had severe visual impairment and 238 students (83.51%) were blind. The main cause of vision impairment was found to be corneal 35.79% and retina diseases, mainly dystrophy, 20.35% followed by problems with the whole globe, lens and optic nerve, accounting for 13.33%, 12.63% and 12.98% respectively. The major etiological factors were those of childhood such as Vitamin A deficiency, measles and similar causes (42.11%) followed by hereditary causes (25.26%). Of the total students examined, 48.07% were visually impaired due to preventable causes and 16.14% treatable aggregating to 64.21% of avoidable blindness. Fifty seven (28.22%) students could read smaller than 2 M print size after low vision assessment for near and 33(15.78%) students benefited with telescopic trial for distance low vision. In Nepal, renewed focus on providing best possible quality of life for visually impaired children by proper low vision assessment and eye health education focusing on, general public and community health workers, with governmental and institutional support is required to achieve Vision 2020 objectives to decrease childhood blindness.

Zif268 mRNA Expression Patterns Reveal a Distinct Impact of Early Pattern Vision Deprivation on the Development of Primary Visual Cortical Areas in the Cat.

PubMed

Laskowska-Macios, Karolina; Zapasnik, Monika; Hu, Tjing-Tjing; Kossut, Malgorzata; Arckens, Lutgarde; Burnat, Kalina

2015-10-01

Pattern vision deprivation (BD) can induce permanent deficits in global motion perception. The impact of timing and duration of BD on the maturation of the central and peripheral visual field representations in cat primary visual areas 17 and 18 remains unknown. We compared early BD, from eye opening for 2, 4, or 6 months, with late onset BD, after 2 months of normal vision, using the expression pattern of the visually driven activity reporter gene zif268 as readout. Decreasing zif268 mRNA levels between months 2 and 4 characterized the normal maturation of the (supra)granular layers of the central and peripheral visual field representations in areas 17 and 18. In general, all BD conditions had higher than normal zif268 levels. In area 17, early BD induced a delayed decrease, beginning later in peripheral than in central area 17. In contrast, the decrease occurred between months 2 and 4 throughout area 18. Lack of pattern vision stimulation during the first 4 months of life therefore has a different impact on the development of areas 17 and 18. A high zif268 expression level at a time when normal vision is restored seems to predict the capacity of a visual area to compensate for BD. © The Author 2014. Published by Oxford University Press.

Common Methodology for Efficient Airspace Operations

NASA Technical Reports Server (NTRS)

Sridhar, Banavar

2012-01-01

Topics include: a) Developing a common methodology to model and avoid disturbances affecting airspace. b) Integrated contrails and emission models to a national level airspace simulation. c) Developed capability to visualize, evaluate technology and alternate operational concepts and provide inputs for policy-analysis tools to reduce the impact of aviation on the environment. d) Collaborating with Volpe Research Center, NOAA and DLR to leverage expertise and tools in aircraft emissions and weather/climate modeling. Airspace operations is a trade-off balancing safety, capacity, efficiency and environmental considerations. Ideal flight: Unimpeded wind optimal route with optimal climb and descent. Operations degraded due to reduction in airport and airspace capacity caused by inefficient procedures and disturbances.

[Initial subretinal localization of acute myeloblastic leukemia (AML5) recurrence].

PubMed

Le Gall, S; François, S; Urier, N; Genevieve, F; d'Hermies, F; Rachieru, P; Ifrah, N

2001-10-13

Reduced visual acuity in patients with acute leucemia can result from many causes including an ocular localization. A patient previously treated for acute myeloblastic leucemia-5 (AML5) developed bilateral vision impairment related to a subretinal localization of the leucemia. Meningeal and bone marrow relapse followed. The subretinal localization responded only to massive systemic steroid treatment. Although asymptomatic, ocular localizations are frequent in leucemia. Their prognostic impact depends on the ocular structure involved and on the chronology of onset--early or late in the leucemia course. The underlying pathophysiological mechanism of ocular involvement remains unexplained but hyperleucocytosis at presentation may be a risk factor and would justify at least systematic specialized examinations and discussion of prophylactic treatment.

Investigating Visual Literacy: Selected Readings from the Annual Conference of the International Visual Literacy Association (22nd, Bloomington/Normal, Illinois, October 1990).

ERIC Educational Resources Information Center

Beauchamp, Darrell G., Ed.; And Others

This volume contains 53 articles grouped under five headings: (1) Research (14 papers on such topics as cognitive style and cognitive strategies, visual literacy training, and the impact of diagrams, type styles, and computer graphics on learning); (2) Theory (nine papers on such topics as the development of visual literacy concepts, cognition and…

Supporting Knowledge Integration in Chemistry with a Visualization-Enhanced Inquiry Unit

ERIC Educational Resources Information Center

Chiu, Jennifer L.; Linn, Marcia C.

2014-01-01

This paper describes the design and impact of an inquiry-oriented online curriculum that takes advantage of dynamic molecular visualizations to improve students' understanding of chemical reactions. The visualization-enhanced unit uses research-based guidelines following the knowledge integration framework to help students develop coherent…

Visual Factors in Reading

ERIC Educational Resources Information Center

Singleton, Chris; Henderson, Lisa-Marie

2006-01-01

This article reviews current knowledge about how the visual system recognizes letters and words, and the impact on reading when parts of the visual system malfunction. The physiology of eye and brain places important constraints on how we process text, and the efficient organization of the neurocognitive systems involved is not inherent but…

Impact of Language on Development of Auditory-Visual Speech Perception

ERIC Educational Resources Information Center

Sekiyama, Kaoru; Burnham, Denis

2008-01-01

The McGurk effect paradigm was used to examine the developmental onset of inter-language differences between Japanese and English in auditory-visual speech perception. Participants were asked to identify syllables in audiovisual (with congruent or discrepant auditory and visual components), audio-only, and video-only presentations at various…

Manneristic behaviors of visually impaired children.

PubMed

Molloy, Alysha; Rowe, Fiona J

2011-09-01

To review the literature on visual impairment in children in order to determine which manneristic behaviors are associated with visual impairment, and to establish why these behaviors occur and whether severity of visual impairment influences these behaviors. A literature search utilizing PubMed, OVID, Google Scholar, and Web of Knowledge databases was performed. The University of Liverpool ( www.liv.ac.uk/orthoptics/research ) and local library facilities were also searched. The main manneristic or stereotypic behaviors associated with visual impairment are eye-manipulatory behaviors, such as eye poking and rocking. The degree of visual impairment influences the type of behavior exhibited by visually impaired children. Totally blind children are more likely to adopt body and head movements whereas sight-impaired children tend to adopt eye-manipulatory behaviors and rocking. The mannerisms exhibited most frequently are those that provide a specific stimulation to the child. Theories to explain these behaviors include behavioral, developmental, functional, and neurobiological approaches. Although the precise etiology of these behaviors is unknown, it is recognized that each of the theories is useful in providing some explanation of why certain behaviors may occur. The age at which the frequency of these behaviors decreases is associated with the child's increasing development, thus those visually impaired children with additional disabilities, whose development is impaired, are at an increased risk of developing and maintaining these behaviors. Certain manneristic behaviors of the visually impaired child may also help indicate the cause of visual impairment. There is a wide range of manneristic behaviors exhibited by visually impaired children. Some of these behaviors appear to be particularly associated with certain causes of visual impairment or severity of visual impairment, thus they may supply the practitioner with useful information. Further research into the prevalence of these behaviors in the visually impaired child is required in order to provide effective management.

[The Performance Analysis for Lighting Sources in Highway Tunnel Based on Visual Function].

PubMed

Yang, Yong; Han, Wen-yuan; Yan, Ming; Jiang, Hai-feng; Zhu, Li-wei

2015-10-01

Under the condition of mesopic vision, the spectral luminous efficiency function is shown as a series of curves. Its peak wavelength and intensity are affected by light spectrum, background brightness and other aspects. The impact of light source to lighting visibility could not be carried out via a single optical parametric characterization. The reaction time of visual cognition is regard as evaluating indexes in this experiment. Under the condition of different speed and luminous environment, testing visual cognition based on vision function method. The light sources include high pressure sodium, electrodeless fluorescent lamp and white LED with three kinds of color temperature (the range of color temperature is from 1 958 to 5 537 K). The background brightness value is used for basic section of highway tunnel illumination and general outdoor illumination, its range is between 1 and 5 cd x m(-)2. All values are in the scope of mesopic vision. Test results show that: under the same condition of speed and luminance, the reaction time of visual cognition that corresponding to high color temperature of light source is shorter than it corresponding to low color temperature; the reaction time corresponding to visual target in high speed is shorter than it in low speed. At the end moment, however, the visual angle of target in observer's visual field that corresponding to low speed was larger than it corresponding to high speed. Based on MOVE model, calculating the equivalent luminance of human mesopic vision, which is on condition of different emission spectrum and background brightness that formed by test lighting sources. Compared with photopic vision result, the standard deviation (CV) of time-reaction curve corresponding to equivalent brightness of mesopic vision is smaller. Under the condition of mesopic vision, the discrepancy between equivalent brightness of different lighting source and photopic vision, that is one of the main reasons for causing the discrepancy of visual recognition. The emission spectrum peak of GaN chip is approximate to the wave length peak of efficiency function in photopic vision. The lighting visual effect of write LED in high color temperature is better than it in low color temperature and electrodeless fluorescent lamp. The lighting visual effect of high pressure sodium is weak. Because of its peak value is around the Na+ characteristic spectra.

Impact of a Braille-Note on Writing: Evaluating the Process, Quality, and Attitudes of Three Students Who Are Visually Impaired

ERIC Educational Resources Information Center

Kamei-Hannan, Cheryl; Lawson, Holly

2012-01-01

Educators of students with visual impairments have long advocated that children who read and write in braille benefit from access to and use of a braille note-taker (BNT) with refreshable braille display. However, little research exists that evaluates whether using a BNT impacts literacy. In this single-subject study, authors investigated if using…

Multimillion Atom Simulations and Visualization of Hypervelocity Impact Damage and Oxidation

DTIC Science & Technology

2004-01-01

MULTIMILLION ATOM SIMULATIONS AND VISUALIZATION OF HYPERVELOCITY IMPACT DAMAGE AND OXIDATION Priya Vashishta*, Rajiv K. Kalia, and Aiichiro Nakano...number. 1. REPORT DATE 2. REPORT TYPE 3. DATES COVERED 00 DEC 2004 N/A 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Multimillion Atom Simulations And...Collaboratory for Advanced Computing and Simulations Department of Materials Science & Engineering, Department of Physics & Astronomy, Department of

Causes of visual disability among Central Africans with diabetes mellitus.

PubMed

Mvitu Muaka, M; Longo-Mbenza, B

2012-06-01

Diabetic Retinopathy (DR) remains a common and one of the major causes of blindness in the developed and western societies. The same situation is shown in emerging economic areas (5,6). In sub-Saharan Africa (SSA) however, the issues of visual disability due to diabetes mellitus (DM) are overshadowed by the presence of the prevalent and common nutritional deficiency diseases and eye infections This clinic-based study was conducted to determine whether diabetic retinopathy is independently related to visual disability in black patients with diabetes mellitus (DM) from Kinshasa, Congo. A total of 299 urban patients with DM and low income including 108 cases of visual disability and matched for time admission and DM type to 191 controls, were assessed. Demographic, clinical, and ophthalmic data were assessed using univariate and multivariate analyses. Age ≥60 years, female sex, presence of diabetic retinopathy (DR), proliferative DR, shorter DM duration, glaucoma, macular oedema, diabetic nephropathy were the univariate risk factors of visual disability. Using logistic regression model, visual disability was significantly associated with female sex and diabetic retinopathy. The risk of visual disability is 4 times higher in patients with diabetic retinopathy and 2 times higher in females with DM. Therefore, to prevent further increase of visual disability, the Congolese Ministry of Health should prioritize the eye care in patients with DM.

Longitudinal Impact on Quality of Life for School-aged Children with Amblyopia Treatment: Perspective from Children.

PubMed

Chen, Yanyan; Chen, Xinhong; Chen, Jie; Zheng, Jingwei; Xu, Jinling; Yu, Xinping

2016-01-01

To evaluate the longitudinal impact on health-related quality of life (HRQOL) during amblyopia treatment for school-aged children from children's perspective. School-aged children prescribed amblyopia treatment for the first time were recruited into the current study. Using a questionnaire, subjects' HRQOL was assessed before patching treatment, and at 8 weeks and 16 weeks after the commencement of patching treatment. Evaluation of visual function and psychosocial aspect was included in the questionnaire. Visual acuity and demographic data of the subjects were recorded. Forty-four children, aged 7-12 years, with anisometropic amblyopia were included in the study. Visual acuity in the amblyopic eye improved 1.90 (0.41-3.74) and 3.98 (2.22-5.11) lines at follow-up weeks 8 and 16, respectively. Both the total score and subscales of the questionnaire were reduced at the first follow-up and recovered at the second follow-up. Scores at week 16 were higher than those before treatment in the psychosocial aspect (p = 0.003), and lower in the visual function aspect (p < 0.001), without significant difference in total score (p = 0.207). Visual acuity in the amblyopic eye and psychosocial expectations for treatment were the most important factors that influenced HRQOL during treatment. From the children's perspective, the impacts on visual function and psychosocial aspect were significant in the first two months of treatment, and could be adapted during therapy for school-aged children. More attention should be paid to negative effects of treatment on daily life and study at the stage of amblyopia treatment for school-aged children. Meanwhile, necessary precautions should be taken to help reduce the impacts.

Who Is the Visually Impaired Child? MAVIS Sourcebook 1.

ERIC Educational Resources Information Center

Efron, Marvin

This booklet is the first in a series of six sourcebooks produced by Project MAVIS (Materials Adaptations for Visually Impaired Students in the Social Studies). Designed primarily for teachers, the booklet defines visual impairment and its causes, explains how to interpret a student's eye report, and reviews aspects of the overall educational plan…

Cortical Visual Impairment in Children: Presentation Intervention, and Prognosis in Educational Settings

ERIC Educational Resources Information Center

Swift, Suzanne H.; Davidson, Roseanna C.; Weems, Linda J.

2008-01-01

Children with cortical visual impairment (CVI) exhibit distinct visual behaviors which are often misinterpreted. As the incidence of CVI is on the rise, this has subsequently caused an increased need for identification and intervention with these children from teaching and therapy service providers. Distinguishing children with CVI from children…

Binocular visual training to promote recovery from monocular deprivation.

PubMed

Murphy, Kathryn M; Roumeliotis, Grayson; Williams, Kate; Beston, Brett R; Jones, David G

2015-01-08

Abnormal early visual experience often leads to poor vision, a condition called amblyopia. Two recent approaches to treating amblyopia include binocular therapies and intensive visual training. These reflect the emerging view that amblyopia is a binocular deficit caused by increased neural noise and poor signal-in-noise integration. Most perceptual learning studies have used monocular training; however, a recent study has shown that binocular training is effective for improving acuity in adult human amblyopes. We used an animal model of amblyopia, based on monocular deprivation, to compare the effect of binocular training either during or after the critical period for ocular dominance plasticity (early binocular training vs. late binocular training). We used a high-contrast, orientation-in-noise stimulus to drive the visual cortex because neurophysiological findings suggest that binocular training may allow the nondeprived eye to teach the deprived eye's circuits to function. We found that both early and late binocular training promoted good visual recovery. Surprisingly, we found that monocular deprivation caused a permanent deficit in the vision of both eyes, which became evident only as a sleeper effect following many weeks of visual training. © 2015 ARVO.

Loss of Neurofilament Labeling in the Primary Visual Cortex of Monocularly Deprived Monkeys

PubMed Central

Duffy, Kevin R.; Livingstone, Margaret S.

2009-01-01

Visual experience during early life is important for the development of neural organizations that support visual function. Closing one eye (monocular deprivation) during this sensitive period can cause a reorganization of neural connections within the visual system that leaves the deprived eye functionally disconnected. We have assessed the pattern of neurofilament labeling in monocularly deprived macaque monkeys to examine the possibility that a cytoskeleton change contributes to deprivation-induced reorganization of neural connections within the primary visual cortex (V-1). Monocular deprivation for three months starting around the time of birth caused a significant loss of neurofilament labeling within deprived-eye ocular dominance columns. Three months of monocular deprivation initiated in adulthood did not produce a loss of neurofilament labeling. The evidence that neurofilament loss was found only when deprivation occurred during the sensitive period supports the notion that the loss permits restructuring of deprived-eye neural connections within the visual system. These results provide evidence that, in addition to reorganization of LGN inputs, the intrinsic circuitry of V-1 neurons is altered when monocular deprivation occurs early in development. PMID:15563721

[Amblyopia and uveitis in childhood].

PubMed

Eckstein, A; Robering, A; Rudolph, G; Esser, J

2007-06-01

Manifestations of uveitis in the sensitive period of childhood can cause amblyopia. In most of the cases band keratopathy, dense cataracts and cyclitic membranes cause deprivation amblyopia. Asymmetrical damage can result in relative amblyopia. Secondary squint can lead to suppression amblyopia. For these reasons every visit during uveitis treatment should be accompanied by a search for amblyogenic factors and visual acuity measurements. In the case of a side difference in the visual acuity, occlusion therapy should be started. The follow-up should not only contain visual acuity measurements but also cycloplegic refraction. Especially when pupil-dilating drugs are necessary for a longer period, bifocals should be prescribed.

Causes of severe visual impairment and blindness in students in schools for the blind in Northwest Ethiopia.

PubMed

Asferaw, Mulusew; Woodruff, Geoffrey; Gilbert, Clare

2017-01-01

To determine the causes of severe visual impairment and blindness (SVI/BL) among students in schools for the blind in Northwest Ethiopia and to identify preventable and treatable causes. Students attending nine schools for the blind in Northwest Ethiopia were examined and causes assigned using the standard WHO record form for children with blindness and low vision in May and June 2015. 383 students were examined, 357 (93%) of whom were severely visually impaired or blind (<6/60 in their better eye). 253 (70.9%) were aged 16 years or above and 228 (63.9%) were males. 100 students aged <16 years were blind and four were SVI, total 104. The major anatomical site of visual loss among those 0-15 years was cornea/phthisis (47.1%), usually due to measles and vitamin A deficiency, followed by whole globe (22.1%), lens (9.6%) and uvea (8.7%). Among students aged 16 years and above, corneal/phthisis (76.3%) was the major anatomical cause, followed by lens (6.3%), whole globe (4.7%), uvea (3.6%) and optic nerve (3.2%). The leading underlying aetiology among students aged <16 years was childhood factors (39.4%) (13.5% measles, 10.6% vitamin A deficiency), followed by unknown aetiology (54.8%), perinatal (2.9%) and hereditary factors (2.9%). In the older group, childhood factors (72.3%) (25% measles, 15% vitamin A deficiency) were major causes, followed by unknown aetiology (24.1%), perinatal (2.4%) and hereditary factors (0.8%). Over 80% of the causes were avoidable with majority being potentially preventable (65%). Corneal blindness, mainly as the result of measles and vitamin A deficiency, is still a public health problem in Northwest Ethiopia, and this has not changed as observed in other low-income countries. More than three-fourth of causes of SVI/BL in students in schools for the blind are potentially avoidable, with measles/vitamin A deficiency and cataract being the leading causes.

The role of visuohaptic experience in visually perceived depth.

PubMed

Ho, Yun-Xian; Serwe, Sascha; Trommershäuser, Julia; Maloney, Laurence T; Landy, Michael S

2009-06-01

Berkeley suggested that "touch educates vision," that is, haptic input may be used to calibrate visual cues to improve visual estimation of properties of the world. Here, we test whether haptic input may be used to "miseducate" vision, causing observers to rely more heavily on misleading visual cues. Human subjects compared the depth of two cylindrical bumps illuminated by light sources located at different positions relative to the surface. As in previous work using judgments of surface roughness, we find that observers judge bumps to have greater depth when the light source is located eccentric to the surface normal (i.e., when shadows are more salient). Following several sessions of visual judgments of depth, subjects then underwent visuohaptic training in which haptic feedback was artificially correlated with the "pseudocue" of shadow size and artificially decorrelated with disparity and texture. Although there were large individual differences, almost all observers demonstrated integration of haptic cues during visuohaptic training. For some observers, subsequent visual judgments of bump depth were unaffected by the training. However, for 5 of 12 observers, training significantly increased the weight given to pseudocues, causing subsequent visual estimates of shape to be less veridical. We conclude that haptic information can be used to reweight visual cues, putting more weight on misleading pseudocues, even when more trustworthy visual cues are available in the scene.

Visual impairment and blindness in Europe and their prevention.

PubMed

Kocur, I; Resnikoff, S

2002-07-01

The European region currently differs in many aspects, such as political, socioeconomic, and geographical. After substantial political changes at the beginning of the 1990s, the majority of central and eastern European countries started to rebuild their healthcare systems. It is apparent that eastern Europe represents a highly diverse region where the difference among countries broadens year after year. In highly industrialised countries of Europe, the leading causes of childhood serious visual loss are lesions of the central nervous system, congenital anomalies and retinal disorders. In the middle income countries of Europe, congenital cataract, glaucoma and, mainly, retinopathy of prematurity are highly expressed. The major cause of serious visual loss in adults in industrialised countries is age related macular degeneration. The other conditions comprise cataract, glaucoma, diabetic retinopathy, and uncorrected/uncorrectable refractive errors, along with low vision. In people of working age, diabetic retinopathy, retinopathy pigmentosa, and optic atrophy are the most frequently reported causes of serious visual loss. In the middle income countries of Europe, advanced cataract, glaucoma, and diabetic retinopathy are more frequently observed.

Visual impairment and blindness in Europe and their prevention

PubMed Central

Kocur, I; Resnikoff, S

2002-01-01

The European region currently differs in many aspects, such as political, socioeconomic, and geographical. After substantial political changes at the beginning of the 1990s, the majority of central and eastern European countries started to rebuild their healthcare systems. It is apparent that eastern Europe represents a highly diverse region where the difference among countries broadens year after year. In highly industrialised countries of Europe, the leading causes of childhood serious visual loss are lesions of the central nervous system, congenital anomalies and retinal disorders. In the middle income countries of Europe, congenital cataract, glaucoma and, mainly, retinopathy of prematurity are highly expressed. The major cause of serious visual loss in adults in industrialised countries is age related macular degeneration. The other conditions comprise cataract, glaucoma, diabetic retinopathy, and uncorrected/uncorrectable refractive errors, along with low vision. In people of working age, diabetic retinopathy, retinopathy pigmentosa, and optic atrophy are the most frequently reported causes of serious visual loss. In the middle income countries of Europe, advanced cataract, glaucoma, and diabetic retinopathy are more frequently observed. PMID:12084735

[Evaluation of visual acuity in a historical cohort of 137 patients treated for amblyopia by occlusion 30-35 years ago].

PubMed

Simonsz-Tóth, B; Loudon, S E; van Kempen-du Saar, H; van de Graaf, E S; Groenewoud, J H; Simonsz, H J

2007-01-01

Opinions differ on the course of the visual acuity in the amblyopic eye after cessation of occlusion therapy. This study evaluated visual acuity in a historical cohort treated for amblyopia with occlusion therapy 30-35 years ago. Between 1968 and 1975, 1250 patients had been treated by the orthoptist in the Waterland Hospital in Purmerend, The Netherlands. Of these, 471 received occlusion treatment for amblyopia (prevalence 5.0%, after comparison with the local birth rate). We were able to contact 203 of these patients, 137 were orthoptically re-examined in 2003. We correlated the current visual acuity with the cause of amblyopia, the age at start and end of treatment, the visual acuity at start and end of treatment, fixation, binocular vision and refractive errors. Mean age at the start of treatment was 5.4 +/- 1.9 years, 7.4 +/- 1.7 years at the end and 37 +/- 2.7 years at follow-up. Current visual acuity in the amblyopic eye was correlated with a low visual acuity at the start (p < 0.0001) and end (p < 0.0001) of occlusion therapy, an eccentric fixation (p < 0.0001), and the cause of amblyopia (p = 0.005). At the end of the treatment, patients with a strabismic amblyopia (n = 98) had a visual acuity in the amblyopic eye of 0.29 logMAR +/- 0.3, and in 2003 0.27 +/- 0.3 logMAR. In patients with an anisometropic amblyopia (> 1 D, n = 16) visual acuity had decreased from 0.17 +/- 0.23 logMAR to 0.21 logMAR +/- 0.23. In patients with both strabismic and anisometropic amblyopia (n = 23), visual acuity had decreased from 0.52 logMAR +/- 0.54 to 0.65 logMAR +/- 0.54. Overall, acuity had decreased in 54 patients (39%) after cessation of treatment. Of these, 18 patients had an acuity decrease to less than 50% of their acuity at the end of treatment. In 15 of these 18 patients anisohypermetropia had increased. A decrease in visual acuity after cessation of occlusion therapy occurred in patients with a combined cause of amblyopia or with an increase in anisohypermetropia.

Meningioma Causing Visual Impairment: Outcomes and Toxicity After Intensity Modulated Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maclean, Jillian, E-mail: jillian.maclean@uclh.nhs.uk; Fersht, Naomi; Bremner, Fion

2013-03-15

Purpose: To evaluate ophthalmologic outcomes and toxicity of intensity modulated radiation therapy (IMRT) in patients with meningiomas causing visual deficits. Methods and Materials: A prospective observational study with formal ophthalmologic and clinical assessment of 30 consecutive cases of meningioma affecting vision treated with IMRT from 2007 to 2011. Prescriptions were 50.4 Gy to mean target dose in 28 daily fractions. The median follow-up time was 28 months. Twenty-six meningiomas affected the anterior visual pathway (including 3 optic nerve sheath meningiomas); 4 were posterior to the chiasm. Results: Vision improved objectively in 12 patients (40%). Improvements were in visual field (5/16more » patients), color vision (4/9 patients), acuity (1/15 patients), extraocular movements (3/11 patients), ptosis (1/5 patients), and proptosis (2/6 patients). No predictors of clinical response were found. Two patients had minor reductions in tumor dimensions on magnetic resonance imaging, 1 patient had radiological progression, and the other patients were stable. One patient experienced grade 2 keratitis, 1 patient had a minor visual field loss, and 5 patients had grade 1 dry eye. Conclusion: IMRT is an effective method for treating meningiomas causing ophthalmologic deficits, and toxicity is minimal. Thorough ophthalmologic assessment is important because clinical responses often occur in the absence of radiological change.« less

Application of electroencephalographic techniques to the study of visual impact of renewable energies.

PubMed

Grima Murcia, M D; Sánchez Ferrer, Francisco; Sorinas, Jennifer; Ferrandez, J M; Fernandez, Eduardo

2017-09-15

Much is currently being studied on the negative visual impact associated to the installation of large wind turbines or photovoltaic farms. However, methodologies for quantitatively assessing landscape impact are scarce. In this work we used electroencephalographic (EEG) recordings to investigate the brain activity of 14 human volunteers when looking at the same landscapes with and without wind turbines, solar panels and nuclear power plants. Our results showed no significant differences for landscapes with solar power systems or without them, and the same happened for wind turbines, what was in agreement with their subjective scores. However, there were clear and significant differences when looking at landscapes with and without nuclear power plants. These differences were more pronounced around a time window of 376-407 msec and showed a clear right lateralization for the pictures containing nuclear power plants. Although more studies are still needed, these results suggest that EEG recordings can be a useful procedure for measuring visual impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulation Study of Impact of Aeroelastic Characteristics on Flying Qualities of a High Speed Civil Transport

NASA Technical Reports Server (NTRS)

Raney, David L.; Jackson, E. Bruce; Buttrill, Carey S.

2002-01-01

A piloted simulation study conducted in NASA Langley Visual Motion Simulator addressed the impact of dynamic aero- servoelastic effects on flying qualities of a High Speed Civil Transport. The intent was to determine effectiveness of measures to reduce the impact of aircraft flexibility on piloting tasks. Potential solutions examined were increasing frequency of elastic modes through structural stiffening, increasing damping of elastic modes through active control, elimination of control effector excitation of the lowest frequency elastic modes, and elimination of visual cues associated with elastic modes. Six test pilots evaluated and performed simulated maneuver tasks, encountering incidents wherein cockpit vibrations due to elastic modes fed back into the control stick through involuntary vibrations of the pilots upper body and arm. Structural stiffening and compensation of the visual display were of little benefit in alleviating this impact, while increased damping and elimination of control effector excitation of the elastic modes both offered great improvements when applied in sufficient degree.

Rapid Assessment of Visual Impairment in Urban Population of Delhi, India

PubMed Central

Gupta, Noopur; Vashist, Praveen; Malhotra, Sumit; Senjam, Suraj Singh; Misra, Vasundhara; Bhardwaj, Amit

2015-01-01

Purpose To determine the prevalence, causes and associated demographic factors related to visual impairment amongst the urban population of New Delhi, India. Methods A population-based, cross-sectional study was conducted in East Delhi district using cluster random sampling methodology. This Rapid Assessment of Visual Impairment (RAVI) survey involved examination of all individuals aged 40 years and above in 24 randomly selected clusters of the district. Visual acuity (VA) assessment and comprehensive ocular examination were done during the door-to-door survey. A questionnaire was used to collect personal and demographic information of the study population. Blindness and Visual Impairment was defined as presenting VA <3/60and <6/18 in the better eye, respectively. Descriptive statistics were computed along with multivariable logistic regression analysis to determine associated factors for visual impairment. Results Of 2421 subjects enumerated, 2331 (96.3%) were available for ophthalmic examination. Among those examined, 49.3% were males. The prevalence of visual impairment (VI) in the study population, was 11.4% (95% C.I. 10.1, 12.7) and that of blindness was 1.2% (95% C.I. 0.8, 1.6). Uncorrected refractive error was the leading cause of VI accounting for 53.4% of all VI followed by cataract (33.8%). With multivariable logistic regression, the odds of having VI increased with age (OR= 24.6[95% C.I.: 14.9, 40.7]; p<0.001). Illiterate participants were more likely to have VI [OR= 1.5 (95% C.I.: 1.1,2.1)] when compared to educated participants. Conclusions The first implementation of the RAVI methodology in a North Indian population revealed that the burden of visual impairment is considerable in this region despite availability of adequate eye care facilities. Awareness generation and simple interventions like cataract surgery and provision of spectacles will help to eliminate the major causes of blindness and visual impairment in this region. PMID:25915659

Rapid assessment of visual impairment in urban population of Delhi, India.

PubMed

Gupta, Noopur; Vashist, Praveen; Malhotra, Sumit; Senjam, Suraj Singh; Misra, Vasundhara; Bhardwaj, Amit

2015-01-01

To determine the prevalence, causes and associated demographic factors related to visual impairment amongst the urban population of New Delhi, India. A population-based, cross-sectional study was conducted in East Delhi district using cluster random sampling methodology. This Rapid Assessment of Visual Impairment (RAVI) survey involved examination of all individuals aged 40 years and above in 24 randomly selected clusters of the district. Visual acuity (VA) assessment and comprehensive ocular examination were done during the door-to-door survey. A questionnaire was used to collect personal and demographic information of the study population. Blindness and Visual Impairment was defined as presenting VA < 3/60 and < 6/18 in the better eye, respectively. Descriptive statistics were computed along with multivariable logistic regression analysis to determine associated factors for visual impairment. Of 2421 subjects enumerated, 2331 (96.3%) were available for ophthalmic examination. Among those examined, 49.3% were males. The prevalence of visual impairment (VI) in the study population, was 11.4% (95% C.I. 10.1, 12.7) and that of blindness was 1.2% (95% C.I. 0.8, 1.6). Uncorrected refractive error was the leading cause of VI accounting for 53.4% of all VI followed by cataract (33.8%). With multivariable logistic regression, the odds of having VI increased with age (OR = 24.6[95% C.I.: 14.9, 40.7]; p < 0.001). Illiterate participants were more likely to have VI [OR = 1.5 (95% C.I.: 1.1,2.1)] when compared to educated participants. The first implementation of the RAVI methodology in a North Indian population revealed that the burden of visual impairment is considerable in this region despite availability of adequate eye care facilities. Awareness generation and simple interventions like cataract surgery and provision of spectacles will help to eliminate the major causes of blindness and visual impairment in this region.

Micrometeorite Impact Test of Flex Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

2016-01-01

Spacecraft with solar arrays operate throughout the near earth environment and are increasingly planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeorite impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. The Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeorite impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at NASA MSFC's Microlight Gas Gun Facility. The SSL-provided coupons consist of three strings, each string with two solar cells in series. Five impacts will be induced at various locations on a powered test coupon under different string voltage (0 volts - 150 volts) and string current (1.1 amperes - 1.65 amperes) conditions. The maximum specified test voltage and current represent margins of 1.5 times for both voltage and current. The test parameters are chosen to demonstrate new array design robustness to any ESD event caused by plasma plumes resulting from a simulated micrometeorite impact. A second unpowered coupon will undergo two impacts: one impact on the front side and one impact on the back side. Following the impact testing, the second coupon will be exposed to a thermal cycle test to determine possible damage propagation and further electrical degradation due to thermally-induced stress. The setup, checkout, and results from the impact testing are discussed. The challenges for impact testing include precise coupon alignment to control impact location; pressure management during the impact process; and measurement of the true transient electrical response during impact on the powered coupon. Results from pre- and post-test visual and electrical functional testing are also discussed.

Task- and age-dependent effects of visual stimulus properties on children's explicit numerosity judgments.

PubMed

Defever, Emmy; Reynvoet, Bert; Gebuis, Titia

2013-10-01

Researchers investigating numerosity processing manipulate the visual stimulus properties (e.g., surface). This is done to control for the confound between numerosity and its visual properties and should allow the examination of pure number processes. Nevertheless, several studies have shown that, despite different visual controls, visual cues remained to exert their influence on numerosity judgments. This study, therefore, investigated whether the impact of the visual stimulus manipulations on numerosity judgments is dependent on the task at hand (comparison task vs. same-different task) and whether this impact changes throughout development. In addition, we examined whether the influence of visual stimulus manipulations on numerosity judgments plays a role in the relation between performance on numerosity tasks and mathematics achievement. Our findings confirmed that the visual stimulus manipulations affect numerosity judgments; more important, we found that these influences changed with increasing age and differed between the comparison and the same-different tasks. Consequently, direct comparisons between numerosity studies using different tasks and age groups are difficult. No meaningful relationship between the performance on the comparison and same-different tasks and mathematics achievement was found in typically developing children, nor did we find consistent differences between children with and without mathematical learning disability (MLD). Copyright © 2013 Elsevier Inc. All rights reserved.

Runtime visualization of the human arterial tree.

PubMed

Insley, Joseph A; Papka, Michael E; Dong, Suchuan; Karniadakis, George; Karonis, Nicholas T

2007-01-01

Large-scale simulation codes typically execute for extended periods of time and often on distributed computational resources. Because these simulations can run for hours, or even days, scientists like to get feedback about the state of the computation and the validity of its results as it runs. It is also important that these capabilities be made available with little impact on the performance and stability of the simulation. Visualizing and exploring data in the early stages of the simulation can help scientists identify problems early, potentially avoiding a situation where a simulation runs for several days, only to discover that an error with an input parameter caused both time and resources to be wasted. We describe an application that aids in the monitoring and analysis of a simulation of the human arterial tree. The application provides researchers with high-level feedback about the state of the ongoing simulation and enables them to investigate particular areas of interest in greater detail. The application also offers monitoring information about the amount of data produced and data transfer performance among the various components of the application.

The Impact of Sexual Media on Second Language Vocabulary Retrieval.

PubMed

Çetin, Yakup

2015-12-01

Both Islam and Christianity warn their adherents not to view or to display obscene matter. Aside from religious consequences in the afterlife for such behavior, this study was conducted to determine if viewing sexual media has a detrimental effect in earthly life. Adolescents (n = 64) 17-22 years were exposed to two types of visual stimuli containing sexual or neutral content for 30 min. The participants, seated in rooms with comfortable chairs and provided with snacks, were shown a selection of 18 German words via a PowerPoint slideshow, which included a picture, an audio recording, and the written form of each word. The experimental group, which was exposed to arousing visual stimuli with mild sexual content (movie trailers, music video clips, and TV commercials), remembered significantly fewer words than the control group, which viewed a nature documentary without sexual content. T-test scores revealed that exposure to sexually arousing media impaired memory for second language (L2) vocabulary. Apart from leading to dire consequences in the hereafter, the results of the study demonstrate that viewing obscene material also causes harm in this life.

Ultimate predators: lionfish have evolved to circumvent prey risk assessment abilities.

PubMed

Lönnstedt, Oona M; McCormick, Mark I

2013-01-01

Invasive species cause catastrophic alterations to communities worldwide by changing the trophic balance within ecosystems. Ever since their introduction in the mid 1980's common red lionfish, Pterois volitans, are having dramatic impacts on the Caribbean ecosystem by displacing native species and disrupting food webs. Introduced lionfish capture prey at extraordinary rates, altering the composition of benthic communities. Here we demonstrate that the extraordinary success of the introduced lionfish lies in its capacity to circumvent prey risk assessment abilities as it is virtually undetectable by prey species in its native range. While experienced prey damselfish, Chromis viridis, respond with typical antipredator behaviours when exposed to a common predatory rock cod (Cephalopholis microprion) they fail to visibly react to either the scent or visual presentation of the red lionfish, and responded only to the scent (not the visual cue) of a lionfish of a different genus, Dendrochirus zebra. Experienced prey also had much higher survival when exposed to the two non-invasive predators compared to P. volitans. The cryptic nature of the red lionfish has enabled it to be destructive as a predator and a highly successful invasive species.

Visualization and analysis of vortex-turbine intersections in wind farms.

PubMed

Shafii, Sohail; Obermaier, Herald; Linn, Rodman; Koo, Eunmo; Hlawitschka, Mario; Garth, Christoph; Hamann, Bernd; Joy, Kenneth I

2013-09-01

Characterizing the interplay between the vortices and forces acting on a wind turbine's blades in a qualitative and quantitative way holds the potential for significantly improving large wind turbine design. This paper introduces an integrated pipeline for highly effective wind and force field analysis and visualization. We extract vortices induced by a turbine's rotation in a wind field, and characterize vortices in conjunction with numerically simulated forces on the blade surfaces as these vortices strike another turbine's blades downstream. The scientifically relevant issue to be studied is the relationship between the extracted, approximate locations on the blades where vortices strike the blades and the forces that exist in those locations. This integrated approach is used to detect and analyze turbulent flow that causes local impact on the wind turbine blade structure. The results that we present are based on analyzing the wind and force field data sets generated by numerical simulations, and allow domain scientists to relate vortex-blade interactions with power output loss in turbines and turbine life expectancy. Our methods have the potential to improve turbine design to save costs related to turbine operation and maintenance.

A Spatial-Spectral Approach for Visualization of Vegetation Stress Resulting from Pipeline Leakage.

PubMed

Van derWerff, Harald; Van der Meijde, Mark; Jansma, Fokke; Van der Meer, Freek; Groothuis, Gert Jan

2008-06-04

Hydrocarbon leakage into the environment has large economic and environmental impact. Traditional methods for investigating seepages and their resulting pollution, such as drilling, are destructive, time consuming and expensive. Remote sensing is an efficient tool that offers a non-destructive investigation method. Optical remote sensing has been extensively tested for exploration of onshore hydrocarbon reservoirs and detection of hydrocarbons at the Earth's surface. In this research, we investigate indirect manifestations of pipeline leakage by way of visualizing vegetation anomalies in airborne hyperspectral imagery. Agricultural land-use causes a heterogeneous landcover; variation in red edge position between fields was much larger than infield red edge position variation that could be related to hydrocarbon pollution. A moving and growing kernel procedure was developed to normalzie red edge values relative to values of neighbouring pixels to enhance pollution related anomalies in the image. Comparison of the spatial distribution of anomalies with geochemical data obtained by drilling showed that 8 out of 10 polluted sites were predicted correctly while 2 out of 30 sites that were predicted clean were actually polluted.

A Spatial-Spectral Approach for Visualization of Vegetation Stress Resulting from Pipeline Leakage

PubMed Central

van der Werff, Harald; van der Meijde, Mark; Jansma, Fokke; van der Meer, Freek; Groothuis, Gert Jan

2008-01-01

Hydrocarbon leakage into the environment has large economic and environmental impact. Traditional methods for investigating seepages and their resulting pollution, such as drilling, are destructive, time consuming and expensive. Remote sensing is an efficient tool that offers a non-destructive investigation method. Optical remote sensing has been extensively tested for exploration of onshore hydrocarbon reservoirs and detection of hydrocarbons at the Earth's surface. In this research, we investigate indirect manifestations of pipeline leakage by way of visualizing vegetation anomalies in airborne hyperspectral imagery. Agricultural land-use causes a heterogeneous landcover; variation in red edge position between fields was much larger than infield red edge position variation that could be related to hydrocarbon pollution. A moving and growing kernel procedure was developed to normalzie red edge values relative to values of neighbouring pixels to enhance pollution related anomalies in the image. Comparison of the spatial distribution of anomalies with geochemical data obtained by drilling showed that 8 out of 10 polluted sites were predicted correctly while 2 out of 30 sites that were predicted clean were actually polluted. PMID:27879905

Cone rod dystrophies

PubMed Central

Hamel, Christian P

2007-01-01

Cone rod dystrophies (CRDs) (prevalence 1/40,000) are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP), also called the rod cone dystrophies (RCDs) resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7). Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far). The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs), CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs), and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs). It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, and the visual prognosis is poor. Management aims at slowing down the degenerative process, treating the complications and helping patients to cope with the social and psychological impact of blindness. PMID:17270046

Spatial Visualization Ability and Impact of Drafting Models: A Quasi Experimental Study

ERIC Educational Resources Information Center

Katsioloudis, Petros J.; Jovanovic, Vukica

2014-01-01

A quasi experimental study was done to determine significant positive effects among three different types of visual models and to identify whether any individual type or combination contributed towards a positive increase of spatial visualization ability for students in engineering technology courses. In particular, the study compared the use of…

Reading Acquisition Enhances an Early Visual Process of Contour Integration

ERIC Educational Resources Information Center

Szwed, Marcin; Ventura, Paulo; Querido, Luis; Cohen, Laurent; Dehaene, Stanislas

2012-01-01

The acquisition of reading has an extensive impact on the developing brain and leads to enhanced abilities in phonological processing and visual letter perception. Could this expertise also extend to early visual abilities outside the reading domain? Here we studied the performance of illiterate, ex-illiterate and literate adults closely matched…

Visual Stereotypes and Virtual Pedagogical Agents

ERIC Educational Resources Information Center

Haake, Magnus; Gulz, Agneta

2008-01-01

The paper deals with the use of visual stereotypes in virtual pedagogical agents and its potential impact in digital learning environments. An analysis of the concept of visual stereotypes is followed by a discussion of affordances and drawbacks as to their use in the context of traditional media. Next, the paper explores whether virtual…

Active Learning in Neuroscience: A Manipulative to Simulate Visual Field Defects

ERIC Educational Resources Information Center

Li, Andrew Yue-Lin; Carvalho, Helena

2016-01-01

Prevalent in 20-57% of stroke patients, visual field defects have been shown to impact quality of life. Studies have shown increased risk of falling, ambulatory difficulties, impaired reading ability, and feelings of panic in crowded or unfamiliar places in patients with visual field defects. Rehabilitation, independence, and mental health may…

Coping with a Visual Impairment through Self-Investigation.

ERIC Educational Resources Information Center

van Huijgevoort, Toos

2002-01-01

This article describes how the self-confrontation method (SCM) can help people cope with visual impairment. The actual impact of the impairment can be studied by establishing how being visually impaired is expressed in self-narratives. The different phases of SCM are explained and two case studies are presented. (Contains references.) (Author/CR)

The Autobiography of Intercultural Encounters through Visual Media: Exploring Images of Others in Telecollaboration

ERIC Educational Resources Information Center

Lindner, Rachel; Méndez Garcia, Maria del Carmen

2014-01-01

Positioned against the background of the Council of Europe's interest in developing intercultural competence through education, the study presented in this paper investigates the impact on intercultural visual literacy of the Council of Europe's "Images of Others--An Autobiography of Intercultural Encounters through Visual Media"…

Transformations in the Visual Representation of a Figural Pattern

ERIC Educational Resources Information Center

Montenegro, Paula; Costa, Cecília; Lopes, Bernardino

2018-01-01

Multiple representations of a given mathematical object/concept are one of the biggest difficulties encountered by students. The aim of this study is to investigate the impact of the use of visual representations in teaching and learning algebra. In this paper, we analyze the transformations from and to visual representations that were performed…

Visual Impairment and Self-Esteem: What Makes a Difference?

ERIC Educational Resources Information Center

Bowen, Jayne

2010-01-01

This account follows on from the research report "Visual impairment and its impact on self-esteem" (Bowen, 2010) published in this journal. The original article reported the results of an investigation of self-esteem levels amongst a sample group of 60 children with visual impairment. Four children, whose self-esteem was measured as…

76 FR 51914 - Duty-Free Treatment of Certain Visual and Auditory Materials

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

...(b) that the proposed amendments, if adopted, will not have a significant economic impact on a... CFR Parts 10 and 163 [USCBP-2011-0030] RIN 1515-AD75 Duty-Free Treatment of Certain Visual and... required for duty-free treatment of certain visual and auditory materials of an educational, scientific, or...

Evidence for Two Attentional Components in Visual Working Memory

ERIC Educational Resources Information Center

Allen, Richard J.; Baddeley, Alan D.; Hitch, Graham J.

2014-01-01

How does executive attentional control contribute to memory for sequences of visual objects, and what does this reveal about storage and processing in working memory? Three experiments examined the impact of a concurrent executive load (backward counting) on memory for sequences of individually presented visual objects. Experiments 1 and 2 found…

"Hot" Facilitation of "Cool" Processing: Emotional Distraction Can Enhance Priming of Visual Search

ERIC Educational Resources Information Center

Kristjansson, Arni; Oladottir, Berglind; Most, Steven B.

2013-01-01

Emotional stimuli often capture attention and disrupt effortful cognitive processing. However, cognitive processes vary in the degree to which they require effort. We investigated the impact of emotional pictures on visual search and on automatic priming of search. Observers performed visual search after task-irrelevant neutral or emotionally…

Impact of Visual, Vocal, and Lexical Cues on Judgments of Counselor Qualities

ERIC Educational Resources Information Center

Strahan, Carole; Zytowski, Donald G.

1976-01-01

Undergraduate students (N=130) rated Carl Rogers via visual, lexical, vocal, or vocal-lexical communication channels. Lexical cues were more important in creating favorable impressions among females. Subsequent exposure to combined visual-vocal-lexical cues resulted in warmer and less distant ratings, but not on a consistent basis. (Author)

Timber management simulated field trip

Treesearch

Ronald M. Walters; Warren R. Bacon; Asa D. Twombly

1979-01-01

Timber Management techniques are changing the appearance of our nation's wildlands. Standard harvest practices often result in harsh visual impacts and public outcry. In some cases, subtle harvesting has been done, but without adequate thought as to what the visual result will be over time. Better visual results can be obtained by careful harvest design which...

[Quality of life in visual impaired children treated for Early Visual Stimulation].

PubMed

Messa, Alcione Aparecida; Nakanami, Célia Regina; Lopes, Marcia Caires Bestilleiro

2012-01-01

To evaluate the quality of life in visually impaired children followed in the Early Visual Stimulation Ambulatory of Unifesp in two moments, before and after rehabilitational intervention of multiprofessional team. A CVFQ quality of life questionnaire was used. This instrument has a version for less than three years old children and another one for children older than three years (three to seven years) divided in six subscales: General health, General vision health, Competence, Personality, Family impact and Treatment. The correlation between the subscales on two moments was significant. There was a statistically significant difference in general vision health (p=0,029) and other important differences obtained in general health, family impact and quality of life general score. The questionnaire showed to be effective in order to measure the quality of life related to vision on families followed on this ambulatory. The multidisciplinary interventions provided visual function and familiar quality of life improvement. The quality of life related to vision in children followed in Early Visual Stimulation Ambulatory of Unifesp showed a significant improvement on general vision health.

Optic nerve compression as a late complication of a hydrogel explant with silicone encircling band.

PubMed

Crama, Niels; Kluijtmans, Leo; Klevering, B Jeroen

2018-06-01

To present a complication of compressive optic neuropathy caused by a swollen hydrogel explant and posteriorly displaced silicone encircling band. A 72-year-old female patient presented with progressive visual loss and a tilted optic disc. Her medical history included a retinal detachment in 1993 that was treated with a hydrogel explant under a solid silicone encircling band. Visual acuity had decreased from 6/10 to 6/20 and perimetry showed a scotoma in the temporal superior quadrant. On Magnetic Resonance Imaging (MRI), compression of the optic nerve by a displaced silicone encircling band inferior nasally in combination with a swollen episcleral hydrogel explant was observed. Surgical removal of the hydrogel explant and silicone encircling band was uneventful and resulted in improvement of visual acuity and visual field loss. This is the first report on compressive optic neuropathy caused by swelling of a hydrogel explant resulting in a dislocated silicone encircling band. The loss of visual function resolved upon removal of the explant and encircling band.

Visual Resource Analysis for Solar Energy Zones in the San Luis Valley

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Robert; Abplanalp, Jennifer M.; Zvolanek, Emily

This report summarizes the results of a study conducted by Argonne National Laboratory’s (Argonne’s) Environmental Science Division for the U.S. Department of the Interior Bureau of Land Management (BLM). The study analyzed the regional effects of potential visual impacts of solar energy development on three BLM-designated solar energy zones (SEZs) in the San Luis Valley (SLV) in Colorado, and, based on the analysis, made recommendations for or against regional compensatory mitigation to compensate residents and other stakeholders for the potential visual impacts to the SEZs. The analysis was conducted as part of the solar regional mitigation strategy (SRMS) task conductedmore » by BLM Colorado with assistance from Argonne. Two separate analyses were performed. The first analysis, referred to as the VSA Analysis, analyzed the potential visual impacts of solar energy development in the SEZs on nearby visually sensitive areas (VSAs), and, based on the impact analyses, made recommendations for or against regional compensatory mitigation. VSAs are locations for which some type of visual sensitivity has been identified, either because the location is an area of high scenic value or because it is a location from which people view the surrounding landscape and attach some level of importance or sensitivity to what is seen from the location. The VSA analysis included both BLM-administered lands in Colorado and in the Taos FO in New Mexico. The second analysis, referred to as the SEZ Analysis, used BLM visual resource inventory (VRI) and other data on visual resources in the former Saguache and La Jara Field Offices (FOs), now contained within the San Luis Valley FO (SLFO), to determine whether the changes in scenic values that would result from the development of utility-scale solar energy facilities in the SEZs would affect the quality and quantity of valued scenic resources in the SLV region as a whole. If the regional effects were judged to be significant, regional compensatory mitigation was recommended. VRI data was not available for the Taos FO and it was not included in the SEZ analysis; the SEZ analysis includes BLM-administered lands in Colorado only.« less

Causes of childhood blindness in a school for the visually impaired in Hong Kong.

PubMed

Fan, D S P; Lai, T Y Y; Cheung, E Y Y; Lam, D S C

2005-04-01

To identify the causes of blindness in children attending a school for the blind in Hong Kong. Cross-sectional observational study. School for blind children in Hong Kong. Eighty-two blind students at the Ebenezer School and Home for the Visually Impaired were examined between December 1998 and August 1999. Demographic data were obtained from students and a questionnaire assessment made of their medical and ocular history. Visual acuity was assessed and visual loss classified according to the World Health Organization classification of visual impairment. Complete ophthalmic assessments were performed in all students including slit-lamp examination and dilated binocular indirect ophthalmoscopy. The mean age of the students was 12.2 years. Ten (12.2%) had a family history of eye disease. Major past medical illnesses were reported in 50% with prematurity and diseases of the central nervous system found in 26.8% and 11.0% of students, respectively. The most common anatomical site for visual impairment was the retina (47.6%), followed by diseases of the optic nerve (14.6%), and diseases of the anterior segment and the lens (14.6%). The pattern of childhood blindness in Hong Kong is similar to that seen in other developed countries. Preventable causes of childhood blindness, such as prematurity and birth asphyxia, were responsible for a large proportion of cases. Early diagnosis and treatment of such conditions may reduce the incidence of childhood blindness in Hong Kong.

Epidemiology of blindness in children.

PubMed

Solebo, Ameenat Lola; Teoh, Lucinda; Rahi, Jugnoo

2017-09-01

An estimated 14 million of the world's children are blind. A blind child is more likely to live in socioeconomic deprivation, to be more frequently hospitalised during childhood and to die in childhood than a child not living with blindness. This update of a previous review on childhood visual impairment focuses on emerging therapies for children with severe visual disability (severe visual impairment and blindness or SVI/BL).For children in higher income countries, cerebral visual impairment and optic nerve anomalies remain the most common causes of SVI/BL, while retinopathy of prematurity (ROP) and cataract are now the most common avoidable causes. The constellation of causes of childhood blindness in lower income settings is shifting from infective and nutritional corneal opacities and congenital anomalies to more resemble the patterns seen in higher income settings. Improvements in maternal and neonatal health and investment in and maintenance of national ophthalmic care infrastructure are the key to reducing the burden of avoidable blindness. New therapeutic targets are emerging for childhood visual disorders, although the safety and efficacy of novel therapies for diseases such as ROP or retinal dystrophies are not yet clear. Population-based epidemiological research, particularly on cerebral visual impairment and optic nerve hypoplasia, is needed in order to improve understanding of risk factors and to inform and support the development of novel therapies for disorders currently considered 'untreatable'. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Intensive video gaming improves encoding speed to visual short-term memory in young male adults.

PubMed

Wilms, Inge L; Petersen, Anders; Vangkilde, Signe

2013-01-01

The purpose of this study was to measure the effect of action video gaming on central elements of visual attention using Bundesen's (1990) Theory of Visual Attention. To examine the cognitive impact of action video gaming, we tested basic functions of visual attention in 42 young male adults. Participants were divided into three groups depending on the amount of time spent playing action video games: non-players (<2h/month, N=12), casual players (4-8h/month, N=10), and experienced players (>15h/month, N=20). All participants were tested in three tasks which tap central functions of visual attention and short-term memory: a test based on the Theory of Visual Attention (TVA), an enumeration test and finally the Attentional Network Test (ANT). The results show that action video gaming does not seem to impact the capacity of visual short-term memory. However, playing action video games does seem to improve the encoding speed of visual information into visual short-term memory and the improvement does seem to depend on the time devoted to gaming. This suggests that intense action video gaming improves basic attentional functioning and that this improvement generalizes into other activities. The implications of these findings for cognitive rehabilitation training are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Exploring the Impact of Phonological Awareness, Visual-Spatial Working Memory, and Preschool Quantity--Number Competencies on Mathematics Achievement in Elementary School: Findings from a 3-year Longitudinal Study

ERIC Educational Resources Information Center

Krajewski, Kristin; Schneider, Wolfgang

2009-01-01

This longitudinal study explored the importance of kindergarten measures of phonological awareness, working memory, and quantity-number competencies (QNC) for predicting mathematical school achievement in third graders (mean age 8 years 8 months). It was found that the impact of phonological awareness and visual-spatial working memory, assessed at…

The Effect of the Color of a Long Cane Used by Individuals Who Are Visually Impaired on the Yielding Behavior of Drivers

ERIC Educational Resources Information Center

Bourquin, Eugene A.; Emerson, Robert Wall; Sauerburger, Dona; Barlow, Janet

2017-01-01

Introduction: A new market trend offers long canes for individuals with visual impairments in a variety of colors; however, the impact of these colors is unknown to orientation and mobility (O&M) specialists and individuals who are blind or who have low vision. The authors examined the impact of cane color on drivers' yielding behaviors; also,…

Classroom Displays--Attraction or Distraction? Evidence of Impact on Attention and Learning from Children with and without Autism

ERIC Educational Resources Information Center

Hanley, Mary; Khairat, Mariam; Taylor, Korey; Wilson, Rachel; Cole-Fletcher, Rachel; Riby, Deborah M.

2017-01-01

Paying attention is a critical first step toward learning. For children in primary school classrooms there can be many things to attend to other than the focus of a lesson, such as visual displays on classroom walls. The aim of this study was to use eye-tracking techniques to explore the impact of visual displays on attention and learning for…

[Acute epidural hematoma of the posterior fossa caused by forehead impact].

PubMed

Abe, S; Furukawa, K; Endo, S; Hoshi, S; Kanaya, H

1988-03-01

A rare case of acute epidural hematoma of the posterior fossa caused by forehead impact is reported. This 36-year-old man fell from a truck and hit his face. He was conscious and was brought to our center 30 minutes after the injury. On admission, a contused wound of the right forehead was noticed. He was restless and had severe pain in the neck and upper extremities. Skull X-ray showed a linear fracture of the frontal bone and computed tomography (CT) scan was normal. He continued to be restless and sudden respiratory arrest and pupillary dilation occurred 10 hours after the admission. A CT scan revealed a lenticular high density area in the left posterior fossa which extended to the supratentorial region. The 4th ventricle was compressed and displaced to the right and also the quadrigeminal and ambient cisterns were not visualized at all. Immediate surgery disclosed a 30 g epidural hematoma of the left posterior fossa and the supratentorium and the clot was completely evacuated. The source of bleeding could not be identified. Opening of the dura revealed contusion in the occipital lobe. He died on the 17th postoperative day. The possible mechanism in the production of the posterior fossa hematoma in this case is discussed.

Exploring Visual Evidence of Human Impact on the Environment with Planetary-Scale Zoomable Timelapse Video

NASA Astrophysics Data System (ADS)

Sargent, R.; Egge, M.; Dille, P. S.; O'Donnell, G. D.; Herwig, C.

2016-12-01

Visual evidence ignites curiosity and inspires advocacy. Zoomable imagery and video on a planetary scale provides compelling evidence of human impact on the environment. Earth Timelapse places the observable impact of 30+ years of human activity into the hands of policy makers, scientists, and advocates, with fluidity and speed that supports inquiry and exploration. Zoomability enables compelling narratives and ready apprehension of environmental changes, connecting human-scale evidence to regional and ecosystem-wide trends and changes. Leveraging the power of Google Earth Engine, join us to explore 30+ years of Landset 30m RGB imagery showing glacial retreat, agricultural deforestation, irrigation expansion, and the disappearance of lakes. These narratives are enriched with datasets showing planetary forest gain/loss, annual cycles of agricultural fires, global changes in the health of coral reefs, trends in resource extraction, and of renewable energy development. We demonstrate the intuitive and inquiry-enabling power of these planetary visualizations, and provide instruction on how scientists and advocates can create and share or contribute visualizations of their own research or topics of interest.

Combined acoustical and visual performance of noise barriers in mitigating the environmental impact of motorways.

PubMed

Jiang, Like; Kang, Jian

2016-02-01

This study investigated the overall performance of noise barriers in mitigating environmental impact of motorways, taking into consideration their effects on reducing noise and visual intrusions of moving traffic, but also potentially inducing visual impact themselves. A laboratory experiment was carried out, using computer-visualised video scenes and motorway traffic noise recordings to present experimental scenarios covering two traffic levels, two distances of receiver to road, two types of background landscape, and five barrier conditions including motorway only, motorway with tree belt, motorways with 3 m timber barrier, 5m timber barrier, and 5m transparent barrier. Responses from 30 participants of university students were gathered and perceived barrier performance analysed. The results show that noise barriers were always beneficial in mitigating environmental impact of motorways, or made no significant changes in environmental quality when the impact of motorways was low. Overall, barriers only offered similar mitigation effect as compared to tree belt, but showed some potential to be more advantageous when traffic level went high. 5m timber barrier tended to perform better than the 3m one at the distance of 300 m but not at 100 m possibly due to its negative visual effect when getting closer. The transparent barrier did not perform much differently from the timber barriers but tended to be the least effective in most scenarios. Some low positive correlations were found between aesthetic preference for barriers and environmental impact reduction by the barriers. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of acute sleep deprivation on visual evoked potentials in professional drivers.

PubMed

Jackson, Melinda L; Croft, Rodney J; Owens, Katherine; Pierce, Robert J; Kennedy, Gerard A; Crewther, David; Howard, Mark E

2008-09-01

Previous studies have demonstrated that as little as 18 hours of sleep deprivation can cause deleterious effects on performance. It has also been suggested that sleep deprivation can cause a "tunnel-vision" effect, in which attention is restricted to the center of the visual field. The current study aimed to replicate these behavioral effects and to examine the electrophysiological underpinnings of these changes. Repeated-measures experimental study. University laboratory. Nineteen professional drivers (1 woman; mean age = 45.3 +/- 9.1 years). Two experimental sessions were performed; one following 27 hours of sleep deprivation and the other following a normal night of sleep, with control for circadian effects. A tunnel-vision task (central versus peripheral visual discrimination) and a standard checkerboard-viewing task were performed while 32-channel EEG was recorded. For the tunnel-vision task, sleep deprivation resulted in an overall slowing of reaction times and increased errors of omission for both peripheral and foveal stimuli (P < 0.05). These changes were related to reduced P300 amplitude (indexing cognitive processing) but not measures of early visual processing. No evidence was found for an interaction effect between sleep deprivation and visual-field position, either in terms of behavior or electrophysiological responses. Slower processing of the sustained parvocellular visual pathway was demonstrated. These findings suggest that performance deficits on visual tasks during sleep deprivation are due to higher cognitive processes rather than early visual processing. Sleep deprivation may differentially impair processing of more-detailed visual information. Features of the study design (eg, visual angle, duration of sleep deprivation) may influence whether peripheral visual-field neglect occurs.

Rainbow glare by retinal imaging

NASA Astrophysics Data System (ADS)

Sun, Han-Ying; Chiang, Yao-Ting; Yeh, Shang-Min; Huang, Shuan-Yu; Horng, Chi-Ting; Wang, Hsiang-Chen

2016-07-01

This study aims to determine whether IntraLase surgery can cause rainbow glare. Monte-Carlo ray tracing method is used to study visual conditions of an ordered microstructure array on the cornea. A corneal flap in the simulated eye model can generate numerous microbubbles caused by IntraLase surgery. Moreover, this study evaluates the visual performance under different conditions such as the size and interval of the microbubble structure on the cornea with vary incident angles and diameters of light. The results of this study can help elucidate the real cause of rainbow glare as a side effect of IntraLase.

Using naturalistic driving study data to investigate the impact of driver distraction on driver's brake reaction time in freeway rear-end events in car-following situation.

PubMed

Gao, Jingru; Davis, Gary A

2017-12-01

The rear-end crash is one of the most common freeway crash types, and driver distraction is often cited as a leading cause of rear-end crashes. Previous research indicates that driver distraction could have negative effects on driving performance, but the specific association between driver distraction and crash risk is still not fully revealed. This study sought to understand the mechanism by which driver distraction, defined as secondary task distraction, could influence crash risk, as indicated by a driver's reaction time, in freeway car-following situations. A statistical analysis, exploring the causal model structure regarding drivers' distraction impacts on reaction times, was conducted. Distraction duration, distraction scenario, and secondary task type were chosen as distraction-related factors. Besides, exogenous factors including weather, visual obstruction, lighting condition, traffic density, and intersection presence and endogenous factors including driver age and gender were considered. There was an association between driver distraction and reaction time in the sample freeway rear-end events from SHRP 2 NDS database. Distraction duration, the distracted status when a leader braked, and secondary task type were related to reaction time, while all other factors showed no significant effect on reaction time. The analysis showed that driver distraction duration is the primary direct cause of the increase in reaction time, with other factors having indirect effects mediated by distraction duration. Longer distraction duration, the distracted status when a leader braked, and engaging in auditory-visual-manual secondary task tended to result in longer reaction times. Given drivers will be distracted occasionally, countermeasures which shorten distraction duration or avoid distraction presence while a leader vehicle brakes are worth considering. This study helps better understand the mechanism of freeway rear-end events in car-following situations, and provides a methodology that can be adopted to study the association between driver behavior and driving features. Copyright © 2017 National Safety Council and Elsevier Ltd. All rights reserved.

Visual accommodation trainer-tester

NASA Technical Reports Server (NTRS)

Randle, R. J., Jr. (Inventor)

1983-01-01

An apparatus for training of the human visual accommodation system is presented, specifically, useful for training a person to volitionally control his focus to his far point (normaly infinity) from a position of myopia due to functional causes. The functional causes could be due, for example, to a behavioral accommodative spasm or the effects of an empty field. The device may also be used to measure accommodation, the accommodation resting position and the near and far points of vision.

Ophthalmologic Disease in HIV Infection: Recent Changes in Pathophysiology and Treatment.

PubMed

Stewart, Michael W

2017-10-19

Ophthalmologic conditions were among the earliest described findings in patients with the acquired immunodeficiency syndrome (AIDS). The purpose of this review is to highlight recent changes in the pathophysiology and management of ophthalmologic conditions in patients infected with the human immunodeficiency virus (HIV). The introduction of highly active antiretroviral therapy (HAART) in 1996 changed ophthalmologic findings from predominantly acute infectious diseases to chronic, slowly progressive, debilitating conditions. HIV-associated neuroretinal disorder infrequently leads to blindness, but it causes visual disability in a large percentage of patients. Cytomegalovirus retinitis is now seen less commonly in the USA, but it remains an important cause of blindness in HIV-infected patients from developing countries. Immune recovery uveitis has emerged as a major cause of visual disability in the USA. As HIV has become a chronic disease, visual disability due to chronic noninfectious diseases have become increasingly important.

The Visual Uncertainty Paradigm for Controlling Screen-Space Information in Visualization

ERIC Educational Resources Information Center

Dasgupta, Aritra

2012-01-01

The information visualization pipeline serves as a lossy communication channel for presentation of data on a screen-space of limited resolution. The lossy communication is not just a machine-only phenomenon due to information loss caused by translation of data, but also a reflection of the degree to which the human user can comprehend visual…

1-cyclohexyl-x-methoxybenzene derivatives, novel psychoactive substances seized on the internet market. Synthesis and in vivo pharmacological studies in mice.

PubMed

Fantinati, Anna; Ossato, Andrea; Bianco, Sara; Canazza, Isabella; De Giorgio, Fabio; Trapella, Claudio; Marti, Matteo

2017-05-01

Among novel psychoactive substances notified to EMCDDA and Europol were 1-cyclohexyl-x-methoxybenzene stereoisomers (ortho, meta, and para). These substances share some structural characteristics with phencyclidine and tramadol. Nowadays, no information on the pharmacological and toxicological effects evoked by 1-cyclohexyl-x-methoxybenzene are reported. The aim of this study was to investigate the effect evoked by each one stereoisomer on visual stimulation, body temperature, acute thermal pain, and motor activity in mice. Mice were evaluated in behavioral tests carried out in a consecutive manner according to the following time scheme: observation of visual placing response, measures of core body temperature, determination of acute thermal pain, and stimulated motor activity. All three stereoisomers dose-dependent inhibit visual placing response (rank order: meta > ortho > para), induce hyperthermia at lower and hypothermia at higher doses (meta > ortho > para) and cause analgesia to thermal stimuli (para > meta = ortho), while they do not alter motor activity. For the first time, this study demonstrates that systemic administration of 1-cyclohexyl-x-methoxybenzene compounds markedly inhibit visual response, promote analgesia, and induce core temperature alterations in mice. This data, although obtained in animal model, suggest their possible hazard for human health (i.e., hyperthermia and sensorimotor alterations). In particular, these novel psychoactive substances may have a negative impact in many daily activities, greatly increasing the risk factors for workplace accidents and traffic injuries. Copyright © 2017 John Wiley & Sons, Ltd.

Universal transition from unstructured to structured neural maps

PubMed Central

Sartori, Fabio; Cuntz, Hermann

2017-01-01

Neurons sharing similar features are often selectively connected with a higher probability and should be located in close vicinity to save wiring. Selective connectivity has, therefore, been proposed to be the cause for spatial organization in cortical maps. Interestingly, orientation preference (OP) maps in the visual cortex are found in carnivores, ungulates, and primates but are not found in rodents, indicating fundamental differences in selective connectivity that seem unexpected for closely related species. Here, we investigate this finding by using multidimensional scaling to predict the locations of neurons based on minimizing wiring costs for any given connectivity. Our model shows a transition from an unstructured salt-and-pepper organization to a pinwheel arrangement when increasing the number of neurons, even without changing the selectivity of the connections. Increasing neuronal numbers also leads to the emergence of layers, retinotopy, or ocular dominance columns for the selective connectivity corresponding to each arrangement. We further show that neuron numbers impact overall interconnectivity as the primary reason for the appearance of neural maps, which we link to a known phase transition in an Ising-like model from statistical mechanics. Finally, we curated biological data from the literature to show that neural maps appear as the number of neurons in visual cortex increases over a wide range of mammalian species. Our results provide a simple explanation for the existence of salt-and-pepper arrangements in rodents and pinwheel arrangements in the visual cortex of primates, carnivores, and ungulates without assuming differences in the general visual cortex architecture and connectivity. PMID:28468802

Uncorrected refractive errors, presbyopia and spectacle coverage: results from a rapid assessment of refractive error survey.

PubMed

Marmamula, Srinivas; Keeffe, Jill E; Rao, Gullapalli N

2009-01-01

To investigate the prevalence of uncorrected refractive errors, presbyopia and spectacle coverage in subjects aged 15-50 years using rapid assessment methodology in the Mahabubnagar district of Andhra Pradesh, India. A population-based cross sectional study was conducted using cluster random sampling to enumerate 3,300 subjects from 55 clusters. Unaided, aided and pinhole visual acuity was assessed using a LogMAR chart at a distance of 4 meters. Near vision was assessed using N notation chart. Uncorrected refractive error was defined as presenting visual acuity worse than 6/12 but improving to at least 6/12 or better on using a pinhole. Presbyopia is defined as binocular near vision worse than N8 in subjects aged more than 35 years with binocular distance visual acuity of 6/12 or better. Of the 3,300 subjects enumerated from 55 clusters, 3,203 (97%) subjects were available for examination. Of these, 1,496 (46.7%) were females and 930 (29%) were > or = 40 years. Age and gender adjusted prevalence of uncorrected refractive errors causing visual impairment in the better eye was 2.7% (95% CI, 2.1-3.2%). Presbyopia was present in 690 (63.7%, 95% CI, 60.8-66.6%) subjects aged over 35 years. Spectacle coverage for refractive error was 29% and for presbyopia it was 19%. There is a large unmet need for refractive correction in this area in India. Rapid assessment methods are an effective means of assessing the need for services and the impact of models of care.

Impact induced damage assessment by means of Lamb wave image processing

NASA Astrophysics Data System (ADS)

Kudela, Pawel; Radzienski, Maciej; Ostachowicz, Wieslaw

2018-03-01

The aim of this research is an analysis of full wavefield Lamb wave interaction with impact-induced damage at various impact energies in order to find out the limitation of the wavenumber adaptive image filtering method. In other words, the relation between impact energy and damage detectability will be shown. A numerical model based on the time domain spectral element method is used for modeling of Lamb wave propagation and interaction with barely visible impact damage in a carbon-epoxy laminate. Numerical studies are followed by experimental research on the same material with an impact damage induced by various energy and also a Teflon insert simulating delamination. Wavenumber adaptive image filtering and signal processing are used for damage visualization and assessment for both numerical and experimental full wavefield data. It is shown that it is possible to visualize and assess the impact damage location, size and to some extent severity by using the proposed technique.

Causes of severe visual impairment and blindness in children in the Republic of Suriname

PubMed Central

Heijthuijsen, Astrid Anna Maria; Beunders, Victoria Apollonia Annemarie; Jiawan, Dinesh; de Mesquita-Voigt, Anne-Marie Bueno; Pawiroredjo, Jerrel; Mourits, Maarten; Tanck, Michael; Verhoeff, Joost; Saeed, Peerooz

2013-01-01

Aims To determine the causes of severe visual impairment and blindness (SVI/BL) in children in Suriname (Dutch Guyana) and to identify preventable and treatable causes. Methods 4643 children under 16 years of age were recruited from two locations: 33 children attending the only school for the blind were examined and 4610 medical records were analysed at an eye clinic. Data have been collected using the WHO Prevention of Blindness Programme eye examination record for children. Results 65 children were identified with SVI/BL, 58.5% were blind and 41.5% were severely visually impaired (SVI). The major anatomical site of SVI/BL was the retina in 33.8%, lens in 15.4% and normal appearing globe in 15.4%. The major underlying aetiology of SVI/BL was undetermined in 56.9% (mainly cataract and abnormality since birth) and perinatal factors 21.5% (mainly retinopathy of prematurity (ROP)). Avoidable causes of SVI/BL accounted for 40% of cases; 7.7% were preventable and 32.3% were treatable with cataracts and ROP the most common causes (15.4% and 12.3%, respectively). Conclusions More than a third of the SVI/BL causes are potentially avoidable, with childhood cataract and ROP the leading causes. Corneal scarring from vitamin A deficiency does not seem to be a continuing issue in Suriname. PMID:23603759

Website Designs for Communicating About Chemicals in Cigarette Smoke.

PubMed

Lazard, Allison J; Byron, M Justin; Vu, Huyen; Peters, Ellen; Schmidt, Annie; Brewer, Noel T

2017-12-13

The Family Smoking Prevention and Tobacco Control Act requires the US government to inform the public about the quantities of toxic chemicals in cigarette smoke. A website can accomplish this task efficiently, but the site's user interface must be usable to benefit the general public. We conducted online experiments with national convenience samples of 1,451 US adult smokers and nonsmokers to examine the impact of four interface display elements: the chemicals, their associated health effects, quantity information, and a visual risk indicator. Outcomes were perceptions of user experience (perceived clarity and usability), motivation (willingness to use), and potential impact (elaboration about the harms of smoking). We found displaying health effects as text with icons, providing quantity information for chemicals (e.g., ranges), and showing a visual risk indicator all improved the user experience of a webpage about chemicals in cigarette smoke (all p < .05). Displaying a combination of familiar and unfamiliar chemicals, providing quantity information for chemicals, and showing a visual risk indicator all improved motivation to use the webpage (all p < .05). Displaying health effects or quantity information increased the potential impact of the webpage (all p < .05). Overall, interface designs displaying health effects of chemicals in cigarette smoke as text with icons and with a visual risk indicator had the greatest impact on the user experience, motivation, and potential impact of the website. Our findings provide guidance for accessible website designs that can inform consumers about the toxic chemicals in cigarette smoke.

Environmental change disrupts communication and sexual selection in a stickleback population.

PubMed

Candolin, Ulrika; Tukiainen, Iina; Bertell, Elina

2016-04-01

Environmental change that disrupts communication during mate choice and alters sexual selection could influence population dynamics. Yet little is known about such long-term effects. We investigated experimentally the consequences that disrupted visual communication during mate choice has for the quantity and viability of offspring produced in a threespine stickleback population (Gasterosteus aculeatus). We further related the results to long-term monitoring of population dynamics in the field to determine if changes are apparent under natural conditions. The results show that impaired visual communication because of algal blooms reduces reliability of male visual signals as indicators of offspring survival during their first weeks of life. This relaxes sexual selection but has no effect on the number of offspring hatching, as most males have a high hatching success in turbid water. Despite eutrophication and high turbidity levels that interfere with communication during mate choice, the population has grown during recent decades. Large numbers of offspring hatching, combined with high variation in juvenile fitness, has probably shifted selection to later life history stages and maintained a viable population. Together with reduced cost of sexual selection and ongoing ecosystem changes caused by human activities, this could have promoted population growth. These results point to the complexity of ecosystems and the necessity to consider all influencing factors when attempting to understand impacts of human activities on populations.

Effects of mobile phone distraction on pedestrians' crossing behavior and visual attention allocation at a signalized intersection: An outdoor experimental study.

PubMed

Jiang, Kang; Ling, Feiyang; Feng, Zhongxiang; Ma, Changxi; Kumfer, Wesley; Shao, Chen; Wang, Kun

2018-06-01

With the rapid growth in mobile phone use worldwide, traffic safety experts have begun to consider the impact of mobile phone distractions on pedestrian crossing safety. This study sought to investigate how mobile phone distractions (music distraction, phone conversation distraction and text distraction) affect the behavior of pedestrians while they are crossing the street. An outdoor-environment experiment was conducted among 28 college student pedestrians. Two HD videos and an eye tracker were employed to record and analyze crossing behavior and visual attention allocation. The results of the research showed that the three mobile phone distractions cause different levels of impairment to pedestrians' crossing performance, with the greatest effect from text distraction, followed by phone conversation distraction and music distraction. Pedestrians distracted by music initiate crossing later, have increased pupil diameter, and reduce their scanning frequency, fixation points and fixation times toward traffic signal area priorities. In addition to the above effects, pedestrians distracted by phone conversation cross the street more slowly, direct fewer fixation points to the right traffic area, and spend less fixation time and lower average fixation duration on the left traffic area. Moreover, pedestrians distracted by texting look left and right less often and switch, distribute and maintain less visual attention on the traffic environment. These findings may inform researchers, policy makers, and pedestrians. Copyright © 2018 Elsevier Ltd. All rights reserved.

Computers, Automation, and the Employment of Persons Who Are Blind or Visually Impaired.

ERIC Educational Resources Information Center

Mather, J.

1994-01-01

This article discusses the impact of technology on the formation of skills and the career advancement of persons who are blind or visually impaired. It concludes that dependence on technology (computerization and automation) and the mechanistic aspects of jobs may trap blind and visually impaired workers in occupations with narrow career paths…

Project visual analysis for the Allegheny National Forest

Treesearch

Gary W. Kell

1979-01-01

The Project Visual Analysis is a landscape assessment procedure involving forest vegetative manipulation. A logical step by step analysis leads the user to a specific set of landscape management guidelines to be used as an aid in designing a project or in evaluating whether the proposed project impacts will meet visual objectives. Key elements within the procedure are...

Visuals for Interactive Video: Old Fashioned Images for a New Fangled Technology.

ERIC Educational Resources Information Center

Braden, Roberts A.

Pointing out that interactive video (IAV) represents a synthesis of four primary technologies--computers, television, visual design, and instructional design--this paper discusses the what, why, and how of IAV visuals. The features and relevant aspects of each technology are briefly discussed, as well as the impact of each of these technologies…

The Impact of Visual Memory Deficits on Academic Achievement in Children and Adolescents

ERIC Educational Resources Information Center

Larsen, Jessica Maria

2011-01-01

Memory assessment can often alert practitioners and educators to learning problems children may be experiencing. Results of a memory assessment may indicate that a child has a specific memory deficit in verbal memory, visual memory, or both. Deficits in visual or verbal modes of memory could potentially have adverse effects on academic…

The Impact of Visual-Spatial Attention on Reading and Spelling in Chinese Children

ERIC Educational Resources Information Center

Liu, Duo; Chen, Xi; Wang, Ying

2016-01-01

The present study investigated the associations of visual-spatial attention with word reading fluency and spelling in 92 third grade Hong Kong Chinese children. Word reading fluency was measured with a timed reading task whereas spelling was measured with a dictation task. Results showed that visual-spatial attention was a unique predictor of…

Spatial Coding of Individuals with Visual Impairments

ERIC Educational Resources Information Center

Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

2012-01-01

The aim of this study is to examine the ability of children and adolescents with visual impairments to code and represent near space. Moreover, it examines the impact of the strategies they use and individual differences in their performance. A total of 30 individuals with visual impairments up to the age of 18 were given eight different object…

The Impact of Online Algorithm Visualization on ICT Students' Achievements in Introduction to Programming Course

ERIC Educational Resources Information Center

Saltan, Fatih

2017-01-01

Online Algorithm Visualization (OAV) is one of the recent developments in the instructional technology field that aims to help students handle difficulties faced when they begin to learn programming. This study aims to investigate the effect of online algorithm visualization on students' achievement in the introduction to programming course. To…

Inappropriate enrollment of children in schools for the visually impaired in east Africa.

PubMed

Tumwesigye, C; Msukwa, G; Njuguna, M; Shilio, B; Courtright, P; Lewallen, S

2009-06-01

Many visually impaired children can learn to read print with appropriate training and simple visual aids. This may allow them to attend normal schools and to be integrated into society, which has lifelong benefits. Yet, in Africa, many visually impaired children are enrolled in special schools and taught only Braille. The purpose of this analysis was to document the extent of inappropriate enrollment of visually impaired children in special schools and annexes for the blind in four African countries. Schools were selected through a population-proportional-to-size method so that they would represent all children attending special schools in Kenya, Malawi, Tanzania and Uganda. Children were examined by ophthalmologists trained in standardised methods to determine visual acuity and the cause of decreased acuity. Of 1062 children examined in special schools and annexes for the blind, 361 (34%, 95% CI 31.2, 36.8) had visual acuity >or=6/60; the most common cause of visual impairment was retinal disease. Of the 120 children with normal vision (>or=6/18), 69 (57.5%) had two normal eyes, 21 (17.5%) had an obvious ocular disfigurement in the fellow eye and 10 (8.4%) had had successful cataract surgery. In these countries, many children are placed inappropriately in special schools and annexes for the blind. The reasons are multiple and to rectify the situation will require advocacy and cooperation between ministries of health and education.

Public perceptions of west-side forests: improving visual impact assessments and designing thinnings and harvests for scenic integrity

Treesearch

Robert G. Ribe

2013-01-01

Perceptions of public forests’ acceptability can be infl uenced by aesthetic qualities, at both broad and project levels, aff ecting managers’ social license to act. Legal and methodological issues related to measuring and managing forest aesthetics in NEPA and NFMA decision-making are discussed. It is argued that conventional visual impact assessments—using...

Prevalence and causes of blindness in an urban area of Paraguay.

PubMed

Yaacov-Peña, Fernando; Jure, David; Ocampos, José; Samudio, Margarita; Furtado, João Marcello; Carter, Marissa; Lansingh, Van Charles

2012-10-01

To determine the prevalence and causes of blindness in Piribebuy, Paraguay. A population based study was conducted from September to November 2007 in Piribebuy, Paraguay. Based on the city map, seven clusters were randomly selected, containing 22 to 36 squares (423 to 578 houses) each, where all subjects > 40 years old who agreed to participate were included in the study. Presenting vision acuity (VA) was obtained for each eye, with 'E' Snellen charts 6 meters far from the patient with appropriate light. Eyes with VA<20/60 were also tested with the pinhole. Objective and subjective refraction was performed, followed by examination of anterior segment under the slit-lamp, Goldmann applanation tonometry, and pupil dilatation with 0.5% tropicamide plus 0.5% phenylephrine, followed by evaluation of the posterior pole. Best corrected visual acuity was used to classify the patients as follows: blindness was defined as visual acuity of the better eye <20/400, low vision as 20/400

A Retrospective Study of Causes of Low Vision in Saud Arabia, A Case of Eye World Medical Complex in Riyadh.

PubMed

Z Alotaibi, Abdullah

2015-10-20

Vision is the ability of seeing with a definite understanding of features, color and contrast, and to distinguish between objects visually. In the year 1999, the World Health Organization (WHO) and the International Agency for the Prevention of Blindness formulated a worldwide project for the eradication of preventable loss of sight with the subject of "Vision 2020: the Right to Sight". This global program aims to eradicate preventable loss of sight by the year 2020. This study was conducted to determine the main causes of low vision in Saudi Arabia and also to assess their visual improvement after using low vision aids (LVD).The study is a retrospective study and was conducted in low vision clinic at Eye World Medical Complex in Riyadh, Saudi Arabia. The file medical record of 280 patients attending low vision clinics from February 2008 to June 2010 was included. A data sheet was filled which include: age, gender, cause of low vision, unassisted visual acuity for long distances and short distances, low vision devices needed for long distances and short distances that provides best visual acuity. The result shows that the main cause of low vision was Optic atrophy (28.9%). Retinitis pigmentosa was the second cause of low vision, accounting for 73 patients (26%) followed by Diabetic retinopathy and Macular degeneration with 44 patients (15.7%) and 16 patients (5.7%) respectively. Inter family marriage could be one of the main causes of low vision. Public awareness should be embarked on for enlightenment on ocular diseases result in consanguineous marriage. Also, it is an important issue to start establishing low vision clinics in order to improve the situation.

Rethinking Airbag Safety: Airbag Injury Causing Bilateral Blindness

PubMed Central

Ogun, Olufunmilola Abimbola; Ikyaa, Sewuese Yangi; Ogun, Gabriel Olabiyi

2014-01-01

A healthy 40-year-old man, restrained in the front passenger seat, suffered visually disabling blunt ocular trauma following spontaneous release of the passenger side air-bag module, during vehicular deceleration, without an automobile crash. Though the driver-side airbag was also released, the driver was unharmed. The passenger suffered bilateral hyphema, bilateral vitreous hemorrhage and suspected posterior scleral rupture in the left eye and also had an eyebrow laceration, from impact with the dashboard panel covering the air-bag module, which was detached by the force of airbag deployment. This is the first reported case from West Africa and the first case in which part of the airbag module detached to cause additional trauma. This report adds to the growing burden of evidence world-wide, for a review of the safety aspects of the automobile airbag. This case clearly illustrates that although airbags reduce mortality, they carry a high risk of ocular morbidity, even with seat belt restraint. PMID:24791116

The global burden of cataract.

PubMed

Rao, Gullapalli N; Khanna, Rohit; Payal, Abhishek

2011-01-01

To review the previous year's literature related to prevalence of blindness in general, blindness due to cataract, cataract surgical coverage (CSC) and cataract surgical rates (CSRs). Cataracts are the major cause of blindness and visual impairment in developing countries and contributes to more than 90% of the total disability adjusted life years. This review shows that coverage continues to be a problem in many countries, especially for the female population, those residing in rural areas and those who are illiterate. Although CSR is an indicator of the availability and acceptability of services, for measuring the impact of the program, we should look at combining CSR with CSC. This strategy would also enable us achieve our goal of eliminating avoidable blindness due to cataracts by the year 2020. Cataracts still continue- to be a major cause of blindness globally and with the rapidly aging population, it is a challenge to tackle. We need to plan a comprehensive strategy addressing issues related to availability, affordability, accessibility and acceptability of eye-care services.

Altered functional connectivity in lesional peduncular hallucinosis with REM sleep behavior disorder.

PubMed

Geddes, Maiya R; Tie, Yanmei; Gabrieli, John D E; McGinnis, Scott M; Golby, Alexandra J; Whitfield-Gabrieli, Susan

2016-01-01

Brainstem lesions causing peduncular hallucinosis (PH) produce vivid visual hallucinations occasionally accompanied by sleep disorders. Overlapping brainstem regions modulate visual pathways and REM sleep functions via gating of thalamocortical networks. A 66-year-old man with paroxysmal atrial fibrillation developed abrupt-onset complex visual hallucinations with preserved insight and violent dream enactment behavior. Brain MRI showed restricted diffusion in the left rostrodorsal pons suggestive of an acute ischemic stroke. REM sleep behavior disorder (RBD) was diagnosed on polysomnography. We investigated the integrity of ponto-geniculate-occipital circuits with seed-based resting-state functional connectivity MRI (rs-fcMRI) in this patient compared to 46 controls. Rs-fcMRI revealed significantly reduced functional connectivity between the lesion and lateral geniculate nuclei (LGN), and between LGN and visual association cortex compared to controls. Conversely, functional connectivity between brainstem and visual association cortex, and between visual association cortex and prefrontal cortex (PFC) was significantly increased in the patient. Focal damage to the rostrodorsal pons is sufficient to cause RBD and PH in humans, suggesting an overlapping mechanism in both syndromes. This lesion produced a pattern of altered functional connectivity consistent with disrupted visual cortex connectivity via de-afferentation of thalamocortical pathways. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Age related macular degeneration and visual disability.

PubMed

Christoforidis, John B; Tecce, Nicola; Dell'Omo, Roberto; Mastropasqua, Rodolfo; Verolino, Marco; Costagliola, Ciro

2011-02-01

Age-related macular degeneration (AMD) is the leading cause of central blindness or low vision among the elderly in industrialized countries. AMD is caused by a combination of genetic and environmental factors. Among modifiable environmental risk factors, cigarette smoking has been associated with both the dry and wet forms of AMD and may increase the likelihood of worsening pre-existing AMD. Despite advances, the treatment of AMD has limitations and affected patients are often referred for low vision rehabilitation to help them cope with their remaining eyesight. The characteristic visual impairment for both forms of AMD is loss of central vision (central scotoma). This loss results in severe difficulties with reading that may be only partly compensated by magnifying glasses or screen-projection devices. The loss of central vision associated with the disease has a profound impact on patient quality of life. With progressive central visual loss, patients lose their ability to perform the more complex activities of daily living. Common vision aids include low vision filters, magnifiers, telescopes and electronic aids. Low vision rehabilitation (LVR) is a new subspecialty emerging from the traditional fields of ophthalmology, optometry, occupational therapy, and sociology, with an ever-increasing impact on the usual concepts of research, education, and services for visually impaired patients. Relatively few ophthalmologists practise LVR and fewer still routinely use prismatic image relocation (IR) in AMD patients. IR is a method of stabilizing oculomotor functions with the purpose of promoting better function of preferred retinal loci (PRLs). The aim of vision rehabilitation therapy consists in the achievement of techniques designed to improve PRL usage. The use of PRLs to compensate for diseased foveae has offered hope to these patients in regaining some function. However, in a recently published meta-analysis, prism spectacles were found to be unlikely to be of substantial benefit in people with age-related macular degeneration. Prescription filters are one of the most beneficial visual aids that people with macular degeneration. In principle, one aims both at reducing short-wavelength light to reduce glare and at identifying light with specific wavelengths (colours) preferred by the patient for viewing. In both instances, such interventions result in apparent improved contrast sensitivity and better visual acuity. Although specific tests are performed to determine the best colour, tint, lens material, and type of frame for the patient's need, no scientific protocol has been developed so far to assist in prescribing tinted or selective transmission lenses . Magnifying optical lenses are available in a wide range of dioptric powers and are made from materials that correct for weight (plastic), thickness (high index), spherical aberrations (aspherical), and variable light intensities (photochromatic). These lenses can be used as loose lenses, mounted on optical frames, or used with a wide variety of attachments. As the dioptric power of plus lenses increases, the viewing distance of the target decreases, hence their usefulness mainly for tasks requiring near resolution acuity, like reading. Magnification can also be achieved with the use of telescopic devices that are built of two or more plus and (or) minus (minifying) optical lenses. Normal resolution acuity levels can be achieved with these devices for all viewing distances. Therefore, all telescopic devices are useful only for stationary patient tasks that do not require mobility and orientation. Electronic magnification has the great advantage over plus lenses of producing an acuity reserve enabling reading skills for almost all levels of visual acuity. The additional benefit provided is preservation of binocularity, even at high levels of visual disparity between the two eyes. Vision rehabilitation can help patients to maximize their remaining vision and adapt to activities of daily living. The support of the patient's social network is critical to patient's well-being as patients adjust to being partially sighted.

Reward-associated stimuli capture the eyes in spite of strategic attentional set.

PubMed

Hickey, Clayton; van Zoest, Wieske

2013-11-01

Theories of reinforcement learning have proposed that the association of reward to visual stimuli may cause these objects to become fundamentally salient and thus attention-drawing. A number of recent studies have investigated the oculomotor correlates of this reward-priming effect, but there is some ambiguity in this literature regarding the involvement of top-down attentional set. Existing paradigms tend to create a situation where participants are actively looking for a reward-associated stimulus before subsequently showing that this selective bias sustains when it no longer has strategic purpose. This perseveration of attentional set is potentially different in nature than the direct impact of reward proposed by theory. Here we investigate the effect of reward on saccadic selection in a paradigm where strategic attentional set is decoupled from the effect of reward. We find that during search for a uniquely oriented target, the receipt of reward following selection of a target characterized by an irrelevant unique color causes subsequent stimuli characterized by this color to be preferentially selected. Importantly, this occurs regardless of whether the color characterizes the target or distractor. Other analyses demonstrate that only features associated with correct selection of the target prime the target representation, and that the magnitude of this effect can be predicted by variability in saccadic indices of feedback processing. These results add to a growing literature demonstrating that reward guides visual selection, often in spite of our strategic efforts otherwise. Copyright © 2013 Elsevier B.V. All rights reserved.

Age-Related Macular Degeneration: Genetics and Biology Coming Together

PubMed Central

Fritsche, Lars G.; Fariss, Robert N.; Stambolian, Dwight; Abecasis, Gonçalo R.; Curcio, Christine A.

2014-01-01

Genetic and genomic studies have enhanced our understanding of complex neurodegenerative diseases that exert a devastating impact on individuals and society. One such disease, age-related macular degeneration (AMD), is a major cause of progressive and debilitating visual impairment. Since the pioneering discovery in 2005 of complement factor H (CFH) as a major AMD susceptibility gene, extensive investigations have confirmed 19 additional genetic risk loci, and more are anticipated. In addition to common variants identified by now-conventional genome-wide association studies, targeted genomic sequencing and exome-chip analyses are uncovering rare variant alleles of high impact. Here, we provide a critical review of the ongoing genetic studies and of common and rare risk variants at a total of 20 susceptibility loci, which together explain 40–60% of the disease heritability but provide limited power for diagnostic testing of disease risk. Identification of these susceptibility loci has begun to untangle the complex biological pathways underlying AMD pathophysiology, pointing to new testable paradigms for treatment. PMID:24773320

Ready, Set, Motivate

ERIC Educational Resources Information Center

Coleman, Jennifer

2005-01-01

The impact that visuals can have on the mind of children while reading in the library is discussed. Thus it is important to provide young readers with a visual feast as they begin to choose reading materials to explore independently.

Vision loss among diabetics in a group model Health Maintenance Organization (HMO).

PubMed

Fong, Donald S; Sharza, Mohktar; Chen, Wansu; Paschal, John F; Ariyasu, Reginald G; Lee, Paul P

2002-02-01

To report the management of diabetic retinopathy in one group model health maintenance organization and assess the quality of care. Cross-sectional study. A chart review of 1200 randomly identified patients with diabetes mellitus, continuously enrolled for 3 years in Kaiser Permanente (KP) Southern California, the largest provider of managed care in Southern California, was performed. A total of 1047 patients were included in the analyses. Patient characteristics as well as information from the last eye examination were abstracted. Charts from patients with visual acuity less than 20/200 in their better eye (legal blindness) were selected for extensive chart review to determine the cause of visual loss and the antecedent process of care. T tests or the Wilcoxon rank sum test was used to compare continuous variables. The chi(2) test or the Fisher exact test was used to compare categorical variables. All analyses were performed on the Statistical Analyses System (SAS Institute, North Carolina). Our study population of 1047 diabetic patients was 51.7% male, had a mean age of 60.4 years, a mean duration of diabetes of 9.6 years, and a mean hemoglobin A1c of 8.3%. During the study period, 77.5% of patients received a screening eye examination with examination by an ophthalmologist, an optometrist, or review of a retinal photograph. Of those with a visual acuity assessment (n = 687, 65.6% of 1047), 1.5% had visual acuity of 20/200 or worse (legally blind) in the better eye, while 8.2% had this level of visual acuity in the worse eye. Of eyes with new onset clinically significant macular edema and visual acuity < 20/40, 40% had documentation of focal laser performed within 1 month of diagnosis. Of eyes with vitreous hemorrhage and visual acuity < 20/40, 50% had documentation of vitrectomy. Among eyes that had vitrectomy, over 80% had this procedure within 1 year of diagnosis of vitreous hemorrhage. The current report is the largest study of diabetic retinopathy outcomes among patients enrolled in a prepaid health plan. Further research is necessary to investigate the impact of managed care on health outcomes.

Comparison of Visual Status of Iranian Military and Commercial Drivers

PubMed Central

Ghasemi, Mohammad; Hoseini Yazdi, Seyed Hosein; Heravian, Javad; Jafarzadehpur, Ebrahim; Rezaee, Maryam

2015-01-01

Background: There is no legal requirement for Iranian military truck drivers to undergo regular visual checkups as compared to commercial truck drivers. Objectives: This study aimed to evaluate the impact of drivers’ visual checkups by comparing the visual function of Iranian military and commercial truck drivers. Patients and Methods: In this comparative cross-sectional study, two hundred military and 200 commercial truck drivers were recruited and their Visual Acuity (VA), Visual Field (VF), color vision and Contrast Sensitivity (CS) were assessed and compared using the Snellen chart, confrontation screening method, D15 test and Pelli-Robson letter chart, respectively. A questionnaire regarding driving exposure and history of motor-vehicle crashes (MVCs) was also filled by drivers. Results were analyzed using an independent samples t-test, one-way ANOVA (assessing difference in number of MVCs across different age groups), chi-square test and Pearson correlation at statistical significance level of P < 0.05. Results: Mean age was 41.6 ± 9.2 for the military truck drivers and 43.4 ± 10.9 for commercial truck drivers (P > 0.05). No significant difference between military and commercial drivers was found in terms of driving experience, number of MVCs, binocular VA, frequency of color vision defects and CS scores. In contrast, the last ocular examination was significantly earlier in military drivers than commercial drivers (P < 0.001). In addition, 4% of military drivers did not meet the national standards to drive as opposed to 2% of commercial drivers. There was a significant but weak correlation between binocular VA and age (r = 0.175, P < 0.001). However, CS showed a significantly moderate correlation with age (r = -0.488, P < 0.001). Conclusions: The absence of legal requirement for regular eye examination in military drivers caused the incompetent drivers to be missed in contrast to commercial drivers. The need for scientific revision of VA standard for Iranian drivers is also discussed. The CS measurement in visual checkups of older drivers deserves to be investigated more thoroughly. PMID:26023333

Bilateral Glaucomatous Optic Neuropathy Caused by Eye Rubbing.

PubMed

Savastano, Alfonso; Savastano, Maria Cristina; Carlomusto, Laura; Savastano, Silvio

2015-01-01

In this report, we describe a particular condition of a 52-year-old man who showed advanced bilateral glaucomatous-like optic disc damage, even though the intraocular pressure resulted normal during all examinations performed. Visual field test, steady-state pattern electroretinogram, retinal nerve fiber layer and retinal tomographic evaluations were performed to evaluate the optic disc damage. Over a 4-year observational period, his visual acuity decreased to 12/20 in the right eye and counting fingers in the left eye. Visual fields were severely compromised, and intraocular pressure values were not superior to 14 mm Hg during routine examinations. An accurate anamnesis and the suspicion of this disease represent a crucial aspect to establish the correct diagnosis. In fact, our patient strongly rubbed his eyes for more than 10 h per day. Recurrent and continuous eye rubbing can induce progressive optic neuropathy, causing severe visual field damage similar to the pathology of advanced glaucoma.

Fall with and without fracture in elderly: what's different?

PubMed

Kantayaporn, Choochat

2012-10-01

Falling fracture was one of the health problems in elderly. This presentation aimed to identify the factors of fall that caused fractures. The retrospective case-control study was designed. Samples were all who experienced fall within 1 year in Lamphun. Factors included age, gender underlying diseases, chronic drugs used, history of parent fragility fracture, age of menopause, steroid used, body mass index, visual acuity and time up and go test were studied. Multivariate regression analysis was used. 336 cases of fractures in 1,244 cases of fall were found. Significant factors of falling fracture group that were different from fall without fracture group included age, female gender, menopause before age of 45 and visual impairment. Visual impairment was the other key factor rather than osteoporosis that caused fall with fracture. The author suggested that falling fracture prevention programs should be included correction of visual impairment other than osteoporosis treatment.

Prevalence of Visual Impairment among 4- to 6-years-old Children in Khon Kaen City Municipality, Thailand.

PubMed

Wongwai, Phanthipha; Anupongongarch, Pacharapan; Suwannaraj, Sirinya; Asawaphureekorn, Somkiat

2016-08-01

To evaluate the prevalence of visual impairment of children aged four to six years in Khon Kaen City Municipality, Thailand. The visual acuity test was performed on 1,286 children in kindergarten schools located in Khon Kaen Municipality. The first test of visual acuity was done by trained teachers and the second test by the pediatric ophthalmologist. The prevalence of visual impairment of both tests was recorded including sensitivity, specificity, likelihood ratio, and predictive value of the test by teachers. The causes of visual impairment were also recorded. There were 39 children with visual impairment from the test by the teacher and 12 children from the test by the ophthalmologist. Myopia is the single cause of visual impairment. Mean spherical equivalence is 1.375 diopters (SD = 0.53). Median spherical equivalence is 1.375 diopters (minimum = 0.5, maximum =4). The detection of visual impairment by trained teachers had a sensitivity of 1.00 (95% CI 0.76-1.00), specificity of 0.98 (95% CI 0.97-0.99), likelihood ratio for a positive test 44.58 (95% CI 30.32-65.54), likelihood ratio for a negative test 0.04 (95% CI 0.003-0.60), positive predictive value of 0.31 (95% CI 0.19-0.47), and negative predictive value of 1.00 (95% CI 0.99-1.00). The prevalence of visual impairment among children aged four to six year old is 0.9%. Trained teachers can be examiners for screening purpose.

78 FR 49600 - Notice of Intent To Prepare an Environmental Impact Statement for the Virginia Beach Transit...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-14

... acquisition, visual impacts, displacements and relocations; cultural resources, including impacts on... acquisition and displacement may occur because of the development of park-and-ride facilities, alignments...

Damage criticality and inspection concerns of composite-metallic aircraft structures under blunt impact

NASA Astrophysics Data System (ADS)

Zou, D.; Haack, C.; Bishop, P.; Bezabeh, A.

2015-04-01

Composite aircraft structures such as fuselage and wings are subject to impact from many sources. Ground service equipment (GSE) vehicles are regarded as realistic sources of blunt impact damage, where the protective soft rubber is used. With the use of composite materials, blunt impact damage is of special interest, since potential significant structural damage may be barely visible or invisible on the structure's outer surface. Such impact can result in local or non-local damage, in terms of internal delamination in skin, interfacial delamination between stiffeners and skin, and fracture of internal reinforced component such as stringers and frames. The consequences of these events result in aircraft damage, delays, and financial cost to the industry. Therefore, it is necessary to understand the criticality of damage under this impact and provide reliable recommendations for safety and inspection technologies. This investigation concerns a composite-metallic 4-hat-stiffened and 5-frame panel, designed to represent a fuselage structure panel generic to the new generation of composite aircraft. The test fixtures were developed based on the correlation between finite element analyses of the panel model and the barrel model. Three static tests at certain amount of impact energy were performed, in order to improve the understanding of the influence of the variation in shear ties, and the added rotational stiffness. The results of this research demonstrated low velocity high mass impacts on composite aircraft fuselages beyond 82.1 kN of impact load, which may cause extensive internal structural damage without clear visual detectability on the external skin surface.

Mapping and Visualization of Storm-Surge Dynamics for Hurricane Katrina and Hurricane Rita

USGS Publications Warehouse

Gesch, Dean B.

2009-01-01

The damages caused by the storm surges from Hurricane Katrina and Hurricane Rita were significant and occurred over broad areas. Storm-surge maps are among the most useful geospatial datasets for hurricane recovery, impact assessments, and mitigation planning for future storms. Surveyed high-water marks were used to generate a maximum storm-surge surface for Hurricane Katrina extending from eastern Louisiana to Mobile Bay, Alabama. The interpolated surface was intersected with high-resolution lidar elevation data covering the study area to produce a highly detailed digital storm-surge inundation map. The storm-surge dataset and related data are available for display and query in a Web-based viewer application. A unique water-level dataset from a network of portable pressure sensors deployed in the days just prior to Hurricane Rita's landfall captured the hurricane's storm surge. The recorded sensor data provided water-level measurements with a very high temporal resolution at surveyed point locations. The resulting dataset was used to generate a time series of storm-surge surfaces that documents the surge dynamics in a new, spatially explicit way. The temporal information contained in the multiple storm-surge surfaces can be visualized in a number of ways to portray how the surge interacted with and was affected by land surface features. Spatially explicit storm-surge products can be useful for a variety of hurricane impact assessments, especially studies of wetland and land changes where knowledge of the extent and magnitude of storm-surge flooding is critical.

Training-Induced Recovery of Low-Level Vision Followed by Mid-Level Perceptual Improvements in Developmental Object and Face Agnosia

ERIC Educational Resources Information Center

Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L.; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

2015-01-01

Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental…

Native-Language Phonological Interference in Early Hakka-Mandarin Bilinguals' Visual Recognition of Chinese Two-Character Compounds: Evidence from the Semantic-Relatedness Decision Task

ERIC Educational Resources Information Center

Wu, Shiyu; Ma, Zheng

2017-01-01

Previous research has indicated that, in viewing a visual word, the activated phonological representation in turn activates its homophone, causing semantic interference. Using this mechanism of phonological mediation, this study investigated native-language phonological interference in visual recognition of Chinese two-character compounds by early…

Rapid recovery from the effects of early monocular deprivation is enabled by temporary inactivation of the retinas.

PubMed

Fong, Ming-Fai; Mitchell, Donald E; Duffy, Kevin R; Bear, Mark F

2016-12-06

A half-century of research on the consequences of monocular deprivation (MD) in animals has revealed a great deal about the pathophysiology of amblyopia. MD initiates synaptic changes in the visual cortex that reduce acuity and binocular vision by causing neurons to lose responsiveness to the deprived eye. However, much less is known about how deprivation-induced synaptic modifications can be reversed to restore normal visual function. One theoretically motivated hypothesis is that a period of inactivity can reduce the threshold for synaptic potentiation such that subsequent visual experience promotes synaptic strengthening and increased responsiveness in the visual cortex. Here we have reduced this idea to practice in two species. In young mice, we show that the otherwise stable loss of cortical responsiveness caused by MD is reversed when binocular visual experience follows temporary anesthetic inactivation of the retinas. In 3-mo-old kittens, we show that a severe impairment of visual acuity is also fully reversed by binocular experience following treatment and, further, that prolonged retinal inactivation alone can erase anatomical consequences of MD. We conclude that temporary retinal inactivation represents a highly efficacious means to promote recovery of function.

Factors affecting the visual outcome in hyphema management in Guinness Eye Center Onitsha.

PubMed

Onyekwe, L O

2008-12-01

This study aims of determining the complications, outcome of hyphema treatment and recommend ways of enhancing good visual outcome. The records of all cases of hyphema seen from 1st January 2001 to 31st December 2005 were reviewed retrospectively. The variables analyzed were the biodata of all the patients, the agents causing hyphema, associated injuries and complications. Visual acuity at presentation, discharge and last visit was analyzed. Seventy four patients that had hyphema were reviewed. The male:female ratio was 3.5:1. Trauma was predominantly main cause of hyphema. The common agents of injury include whip (23.2%) and fist (18.8%). The common complications were secondary glaucoma (52.5%), corneal siderosis (30.0%) and rebleeding (10%). Visual outcome is related to time ofpresentation, complications and treatment. Significant improvement was achieved following treatment. Hyphema is a common complication of eye injuries. It is commonly associated with other eye injuries like vitreous haemorrhage and cataract. Common complications include secondary glaucoma, corneal siderosis and rebleeding. Visual outcome is dependent on time of presentation, severity and nature of complications. Visual outcome can be improved by early presentation and detection of complications and appropriate treatment.

The Nigerian national blindness and visual impairment survey: Rationale, objectives and detailed methodology

PubMed Central

Dineen, Brendan; Gilbert, Clare E; Rabiu, Mansur; Kyari, Fatima; Mahdi, Abdull M; Abubakar, Tafida; Ezelum, Christian C; Gabriel, Entekume; Elhassan , Elizabeth; Abiose, Adenike; Faal, Hannah; Jiya, Jonathan Y; Ozemela, Chinenyem P; Lee, Pak Sang; Gudlavalleti, Murthy VS

2008-01-01

Background Despite having the largest population in Africa, Nigeria has no accurate population based data to plan and evaluate eye care services. A national survey was undertaken to estimate the prevalence and determine the major causes of blindness and low vision. This paper presents the detailed methodology used during the survey. Methods A nationally representative sample of persons aged 40 years and above was selected. Children aged 10–15 years and individuals aged <10 or 16–39 years with visual impairment were also included if they lived in households with an eligible adult. All participants had their height, weight, and blood pressure measured followed by assessment of presenting visual acuity, refractokeratomery, A-scan ultrasonography, visual fields and best corrected visual acuity. Anterior and posterior segments of each eye were examined with a torch and direct ophthalmoscope. Participants with visual acuity of < = 6/12 in one or both eyes underwent detailed examination including applanation tonometry, dilated slit lamp biomicroscopy, lens grading and fundus photography. All those who had undergone cataract surgery were refracted and best corrected vision recorded. Causes of visual impairment by eye and for the individual were determined using a clinical algorithm recommended by the World Health Organization. In addition, 1 in 7 adults also underwent a complete work up as described for those with vision < = 6/12 for constructing a normative data base for Nigerians. Discussion The field work for the study was completed in 30 months over the period 2005–2007 and covered 305 clusters across the entire country. Concurrently persons 40+ years were examined to form a normative data base. Analysis of the data is currently underway. Conclusion The methodology used was robust and adequate to provide estimates on the prevalence and causes of blindness in Nigeria. The survey would also provide information on barriers to accessing services, quality of life of visually impaired individuals and also provide normative data for Nigerian eyes. PMID:18808712