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Sample records for colour vision impairment

  1. Colour Vision Impairment in Young Alcohol Consumers

    PubMed Central

    Brasil, Alódia; Castro, Antônio José O.; Martins, Isabelle Christine V. S.; Lacerda, Eliza Maria C. B.; Souza, Givago S.; Herculano, Anderson Manoel; Rosa, Alexandre Antônio M.; Rodrigues, Anderson R.; Silveira, Luiz Carlos L.

    2015-01-01

    Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns. Twenty-four young adults were evaluated by an ophthalmologist and performed three psychophysical tests to evaluate their vision functions. We estimated the spatial luminance contrast sensitivity function at 11 spatial frequencies ranging from 0.1 to 30 cycles/degree. No difference in contrast sensitivity was observed comparing alcohol consumers and control subjects. For the evaluation of colour vision, we used the Farnsworth-Munsell 100 hue test (FM 100 test) to test subject’s ability to perform a colour arrangement task and the Mollon-Reffin test (MR test) to measure subject’s colour discrimination thresholds. Alcohol consumers made more mistakes than controls in the FM100 test, and their mistakes were diffusely distributed in the FM colour space without any colour axis preference. Alcohol consumers also performed worse than controls in the MR test and had higher colour discrimination thresholds compared to controls around three different reference points of a perceptually homogeneous colour space, the CIE 1976 chromaticity diagram. There was no colour axis preference in the threshold elevation observed among alcoholic subjects. Young adult weekly alcohol consumers showed subclinical colour vision losses with preservation of spatial luminance contrast sensitivity. Adolescence and young adult age are periods of important neurological development and alcohol exposure during this period of life might be responsible for deficits in visual functions, especially colour vision that is very sensitive to neurotoxicants. PMID

  2. Colour vision loss among disabled workers with neuropsychological impairment.

    PubMed

    Mergler, D; Bowler, R; Cone, J

    1990-01-01

    Test performance on a neurobehavioural battery was examined with respect to acquired colour vision loss among patients with a history of neurotoxin exposure. The study group included 14 men and 7 women with clinically diagnosed neuropsychological impairment (mean age: 41.3 +/- 8.1 years; mean educational level: 13.4 +/- 1.4 years). Verbal and visual ability, memory and psychomotor function were assessed with the California Neuropsychological Screening Battery. Colour vision was assessed with the Lanthony D-15 desaturated colour arrangement panel. Acquired dyschromatopsia was present in 17 patients (80.9%), 11 of whom manifested patterns of Type II colour vision loss. Simple regression analysis of neuropsychological test performance with respect to colour vision loss, using age-adjusted Z-scores, revealed significant relationships (p less than or equal to 0.05) solely for tests which rely heavily on the visual system. Significant differences in visual task test scores were also observed with the type of dyschromatopsia (Kruskal-Wallis, p less than or equal to 0.05). These findings suggest that poor performance on visual tasks and colour vision loss may both result from damage to neuro-ophthalmic pathways or that loss of integrity of the peripheral visual pathways may affect visual task performance. The authors propose that visual testing should be incorporated into neurobehavioural test batteries. PMID:2255314

  3. Blue-yellow colour vision impairment and cognitive deficits in occasional and dependent stimulant users.

    PubMed

    Hulka, Lea M; Wagner, Michael; Preller, Katrin H; Jenni, Daniela; Quednow, Boris B

    2013-04-01

    Specific blue-yellow colour vision impairment has been reported in dependent cocaine users and it was postulated that drug-induced changes in retinal dopamine neurotransmission are responsible. However, it is unclear whether these changes are confined to chronic cocaine users, whether they are specific for dopaminergic stimulants such as cocaine and amphetamine and whether they are related to cognitive functions such as working memory, encoding and consolidation. In 47 occasional and 29 dependent cocaine users, 23 MDMA (commonly known as 'ecstasy') users and 47 stimulant-naive controls, colour vision discrimination was measured with the Lanthony Desaturated Panel D-15 Test and memory performance with the Auditory Verbal Learning Test. Both occasional and dependent cocaine users showed higher colour confusion indices than controls. Users of the serotonergic stimulant MDMA (26%), occasional (30%) and dependent cocaine users (34%) exhibited more frequent blue-yellow colour vision disorders compared to controls (9%). Inferior performance of MDMA users was caused by a subgroup with high amphetamine co-use (55%), while MDMA use alone was not associated with decreased blue-yellow discrimination (0%). Cognitive performance was worse in cocaine users with colour vision disorder compared to users and controls with intact colour vision and both colour vision impairment and cognitive deficits were related to cocaine use. Occasional cocaine and amphetamine use might induce blue-yellow colour vision impairment, whereas the serotonergic stimulant MDMA does not impair colour vision. The association between colour vision impairment and cognitive deficits in cocaine users may reflect that retinal and cerebral dopamine alterations are linked to a certain degree. PMID:22704223

  4. Unconventional colour vision.

    PubMed

    Marshall, Justin; Arikawa, Kentaro

    2014-12-15

    Butterflies and stomatopods are certainly outliers in their unconventional colour sense and despite some similarities at first glance, in fact sample the world of colour very differently. In one way, butterflies are relatively conventional, possessing either tri-or tetrachromatic colour vision, then just adding one or several task-specific sub-mechanisms onto this. It is the stomatopods so far that have really pushed the boat out into a different colour vision mechanism. Over 400 million years of independent evolution they have arrived at a solution with more in common with the way a satellite sensor examines the colours of the earth than other animals. Remember, however, that unconventional colour vision is not just the realm of the serially polychromatic. Apparently waterfleas with four classes of spectral receptors living in ponds operate a task-specific spectral sense with no need, or indeed neural processing power, to construct a complex discriminatory mechanism. It seems they have the butterfly added-extra set without the more complex comparative chromatic mechanisms, although in truth, conclusive behavioural proof is lacking. Behavioural observation of colour vision in the ecological context of each animal is vital before making the distinction between conventional and unconventional. Just counting spectral sensitivities is never enough. PMID:25514002

  5. All Vision Impairment

    MedlinePlus

    ... Jobs Home > Statistics and Data > All Vision Impairment All Vision Impairment Vision Impairment Defined Vision impairment is ... being blind by the U.S. definition.) The category “All Vision Impairment” includes both low vision and blindness. ...

  6. Colour vision in marine organisms.

    PubMed

    Marshall, Justin; Carleton, Karen L; Cronin, Thomas

    2015-10-01

    Colour vision in the marine environment is on average simpler than in terrestrial environments with simple or no colour vision through monochromacy or dichromacy. Monochromacy is found in marine mammals and elasmobranchs, including whales and sharks, but not some rays. Conversely, there is also a greater diversity of colour vision in the ocean than on land, examples being the polyspectral stomatopods and the many colour vision solutions found among reef fish. Recent advances in sequencing reveal more opsin (visual pigment) types than functionally useful at any one time. This diversity arises through opsin duplication and conversion. Such mechanisms allow pick-and-mix adaptation that tunes colour vision on a variety of very short non-evolutionary timescales. At least some of the diversity in marine colour vision is best explained as unconventional colour vision or as neutral drift. PMID:25725325

  7. A Colour Vision Experiment.

    ERIC Educational Resources Information Center

    Lovett, David; Hore, Kevin

    1991-01-01

    The model for color vision put forward by Edwin Land is explained. The aspects of the theory that can be demonstrated within the classroom are described. A random arrangement of straight-edged colored areas mounted on a screen, called a Mondrian, projectors, and a computer are used to calculate reflectance. (KR)

  8. Neurological deficits in solvent-exposed painters: a syndrome including impaired colour vision, cognitive defects, tremor and loss of vibration sensation.

    PubMed

    Dick, F; Semple, S; Chen, R; Seaton, A

    2000-10-01

    Five individuals are described who had participated in a study of former dockyard painters. All had worked between 16 years and 45 years as industrial painters, much of the time inside ships. All underwent structured neurological examination, colour vision testing (allowing calculation of a colour confusion index corrected for age and alcohol), and detailed psychometric testing. An occupational history sufficient to allow estimation of past exposure to solvents was taken. All gave a history of exposure to high concentrations of solvents at work, and several described episodes of acute narcosis. All showed neurological deficits and some had overt neurological disease, although in no case had this previously been linked to their work. The most striking features, sufficient to constitute a syndrome, were acquired blue-yellow colour vision deficits, coarse tremor, impaired vibration sensation in the legs and cognitive impairment. Their estimated cumulative exposures to solvents ranged between the equivalent of 13 and 37 calendar years working at the Occupational Exposure Standard concentration (OES years). This study for the first time gives an indication of the concentrations of solvents likely to lead to serious neurological disease in humans. It serves as a reminder to physicians to take an occupational history from patients with obscure neurological or psychological impairment. PMID:11029475

  9. Impairments to Vision

    MedlinePlus

    ... an external Non-Government web site. Impairments to Vision Normal Vision Diabetic Retinopathy Age-related Macular Degeneration In this ... pictures, fixate on the nose to simulate the vision loss. In diabetic retinopathy, the blood vessels in ...

  10. Colour vision deficiency and physics teaching

    NASA Astrophysics Data System (ADS)

    Maule, Louise; Featonby, David

    2016-05-01

    1 in 12 males suffer from some form of colour vision deficiency (CVD) which in the present colour dominated world of education presentation can be a severe disadvantage. Although aware of ‘colourblindness’ most teachers make little or no adjustment for these pupils for whom tasks may be more difficult. This article examines colour vision deficiency and looks at ways in which we can help the many students who have this problem.

  11. Impairment of Colour Vision in Diabetes with No Retinopathy: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetics Study (SNDREAMS- II, Report 3)

    PubMed Central

    Gella, Laxmi; Raman, Rajiv; Kulothungan, Vaitheeswaran; Pal, Swakshyar Saumya; Ganesan, Suganeswari; Sharma, Tarun

    2015-01-01

    Purpose To assess impairment of colour vision in type 2 diabetics with no diabetic retinopathy and elucidate associated risk factors in a population-based cross-sectional study. Methods This is part of Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular-genetics Study (SN-DREAMS II) which was conducted between 2007–2010. FM 100 hue-test was performed in 253 subjects with no clinical evidence of diabetic retinopathy. All subjects underwent detailed ophthalmic evaluation including cataract grading using LOCS III and 45° 4-field stereoscopic fundus photography. Various ocular and systemic risk factors for impairment of colour vision (ICV) were assessed in subjects with diabetes but no retinopathy. P value of < 0.05 was considered statistically significant. Results The mean age of the study sample was 57.08 ± 9.21 (range: 44–86 years). Gender adjusted prevalence of ICV among subjects with diabetes with no retinopathy was 39.5% (CI: 33.5–45.5). The mean total error score in the study sample was 197.77 ± 100 (range: 19–583). The risk factors for ICV in the study were women OR: 1.79 (1.00–3.18), increased resting heart rate OR: 1.04 (1.01–1.07) and increased intraocular pressure OR: 1.12 (1.00–1.24). Significant protective factor was serum high-density lipoprotein OR: 0.96 (0.93–0.99). Conclusions Acquired ICV is an early indicator of neurodegenerative changes in the retina. ICV found in diabetic subjects without retinopathy may be of non-vascular etiology. PMID:26053017

  12. Evolution of colour vision in mammals

    PubMed Central

    Jacobs, Gerald H.

    2009-01-01

    Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The basic biological mechanisms on which vertebrate colour vision ultimately rests, the cone opsin genes and the photopigments they specify, are highly conserved. Within that constraint, however, the utilization of these basic elements varies in striking ways in that they appear, disappear and emerge in altered form during the course of evolution. These changes, along with other alterations in the visual system, have led to profound variations in the nature and salience of colour vision among the vertebrates. This article concerns the evolution of colour vision among the mammals, viewing that process in the context of relevant biological mechanisms, of variations in mammalian colour vision, and of the utility of colour vision. PMID:19720656

  13. Kids' Quest: Vision Impairment

    MedlinePlus

    ... important job. Â Return to Steps World-Wide Web Search Kids Health: What is Vision Impairment What ... for the Blind (AFB) created the Braille Bug web site to teach sighted children about braille, and ...

  14. Colour vision: parallel pathways intersect in Drosophila.

    PubMed

    Kelber, Almut; Henze, Miriam J

    2013-12-01

    In the last one hundred years, colour vision has been demonstrated in bees and many other insects. But the underlying neural wiring remained elusive. A new study on Drosophila melanogaster combining behavioural and genetic tools yields surprising insights. PMID:24309280

  15. The Physics of Colour Vision.

    ERIC Educational Resources Information Center

    Goldman, Martin

    1985-01-01

    An elementary physical model of cone receptor cells is explained and applied to complexities of human color vision. One-, two-, and three-receptor systems are considered, with the later shown to be the best model for the human eye. Color blindness is also discussed. (DH)

  16. Modelling colour constancy in fish: implications for vision and signalling in water.

    PubMed

    Wilkins, Lucas; Marshall, N Justin; Johnsen, Sönke; Osorio, D

    2016-06-15

    Colour vision and colour signals are important to aquatic animals, but light scattering and absorption by water distorts spectral stimuli. To investigate the performance of colour vision in water, and to suggest how photoreceptor spectral sensitivities and body colours might evolve for visual communication, we model the effects of changes in viewing distance and depth on the appearance of fish colours for three teleosts: a barracuda, Sphyraena helleri, which is dichromatic and two damselfishes, Chromis verater and Chromis hanui, which are trichromatic. We assume that photoreceptors light-adapt to the background, thereby implementing the von Kries transformation, which can largely account for observed colour constancy in humans and other animals, including fish. This transformation does not, however, compensate for light scattering over variable viewing distances, which in less than a metre seriously impairs dichromatic colour vision, and makes judgement of colour saturation unreliable for trichromats. The von Kries transformation does substantially offset colour shifts caused by changing depth, so that from depths of 0 to 30 m modelled colour changes (i.e. failures of colour constancy) are sometimes negligible. However, the magnitudes and directions of remaining changes are complex, depending upon the specific spectral sensitivities of the receptors and the reflectance spectra. This predicts that when judgement of colour is important, the spectra of signalling colours and photoreceptor spectral sensitivities should be evolutionarily linked, with the colours dependent on photoreceptor spectral sensitivities, and vice versa. PMID:27045090

  17. Mechanisms, functions and ecology of colour vision in the honeybee.

    PubMed

    Hempel de Ibarra, N; Vorobyev, M; Menzel, R

    2014-06-01

    Research in the honeybee has laid the foundations for our understanding of insect colour vision. The trichromatic colour vision of honeybees shares fundamental properties with primate and human colour perception, such as colour constancy, colour opponency, segregation of colour and brightness coding. Laborious efforts to reconstruct the colour vision pathway in the honeybee have provided detailed descriptions of neural connectivity and the properties of photoreceptors and interneurons in the optic lobes of the bee brain. The modelling of colour perception advanced with the establishment of colour discrimination models that were based on experimental data, the Colour-Opponent Coding and Receptor Noise-Limited models, which are important tools for the quantitative assessment of bee colour vision and colour-guided behaviours. Major insights into the visual ecology of bees have been gained combining behavioural experiments and quantitative modelling, and asking how bee vision has influenced the evolution of flower colours and patterns. Recently research has focussed on the discrimination and categorisation of coloured patterns, colourful scenes and various other groupings of coloured stimuli, highlighting the bees' behavioural flexibility. The identification of perceptual mechanisms remains of fundamental importance for the interpretation of their learning strategies and performance in diverse experimental tasks. PMID:24828676

  18. Colour vision experimental studies in teaching of optometry

    NASA Astrophysics Data System (ADS)

    Ozolinsh, Maris; Ikaunieks, Gatis; Fomins, Sergejs

    2005-10-01

    Following aspects related to human colour vision are included in experimental lessons for optometry students of University of Latvia. Characteristics of coloured stimuli (emitting and reflective), determination their coordinates in different colour spaces. Objective characteristics of transmitting of colour stimuli through the optical system of eye together with various types of appliances (lenses, prisms, Fresnel prisms). Psychophysical determination of mono- and polychromatic stimuli perception taking into account physiology of eye, retinal colour photoreceptor topography and spectral sensitivity, spatial and temporal characteristics of retinal receptive fields. Ergonomics of visual perception, influence of illumination and glare effects, testing of colour vision deficiencies.

  19. Colour vision deficiency in the medical profession.

    PubMed Central

    Spalding, J A

    1999-01-01

    Colour is often used as a sign in medicine, yet there have been few studies into the effects of a colour vision deficiency (CVD) on doctors' medical skills. Using a literature search, the results indicate the prevalence of CVD in the medical profession and its effects on medical skills. For the congenital form among male doctors in the United Kingdom, the prevalence is shown to be probably about the same as for the population at large; i.e. 8%. However, the data is insufficient for any estimate to be made of the small number of female doctors and for the acquired forms of CVD. The effect on skills is also shown. Because of certain features of their work, general practitioners may have special problems. Thus, it is concluded that medical students and doctors should be screened for the deficiency and advised about it, and that there should be more study of the effects of CVD on decision-making in general practice and some specialties. PMID:10562750

  20. Vision Impairment and Blindness

    MedlinePlus

    ... blindness in the United States are age-related eye diseases: macular degeneration, cataract and glaucoma. Other eye disorders, ... and braille books. The sooner vision loss or eye disease is found and treated, the greater your chances ...

  1. Colour vision in diurnal and nocturnal hawkmoths.

    PubMed

    Kelber, Almut; Balkenius, Anna; Warrant, Eric J

    2003-08-01

    Diurnal and nocturnal hawkmoths (Sphingidae, Lepidoptera) have three spectral types of receptor sensitive to ultraviolet, blue and green light. As avid flower visitors and pollinators, they use olfactory and visual cues to find and recognise flowers. Moths of the diurnal species Macroglossum stellatarum and the nocturnal species Deilephila elpenor, Hyles lineata and Hyles gallii use and learn the colour of flowers. Nocturnal species can discriminate flowers at starlight intensities when humans and honeybees are colour-blind. M. stellatarum can use achromatic, intensity-related cues if colour cues are absent, and this is probably also true for D. elpenor. Both species can recognise colours even under a changed illumination colour. PMID:21680465

  2. Parallel inputs to memory in bee colour vision.

    PubMed

    Horridge, Adrian

    2016-03-01

    In the 19(th) century, it was found that attraction of bees to light was controlled by light intensity irrespective of colour, and a few critical entomologists inferred that vision of bees foraging on flowers was unlike human colour vision. Therefore, quite justly, Professor Carl von Hess concluded in his book on the Comparative Physiology of Vision (1912) that bees do not distinguish colours in the way that humans enjoy. Immediately, Karl von Frisch, an assistant in the Zoology Department of the same University of Münich, set to work to show that indeed bees have colour vision like humans, thereby initiating a new research tradition, and setting off a decade of controversy that ended only at the death of Hess in 1923. Until 1939, several researchers continued the tradition of trying to untangle the mechanism of bee vision by repeatedly testing trained bees, but made little progress, partly because von Frisch and his legacy dominated the scene. The theory of trichromatic colour vision further developed after three types of receptors sensitive to green, blue, and ultraviolet (UV), were demonstrated in 1964 in the bee. Then, until the end of the century, all data was interpreted in terms of trichromatic colour space. Anomalies were nothing new, but eventually after 1996 they led to the discovery that bees have a previously unknown type of colour vision based on a monochromatic measure and distribution of blue and measures of modulation in green and blue receptor pathways. Meanwhile, in the 20(th) century, search for a suitable rationalization, and explorations of sterile culs-de-sac had filled the literature of bee colour vision, but were based on the wrong theory. PMID:26960353

  3. Bird colour vision: behavioural thresholds reveal receptor noise.

    PubMed

    Olsson, Peter; Lind, Olle; Kelber, Almut

    2015-01-15

    Birds have impressive physiological adaptations for colour vision, including tetrachromacy and coloured oil droplets, yet it is not clear exactly how well birds can discriminate the reflecting object colours that they encounter in nature. With behavioural experiments, we determined colour discrimination thresholds of chickens in bright and dim light. We performed the experiments with two colour series, orange and green, covering two parts of chicken colour space. These experiments allowed us to compare behavioural results with model expectations and determine how different noise types limit colour discrimination. At intensities ranging from bright light to those corresponding to early dusk (250-10 cd m(-2)), we describe thresholds accurately by assuming a constant signal-to-noise ratio, in agreement with an invariant Weber fraction of Weber's law. Below this intensity, signal-to-noise ratio decreases and Weber's law is violated because photon-shot noise limits colour discrimination. In very dim light (below 0.05 cd m(-2) for the orange series or 0.2 cd m(-2) for the green series) colour discrimination is possibly constrained by dark noise, and the lowest intensity at which chickens can discriminate colours is 0.025 and 0.08 cd m(-2) for the orange and green series, respectively. Our results suggest that chickens use spatial pooling of cone outputs to mitigate photon-shot noise. Surprisingly, we found no difference between colour discrimination of chickens and humans tested with the same test in bright light. PMID:25609782

  4. Dark Adaptation of Colour Vision in Diabetic Subjects

    NASA Astrophysics Data System (ADS)

    Márquez-Gamiño, S.; Cortés-Peñaloza, J. L.; Pérez-Hernández, J. U.; Cruz-Rodríguez, E.; Caudillo, C.

    2004-09-01

    Eye disease, a late complication of diabetes mellitus (DM) occurs even under a careful glicemic control. It includes optic nerve, retina, vitreous humor, crystalline lens and pupillary affection. The physiopathological process could be independent of blood glucose levels or start at initial stages of the disease. Photoreceptors have specific physiological functions. The functional substrate of day light or colour vision in superior primates, the cones have different spectral sensitivity, 455, 530 and 560 nm. The rods, maximal sensitivity at 505 nm, are much more sensitive to light than are cones. Dark adaptation was tested to evaluate functional impairment differences in photoreceptors of diabetic subjects. 14 DM2 (type 2 DM), and 5 DM1 (type 1 DM) patients, as well as 9 healthy subjects were studied. Retinal affected individuals, were excluded. Dark adaptation curves seemed to be different between DM, and healthy subjects. Cones, specially those sensitive to 560 nm type, seems to be more labile to DM, as demonstrated by the lack of sensitivity to low, and medium intensity stimuli. Medical Physics and elementary Biomedical Engineering exhibited to be useful to discern malfunction between different types of photorreceptors. The inexpensive method used could be applied for early color vision alteration detection.

  5. Correlation between dichromatic colour vision and jumping performance in horses.

    PubMed

    Spaas, Julie; Helsen, Werner F; Adriaenssens, Maurits; Broeckx, Sarah; Duchateau, Luc; Spaas, Jan H

    2014-10-01

    There is general agreement that horses have dichromatic colour vision with similar capabilities to human beings with red-green colour deficiencies. However, whether colour perception has an impact on equine jumping performance and how pronounced the colour stimulus might be for a horse is unknown. The present study investigated the relationship between the colour of the fences (blue or green) and the show jumping performance of 20 horses ridden by two riders using an indoor and outdoor set of green and blue fences. In the indoor arena, significantly more touches and faults were made on blue fences in comparison to green fences (median difference of 2.5 bars). When only touched bars were included, a significant median difference of one bar was found. Mares (n = 4) demonstrated more faults and had a significantly greater difference in touches and faults between the two colours than male horses (n = 16). Repeating the same experiment with eight horses in an outdoor grass arena revealed no significant differences between the two colours. In order to draw any definite conclusions, more research concerning the colour perception, influence of contrast with the arena surface and sex of horse is required. PMID:25193409

  6. Detecting chloroquine retinopathy: electro-oculogram versus colour vision

    PubMed Central

    Neubauer, A S; Samari-Kermani, K; Schaller, U; Welge-Lüβen, U; Rudolph, G; Berninger, T

    2003-01-01

    Aim: To investigate the relative sensitivity and specificity of two tests of retinal function (the electro-oculogram (EOG) and a computerised colour vision test) in screening for ocular toxicity caused by chloroquine and hydroxychloroquine. Methods: 93 patients with rheumatic diseases receiving long term chloroquine and hydroxychloroquine therapy were followed for an average of 2.6 years. Clinical examination, an EOG, and a quantitative test of colour vision were carried out every 6 months. Results: Mild fundus changes were observed in 38 patients. Four patients developed typical bull’s eye maculopathy, three of whom had received 250, 365, and 550 g total dose of chloroquine, and one 1500 g of hydroxychloroquine. Statistical analysis of all patients showed that for those with no fundus changes or stippled pigmentation a number showed elevation of tritan threshold, so that if macular stippling is a sign of mild retinopathy the test on tritan changes has a 64% sensitivity and 63% specificity for an upper threshold value of 7%. All four patients with bull’s eye lesions showed a marked disturbance of tritan colour vision, with a threshold of 14.8%, a sensitivity of 75%, and a specificity of 94%. For protan colour vision a threshold of 10% gives 75% sensitivity and 91% specificity. By contrast, neither an absolute nor a relative EOG reduction was a valid criterion for early or late chloroquine retinopathy. In advanced retinopathy an Arden coefficient (AQ) <180% yields 50% sensitivity and 54% specificity. When AQ <160% is the threshold, sensitivity does not increase but specificity rises to 82%. Occurrence of marked corneal deposits on clinical examination yields 50% sensitivity and 90% specificity in this situation. Conclusion: Screening for chloroquine retinopathy can be improved by using a sensitive colour test. Disturbance of the tritan axis appears to occur first. A normal test result on computerised colour testing virtually excludes any retinopathy by

  7. Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

    PubMed Central

    Eguchi, T; Kishi, R; Harabuchi, I; Yuasa, J; Arata, Y; Katakura, Y; Miyake, H

    1995-01-01

    OBJECTIVES--To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. METHODS--Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI). RESULTS--The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss. CONCLUSIONS--These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene. PMID:7663639

  8. Theory and practice of colour vision testing: A review Part 1

    PubMed Central

    Lakowski, R.

    1969-01-01

    Lakowski, R. (1969).Brit. J. industr. Med.,26, 173-189. Theory and practice of colour vision testing: A review Part I. It is the concern of this paper to examine not only the effectiveness of tests for detecting colour confusion but also their usefulness in assessing colour vision generally. In part 1, problems of administration and age and the question of the basic elements of such tests are discussed. The existing theory of colour vision and colour defect is outlined and the principle of objective colour specification, which is believed to be valuable for understanding these tests, is introduced. PMID:4893872

  9. Colour change in cyanosis and the confusions of congenital colour vision deficient observers.

    PubMed

    McNamara, Renae; Taylor, Clair M; McKenzie, David K; Coroneo, Minas T; Dain, Stephen J

    2010-09-01

    Visual recognition of cyanosis is an important clinical activity. While pulse oximetry is almost universal in the hospital environment, there are circumstances where it is not available or may be unreliable. Cyanosis recognition is affected by lighting colour. In addition, there is, mainly anecdotal, evidence that people with greater colour vision deficiencies (CVDs) have particular difficulty and there is no effective lighting strategy to assist in the observation. The change of blood colour with oxygenation has been shown to lie close to the direction of colour confusions made by congenital red-green dichromats. The important sites of observation are lips, nail beds and palm creases. 10 subjects who were known to be chronically hypoxaemic were recruited from the chronic respiratory program. Their blood oxygen saturation (SpO(2)) varied from 84% to 96% pre-exercise, and 61-84% post-exercise. Ten normal subjects were recruited whose SpO(2) was 99% or 100%. The spectral radiances of lips, nail beds and palm creases were measured using a telespectroradiometer and compared with the spectral radiances of a white tile of known spectral reflectances measured in the same location. This is a non-contact method of measurement, avoiding the blanching caused by pressure of contact methods. The spectral reflectances were calculated, and the chromaticities calculated for a Planckian radiator T = 4000K. Measurements on lips yielded the most consistent results. The colour changes pre- and post-exercise and compared with normal colour lie generally along a deutan confusion line. These results show the direction of the colour change and confirm the, previously anecdotal, difficulties in detecting cyanosis by observers with CVDs. PMID:20883357

  10. Colour vision and response bias in a coral reef fish.

    PubMed

    Cheney, Karen L; Newport, Cait; McClure, Eva C; Marshall, N Justin

    2013-08-01

    Animals use coloured signals for a variety of communication purposes, including to attract potential mates, recognize individuals, defend territories and warn predators of secondary defences (aposematism). To understand the mechanisms that drive the evolution and design of such visual signals, it is important to understand the visual systems and potential response biases of signal receivers. Here, we provide raw data on the spectral capabilities of a coral reef fish, the Picasso triggerfish Rhinecanthus aculeatus, which is potentially trichromatic with three cone sensitivities of 413 nm (single cone), 480 nm (double cone, medium sensitivity) and 528 nm (double cone, long sensitivity), and a rod sensitivity of 498 nm. The ocular media have a 50% transmission cut off at 405 nm. Behavioural experiments confirmed colour vision over their spectral range; triggerfish were significantly more likely to choose coloured stimuli over grey distractors, irrespective of luminance. We then examined whether response biases existed towards coloured and patterned stimuli to provide insight into how visual signals - in particular, aposematic colouration - may evolve. Triggerfish showed a preferential foraging response bias to red and green stimuli, in contrast to blue and yellow, irrespective of pattern. There was no response bias to patterned over monochromatic non-patterned stimuli. A foraging response bias towards red in fish differs from that of avian predators, who often avoid red food items. Red is frequently associated with warning colouration in terrestrial environments (ladybirds, snakes, frogs), whilst blue is used in aquatic environments (blue-ringed octopus, nudibranchs); whether the design of warning (aposematic) displays is a cause or consequence of response biases is unclear. PMID:23580729

  11. Should prospective dental students be screened for colour vision deficits?

    PubMed

    Mushtaq, F; Baraas, R C; Al-Saud, L M; Mirghani, I; van der Zee, C; Yates, E; Keeling, A; Mon-Williams, M A; Manogue, M

    2016-09-01

    A perennial question in dental education is: what skills and aptitudes should be assessed in prospective dental students? Intellectual capacity and manual dexterity understandably rank highly, but are there minimum thresholds for visual perception that applicants need be able to demonstrate before they enter the profession? We have recently flagged this issue with regard to the thresholds of stereoscopic acuity required for a dentist when operating on teeth. In the present article, we highlight the issue of identifying a minimum acceptable level of colour vision. PMID:27608568

  12. iPad colour vision apps for dyschromatopsia screening.

    PubMed

    Campbell, Thomas Gordon; Lehn, Alexander; Blum, Stefan; Airey, Caroline; Brown, Helen

    2016-07-01

    Optic neuritis (ON) is a common and important cause of vision loss or vision disturbances in the community, particularly amongst the young, and it is often associated with a persistent dyschromatopsia. Traditionally screening for dyschromatopsia has been carried out using pseudo-isochromatic Ishihara plates. These colour plates were originally developed for testing of colour blindness, and indeed have only more recently been applied to ON. As the Ishihara plate books used for testing are expensive, unwieldy, and are not commonly available in many clinics or wards, many neurologists and ophthalmologists have taken to using untested and unstudied downloadable software packages on portable electronic devices for testing. This study compared the efficacy of printed and iPad (Apple, Cupertino, CA, USA) versions of the Ishihara plates in screening for dyschromatopsia in patients who were suspected of having ON. The main finding was that dyschromatopsia testing using a commercially available application on an iPad was comparable to using the current pragmatic clinical benchmark, the pseudo-isochromatic plates of Ishihara. These findings provide support for the increasingly common practice of screening for dyschromatopsia using the iPad. PMID:26896905

  13. Stochastic spineless expression creates the retinal mosaic for colour vision.

    PubMed

    Wernet, Mathias F; Mazzoni, Esteban O; Celik, Arzu; Duncan, Dianne M; Duncan, Ian; Desplan, Claude

    2006-03-01

    Drosophila colour vision is achieved by R7 and R8 photoreceptor cells present in every ommatidium. The fly retina contains two types of ommatidia, called 'pale' and 'yellow', defined by different rhodopsin pairs expressed in R7 and R8 cells. Similar to the human cone photoreceptors, these ommatidial subtypes are distributed stochastically in the retina. The choice between pale versus yellow ommatidia is made in R7 cells, which then impose their fate onto R8. Here we report that the Drosophila dioxin receptor Spineless is both necessary and sufficient for the formation of the ommatidial mosaic. A short burst of spineless expression at mid-pupation in a large subset of R7 cells precedes rhodopsin expression. In spineless mutants, all R7 and most R8 cells adopt the pale fate, whereas overexpression of spineless is sufficient to induce the yellow R7 fate. Therefore, this study suggests that the entire retinal mosaic required for colour vision is defined by the stochastic expression of a single transcription factor, Spineless. PMID:16525464

  14. Suitability of School Textbooks for 5 to 7 Year Old Children with Colour Vision Deficiencies

    ERIC Educational Resources Information Center

    Torrents, Aurora; Bofill, Francesc; Cardona, Genis

    2011-01-01

    Purpose: The aim of the present study was to determine, through colorimetric analysis, whether school textbooks for children aged 5 to 7 years contained tasks requiring normal colour vision discrimination for their resolution. In addition, the performance of a group of observers with diverse colour vision deficiencies was evaluated while…

  15. The fiddler crab Uca mjoebergi uses colour vision in mate choice.

    PubMed

    Detto, Tanya

    2007-11-22

    Although the role of colour in mate choice is well known, few tests of colour vision have been based on mating behaviour. Females of the fiddler crab Uca mjoebergi have recently been shown to use claw coloration to recognize conspecific males. In this study I demonstrate that the females use colour vision for this task; preferentially approaching yellow claws over grey claws regardless of their intensity while failing to discriminate between yellow claws differing in intensity. This is one of only a handful of studies confirming the involvement of colour vision in mate choice and the first conclusive evidence in fiddler crabs. PMID:17848366

  16. The fiddler crab Uca mjoebergi uses colour vision in mate choice

    PubMed Central

    Detto, Tanya

    2007-01-01

    Although the role of colour in mate choice is well known, few tests of colour vision have been based on mating behaviour. Females of the fiddler crab Uca mjoebergi have recently been shown to use claw coloration to recognize conspecific males. In this study I demonstrate that the females use colour vision for this task; preferentially approaching yellow claws over grey claws regardless of their intensity while failing to discriminate between yellow claws differing in intensity. This is one of only a handful of studies confirming the involvement of colour vision in mate choice and the first conclusive evidence in fiddler crabs. PMID:17848366

  17. Low Vision Aids for Visually Impaired Children

    ERIC Educational Resources Information Center

    Schurink, J.; Cox, R. F. A.; Cillessen, A. H. N.; van Rens, G. H. M. B.; Boonstra, F. N.

    2011-01-01

    It is a widely accepted belief in clinical practice that children with a visual impairment can profit from the use of a low vision aid (LVA). However, we found a considerable gap in our scientific understanding of LVA use, particularly in young children. This is the reason for the analysis presented in this paper. A selected overview of LVA use in…

  18. Psychological Adjustment in Adolescents with Vision Impairment

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2012-01-01

    The present study compared psychological adjustment of 158 adolescents with vision impairment and 158 sighted adolescents with a matched-pair design using the Strengths and Difficulties Questionnaire. Adolescent self-reports and teacher reports on emotional problems, peer problems, and total difficulties showed higher scores in students with…

  19. Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed Central

    Rogers, Timothy T.; Graham, Kim S.; Patterson, Karalyn

    2015-01-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:25637227

  20. Resilience and vision impairment in older people.

    PubMed

    Thetford, Clare; Bennett, Kate M; Hodge, Suzanne; Knox, Paul C; Robinson, Jude

    2015-12-01

    Some people fare better than others when faced with adversity; they appear to be more 'resilient'. This article explores the concept of resilience in the context of vision impairment using two linked sets of narrative interview data from 2007 to 2010. Three case studies were analysed in detail using a framework approach based upon a social-ecological model of resilience and vision impairment. Within the model a range of assets and resources are identified which influence an individual's capacity for resilience. A set of criteria were used to establish the extent to which each individual appeared to be resilient at each point in time. Analysis revealed that it is not merely the presence or absence of individual, social, and community resources - but how these resources interact with each other - that influences resilience and can create a risk to wellbeing. To possess only some of these resources is not sufficient; there is a co-dependency between these resources which requires the presence of other resources for resilience to be achieved. Resilience is not a fixed state; individuals can become more or less resilient as their circumstances and resources change over time. We suggest that the concept of resilience has much to offer the field of vision impairment as it allows the identification of enablers as well as areas of barriers to improving people's health and wellbeing and suggests further opportunities for service providers to engage with clients, even those who appear to be supported, as people's social, economic and emotional landscapes continue to change over time, rather than identifying deficit. PMID:26568213

  1. A review of the evolution of animal colour vision and visual communication signals.

    PubMed

    Osorio, D; Vorobyev, M

    2008-09-01

    The visual displays of animals and plants are often colourful, and colour vision allows animals to respond to these signals as they forage for food, choose mates and so-forth. This article discusses the evolutionary relationship between photoreceptor spectral sensitivities of four groups of land animals--birds, butterflies, primates and hymenopteran insects (bees and wasps)--, the colour signals that are relevant to them, and how understanding is informed by models of spectral coding and colour vision. Although the spectral sensitivities of photoreceptors are known to vary adaptively under natural selection there is little evidence that those of hymenopterans, birds and primates are specifically adapted to the reflectance spectra of food plants or animal visual signals. On the other hand, the colours of fruit, flowers and feathers may have evolved to be more discriminable for the colour vision of their natural receivers than for other groups of animals. Butterflies are unusual in that they have enjoyed a major radiation in receptor numbers and spectral sensitivities. The reasons for the radiation and diversity of butterfly colour vision remain unknown, but may include their need to find food plants and to select mates. PMID:18627773

  2. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test.

    PubMed

    Dain, Stephen J; AlMerdef, Ali

    2016-05-01

    Given the versatility of smart phone displays, it was inevitable that applications (apps) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation. The colours of the displays produced by the apps are assessed with reference to the colours of a printed Ishihara test. The visual task is assessed on the basis of the colour differences and the alignment to the dichromatic confusion lines. The apps vary in quality and while some are colorimetrically acceptable, there are also some problems with their construction in making them a clinically useful app rather than curiosity driven self-testing. There is no reason why, in principle, a suitable test cannot be designed for smart phones. PMID:27146711

  3. Polymorphism of the long-wavelength cone in normal human colour vision

    NASA Astrophysics Data System (ADS)

    Neitz, Jay; Jacobs, Gerald H.

    1986-10-01

    Colour vision is based on the presence of multiple classes of cone each of which contains a different type of photopigment1. Colour matching tests have long revealed that the normal human has three cone types. Results from these tests have also been used to provide estimates of cone spectral sensitivities2. There are significant variations in colour matches made by individuals whose colour vision is classified as normal3-6. Some of this is due to individual differences in preretinal absorption and photopigment density, but some is also believed to arise because there is variation in the spectral positioning of the cone pigments among those who have normal colour vision. We have used a sensitive colour matching test to examine the magnitude and nature of this individual variation and here report evidence for the existence of two different long-wavelength cone mechanisms in normal humans. The different patterns of colour matches made by male and female subjects indicate these two mechanisms are inherited as an X-chromosome linked trait.

  4. Vision impairment and nutritional status among older assisted living residents.

    PubMed

    Muurinen, Seija M; Soini, Helena H; Suominen, Merja H; Saarela, Riitta K T; Savikko, Niina M; Pitkälä, Kaisu H

    2014-01-01

    Vision impairment is common among older persons. It is a risk factor for disability, and it may be associated with nutritional status via decline in functional status. However, only few studies have examined the relationship between vision impairment and nutritional status, which was investigated in this cross-sectional study. The study included all residents living in the assisted living facilities in Helsinki and Espoo in 2007. Residents in temporary respite care were excluded (5%). Of permanent residents (N=2214), 70% (N=1475) consented. Trained nurses performed a personal interview and assessment of each resident including the Mini Nutritional Assessment (MNA), functional and health status. Patient records were used to confirm demographic data and medical history. Mortality in 2010 was retrieved from central registers. Of the residents, 17.5% (N=245) had vision impairment and they were not able to read regular print. Those with vision impairment were older, more often females, and malnourished according to MNA. They had lower BMI, and suffered more often from dementia and chewing problems than those without vision impairment. In logistic regression analysis controlling for age, gender, chewing problems and dementia, vision impairment was independently associated with resident's malnutrition (OR 2.51, 95% CI 1.80-3.51). According to our results older residents in assisted living with vision impairment are at high risk for malnutrition. Therefore it is important to assess nutritional status of persons with vision impairment. It would be beneficial to repeat this kind of a study also in elderly community population. PMID:24398167

  5. Red-Green Color Vision Impairment in Duchenne Muscular Dystrophy

    PubMed Central

    Costa, Marcelo Fernandes ; Oliveira, Andre Gustavo Fernandes ; Feitosa-Santana, Claudia ; Zatz, Mayana ; Ventura, Dora Fix 

    2007-01-01

    The present study evaluated the color vision of 44 patients with Duchenne muscular dystrophy (DMD) (mean age 14.8 years; SD 4.9) who were submitted to a battery of four different color tests: Cambridge Colour Test (CCT), Neitz Anomaloscope, Ishihara, and American Optical Hardy-Rand-Rittler (AO H-R-R). Patients were divided into two groups according to the region of deletion in the dystrophin gene: upstream of exon 30 (n=12) and downstream of exon 30 (n=32). The control group was composed of 70 age-matched healthy male subjects with no ophthalmological complaints. Of the patients with DMD, 47% (21/44) had a red-green color vision defect in the CCT, confirmed by the Neitz Anomaloscope with statistical agreement (P<.001). The Ishihara and the AO H-R-R had a lower capacity to detect color defects—5% and 7%, respectively, with no statistical similarity between the results of these two tests nor between CCT and Anomaloscope results (P>.05). Of the patients with deletion downstream of exon 30, 66% had a red-green color defect. No color defect was found in the patients with deletion upstream of exon 30. A negative correlation between the color thresholds and age was found for the controls and patients with DMD, suggesting a nonprogressive color defect. The percentage (66%) of patients with a red-green defect was significantly higher than the expected <10% for the normal male population (P<.001). In contrast, patients with DMD with deletion upstream of exon 30 had normal color vision. This color defect might be partially explained by a retina impairment related to dystrophin isoform Dp260. PMID:17503325

  6. The intensity threshold of colour vision in a passerine bird, the blue tit (Cyanistes caeruleus).

    PubMed

    Gomez, Doris; Grégoire, Arnaud; Del Rey Granado, Maria; Bassoul, Marine; Degueldre, David; Perret, Philippe; Doutrelant, Claire

    2014-11-01

    Many vertebrates use colour vision for vital behaviour but their visual performance in dim light is largely unknown. The light intensity threshold of colour vision is known only for humans, horses and two parrot species. Here, we first explore this threshold in a passerine bird, the blue tit (Cyanistes caeruleus). Using classic conditioning of colour cues to food rewards in three individuals, we find a threshold ranging from 0.05 to 0.2 cd m(-2). Results are comparable to the two previously tested bird species. For tits, nest light conditions probably exceed that threshold, at least after sunrise. These results shed new light on the lively debate questioning the visual performance of cavity nesters and the evolutionary significance of egg and chick coloration. Although this needs further investigation, it is possible that blue tits exploit both colour and brightness cues when viewing their eggs, chicks or conspecifics in their nests. PMID:25214487

  7. Color vision characteristics of visually impaired children.

    PubMed

    Kalloniatis, M; Johnston, A W

    1990-03-01

    A classroom assessment of color vision characteristics of children with low vision was conducted using a battery of tests. The results showed 75% of the children failed one or more tests, although only 24% had a moderate or severe color vision defect. Comparisons with the low vision clinic color vision assessment showed that many of the children were not identified as being color vision defective. Considering the use of color-coded information in education, greater emphasis on color vision evaluations in routine low vision examinations is recommended. PMID:2320360

  8. Normality of colour vision in a compound heterozygous female carrying a protan and deutan defect

    PubMed Central

    Tait, Diane M.; Carroll, Joseph

    2012-01-01

    Background Inherited red-green colour vision defects are quite common, affecting nearly 1 in 10 males, but are less common in women, affecting about 1 in 250. However because red-green defects are X-linked, nearly 15% of females are heterozygous carriers of red-green colour deficiency. In addition, about 1 in 150 females are “double carriers”, where both of their X chromosomes have L/M gene arrays encoding a red-green defect. If a woman carries the same type of colour vision defect on each X-chromosome, she herself will be red-green colour deficient, whereas if she carries opposing defects (protan vs. deutan) on each X chromosome she will be trichromatic, owing to the process of X-inactivation. These women are referred to as compound heterozygotes, though very few have been reported. Moreover, questions remain as to whether the colour vision capacity of these women is comparable to that of “normal” trichromats. Methods We examined a compound heterozygote carrier of both protanopia and deuteranomaly. We also examined male members of her family representing both forms of red-green defect carried by the female proband. Complete colour vision testing was done, including Rayleigh matches, pseudoichromatic plates, unique hue measurements, and 100-Hue tests. Flicker-photometric ERG estimates of L:M cone ratio were obtained, as were Medmont C100 settings. Results Genetic analyses provided direct confirmation of compound heterozygosity. The compound heterozygote showed Schmidt’s sign, consistent with an extreme skew in her L:M cone ratio, and usually associated with protan carrier status. Conclusion Apart from Schmidt’s sign, we found the colour vision of the compound heterozygote to be indistinguishable from that of a normal trichromat. PMID:19473349

  9. Vision Impairment Among Older Adults Residing in Subsidized Housing Communities

    PubMed Central

    McGwin, Gerald; Kline, Lanning B.; Owsley, Cynthia

    2015-01-01

    Purpose of the Study: To examine the rate of vision impairment and the relationship between vision impairment, cognitive impairment, and chronic comorbid conditions in residents of federally subsidized senior housing facilities. Design: Cross-sectional, observational study. Methods: Vision screening events were held at 14 subsidized senior housing facilities in Jefferson County, Alabama for residents aged 60 years and older. Visual function (distance vision, near vision, and contrast sensitivity) measured with habitual correction if worn, cognitive status, and chronic comorbid conditions (hypertension, heart problems, circulation problems, and diabetes) were assessed. Results: A total of 238 residents participated in the vision screenings. Most residents (75%) were African American. Vision impairment was common, with 40% of participants failing the distance acuity screening and 58% failing the near acuity screening; failure was defined as vision worse than 20/40 in either eye. Additionally, 65% failed the contrast sensitivity screening. A total of 30.6% of seniors had cognitive impairment. Regarding comorbid chronic conditions, 31% had circulation problems, 39% had diabetes, 41% had heart problems, and 76% had hypertension (59% had 2 or more of these). Visual acuity differed significantly between cognitive status groups and with the presence of heart and circulation problems. Implications: This study is among the first to provide information about vision impairment in this socioeconomically disadvantaged group of older adults. Vision impairment was common. Cognitive impairment and comorbid chronic conditions accounted for a small to moderate percentage of the variance in distance vision, near vision, and contrast sensitivity. Future studies should focus on strategies to facilitate access to eye care in this vulnerable population. PMID:26055771

  10. A neuronal circuit for colour vision based on rod-cone opponency.

    PubMed

    Joesch, Maximilian; Meister, Markus

    2016-04-14

    In bright light, cone-photoreceptors are active and colour vision derives from a comparison of signals in cones with different visual pigments. This comparison begins in the retina, where certain retinal ganglion cells have 'colour-opponent' visual responses-excited by light of one colour and suppressed by another colour. In dim light, rod-photoreceptors are active, but colour vision is impossible because they all use the same visual pigment. Instead, the rod signals are thought to splice into retinal circuits at various points, in synergy with the cone signals. Here we report a new circuit for colour vision that challenges these expectations. A genetically identified type of mouse retinal ganglion cell called JAMB (J-RGC), was found to have colour-opponent responses, OFF to ultraviolet (UV) light and ON to green light. Although the mouse retina contains a green-sensitive cone, the ON response instead originates in rods. Rods and cones both contribute to the response over several decades of light intensity. Remarkably, the rod signal in this circuit is antagonistic to that from cones. For rodents, this UV-green channel may play a role in social communication, as suggested by spectral measurements from the environment. In the human retina, all of the components for this circuit exist as well, and its function can explain certain experiences of colour in dim lights, such as a 'blue shift' in twilight. The discovery of this genetically defined pathway will enable new targeted studies of colour processing in the brain. PMID:27049951

  11. Loss of form vision impairs spatial imagery

    PubMed Central

    Occelli, Valeria; Lin, Jonathan B.; Lacey, Simon; Sathian, K.

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences (“cognitive style”) on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  12. Loss of form vision impairs spatial imagery.

    PubMed

    Occelli, Valeria; Lin, Jonathan B; Lacey, Simon; Sathian, K

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences ("cognitive style") on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  13. A complex carotenoid palette tunes avian colour vision.

    PubMed

    Toomey, Matthew B; Collins, Aaron M; Frederiksen, Rikard; Cornwall, M Carter; Timlin, Jerilyn A; Corbo, Joseph C

    2015-10-01

    The brilliantly coloured cone oil droplets of the avian retina function as long-pass cut-off filters that tune the spectral sensitivity of the photoreceptors and are hypothesized to enhance colour discrimination and improve colour constancy. Although it has long been known that these droplets are pigmented with carotenoids, their precise composition has remained uncertain owing to the technical challenges of measuring these very small, dense and highly refractile optical organelles. In this study, we integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken (Gallus gallus). We find that each of the four carotenoid-containing droplet types consists of a complex mixture of carotenoids, with a single predominant carotenoid determining the wavelength of the spectral filtering cut-off. Consistent with previous reports, we find that the predominant carotenoid type in the oil droplets of long-wavelength-sensitive, medium-wavelength-sensitive and short-wavelength-sensitive type 2 cones are astaxanthin, zeaxanthin and galloxanthin, respectively. In addition, the oil droplet of the principal member of the double cone contains a mixture of galloxanthin and two hydroxycarotenoids (lutein and zeaxanthin). Short-wavelength-absorbing apocarotenoids are present in all of the droplet types, providing filtering of light in a region of the spectrum where filtering by hydroxy- and ketocarotenoids may be incomplete. Thus, birds rely on a complex palette of carotenoid pigments within their cone oil droplets to achieve finely tuned spectral filtering. PMID:26446559

  14. Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin’s Ellipses and the Farnsworth-Munsell 100-Hue Test

    PubMed Central

    Bento-Torres, Natáli Valim Oliver; Rodrigues, Anderson Raiol; Côrtes, Maria Izabel Tentes; Bonci, Daniela Maria de Oliveira; Ventura, Dora Fix

    2016-01-01

    We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse’s long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u’ = 0.225, v’ = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies. PMID:27101124

  15. The nature of sound and vision in relation to colour

    NASA Astrophysics Data System (ADS)

    Greated, Marianne

    2011-03-01

    The increasing role of sound within the visual arts context and the trend in postmodernism towards interdisciplinary artworks has demanded a heightened awareness of the audio-visual. This paper explores some of the fundamental physical properties of both sound and colour, their similarities and differences and how the audio and visual senses are related. Ways in which soundscapes have been combined with paintings in exhibitions by the author will be used to illustrate how the two media can be combined to enhance the overall artistic experience.

  16. Vision impairment in the Pacific region

    PubMed Central

    Keeffe, J E; Konyama, K; Taylor, H R

    2002-01-01

    The Western Pacific region is one of great diversity, containing the most populous country, China, and many small Pacific island countries. This review describes the prevalence of blindness and vision loss, illustrates the changing trends in the important causes of vision loss and blindness, and the stages of development of the delivery of eye care services across this region. PMID:12034678

  17. Vision impairment and dual sensory problems in middle age

    PubMed Central

    Dawes, Piers; Dickinson, Christine; Emsley, Richard; Bishop, Paul; Cruickshanks, Karen; Edmondson-Jones, Mark; McCormack, Abby; Fortnum, Heather; Moore, David R.; Norman, Paul; Munro, Kevin

    2014-01-01

    Purpose Vision and hearing impairments are known to increase in middle age. In this study we describe the prevalence of vision impairment and dual sensory impairment in UK adults aged 40 to 69 years in a very large and recently ascertained data set. The associations between vision impairment, age, sex, socioeconomic status, and ethnicity are reported. Methods This research was conducted using the UK Biobank Resource, with subsets of UK Biobank data analysed with respect to self-report of eye problems and glasses use. Better-eye visual acuity with habitually worn refractive correction was assessed with a logMAR chart (n = 116,682). Better-ear speech reception threshold was measured with an adaptive speech in noise test, the Digit Triplet Test (n = 164,770). Prevalence estimates were weighted with respect to UK 2001 Census data. Results Prevalence of mild visual impairment and low vision was estimated at 15.2% (95% CI 14.9–15.5%) and 0.9% (95% CI 0.8–1.0%), respectively. Use of glasses was 88.0% (95% CI 87.9–88.1%). The prevalence of dual sensory impairment was 3.1% (95% CI 3.0–3.2%) and there was a nine-fold increase in the prevalence of dual sensory problems between the youngest and oldest age groups. Older adults, those from low socioeconomic and ethnic minority backgrounds were most at risk for vision problems. Conclusions Mild vision impairment is common in middle aged UK adults, despite widespread use of spectacles. Possible barriers to optometric care for those from low socioeconomic and ethnic minority backgrounds may require attention. A higher than expected prevalence of dual impairment suggests that hearing and vision problems share common causes. Optometrists should consider screening for hearing problems, particularly among older adults. PMID:24888710

  18. Project VISION: Visually Impaired Students and Internet Opportunities Now.

    ERIC Educational Resources Information Center

    Kapperman, Gaylen; And Others

    Project VISION (Visually Impaired Students and Internet Opportunities Now) was a 2-year effort to develop and test methods and strategies by which blind and visually impaired students can use assistive technology to gain access to the resources found on the Internet. The project produced a manual and a videotape. Nine students were provided with…

  19. IMAGE ENHANCEMENT FOR IMPAIRED VISION: THE CHALLENGE OF EVALUATION

    PubMed Central

    PELI, ELI; WOODS, RUSSELL L

    2009-01-01

    With the aging of the population, the prevalence of eye diseases and thus of vision impairment is increasing. The TV watching habits of people with vision impairments are comparable to normally sighted people1, however their vision loss prevents them from fully benefiting from this medium. For over 20 years we have been developing video image-enhancement techniques designed to assist people with visual impairments, particularly those due to central retinal vision loss. A major difficulty in this endeavor is the lack of evaluation techniques to assess and compare the effectiveness of various enhancement methods. This paper reviews our approaches to image enhancement and the results we have obtained, with special emphasis on the difficulties encountered in the evaluation of the benefits of enhancement and the solutions we have developed to date. PMID:20161188

  20. Dichromatic Colour Vision in Wallabies as Characterised by Three Behavioural Paradigms

    PubMed Central

    Ebeling, Wiebke; Hemmi, Jan M.

    2014-01-01

    Despite lacking genetic evidence of a third cone opsin in the retina of any Australian marsupial, most species tested so far appear to be trichromatic. In the light of this, we have re-examined colour vision of the tammar wallaby which had previously been identified as a dichromat. Three different psychophysical tests, based on an operant conditioning paradigm, were used to confirm that colour perception in the wallaby can be predicted and conclusively explained by the existence of only two cone types. Firstly, colour-mixing experiments revealed a Confusion Point between the three primary colours of a LCD monitor that can be predicted by the cone excitation ratio of the short- and middle-wavelength sensitive cones. Secondly, the wavelength discrimination ability in the wallaby, when tested with monochromatic stimuli, was found to be limited to a narrow range between 440 nm and 500 nm. Lastly, an experiment designed to test the wallaby’s ability to discriminate monochromatic lights from a white light provided clear evidence for a Neutral Point around 485 nm where discrimination consistently failed. Relative colour discrimination seemed clearly preferred but it was possible to train a wallaby to perform absolute colour discriminations. The results confirm the tammar wallaby as a dichromat, and so far the only behaviourally confirmed dichromat among the Australian marsupials. PMID:24489742

  1. Dichromatic colour vision in wallabies as characterised by three behavioural paradigms.

    PubMed

    Ebeling, Wiebke; Hemmi, Jan M

    2014-01-01

    Despite lacking genetic evidence of a third cone opsin in the retina of any Australian marsupial, most species tested so far appear to be trichromatic. In the light of this, we have re-examined colour vision of the tammar wallaby which had previously been identified as a dichromat. Three different psychophysical tests, based on an operant conditioning paradigm, were used to confirm that colour perception in the wallaby can be predicted and conclusively explained by the existence of only two cone types. Firstly, colour-mixing experiments revealed a Confusion Point between the three primary colours of a LCD monitor that can be predicted by the cone excitation ratio of the short- and middle-wavelength sensitive cones. Secondly, the wavelength discrimination ability in the wallaby, when tested with monochromatic stimuli, was found to be limited to a narrow range between 440 nm and 500 nm. Lastly, an experiment designed to test the wallaby's ability to discriminate monochromatic lights from a white light provided clear evidence for a Neutral Point around 485 nm where discrimination consistently failed. Relative colour discrimination seemed clearly preferred but it was possible to train a wallaby to perform absolute colour discriminations. The results confirm the tammar wallaby as a dichromat, and so far the only behaviourally confirmed dichromat among the Australian marsupials. PMID:24489742

  2. Beyond W3C: TruVision--Enhanced Online Learning for People Blind or Vision Impaired.

    ERIC Educational Resources Information Center

    Bate, Frank; Oliver, Ron

    This paper describes the design and development of TruVision, an online learning environment designed to enable blind and vision impaired students to develop skills and expertise in elementary and advanced information processing strategies to enable them to seek full-time employment within industry in such positions as administrative assistants,…

  3. Mineralized rods and cones suggest colour vision in a 300 Myr-old fossil fish.

    PubMed

    Tanaka, Gengo; Parker, Andrew R; Hasegawa, Yoshikazu; Siveter, David J; Yamamoto, Ryoichi; Miyashita, Kiyoshi; Takahashi, Yuichi; Ito, Shosuke; Wakamatsu, Kazumasa; Mukuda, Takao; Matsuura, Marie; Tomikawa, Ko; Furutani, Masumi; Suzuki, Kayo; Maeda, Haruyoshi

    2014-01-01

    Vision, which consists of an optical system, receptors and image-processing capacity, has existed for at least 520 Myr. Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain decay rapidly after death, such as within 64 days and 11 days, respectively. The Upper Carboniferous Hamilton Formation (300 Myr) in Kansas, USA, yields exceptionally well-preserved animal fossils in an estuarine depositional setting. Here we show that the original colour, shape and putative presence of eumelanin have been preserved in the acanthodii fish Acanthodes bridgei. We also report on the tissues of its eye, which provides the first record of mineralized rods and cones in a fossil and indicates that this 300 Myr-old fish likely possessed colour vision. PMID:25536302

  4. Molecular logic behind the three-way stochastic choices that expand butterfly colour vision.

    PubMed

    Perry, Michael; Kinoshita, Michiyo; Saldi, Giuseppe; Huo, Lucy; Arikawa, Kentaro; Desplan, Claude

    2016-07-14

    Butterflies rely extensively on colour vision to adapt to the natural world. Most species express a broad range of colour-sensitive Rhodopsin proteins in three types of ommatidia (unit eyes), which are distributed stochastically across the retina. The retinas of Drosophila melanogaster use just two main types, in which fate is controlled by the binary stochastic decision to express the transcription factor Spineless in R7 photoreceptors. We investigated how butterflies instead generate three stochastically distributed ommatidial types, resulting in a more diverse retinal mosaic that provides the basis for additional colour comparisons and an expanded range of colour vision. We show that the Japanese yellow swallowtail (Papilio xuthus, Papilionidae) and the painted lady (Vanessa cardui, Nymphalidae) butterflies have a second R7-like photoreceptor in each ommatidium. Independent stochastic expression of Spineless in each R7-like cell results in expression of a blue-sensitive (Spineless(ON)) or an ultraviolet (UV)-sensitive (Spineless(OFF)) Rhodopsin. In P. xuthus these choices of blue/blue, blue/UV or UV/UV sensitivity in the two R7 cells are coordinated with expression of additional Rhodopsin proteins in the remaining photoreceptors, and together define the three types of ommatidia. Knocking out spineless using CRISPR/Cas9 (refs 5, 6) leads to the loss of the blue-sensitive fate in R7-like cells and transforms retinas into homogeneous fields of UV/UV-type ommatidia, with corresponding changes in other coordinated features of ommatidial type. Hence, the three possible outcomes of Spineless expression define the three ommatidial types in butterflies. This developmental strategy allowed the deployment of an additional red-sensitive Rhodopsin in P. xuthus, allowing for the evolution of expanded colour vision with a greater variety of receptors. This surprisingly simple mechanism that makes use of two binary stochastic decisions coupled with local coordination may prove

  5. Global cost of correcting vision impairment from uncorrected refractive error

    PubMed Central

    Fricke, TR; Wilson, DA; Schlenther, G; Naidoo, KS; Resnikoff, S; Frick, KD

    2012-01-01

    Abstract Objective To estimate the global cost of establishing and operating the educational and refractive care facilities required to provide care to all individuals who currently have vision impairment resulting from uncorrected refractive error (URE). Methods The global cost of correcting URE was estimated using data on the population, the prevalence of URE and the number of existing refractive care practitioners in individual countries, the cost of establishing and operating educational programmes for practitioners and the cost of establishing and operating refractive care facilities. The assumptions made ensured that costs were not underestimated and an upper limit to the costs was derived using the most expensive extreme for each assumption. Findings There were an estimated 158 million cases of distance vision impairment and 544 million cases of near vision impairment caused by URE worldwide in 2007. Approximately 47 000 additional full-time functional clinical refractionists and 18 000 ophthalmic dispensers would be required to provide refractive care services for these individuals. The global cost of educating the additional personnel and of establishing, maintaining and operating the refractive care facilities needed was estimated to be around 20 000 million United States dollars (US$) and the upper-limit cost was US$ 28 000 million. The estimated loss in global gross domestic product due to distance vision impairment caused by URE was US$ 202 000 million annually. Conclusion The cost of establishing and operating the educational and refractive care facilities required to deal with vision impairment resulting from URE was a small proportion of the global loss in productivity associated with that vision impairment. PMID:23109740

  6. Highly polymorphic colour vision in a New World monkey with red facial skin, the bald uakari (Cacajao calvus).

    PubMed

    Corso, Josmael; Bowler, Mark; Heymann, Eckhard W; Roos, Christian; Mundy, Nicholas I

    2016-04-13

    Colour vision is highly variable in New World monkeys (NWMs). Evidence for the adaptive basis of colour vision in this group has largely centred on environmental features such as foraging benefits for differently coloured foods or predator detection, whereas selection on colour vision for sociosexual communication is an alternative hypothesis that has received little attention. The colour vision of uakaris (Cacajao) is of particular interest because these monkeys have the most dramatic red facial skin of any primate, as well as a unique fission/fusion social system and a specialist diet of seeds. Here, we investigate colour vision in a wild population of the bald uakari,C. calvus, by genotyping the X-linked opsin locus. We document the presence of a polymorphic colour vision system with an unprecedented number of functional alleles (six), including a novel allele with a predicted maximum spectral sensitivity of 555 nm. This supports the presence of strong balancing selection on different alleles at this locus. We consider different hypotheses to explain this selection. One possibility is that trichromacy functions in sexual selection, enabling females to choose high-quality males on the basis of red facial coloration. In support of this, there is some evidence that health affects facial coloration in uakaris, as well as a high prevalence of blood-borne parasitism in wild uakari populations. Alternatively, the low proportion of heterozygous female trichromats in the population may indicate selection on different dichromatic phenotypes, which might be related to cryptic food coloration. We have uncovered unexpected diversity in the last major lineage of NWMs to be assayed for colour vision, which will provide an interesting system to dissect adaptation of polymorphic trichromacy. PMID:27053753

  7. Spotting fruit versus picking fruit as the selective advantage of human colour vision

    PubMed Central

    Bompas, Aline; Kendall, Grace; Sumner, Petroc

    2013-01-01

    The spatiochromatic properties of the red–green dimension of human colour vision appear to be optimized for picking fruit in leaves at about arms' reach. However, other evidence suggests that the task of spotting fruit from a distance might be more important. This discrepancy may arise because the task a system (e.g. human trichromacy) is best at is not necessarily the same task where the largest advantage occurs over the evolutionary alternatives (dichromacy or anomalous trichromacy). We tested human dichromats, anomalous trichromats and “normal” trichromats in a naturalistic visual search task in which they had to find fruit pieces in a bush at 1, 4, 8 or 12 m viewing distance. We found that the largest advantage (in terms of either performance ratio or performance difference) of normal trichromacy over both types of colour deficiency was for the largest viewing distance. We infer that in the evolution of human colour vision, spotting fruit from a distance was a more important selective advantage than picking fruit at arms' reach. PMID:23755352

  8. Shades of red: bird-pollinated flowers target the specific colour discrimination abilities of avian vision.

    PubMed

    Shrestha, Mani; Dyer, Adrian G; Boyd-Gerny, Skye; Wong, Bob B M; Burd, Martin

    2013-04-01

    Colour signals are a major cue in putative pollination syndromes. There is evidence that the reflectance spectra of many flowers target the distinctive visual discrimination abilities of hymenopteran insects, but far less is known about bird-pollinated flowers. Birds are hypothesized to exert different selective pressures on floral colour compared with hymenopterans because of differences in their visual systems. We measured the floral reflectance spectra of 206 Australian angiosperm species whose floral visitors are known from direct observation rather than inferred from floral characteristics. We quantified the match between these spectra and the hue discrimination abilities of hymenopteran and avian vision, and analysed these metrics in a phylogenetically informed comparison of flowers in different pollination groups. We show that bird-visited flowers and insect-visited flowers differ significantly from each other in the chromatic cues they provide, and that the differences are concentrated near wavelengths of optimal colour discrimination by whichever class of pollinator visits the flowers. Our results indicate that angiosperms have evolved the spectral signals most likely to reinforce their pollinators' floral constancy (the tendency of individual pollinators to visit flowers of the same species) in communities of similarly coloured floral competitors. PMID:23368754

  9. Register of Children with Impaired Vision and Hearing.

    ERIC Educational Resources Information Center

    Wagner, Elizabeth

    The register of children (under 20 years of age) with impaired vision and hearing provides the number of children in deaf blind programs, other educational programs, at home, and in institutions for the mentally handicapped for the academic year 1968-9. Additional information on the 777 handicapped children registered by the American Foundation…

  10. Insights into the Support Services for Students with Vision Impairment

    ERIC Educational Resources Information Center

    Datta, Poulomee; Palmer, Carolyn

    2015-01-01

    There is a general need for research in Australia on whether the support services provided in schools prove useful for students with disabilities (Datta, 2015; O'Rourke & Houghton, 2006), especially students with vision impairment. This qualitative study aimed to provide insights into the influence of the support services delivered in South…

  11. The Impact of Vision Impairment on Students' Self-Concept

    ERIC Educational Resources Information Center

    Datta, Poulomee; Talukdar, Joy

    2016-01-01

    This study investigated the self-concept of students with vision impairment who were placed in specialist and mainstream educational settings in South Australia. Self-Concept was explored across six dimensions, namely Physical, Moral, Personal, Family, Social and Academic Self-Concepts and the Total Self-Concept. The "Tennessee Self-Concept…

  12. The Evolution of the Multicoloured Face of Mandrills: Insights from the Perceptual Space of Colour Vision

    PubMed Central

    Renoult, Julien P.; Schaefer, H. Martin; Sallé, Bettina; Charpentier, Marie J. E.

    2011-01-01

    Multicomponent signals consist of several traits that are perceived as a whole. Although many animals rely on multicomponent signals to communicate, the selective pressures shaping these signals are still poorly understood. Previous work has mainly investigated the evolution of multicomponent signals by studying each trait individually, which may not accurately reflect the selective pressures exerted by the holistic perception of signal receivers. Here, we study the design of the multicoloured face of an Old World primate, the mandrill (Mandrillus sphinx), in relation to two aspects of signalling that are expected to be selected by receivers: conspicuousness and information. Using reflectance data on the blue and red colours of the faces of 34 males and a new method of hue vectorisation in a perceptual space of colour vision, we show that the blue hue maximises contrasts to both the red hue and the foliage background colouration, thereby increasing the conspicuousness of the whole display. We further show that although blue saturation, red saturation and the contrast between blue and red colours are all correlated with dominance, dominance is most accurately indicated by the blue-red contrast. Taken together our results suggest that the evolution of blue and red facial colours in male mandrills are not independent and are likely driven by the holistic perception of conspecifics. In this view, we propose that the multicoloured face of mandrills acts as a multicomponent signal. Last, we show that information accuracy increases with the conspicuousness of the whole display, indicating that both aspects of signalling can evolve in concert. PMID:22216180

  13. Vision impairment predicts five-year mortality.

    PubMed Central

    Taylor, H R; McCarty, C A; Nanjan, M B

    2000-01-01

    PURPOSE: To describe predictors of mortality in the 5-year follow-up of the Melbourne Visual Impairment Project (VIP) cohort. METHODS: The Melbourne VIP was a population-based study of the distribution and determinants of age-related eye disease in a cluster random sample of Melbourne residents aged 40 years and older. Baseline examinations were conducted between 1992 and 1994. In 1997, 5-year follow-up examinations of the original cohort commenced. Causes of death were obtained from the National Death Index for all reported deaths. RESULTS: Of the original 3,271 participants, 231 (7.1%) were reported to have died in the intervening 5 years. Of the remaining 3,040 participants eligible to return for follow-up examinations, 2,594 (85% of eligible) did participate, 51 (2%) had moved interstate or overseas, 83 (3%) could not be traced, and 312 (10%) refused to participate. Best corrected visual acuity < 6/12 and cortical cataract were associated with a significantly increased risk of mortality, as were increasing age, male sex, increased duration of cigarette smoking, increased duration of hypertension, and arthritis. CONCLUSIONS: Even mild visual impairment increases the risk of death more than twofold. PMID:11190044

  14. Photoreceptor sectral sensitivities in terrestrial animals: adaptations for luminance and colour vision

    PubMed Central

    Osorio, D; Vorobyev, M

    2005-01-01

    This review outlines how eyes of terrestrial vertebrates and insects meet the competing requirements of coding both spatial and spectral information. There is no unique solution to this problem. Thus, mammals and honeybees use their long-wavelength receptors for both achromatic (luminance) and colour vision, whereas flies and birds probably use separate sets of photoreceptors for the two purposes. In particular, we look at spectral tuning and diversification among ‘long-wavelength’ receptors (sensitivity maxima at greater than 500 nm), which play a primary role in luminance vision. Data on spectral sensitivities and phylogeny of visual photopigments can be incorporated into theoretical models to suggest how eyes are adapted to coding natural stimuli. Models indicate, for example, that animal colour vision—involving five or fewer broadly tuned receptors—is well matched to most natural spectra. We can also predict that the particular objects of interest and signal-to-noise ratios will affect the optimal eye design. Nonetheless, it remains difficult to account for the adaptive significance of features such as co-expression of photopigments in single receptors, variation in spectral sensitivities of mammalian L-cone pigments and the diversification of long-wavelength receptors that has occurred in several terrestrial lineages. PMID:16096084

  15. Blue-yellow colour vision in an onchocercal area of northern Nigeria

    PubMed Central

    Landers, A; Murdoch, I; Birch, J; Cousens, S; Babalola, O; Lawal, B; Abiose, A; Jones, B

    1998-01-01

    AIM—To determine if the City University Tritan Test is a useful addition to visual function assessment in rural communities in northern Nigeria.
METHODS—The study was a cross sectional survey. The participants were 8394 people, aged 5 years and over, living in 37 rural communities, mesoendemic and non-endemic for onchocerciasis, in Kaduna State in northern Nigeria. The main outcome measures were the detection of a defect in blue-yellow colour vision by two criteria: (1) failure with the City University tritan screening plates; (2) failure with the City University grading plates to identify severe tritan defects.
RESULTS—91% of those aged 10 years and above could perform the test. Below this age, there were difficulties in comprehension. The test showed good inter- and intraobserver agreement. After adjustment for confounders the odds of failing the screening plates were significantly increased in the presence of optic atrophy or glaucoma (3.55 (2.48-5.08) and 15.9 (4.22-60.2) respectively). There was a greater increase in the adjusted odds of failing the grading plates in the presence of optic atrophy or glaucoma (5.30 (2.97-9.45) and 8.87 (1.61-48.7) respectively). Cataract had a smaller effect on the screening plates, adjusted odds 1.63 (0.95-2.80).
CONCLUSION—Blue-yellow colour vision testing is a useful addition to visual function assessment in those aged 10 years and above in rural northern Nigeria, particularly in the detection of optic nerve disease.

 Keywords: tritan defects; optic nerve disease; onchocerciasis; visual function assessment PMID:9713057

  16. Advanced IT Education for the Vision Impaired via e-Learning

    ERIC Educational Resources Information Center

    Armstrong, Helen L.

    2009-01-01

    Lack of accessibility in the design of e-learning courses continues to hinder students with vision impairment. E-learning materials are predominantly vision-centric, incorporating images, animation, and interactive media, and as a result students with acute vision impairment do not have equal opportunity to gain tertiary qualifications or skills…

  17. Computer vision-based analysis of foods: a non-destructive colour measurement tool to monitor quality and safety.

    PubMed

    Mogol, Burçe Ataç; Gökmen, Vural

    2014-05-01

    Computer vision-based image analysis has been widely used in food industry to monitor food quality. It allows low-cost and non-contact measurements of colour to be performed. In this paper, two computer vision-based image analysis approaches are discussed to extract mean colour or featured colour information from the digital images of foods. These types of information may be of particular importance as colour indicates certain chemical changes or physical properties in foods. As exemplified here, the mean CIE a* value or browning ratio determined by means of computer vision-based image analysis algorithms can be correlated with acrylamide content of potato chips or cookies. Or, porosity index as an important physical property of breadcrumb can be calculated easily. In this respect, computer vision-based image analysis provides a useful tool for automatic inspection of food products in a manufacturing line, and it can be actively involved in the decision-making process where rapid quality/safety evaluation is needed. PMID:24288215

  18. The Reliability of the CVI Range: A Functional Vision Assessment for Children with Cortical Visual Impairment

    ERIC Educational Resources Information Center

    Newcomb, Sandra

    2010-01-01

    Children who are identified as visually impaired frequently have a functional vision assessment as one way to determine how their visual impairment affects their educational performance. The CVI Range is a functional vision assessment for children with cortical visual impairment. The purpose of the study presented here was to examine the…

  19. Exercise and Drinking May Play a Role in Vision Impairment Risk

    MedlinePlus

    ... Exercise and Drinking May Play a Role in Vision Impairment Risk Mar. 20, 2014 In 2020, the ... 477–85. Related Stories Age-Related Macular Degeneration Vision Simulator Mar 01, 2016 What Is Optical Coherence ...

  20. VISION PROBLEMS IN THE U.S.-PREVALENCE OF ADULT VISION IMPAIRMENT AND AGE-RELATED EYE DISEASES IN AMERICA

    EPA Science Inventory

    Leading causes of vision impairment and blindness in the United States. Diabetic retinopathy? Age-related macular degeneration (AMD)? Cataract? Glaucoma? The Vision Problems in the U.S. study was the result of a 2001 consensus meeting, convened by the National Eye Institute and ...

  1. The Potential Impact of Undiagnosed Vision Impairment on Reading Development in the Early Years of School

    ERIC Educational Resources Information Center

    Thurston, Allen

    2014-01-01

    This article presents a critical review of the literature surrounding the potential impact of undiagnosed and untreated vision impairment on reading development in the early years of primary school. Despite pre-school screening programmes, it is still possible for children to enter school with undiagnosed, uncorrected vision impairments. This can…

  2. 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…

  3. Vision of the active limb impairs bimanual motor tracking in young and older adults

    PubMed Central

    Boisgontier, Matthieu P.; Van Halewyck, Florian; Corporaal, Sharissa H. A.; Willacker, Lina; Van Den Bergh, Veerle; Beets, Iseult A. M.; Levin, Oron; Swinnen, Stephan P.

    2014-01-01

    Despite the intensive investigation of bimanual coordination, it remains unclear how directing vision toward either limb influences performance, and whether this influence is affected by age. To examine these questions, we assessed the performance of young and older adults on a bimanual tracking task in which they matched motor-driven movements of their right hand (passive limb) with their left hand (active limb) according to in-phase and anti-phase patterns. Performance in six visual conditions involving central vision, and/or peripheral vision of the active and/or passive limb was compared to performance in a no vision condition. Results indicated that directing central vision to the active limb consistently impaired performance, with higher impairment in older than young adults. Conversely, directing central vision to the passive limb improved performance in young adults, but less consistently in older adults. In conditions involving central vision of one limb and peripheral vision of the other limb, similar effects were found to those for conditions involving central vision of one limb only. Peripheral vision alone resulted in similar or impaired performance compared to the no vision (NV) condition. These results indicate that the locus of visual attention is critical for bimanual motor control in young and older adults, with older adults being either more impaired or less able to benefit from a given visual condition. PMID:25452727

  4. Falls Among Persons Aged ≥65 Years With and Without Severe Vision Impairment - United States, 2014.

    PubMed

    Crews, John E; Chou, Chiu-Fung; Stevens, Judy A; Saaddine, Jinan B

    2016-01-01

    In 2014, an estimated 2.8 million persons aged ≥65 years in the United States reported severe vision impairment* defined as being blind or having severe difficulty seeing, even with eyeglasses. Good vision is important for maintaining balance as well as for identifying low-contrast hazards, estimating distances, and discerning spatial relationships. Conversely, having poor vision increases the risk for falls (1,2). Falls among older adults are common and can cause serious injuries, disabilities, and premature death (1,3). To date, no state-level investigations have examined the annual prevalence of falls among persons with and without severe vision impairment. CDC analyzed data from the 2014 Behavioral Risk Factor Surveillance System (BRFSS) to estimate the state-specific annual prevalence of falls among persons aged ≥65 years with and without self-reported severe vision impairment. Overall, 46.7% of persons with, and 27.7% of older adults without, self-reported severe vision impairment reported having fallen during the previous year. The state-specific annual prevalence of falls among persons aged ≥65 years with severe vision impairment ranged from 30.8% (Hawaii) to 59.1% (California). In contrast, the prevalence of falls among persons aged ≥65 years without severe vision impairment ranged from 20.4% (Hawaii) to 32.4% (Alaska). Developing fall-prevention interventions intended for persons with severe vision impairment will help states manage the impact of vision impairment and falls on health care resources, and can inform state-specific fall prevention initiatives. PMID:27148832

  5. Parallel evolution of angiosperm colour signals: common evolutionary pressures linked to hymenopteran vision

    PubMed Central

    Dyer, Adrian G.; Boyd-Gerny, Skye; McLoughlin, Stephen; Rosa, Marcello G. P.; Simonov, Vera; Wong, Bob B. M.

    2012-01-01

    Flowering plants in Australia have been geographically isolated for more than 34 million years. In the Northern Hemisphere, previous work has revealed a close fit between the optimal discrimination capabilities of hymenopteran pollinators and the flower colours that have most frequently evolved. We collected spectral data from 111 Australian native flowers and tested signal appearance considering the colour discrimination capabilities of potentially important pollinators. The highest frequency of flower reflectance curves is consistent with data reported for the Northern Hemisphere. The subsequent mapping of Australian flower reflectances into a bee colour space reveals a very similar distribution of flower colour evolution to the Northern Hemisphere. Thus, flowering plants in Australia are likely to have independently evolved spectral signals that maximize colour discrimination by hymenoptera. Moreover, we found that the degree of variability in flower coloration for particular angiosperm species matched the range of reflectance colours that can only be discriminated by bees that have experienced differential conditioning. This observation suggests a requirement for plasticity in the nervous systems of pollinators to allow generalization of flowers of the same species while overcoming the possible presence of non-rewarding flower mimics. PMID:22673351

  6. [Acute bilateral impaired vision with central scotoma in an 11-year-old boy].

    PubMed

    Pollithy, S; Ach, T; Schaal, K B; Dithmar, S

    2012-09-01

    This article presents a case of acute bilateral impaired vision and central scotoma in an 11-year-old boy. Looking directly into a laser beam of a laser pointer for only a few seconds can cause retinal damage in the form of lesions of the retinal pigment epithelium and the photoreceptor layer, up to retinal hemorrhage. Patients often complain about impaired vision and a central scotoma of the affected eye. PMID:22740016

  7. Colour vision in the glow-worm Lampyris noctiluca (L.) (Coleoptera: Lampyridae): evidence for a green-blue chromatic mechanism.

    PubMed

    Booth, David; Stewart, Alan J A; Osorio, Daniel

    2004-06-01

    Male glow-worms Lampyris noctiluca find their bioluminescent mates at night by phototaxis. There is good evidence that location of mates by lampyrid beetles is achieved by a single spectral class of photoreceptor, whose spectral sensitivity is tuned to the bioluminescent spectrum emitted by conspecifics, and is achromatic. We ask whether glow-worm phototaxis involves interactions between two spectral classes of photoreceptor. Binary choice experiments were conducted in which males were presented with artificial light stimuli that differ in spectral composition. The normal preference for a green stimulus (lambdamax=555 nm), corresponding to the bioluminescence wavelength produced by signalling females, was significantly reduced by adding a blue (lambdamax=485 nm) component to the signal. This implies an antagonistic interaction between long- and short-wavelength sensitive photoreceptors, suggesting colour vision based on chromatic opponency. Cryosections showed a band of yellow filter pigment in the fronto-dorsal region of the male compound eye, which could severely constrain colour vision in the dim conditions in which the insects signal. This apparent paradox is discussed in the context of the distribution of the pigment within the eye and the photic niche of the species. PMID:15184509

  8. Beauty in the eyes of the beholders: colour vision is tuned to mate preference in the Trinidadian guppy (Poecilia reticulata).

    PubMed

    Sandkam, Benjamin; Young, C Megan; Breden, Felix

    2015-02-01

    A broad range of animals use visual signals to assess potential mates, and the theory of sensory exploitation suggests variation in visual systems drives mate preference variation due to sensory bias. Trinidadian guppies (Poecilia reticulata), a classic system for studies of the evolution of female mate choice, provide a unique opportunity to test this theory by looking for covariation in visual tuning, light environment and mate preferences. Female preference co-evolves with male coloration, such that guppy females from 'low-predation' environments have stronger preferences for males with more orange/red coloration than do females from 'high-predation' environments. Here, we show that colour vision also varies across populations, with 'low'-predation guppies investing more of their colour vision to detect red/orange coloration. In independently colonized watersheds, guppies expressed higher levels of both LWS-1 and LWS-3 (the most abundant LWS opsins) in 'low-predation' populations than 'high-predation' populations at a time that corresponds to differences in cone cell abundance. We also observed that the frequency of a coding polymorphism differed between high- and low-predation populations. Together, this shows that the variation underlying preference could be explained by simple changes in expression and coding of opsins, providing important candidate genes to investigate the genetic basis of female preference variation in this model system. PMID:25556876

  9. Is colour cognitive?

    NASA Astrophysics Data System (ADS)

    Skorupski, Peter; Chittka, Lars

    2011-03-01

    In recent years, colour-vision abilities have been rather generously ascribed to various invertebrates and even bacteria. This uncertainty of when to diagnose colour vision stems in part from confusing what colour vision can do with what it is. What colour vision can do is discriminate wavelength independent of intensity. However, if we take this as a definition of what colour vision is, then we might be obliged to conclude that some plants and bacteria have colour vision. Moreover, there is a similar confusion of what are necessary and what are sufficient mechanisms and behavioural abilities for colour vision. To humans, seeing in colour means seeing an image in which objects/lights have chromatic attributes—in contrast to the sensation that we have when viewing monochrome movies, or our experience in dim light when only rod vision is possible. The necessary basic equipment for this is to have at least two types of photoreceptors that differ in spectral sensitivity, and at least one type of spectrally opponent cell to compare the signals from the photoreceptors. Clearly, however, a necessary additional prerequisite for colour vision is to have vision, which entails the identification of shapes, sizes and locations of objects in the world. Thus, if an animal has colour vision, it should see an image in which distinct objects/lights have colour attributes. This distinguishes colour vision from wavelength discrimination, but also from what has historically been called wavelength-specific behaviour: a type of behaviour triggered by fixed configurations of spectral receptor signals; however, we discuss difficulties in diagnosing wavelength-specific behaviour as an indicator of the absence of colour vision. Finally, we discuss whether colour vision, by definition, contains a cognitive dimension for ordering and classifying perceptual experience.

  10. The Effect of Gender and Level of Vision on the Physical Activity Level of Children and Adolescents with Visual Impairment

    ERIC Educational Resources Information Center

    Aslan, Ummuhan Bas; Calik, Bilge Basakci; Kitis, Ali

    2012-01-01

    This study was planned in order to determine physical activity levels of visually impaired children and adolescents and to investigate the effect of gender and level of vision on physical activity level in visually impaired children and adolescents. A total of 30 visually impaired children and adolescents (16 low vision and 14 blind) aged between…

  11. Colour Perception in ADHD

    ERIC Educational Resources Information Center

    Banaschewski, Tobias; Ruppert, Sinje; Tannock, Rosemary; Albrecht, Bjorn; Becker, Andreas; Uebel, Henrik; Sergeant, Joseph A.; Rothenberger, Aribert

    2006-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children…

  12. Impact of Pediatric Vision Impairment on Daily Life: Results of Focus Groups

    PubMed Central

    DeCarlo, Dawn K.; McGwin, Gerald; Bixler, Martha L.; Wallander, Jan; Owsley, Cynthia

    2012-01-01

    Purpose To identify through focus groups of visually impaired children and their parents, relevant content for a vision-targeted health-related quality of life questionnaire designed for children ages 6-12. Methods Six focus groups of children with vision impairment ages 6 -12 and six focus groups of their parents were conducted by trained facilitators using a guided script. Sessions were recorded, transcribed and coded per a standardized protocol for content analysis. Comments were placed in thematic categories and each coded as positive, negative or neutral. Results Twenty-four children (mean age 9.4 years) with vision impairment from a variety of causes and 23 parents participated. The child focus groups generated 1,163 comments, of which 52% (n=599) were negative, 12% (n=138) were neutral and 37% (n=426) were positive. The three most common topical areas among children were: glasses and adaptive equipment (18%), psychosocial (14%) and school (14%). The parent focus groups generated 1,952 comments of which 46% (n=895) were negative, 16% (n=323) were neutral and 38% (n=734) were positive. The three most common topical areas among parents were: school (21%), expectations or frustrations (14%) and psychosocial (13%). Conclusions Pediatric vision impairment has significant effects on health related quality of life, as reported by children with vision impairment and their parents in their own words. These findings will provide the content to guide construction of a survey instrument to assess vision-specific, health-related quality of life in children with vision impairment. PMID:22863790

  13. Visual Impairment Secondary to Congenital Glaucoma in Children: Visual Responses, Optical Correction and Use of Low Vision Aids

    PubMed Central

    Haddad, Maria Aparecida Onuki; Sampaio, Marcos Wilson; Oltrogge, Ernst Werner; Kara-José, Newton; Betinjane, Alberto Jorge

    2009-01-01

    INTRODUCTION Congenital glaucoma is frequently associated with visual impairment due to optic nerve damage, corneal opacities, cataracts and amblyopia. Poor vision in childhood is related to global developmental problems, and referral to vision habilitation/rehabilitation services should be without delay to promote efficient management of the impaired vision. OBJECTIVE To analyze data concerning visual response, the use of optical correction and prescribed low vision aids in a population of children with congenital glaucoma. METHOD The authors analyzed data from 100 children with congenital glaucoma to assess best corrected visual acuity, prescribed optical correction and low vision aids. RESULTS Fifty-five percent of the sample were male, 43% female. The mean age was 6.3 years. Two percent presented normal visual acuity levels, 29% mild visual impairment, 28% moderate visual impairment, 15% severe visual impairment, 11% profound visual impairment, and 15% near blindness. Sixty-eight percent received optical correction for refractive errors. Optical low vision aids were adopted for distance vision in 34% of the patients and for near vision in 6%. A manual monocular telescopic system with 2.8 × magnification was the most frequently prescribed low vision aid for distance, and for near vision a +38 diopter illuminated stand magnifier was most frequently prescribed. DISCUSSION AND CONCLUSION Careful low vision assessment and the appropriate prescription of optical corrections and low vision aids are mandatory in children with congenital glaucoma, since this will assist their global development, improving efficiency in daily life activities and promoting social and educational inclusion. PMID:19690654

  14. Frugivory and colour vision in Alouatta seniculus, a trichromatic platyrrhine monkey.

    PubMed

    Regan, B C; Julliot, C; Simmen, B; Viénot, F; Charles-Dominique, P; Mollon, J D

    1998-11-01

    It is a long-standing hypothesis that primate trichromacy evolved to help fruit-eating primates find fruits amongst leaves. We measured the reflectance spectra of fruits eaten by a trichromatic primate, Alouatta seniculus, in the rainforest of French Guiana, as well as those of the leaves that form the natural background to fruits. We develop a method of specifying these natural colour signals in a chromaticity diagram appropriate for A. seniculus. By treating the task facing frugivorous monkeys as a signal detection task, we show that the spectral tuning of the L and M cone pigments in A. seniculus is optimal for detecting fruits amongst leaves. PMID:9893844

  15. Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabrication.

    PubMed

    Zhang, Min; Li, Songjing

    2016-01-01

    In this work, liquid colour-changing lenses for vision protection, camouflage and optical filtering are developed by circulating colour liquids through microfluidic channels on the lenses manually. Soft lithography technology is applied to fabricate the silicone liquid colour-changing layers with microfluidic channels on the lenses instead of mechanical machining. To increase the hardness and abrasion resistance of the silicone colour-changing layers on the lenses, proper fabrication parameters such as 6:1 (mass ration) mixing proportion and 100 °C curing temperature for 2 h are approved for better soft lithography process of the lenses. Meanwhile, a new surface treatment for the irreversible bonding of silicone colour-changing layer with optical resin (CR39) substrate lens by using 5 % (volume ratio) 3-Aminopropyltriethoxysilane solution is proposed. Vision protection, camouflage and optical filtering functions of the lenses are investigated with different designs of the channels and multi-layer structures. Each application can not only well achieve their functional demands, but also shows the advantages of functional flexibility, rapid prototyping and good controllability compared with traditional ways. Besides optometry, some other designs and applications of the lenses are proposed for potential utility in the future. PMID:27247877

  16. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  17. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  18. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  19. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  20. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  1. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  2. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  3. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  4. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  5. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  6. Test Anxiety Research: Students with Vision Impairments and Students with Mild Intellectual Disabilities

    ERIC Educational Resources Information Center

    Datta, Poulomee

    2014-01-01

    There is an absence of research on test anxiety in students with disabilities although such testing is taken for granted among students without disabilities. This study investigated the test anxiety of the students in each of the two disability groups, those with vision impairments and those with intellectual disabilities who are placed in…

  7. The "Inclusion" of Students with Vision Impairments: Generational Perspectives in Australia

    ERIC Educational Resources Information Center

    Whitburn, Ben

    2014-01-01

    In this paper I draw upon findings of a recent qualitative project conducted in Queensland, Australia in which all actors--the researcher and 5 participants aged 13-17 years--were linked together by our shared experiences of being students with impaired vision (VI) and who were educated in inclusive secondary schools in Australia during the last…

  8. Audio from Orbit: The Future of Libraries for Individuals Who Are Blind or Vision Impaired

    ERIC Educational Resources Information Center

    Steer, Michael; Cheetham, Leonie

    2005-01-01

    Free library service is a component of the foundations of democracy, citizenship, economic and social development, scholarship and education, in progressive societies. The evolution of libraries for people who are blind or vision impaired is briefly discussed and an innovative project, a talking book and daily newspaper delivery system that…

  9. An Overview of a UK Paediatric Visual Impaired Population and Low Vision Aid Provision

    ERIC Educational Resources Information Center

    Theodorou, Nana; Shipman, Tracey

    2013-01-01

    A retrospective study was carried out to evaluate the paediatric visual impaired population attending the Low Vision Clinic at Sheffield Teaching Hospitals NHS Foundation Trust, over a period of 14 years. Data were collected and analysed for children less than 17 years for prevalence, demographics, registration status, aetiologies, and types of…

  10. Students with Low Vision Describe Their Visual Impairments and Visual Functioning

    ERIC Educational Resources Information Center

    Guerette, Amy R.; Lewis, Sandra; Mattingly, Cameron

    2011-01-01

    In the study reported here, the responses to a survey that was designed to determine the knowledge of their visual impairment of 51 students with low vision were analyzed. Although the students described their visual weaknesses and strengths, they had limited knowledge of, and difficulty communicating about, the medical aspects of their…

  11. Space Vision: Making Astronomy Accessible to Visually Impaired Students

    NASA Astrophysics Data System (ADS)

    Ries, J. G.; Baguio, M. R.; Jurgens, T. D.; Pruett, K. M.

    2004-05-01

    Astronomy, with good reason, is thought of as a visual science. Spectacular images of deep space objects or other worlds of our solar system inspire public interest in Astronomy. People encounter news about the universe during their daily life. Developing concepts about celestial objects presents an extra challenge of abstraction for people with visual impairments. The Texas Space Grant Consortium with educators at the Texas School for the Blind and Visually Impaired have developed a 2 day workshop to be held in April 2004 to help students with visual impairments understand these concepts. Hands-on activities and experiments will emphasize non-visual senses. For example, students will learn about: - Constellations as historical ways of finding one's way across the sky. - The size and structure of the Solar System by building a scale model on a running track. They will also: - Plan a planetary exploration mission. - Explore wave phenomenon using heat and sound waves. In preparation for the workshop we worked with teens involved in the countywide 4-H Teens Leading with Character (TLC) program to create the tactile materials necessary for the activities. The teens attended solar system education training so they would have the skills necessary to make the tactile displays to be used during the workshop. The results and evaluation of the workshop will be presented at the meeting. Touch the Universe: A NASA Braille Book of Astronomy inspired this workshop, and it is supported by HST Grant HST-ED-90255.01-A.

  12. Seroepidemiology of Toxocara Infection in Patients With Vision Impairment and Blindness in Durango, Mexico

    PubMed Central

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco

    2015-01-01

    Background Toxocara infection is a cause of vision impairment and blindness. We aimed to determine the seroprevalence and correlates of Toxocara infection in patients suffering from vision impairment and blindness in Durango City, Mexico. Methods Through a cross-sectional seroprevalence study, 204 patients with vision impairment and 19 blind patients were studied for the presence of anti-Toxocara IgG antibodies in Durango City, Mexico. Seroprevalence association with socio-demographic, housing, clinical, and behavioral characteristics of participants was also investigated. Results Five (2.5%) of the 204 patients with vision impairment, and none of the 19 patients with blindness were positive for anti-Toxocara IgG antibodies. In total, five of the 223 (2.2%) patients were positive for anti-Toxocara IgG antibodies. Seropositivity to Toxocara was not associated with age, sex, educational level, socio-economic status, presence of underlying diseases or behavioral characteristics of the patients. In contrast, multivariate analysis showed that Toxocara seropositivity was associated with living in a house with soil floor (odds ratio (OR) = 11.14; 95% confidence interval (CI): 1.57 - 78.74; P = 0.01). Conclusions This is the first report of Toxocara exposure in patients with vision impairment and blindness in Mexico, and of an association of Toxocara exposure with living in a house with soil floors. Results suggest a low Toxocara exposure in these patients in Durango, Mexico. The risk factor associated with Toxocara exposure identified in this study warrants for further investigation. PMID:25584103

  13. Neural Correlates of Impaired Vision in Adolescents Born Extremely Preterm and/or Extremely Low Birthweight

    PubMed Central

    Kelly, Claire E.; Cheong, Jeanie L. Y.; Molloy, Carly; Anderson, Peter J.; Lee, Katherine J.; Burnett, Alice C.; Connelly, Alan; Doyle, Lex W.; Thompson, Deanne K.

    2014-01-01

    Background Adolescents born extremely preterm (EP; <28 weeks' gestation) and/or extremely low birthweight (ELBW; <1000 g) experience high rates of visual impairments, however the potential neural correlates of visual impairments in EP/ELBW adolescents require further investigation. This study aimed to: 1) compare optic radiation and primary visual cortical structure between EP/ELBW adolescents and normal birthweight controls; 2) investigate associations between perinatal factors and optic radiation and primary visual cortical structure in EP/ELBW adolescents; 3) investigate associations between optic radiation and primary visual cortical structure in EP/ELBW adolescents and the odds of impaired vision. Methods 196 EP/ELBW adolescents and 143 controls underwent magnetic resonance imaging at a mean age of 18 years. Optic radiations were delineated using constrained spherical deconvolution based probabilistic tractography. Primary visual cortices were segmented using FreeSurfer software. Diffusion tensor variables and tract volume of the optic radiations, as well as volume, surface area and thickness of the primary visual cortices, were estimated. Results Axial, radial and mean diffusivities within the optic radiations, and primary visual cortical thickness, were higher in the EP/ELBW adolescents than controls. Within EP/ELBW adolescents, postnatal corticosteroid exposure was associated with altered optic radiation diffusion values and lower tract volume, while decreasing gestational age at birth was associated with increased primary visual cortical volume, area and thickness. Furthermore, decreasing optic radiation fractional anisotropy and tract volume, and increasing optic radiation diffusivity in EP/ELBW adolescents were associated with increased odds of impaired vision, whereas primary visual cortical measures were not associated with the odds of impaired vision. Conclusions Optic radiation and primary visual cortical structure are altered in EP/ELBW adolescents

  14. Mobility restriction and comorbidity in vision-impaired individuals living in the community.

    PubMed

    Mac Cobb, Siobhan

    2013-12-01

    A review of data presented in a national study of perceptions and experiences of mobility with an age-stratified sample of 564 Irish adults with vision impairment found that mobility was a significant issue. Comorbidity is a factor with 97 (29.5%) of the under-65 age group and 135 (59%) of the older age group reporting additional health challenges. Adapting to vision loss and ageing has psychological, functional, social and health implications and help-seeking is a complex process. This may explain the limited use of mobility aids and guide dogs in the total sample (5%), with a notable absence of use in the older age group. A broad view of the Person-Environment-Occupation Model was proposed for primary and community care services, in collaboration with specialist vision impairment agencies to enhance mobility, maintain functional capacity, influence positive and healthy adaptation to vision impairment, social inclusion and quality of life in a population expected to increase by more than 170% over the next 25 years. PMID:24335794

  15. Rapid adaptive evolution of colour vision in the threespine stickleback radiation.

    PubMed

    Rennison, Diana J; Owens, Gregory L; Heckman, Nancy; Schluter, Dolph; Veen, Thor

    2016-05-11

    Vision is a sensory modality of fundamental importance for many animals, aiding in foraging, detection of predators and mate choice. Adaptation to local ambient light conditions is thought to be commonplace, and a match between spectral sensitivity and light spectrum is predicted. We use opsin gene expression to test for local adaptation and matching of spectral sensitivity in multiple independent lake populations of threespine stickleback populations derived since the last ice age from an ancestral marine form. We show that sensitivity across the visual spectrum is shifted repeatedly towards longer wavelengths in freshwater compared with the ancestral marine form. Laboratory rearing suggests that this shift is largely genetically based. Using a new metric, we found that the magnitude of shift in spectral sensitivity in each population corresponds strongly to the transition in the availability of different wavelengths of light between the marine and lake environments. We also found evidence of local adaptation by sympatric benthic and limnetic ecotypes to different light environments within lakes. Our findings indicate rapid parallel evolution of the visual system to altered light conditions. The changes have not, however, yielded a close matching of spectrum-wide sensitivity to wavelength availability, for reasons we discuss. PMID:27147098

  16. The effects of simulated vision impairments on the cone of gaze.

    PubMed

    Hecht, Heiko; Hörichs, Jenny; Sheldon, Sarah; Quint, Jessilin; Bowers, Alex

    2015-10-01

    Detecting the gaze direction of others is critical for many social interactions. We explored factors that may make the perception of mutual gaze more difficult, including the degradation of the stimulus and simulated vision impairment. To what extent do these factors affect the complex assessment of mutual gaze? Using an interactive virtual head whose eye direction could be manipulated by the subject, we conducted two experiments to assess the effects of simulated vision impairments on mutual gaze. Healthy subjects had to demarcate the center and the edges of the cone of gaze-that is, the range of gaze directions that are accepted for mutual gaze. When vision was impaired by adding a semitransparent white contrast reduction mask to the display (Exp. 1), judgments became more variable and more influenced by the head direction (indicative of a compensation strategy). When refractive blur was added (Exp. 1), the gaze cone shrank from 12.9° (no blur) to 11.3° (3-diopter lens), which cannot be explained by a low-level process but might reflect a tightening of the criterion for mutual gaze as a response to the increased uncertainty. However, the overall effects of the impairments were relatively modest. Elderly subjects (Exp. 2) produced more variability but did not differ qualitatively from the younger subjects. In the face of artificial vision impairments, compensation mechanisms and criterion changes allow us to perform better in mutual gaze perception than would be predicted by a simple extrapolation from the losses in basic visual acuity and contrast sensitivity. PMID:26018645

  17. The Influence of Manifest Strabismus and Stereoscopic Vision on Non-Verbal Abilities of Visually Impaired Children

    ERIC Educational Resources Information Center

    Gligorovic, Milica; Vucinic, Vesna; Eskirovic, Branka; Jablan, Branka

    2011-01-01

    This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest…

  18. High Tech Aids Low Vision: A Review of Image Processing for the Visually Impaired

    PubMed Central

    Moshtael, Howard; Aslam, Tariq; Underwood, Ian; Dhillon, Baljean

    2015-01-01

    Recent advances in digital image processing provide promising methods for maximizing the residual vision of the visually impaired. This paper seeks to introduce this field to the readership and describe its current state as found in the literature. A systematic search revealed 37 studies that measure the value of image processing techniques for subjects with low vision. The techniques used are categorized according to their effect and the principal findings are summarized. The majority of participants preferred enhanced images over the original for a wide range of enhancement types. Adapting the contrast and spatial frequency content often improved performance at object recognition and reading speed, as did techniques that attenuate the image background and a technique that induced jitter. A lack of consistency in preference and performance measures was found, as well as a lack of independent studies. Nevertheless, the promising results should encourage further research in order to allow their widespread use in low-vision aids. PMID:26290777

  19. Application of machine vision technology to the development of aids for the visually impaired

    NASA Astrophysics Data System (ADS)

    Molloy, Derek; McGowan, T.; Clarke, K.; McCorkell, C.; Whelan, Paul F.

    1994-10-01

    This paper presents an experimental system for the combination of three areas of visual cues to aid recognition. The research is aimed at investigating the possibility of using this combination of information for scene description for the visually impaired. The areas identified as providing suitable visual cues are motion, shape and color. The combination of these provide a significant amount of information for recognition and description purposes by machine vision equipment and also allow the possibility of giving the user a more complete description of their environment. Research and development in the application of machine vision technologies to rehabilitative technologies has generally concentrated on utilizing a single visual cue. A novel method for the combination of techniques and technologies successful in machine vision is being explored. Work to date has concentrated on the integration of shape recognition, motion tracking, color extraction, speech synthesis, symbolic programming and auditory imaging of colors.

  20. Colour association and "colour amnesia" in aphasia.

    PubMed Central

    Varney, N R

    1982-01-01

    "Colour association" performance of 50 aphasic patients was investigated by means of a test in which they identified the characteristic colours of objects shown in line drawings. All aphasics with defects in colour association were impaired in reading comprehension. However, some (33%) retained normal aural comprehension. Approximately half the aphasics with receptive language impairment performed normally in colour association. The findings suggest that "colour amnesia" may be the result of a specific cognitive disturbance which is also responsible for a subtype of aphasic alexia. PMID:7086445

  1. Sinus Balloon Dilation as Treatment for Acute Sphenoid Sinusitis with Impaired Vision for a Child

    PubMed Central

    Zhao, Yin; Chen, Kangbing; Wang, Zonggui

    2016-01-01

    This paper is about sinus balloon dilatation in treatment of acute left sphenoid sinusitis with left impaired vision in a child. Balloon catheter dilatation (BCD) of the sinus ostia is a new technique. It has been shown to be a minimally invasive technique to manage chronic sinusitis. However, this method is rarely used in the treatment of acute sinusitis. So far, we know of no reported cases of sinus balloon dilatation in treatment of this case, especially for children. PMID:27006660

  2. The Use of a Tactile-Vision Sensory Substitution System as an Augmentative Tool for Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Williams, Michael D.; Ray, Christopher T.; Griffith, Jennifer; De l'Aune, William

    2011-01-01

    The promise of novel technological strategies and solutions to assist persons with visual impairments (that is, those who are blind or have low vision) is frequently discussed and held to be widely beneficial in countless applications and daily activities. One such approach involving a tactile-vision sensory substitution modality as a mechanism to…

  3. Comparison on testability of visual acuity, stereo acuity and colour vision tests between children with learning disabilities and children without learning disabilities in government primary schools

    PubMed Central

    Abu Bakar, Nurul Farhana; Chen, Ai-Hong

    2014-01-01

    Context: Children with learning disabilities might have difficulties to communicate effectively and give reliable responses as required in various visual function testing procedures. Aims: The purpose of this study was to compare the testability of visual acuity using the modified Early Treatment Diabetic Retinopathy Study (ETDRS) and Cambridge Crowding Cards, stereo acuity using Lang Stereo test II and Butterfly stereo tests and colour perception using Colour Vision Test Made Easy (CVTME) and Ishihara's Test for Colour Deficiency (Ishihara Test) between children in mainstream classes and children with learning disabilities in special education classes in government primary schools. Materials and Methods: A total of 100 primary school children (50 children from mainstream classes and 50 children from special education classes) matched in age were recruited in this cross-sectional comparative study. The testability was determined by the percentage of children who were able to give reliable respond as required by the respective tests. ‘Unable to test’ was defined as inappropriate response or uncooperative despite best efforts of the screener. Results: The testability of the modified ETDRS, Butterfly stereo test and Ishihara test for respective visual function tests were found lower among children in special education classes (P < 0.001) but not in Cambridge Crowding Cards, Lang Stereo test II and CVTME. Conclusion: Non verbal or “matching” approaches were found to be more superior in testing visual functions in children with learning disabilities. Modifications of vision testing procedures are essential for children with learning disabilities. PMID:24008790

  4. Loss of strumpellin in the melanocytic lineage impairs the WASH Complex but does not affect coat colour.

    PubMed

    Tyrrell, Benjamin J; Woodham, Emma F; Spence, Heather J; Strathdee, Douglas; Insall, Robert H; Machesky, Laura M

    2016-09-01

    The five-subunit WASH complex generates actin networks that participate in endocytic trafficking, migration and invasion in various cell types. Loss of one of the two subunits WASH or strumpellin in mice is lethal, but little is known about their role in mammals in vivo. We explored the role of strumpellin, which has previously been linked to hereditary spastic paraplegia, in the mouse melanocytic lineage. Strumpellin knockout in melanocytes revealed abnormal endocytic vesicle morphology but no impairment of migration in vitro or in vivo and no change in coat colour. Unexpectedly, WASH and filamentous actin could still localize to vesicles in the absence of strumpellin, although the shape and size of vesicles was altered. Blue native PAGE revealed the presence of two distinct WASH complexes, even in strumpellin knockout cells, revealing that the WASH complex can assemble and localize to endocytic compartments in cells in the absence of strumpellin. PMID:27390154

  5. Emotion Recognition/Understanding Ability in Hearing or Vision-Impaired Children: Do Sounds, Sights, or Words Make the Difference?

    ERIC Educational Resources Information Center

    Dyck, Murray J.; Farrugia, Charles; Shochet, Ian M.; Holmes-Brown, Martez

    2004-01-01

    Background: This study was designed to assess whether children with a sensory disability have consistent delays in acquiring emotion recognition and emotion understanding abilities. Method: Younger (6-11 years) and older (12-18 years) hearing-impaired children (HI; n = 49), vision-impaired children (VI; n = 42), and children with no sensory…

  6. Device for diagnosis and treatment of impairments on binocular vision and stereopsis

    NASA Astrophysics Data System (ADS)

    Bahn, Jieun; Choi, Yong-Jin; Son, Jung-Young; Kodratiev, N. V.; Elkhov, Victor A.; Ovechkis, Yuri N.; Chung, Chan-sup

    2001-06-01

    Strabismus and amblyopia are two main impairments of our visual system, which are responsible for the loss of stereovision. A device is developed for diagnosis and treatment of strabismus and amblyopia, and for training and developing stereopsis. This device is composed of a liquid crystal glasses (LCG), electronics for driving LCG and synchronizing with an IBM PC, and a special software. The software contains specially designed patterns and graphics for enabling to train and develop stereopsis, and do objective measurement of some stereoscopic vision parameters such as horizontal and vertical phoria, fusion, fixation disparity, and stereoscopic visual threshold.

  7. Early Chronic Low-Level Methylmercury Poisoning in Monkeys Impairs Spatial Vision

    NASA Astrophysics Data System (ADS)

    Rice, Deborah C.; Gilbert, Steven G.

    1982-05-01

    Five monkeys were treated from birth with oral doses of mercury as methylmercury (50 micrograms per kilogram of body weight per day); concentrations in the blood peaked at 1.2 to 1.4 parts per million; and declined after weaning from infant formula to a steady level of 0.6 to 0.9 part per million. There were no overt signs of toxicity. When tested between 3 and 4 years of age under conditions of both high and low luminance, treated monkeys exhibited spatial vision that was impaired compared with that of control monkeys.

  8. 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

    2016-01-01

    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

  9. 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

  10. Oculopharyngeal Weakness, Hypophrenia, Deafness, and Impaired Vision: A Novel Autosomal Dominant Myopathy with Rimmed Vacuoles

    PubMed Central

    Chen, Ting; Lu, Xiang-Hui; Wang, Hui-Fang; Ban, Rui; Liu, Hua-Xu; Shi, Qiang; Wang, Qian; Yin, Xi; Pu, Chuan-Qiang

    2016-01-01

    Background: Myopathies with rimmed vacuoles are a heterogeneous group of muscle disorders with progressive muscle weakness and varied clinical manifestations but similar features in muscle biopsies. Here, we describe a novel autosomal dominant myopathy with rimmed vacuoles in a large family with 11 patients of three generations affected. Methods: A clinical study including family history, obstetric, pediatric, and development history was recorded. Clinical examinations including physical examination, electromyography (EMG), serum creatine kinase (CK), bone X-rays, and brain magnetic resonance imaging (MRI) were performed in this family. Open muscle biopsies were performed on the proband and his mother. To find the causative gene, the whole-exome sequencing was carried out. Results: Disease onset was from adolescence to adulthood, but the affected patients of the third generation presented an earlier onset and more severe clinical manifestations than the older generations. Clinical features were characterized as dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision. However, not every patient manifested all symptoms. Serum CK was mildly elevated and EMG indicated a myopathic pattern. Brain MRI showed cerebellum and brain stem mildly atrophy. Rimmed vacuoles and inclusion bodies were observed in muscle biopsy. The whole-exome sequencing was performed, but the causative gene has not been found. Conclusions: We reported a novel autosomal dominant myopathy with rimmed vacuoles characterized by dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision, but the causative gene has not been found and needs further study. PMID:27453229

  11. Impairing the useful field of view in natural scenes: Tunnel vision versus general interference.

    PubMed

    Ringer, Ryan V; Throneburg, Zachary; Johnson, Aaron P; Kramer, Arthur F; Loschky, Lester C

    2016-01-01

    A fundamental issue in visual attention is the relationship between the useful field of view (UFOV), the region of visual space where information is encoded within a single fixation, and eccentricity. A common assumption is that impairing attentional resources reduces the size of the UFOV (i.e., tunnel vision). However, most research has not accounted for eccentricity-dependent changes in spatial resolution, potentially conflating fixed visual properties with flexible changes in visual attention. Williams (1988, 1989) argued that foveal loads are necessary to reduce the size of the UFOV, producing tunnel vision. Without a foveal load, it is argued that the attentional decrement is constant across the visual field (i.e., general interference). However, other research asserts that auditory working memory (WM) loads produce tunnel vision. To date, foveal versus auditory WM loads have not been compared to determine if they differentially change the size of the UFOV. In two experiments, we tested the effects of a foveal (rotated L vs. T discrimination) task and an auditory WM (N-back) task on an extrafoveal (Gabor) discrimination task. Gabor patches were scaled for size and processing time to produce equal performance across the visual field under single-task conditions, thus removing the confound of eccentricity-dependent differences in visual sensitivity. The results showed that although both foveal and auditory loads reduced Gabor orientation sensitivity, only the foveal load interacted with retinal eccentricity to produce tunnel vision, clearly demonstrating task-specific changes to the form of the UFOV. This has theoretical implications for understanding the UFOV. PMID:27050950

  12. Prevalence of vision impairment and refractive error in school children in Ba Ria – Vung Tau province, Vietnam

    PubMed Central

    Paudel, Prakash; Ramson, Prasidh; Naduvilath, Thomas; Wilson, David; Phuong, Ha Thanh; Ho, Suit M; Giap, Nguyen V

    2014-01-01

    Background To assess the prevalence of vision impairment and refractive error in school children 12–15 years of age in Ba Ria – Vung Tau province, Vietnam. Design Prospective, cross-sectional study. Participants 2238 secondary school children. Methods Subjects were selected based on stratified multistage cluster sampling of 13 secondary schools from urban, rural and semi-urban areas. The examination included visual acuity measurements, ocular motility evaluation, cycloplegic autorefraction, and examination of the external eye, anterior segment, media and fundus. Main Outcome Measures Visual acuity and principal cause of vision impairment. Results The prevalence of uncorrected and presenting visual acuity ≤6/12 in the better eye were 19.4% (95% confidence interval, 12.5–26.3) and 12.2% (95% confidence interval, 8.8–15.6), respectively. Refractive error was the cause of vision impairment in 92.7%, amblyopia in 2.2%, cataract in 0.7%, retinal disorders in 0.4%, other causes in 1.5% and unexplained causes in the remaining 2.6%. The prevalence of vision impairment due to myopia in either eye (–0.50 diopter or greater) was 20.4% (95% confidence interval, 12.8–28.0), hyperopia (≥2.00 D) was 0.4% (95% confidence interval, 0.0–0.7) and emmetropia with astigmatism (≥0.75 D) was 0.7% (95% confidence interval, 0.2–1.2). Vision impairment due to myopia was associated with higher school grade and increased time spent reading and working on a computer. Conclusions Uncorrected refractive error, particularly myopia, among secondary school children in Vietnam is a major public health problem. School-based eye health initiative such as refractive error screening is warranted to reduce vision impairment. PMID:24299145

  13. Prevalence and patterns of comorbid cognitive impairment in low vision rehabilitation for macular disease.

    PubMed

    Whitson, Heather E; Ansah, Deidra; Whitaker, Diane; Potter, Guy; Cousins, Scott W; MacDonald, Heather; Pieper, Carl F; Landerman, Lawrence; Steffens, David C; Cohen, Harvey J

    2010-01-01

    The prevalence of comorbid cognitive impairment among older adults referred to low vision rehabilitation (LVR) for macular disease is unknown. We performed cognitive testing on 101 adults aged 65 years or older with macular disease who were referred to The Duke LVR Clinic between September 2007 and March 2008. Scores on the telephone interview for cognitive status-modified (TICS-m) ranged from 7 to 44, with 18.8% of scores below an established cutoff for cognitive impairment (< or = 27) and an additional 27.7% of scores considered marginal (28-30). On letter fluency, 46% of participants scored at least 1 x standard deviation (SD) below the mean for their age, gender, race, and education level, and 18% of participants scored at least 2 x below their demographic mean. On logical memory, 26% of participants scored at least 1x below the mean for their age group and race and 6% scored at least 2 x below their demographic mean. High prevalence of cognitive impairment, with particular difficulty in verbal fluency and verbal memory, may compromise the success of LVR interventions among macular disease patients. Additional work is needed to develop strategies to maximize function in older adults with this common comorbidity. PMID:19427045

  14. Object knowledge modulates colour appearance

    PubMed Central

    Witzel, Christoph; Valkova, Hanna; Hansen, Thorsten; Gegenfurtner, Karl R

    2011-01-01

    We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis. PMID:23145224

  15. Measuring perceived video quality of MPEG enhancement by people with impaired vision

    PubMed Central

    Fullerton, Matthew; Woods, Russell L.; Vera-Diaz, Fuensanta A.; Peli, Eli

    2007-01-01

    We used a new method to measure the perceived quality of contrast-enhanced motion video. Patients with impaired vision (n = 24) and normally-sighted subjects (n = 6) adjusted the level of MPEG-based enhancement of 8 videos (4 minutes each) drawn from 4 categories. They selected the level of enhancement that provided the preferred view of the videos, using a reducing-step-size staircase procedure. Most patients made consistent selections of the preferred level of enhancement, indicating an appreciation of and a perceived benefit from the MPEG-based enhancement. The selections varied between patients and were correlated with letter contrast sensitivity, but the selections were not affected by training, experience or video category. We measured just noticeable differences (JNDs) directly for videos, and mapped the image manipulation (enhancement in our case) onto an approximately linear perceptual space. These tools and approaches will be of value in other evaluations of the image quality of motion video manipulations. PMID:18059909

  16. Retinal Image Quality Assessment for Spaceflight-Induced Vision Impairment Study

    NASA Technical Reports Server (NTRS)

    Vu, Amanda Cadao; Raghunandan, Sneha; Vyas, Ruchi; Radhakrishnan, Krishnan; Taibbi, Giovanni; Vizzeri, Gianmarco; Grant, Maria; Chalam, Kakarla; Parsons-Wingerter, Patricia

    2015-01-01

    Long-term exposure to space microgravity poses significant risks for visual impairment. Evidence suggests such vision changes are linked to cephalad fluid shifts, prompting a need to directly quantify microgravity-induced retinal vascular changes. The quality of retinal images used for such vascular remodeling analysis, however, is dependent on imaging methodology. For our exploratory study, we hypothesized that retinal images captured using fluorescein imaging methodologies would be of higher quality in comparison to images captured without fluorescein. A semi-automated image quality assessment was developed using Vessel Generation Analysis (VESGEN) software and MATLAB® image analysis toolboxes. An analysis of ten images found that the fluorescein imaging modality provided a 36% increase in overall image quality (two-tailed p=0.089) in comparison to nonfluorescein imaging techniques.

  17. Global Vision Impairment and Blindness Due to Uncorrected Refractive Error, 1990-2010.

    PubMed

    Naidoo, Kovin S; Leasher, Janet; Bourne, Rupert R; Flaxman, Seth R; Jonas, Jost B; Keeffe, Jill; Limburg, Hans; Pesudovs, Konrad; Price, Holly; White, Richard A; Wong, Tien Y; Taylor, Hugh R; Resnikoff, Serge

    2016-03-01

    : The purpose of this systematic review was to estimate worldwide the number of people with moderate and severe visual impairment (MSVI; presenting visual acuity <6/18, ≥3/60) or blindness (presenting visual acuity <3/60) due to uncorrected refractive error (URE), to estimate trends in prevalence from 1990 to 2010, and to analyze regional differences. The review focuses on uncorrected refractive error which is now the most common cause of avoidable visual impairment globally. : The systematic review of 14,908 relevant manuscripts from 1990 to 2010 using Medline, Embase, and WHOLIS yielded 243 high-quality, population-based cross-sectional studies which informed a meta-analysis of trends by region. The results showed that in 2010, 6.8 million (95% confidence interval [CI]: 4.7-8.8 million) people were blind (7.9% increase from 1990) and 101.2 million (95% CI: 87.88-125.5 million) vision impaired due to URE (15% increase since 1990), while the global population increased by 30% (1990-2010). The all-age age-standardized prevalence of URE blindness decreased 33% from 0.2% (95% CI: 0.1-0.2%) in 1990 to 0.1% (95% CI: 0.1-0.1%) in 2010, whereas the prevalence of URE MSVI decreased 25% from 2.1% (95% CI: 1.6-2.4%) in 1990 to 1.5% (95% CI: 1.3-1.9%) in 2010. In 2010, URE contributed 20.9% (95% CI: 15.2-25.9%) of all blindness and 52.9% (95% CI: 47.2-57.3%) of all MSVI worldwide. The contribution of URE to all MSVI ranged from 44.2 to 48.1% in all regions except in South Asia which was at 65.4% (95% CI: 62-72%). : We conclude that in 2010, uncorrected refractive error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting a total of 108 million people or 1 in 90 persons. PMID:26905537

  18. In-home monitoring of older adults with vision impairment: exploring patients’, caregivers’ and professionals’ views

    PubMed Central

    Larizza, Melanie Frances; Zukerman, Ingrid; Bohnert, Fabian; Busija, Lucy; Bentley, Sharon Ann; Russell, R Andrew; Rees, Gwyneth

    2014-01-01

    Objective To develop a conceptual framework for the design of an in-home monitoring system (IMS) based on the requirements of older adults with vision impairment (VI), informal caregivers and eye-care rehabilitation professionals. Materials and Methods Concept mapping, a mixed-methods statistical research tool, was used in the construction of the framework. Overall, 40 participants brainstormed or sorted and rated 83 statements concerning an IMS for older adults with VI. Multidimensional scaling and hierarchical cluster analysis were employed to construct the framework. A questionnaire yielded further insights into the views of a wider sample of older adults with VI (n=78) and caregivers (n=25) regarding IMS. Results Concept mapping revealed a nine-cluster model of IMS-related aspects including affordability, awareness of system capabilities, simplicity of installation, operation and maintenance, system integrity and reliability, fall detection and safe movement, user customization, user preferences regarding information delivery, and safety alerts for patients and caregivers. From the questionnaire, independence, safety and fall detection were the most commonly reported reasons for older adults and caregivers to accept an IMS. Concerns included cost, privacy, security of the information obtained through monitoring, system accuracy, and ease of use. Discussion Older adults with VI, caregivers and professionals are receptive to in-home monitoring, mainly for fall detection and safety monitoring, but have concerns that must be addressed when developing an IMS. Conclusion Our study provides a novel conceptual framework for the design of an IMS that will be maximally acceptable and beneficial to our ageing and vision-impaired population. PMID:23676244

  19. Epidemiological assessment of lens opacifications that impaired vision in patients injected with radium-224

    SciTech Connect

    Chmelevsky, D.; Mays, C.W.; Spiess, H.; Stefani, F.H.; Kellerer, A.M.

    1988-08-01

    The incidence of lens opacifications that impaired vision (cataract) was analyzed among 831 patients who were injected with known dosages of /sup 224/Ra in Germany shortly after World War II. The dependence of the incidence on dosage, i.e., injected activity per unit body weight, and on time after treatment was determined. The observations are equally consistent with proportionality of the incidence of cataract to the square of dosage or with a linear dependence beyond a threshold of 0.5 MBq/kg. The possibility of a linear dependence without threshold was strongly rejected (P less than 0.001). The analysis of temporal dependences yielded a component that was correlated with the injected amount of /sup 224/Ra and a component that was uncorrelated. The former was inferred by a maximum likelihood analysis to increase approximately as the square of the time after treatment. The component unrelated to the treatment was found to increase steeply with age and to become dominant within the collective of patients between age 50 and 60. The relative magnitudes of the two components were such that a fraction of 55 to 60% of the total of 58 cataracts had to be ascribed to the dose-related incidence. Impaired vision due to cataract was diagnosed before age 54 in 25 cases. In terms of injected activity per unit body weight no dependence of the sensitivity on age was found; specifically there was no indication of a faster occurrence of the treatment-related cataracts in patients treated at older ages.

  20. The relative contributions of colour and luminance signals towards the visuomotor localisation of targets in human peripheral vision.

    PubMed

    Ashida, Hiroshi; Yamagishi, Noriko; Anderson, Stephen J

    2007-12-01

    We sought to determine the extent to which colour (and luminance) signals contribute towards the visuomotor localization of targets. To do so we exploited the movement-related illusory displacement a small stationary window undergoes when it has a continuously moving carrier grating behind it. We used drifting (1.0-4.2 Hz) red/green-modulated isoluminant gratings or yellow/black luminance-modulated gratings as carriers, each curtailed in space by a stationary, two-dimensional window. After each trial, the perceived location of the window was recorded with reference to an on-screen ruler (perceptual task) or the on-screen touch of a ballistic pointing movement made without visual feedback (visuomotor task). Our results showed that the perceptual displacement measures were similar for each stimulus type and weakly dependent on stimulus drift rate. However, while the visuomotor displacement measures were similar for each stimulus type at low drift rates (<4 Hz), they were significantly larger for luminance than colour stimuli at high drift rates (>4 Hz). We show that the latter cannot be attributed to differences in perceived speed between stimulus types. We assume, therefore, that our visuomotor localization judgements were more susceptible to the (carrier) motion of luminance patterns than colour patterns. We suggest that, far from being detrimental, this susceptibility may indicate the operation of mechanisms designed to counter the temporal asynchrony between perceptual experiences and the physical changes in the environment that give rise to them. We propose that perceptual localisation is equally supported by both colour and luminance signals but that visuomotor localisation is predominantly supported by luminance signals. We discuss the neural pathways that may be involved with visuomotor localization. PMID:17643232

  1. Accessibility and Autonomy Preconditions to "Our" Inclusion: A Grounded Theory Study of the Experiences of Secondary Students with Vision Impairment

    ERIC Educational Resources Information Center

    Whitburn, Ben

    2014-01-01

    In this paper, I report core findings of a small-scale qualitative study that I conducted with a group of young people with vision impairment who attended an inclusive secondary school in the Australian state of Queensland. My objective was to capture their voiced experiences of their schooling through face-to-face interviews and to develop a…

  2. Visual search performance of patients with vision impairment: Effect of JPEG image enhancement

    PubMed Central

    Luo, Gang; Satgunam, PremNandhini; Peli, Eli

    2012-01-01

    Purpose To measure natural image search performance in patients with central vision impairment. To evaluate the performance effect for a JPEG based image enhancement technique using the visual search task. Method 150 JPEG images were presented on a touch screen monitor in either an enhanced or original version to 19 patients (visual acuity 0.4 to 1.2 logMAR, 6/15 to 6/90, 20/50 to 20/300) and 7 normally sighted controls (visual acuity −0.12 to 0.1 logMAR, 6/4.5 to 6/7.5, 20/15 to 20/25). Each image fell into one of three categories: faces, indoors, and collections. The enhancement was realized by moderately boosting a mid-range spatial frequency band in the discrete cosine transform (DCT) coefficients of the image luminance component. Participants pointed to an object in a picture that matched a given target displayed at the upper-left corner of the monitor. Search performance was quantified by the percentage of correct responses, the median search time of correct responses, and an “integrated performance” measure – the area under the curve of cumulative correct response rate over search time. Results Patients were able to perform the search tasks but their performance was substantially worse than the controls. Search performances for the 3 image categories were significantly different (p≤0.001) for all the participants, with searching for faces being the most difficult. When search time and correct response were analyzed separately, the effect of enhancement led to increase in one measure but decrease in another for many patients. Using the integrated performance, it was found that search performance declined with decrease in acuity (p=0.005). An improvement with enhancement was found mainly for the patients whose acuity ranged from 0.4 to 0.8 logMAR (6/15 to 6/38, 20/50 to 20/125). Enhancement conferred a small but significant improvement in integrated performance for indoor and collection images (p=0.025) in the patients. Conclusion Search performance

  3. Causes of childhood visual impairment and unmet low-vision care in blind school students in Ghana.

    PubMed

    Ntim-Amponsah, C T; Amoaku, W M K

    2008-10-01

    The purpose of this study was to determine the causes of childhood visual impairment and blindness in students of a school for blind children, to determine how many students had some residual vision, and to evaluate any unmet low-vision care. A survey of students in the blind school was conducted in two parts in May-June and then October 2003. The sample consisted of 201 students who became blind before the age of 16. Information was obtained from student interviews, doctors' referral notes and ophthalmic examination of all students who consented. Students with residual vision had low-vision assessments. These investigations were supplemented with active participation of the investigators in Parent-Teacher Association meetings and focus group discussions with parents. One hundred and ninety-nine students consented and were recruited, whereas two declined. Ninety-six became visually impaired within their first year of life and 33 by the age of 5 years. Pathology of the cornea and then the lens were the commonest causes of blindness. One hundred and eight students were totally blind, whereas 87 (43.7%) had some residual vision and formed the target for the second part of the study. Fifty-one out of 77 of this target group who turned up for low-vision examination had useful residual vision by the World Health Organisation (WHO) low-vision examination chart. Spectacle magnifiers aided two students to read normal print at N5 and N8, respectively. Different visual aids would help enhance the residual vision in some of the others. Emotional trauma was apparent in parents and teachers. Children who became blind later in life remained in shock for a longer time and adapted less well to their visual impairment. Visual impairment in the population is not uncommon. Some causes are preventable. There is a significant unmet need for low-vision care, particularly amongst children in Ghana, and perhaps many countries in the West Africa subregion. It is hoped that the findings from

  4. The Impact of Vision Impairment (IVI) Questionnaire; Validation of the Thai-Version and the Implementation on Vision-Related Quality of Life in Thai Rural Community

    PubMed Central

    Ratanasukon, Mansing; Tongsomboon, Jongjit; Bhurayanontachai, Patama; Jirarattanasopa, Pichai

    2016-01-01

    The objective of this study is to validate the Thai-version of the impact of vision impairment (IVI) questionnaire and to evaluate its impact on vision-related quality of life (VRQoL) in southern Thailand. The IVI questionnaire was translated into Thai according to WHO translation guidelines. In addition to the routine ophthalmological examinations, a Thai version of the IVI questionnaire was administered to all participants. A total of 120 patients with visual impairment who presented at Songklanagarind hospital, Songkhla province, were enrolled in the study; 30 had age-related macular degeneration (AMD), 30 had cataract, 30 had diabetic retinopathy, 30 had glaucoma, and 30 non-visually impaired individuals comprised the control group. Statistical analysis demonstrated the Thai-version IVI questionnaire is valid and reliable to evaluate the VRQoL of the Thai patients through three subscales: (i) mobility and independence, (ii) reading and accessing information, and (iii) emotional well-being. The results demonstrated high consistency in all subscales with Cronbach’s alpha ranging from 0.787 to 0.849. Rasch analysis revealed the validity of the Thai-version IVI to assess VRQoL through all three subscales. Test-retest reliability was also high (intraclass correlation coefficient = 0.96). The composite score of the IVI was significantly higher in participants with visual impairment compared with healthy participants. Moreover, the subscale scores of reading and accessing information, and emotional well-being were highest in participants with AMD. While the subscale scores of mobility and independence were highest among those with either cataracts or diabetic retinopathy. The symptoms of the common vision impairment diseases are associated with an adverse impact on VRQoL in a clinic-based population as demonstrated in this study. PMID:27191960

  5. Book4All: A Tool to Make an e-Book More Accessible to Students with Vision/Visual-Impairments

    NASA Astrophysics Data System (ADS)

    Calabrò, Antonello; Contini, Elia; Leporini, Barbara

    Empowering people who are blind or otherwise visually impaired includes ensuring that products and electronic materials incorporate a broad range of accessibility features and work well with screen readers and other assistive technology devices. This is particularly important for students with vision impairments. Unfortunately, authors and publishers often do not include specific criteria when preparing the contents. Consequently, e-books can be inadequate for blind and low vision users, especially for students. In this paper we describe a semi-automatic tool developed to support operators who adapt e-documents for visually impaired students. The proposed tool can be used to convert a PDF e-book into a more suitable accessible and usable format readable on desktop computer or on mobile devices.

  6. Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range

    PubMed Central

    Lehtonen, P K; Laaksonen, T; Artemyev, A V; Belskii, E; Berg, P R; Both, C; Buggiotti, L; Bureš, S; Burgess, M D; Bushuev, A V; Krams, I; Moreno, J; Mägi, M; Nord, A; Potti, J; Ravussin, P-A; Sirkiä, P M; Sætre, G-P; Winkel, W; Primmer, C R

    2012-01-01

    The role of natural selection in shaping adaptive trait differentiation in natural populations has long been recognized. Determining its molecular basis, however, remains a challenge. Here, we search for signals of selection in candidate genes for colour and its perception in a passerine bird. Pied flycatcher plumage varies geographically in both its structural and pigment-based properties. Both characteristics appear to be shaped by selection. A single-locus outlier test revealed 2 of 14 loci to show significantly elevated signals of divergence. The first of these, the follistatin gene, is expressed in the developing feather bud and is found in pathways with genes that determine the structure of feathers and may thus be important in generating variation in structural colouration. The second is a gene potentially underlying the ability to detect this variation: SWS1 opsin. These two loci were most differentiated in two Spanish pied flycatcher populations, which are also among the populations that have the highest UV reflectance. The follistatin and SWS1 opsin genes thus provide strong candidates for future investigations on the molecular basis of adaptively significant traits and their co-evolution. PMID:22027894

  7. Colour constancy in insects.

    PubMed

    Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

    2014-06-01

    Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects. PMID:24647930

  8. Electronic bracelet and vision-enabled waist-belt for mobility of visually impaired people.

    PubMed

    Bhatlawande, Shripad; Sunkari, Amar; Mahadevappa, Manjunatha; Mukhopadhyay, Jayanta; Biswas, Mukul; Das, Debabrata; Gupta, Somedeb

    2014-01-01

    A wearable assistive system is proposed to improve mobility of visually impaired people (subjects). This system has been implemented in the shape of a bracelet and waist-belt in order to increase its wearable convenience and cosmetic acceptability. A camera and an ultrasonic sensor are attached to a customized waist-belt and bracelet, respectively. The proposed modular system will act as a complementary aid along with a white cane. Its vision-enabled waist-belt module detects the path and distribution of obstacles on the path. This module conveys the required information to a subject via a mono earphone by activating relevant spoken messages. The electronic bracelet module assists the subject to verify this information and to perceive distance of obstacles along with their locations. The proposed complementary system provides an improved understanding of the surrounding environment with less cognitive and perceptual efforts as compared to a white cane alone. This system was subjected to clinical evaluations with 15 totally blind subjects. Results of usability experiments demonstrated effectiveness of the system as a mobility aid. Amongst the participated subjects, 93.33% expressed satisfaction with the information content of this system, 86.66% subjects comprehended its operational convenience, and 80% appreciated the comfort of the system. PMID:25771603

  9. The "voice" has it: screen reader adoption and switching behavior among vision impaired persons in India.

    PubMed

    McCarthy, Ted; Pal, Joyojeet; Cutrell, Edward

    2013-01-01

    We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, text-to-speech "voice" quality, particularly a "human-sounding voice" as one of the key features differentiating free/open source products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives--first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior. PMID:24620705

  10. The influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children.

    PubMed

    Gligorović, Milica; Vučinić, Vesna; Eškirović, Branka; Jablan, Branka

    2011-01-01

    This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest and polaroid glasses were used for the examination of stereoscopic vision, while Cover test and Hirschberg's pupils reflex test were used for the evaluation of strabismus. In the area of non-verbal abilities was evaluated visual discrimination, visuomotor integration, constructive praxia, visual memory, strategy formation, non-verbal reasoning and the representational dimension of drawings. Subtests of ACADIA test of developmental abilities were used for the evaluation of non-verbal abilities (Atkinson et al., 1972). Statistically significant relations between strabismus and constructive praxia (p=0.009), visual memory (p=0.037), strategy formation (0.040) and the quality of drawings were determined by the results analysis. According to our findings, children with divergent strabismus achieve the best results. Children with stereoscopic vision generally achieve better results in all the examined areas of non-verbal abilities, and statistically significant relations were determined in the areas of visuomotor coordination (0.002), constructive praxia (0.026) and non-verbal reasoning (0.015), which are directly connected to visuospatial abilities. Children with convergent strabismus achieve significantly lower results in the areas of constructive praxia, visual memory, strategy formation and representational dimension of drawings, and children with the lack of stereoscopic vision--in the areas of visuomotor integration, constructive praxia and non-verbal reasoning. PMID:21536409

  11. A telephone survey of low vision services in U.S. schools for the blind and visually impaired.

    PubMed

    Kran, Barry S; Wright, Darick W

    2008-07-01

    The scope of clinical low vision services and access to comprehensive eye care through U.S. schools for the blind and visually impaired is not well known. Advances in medicine and educational trends toward inclusion have resulted in higher numbers of visually impaired children with additional cognitive, motor, and developmental impairments enrolled in U.S. schools for the blind and visually impaired. The availability and frequency of eye care and vision education services for individuals with visual and multiple impairments at schools for the blind is explored in this report using data collected in a 24-item telephone survey from 35 of 42 identified U.S. schools for the blind. The results indicate that 54% of the contacted schools (19) offer clinical eye examinations. All of these schools provide eye care to the 6 to 21 age group, yet only 10 schools make this service available to children from birth to 3 years of age. In addition, two thirds of these schools discontinue eye care when the students graduate or transition to adult service agencies. The majority (94.7%) of eye care is provided by optometrists or a combination of optometry and ophthalmology, and 42.1% of these schools have an affiliation with an optometric institution. When there is a collaborative agreement, clinical services for students are available more frequently. The authors find that questions emerge regarding access to care, identification of appropriate models of care, and training of educational/medical/optometric personnel to meet the needs of a very complex patient population. PMID:18577495

  12. Coloured plastinates.

    PubMed

    Steinke, Hanno; Spanel-Borowski, Katharina

    2006-03-01

    To obtain coloured plastinates by colouring anatomical structures in e.g. red, blue and yellow we used different types of chemical reagents. The colours remained stable during dehydration, degreasing and impregnation of specimen with silicone resin. The colours, which penetrated into the specimen, appeared to be included in the plastination process. To prove their stability, the coloured plastinates were exposed to light and heat for more than 5 years. A permanent colouration remained. The coloured plastinates are dry and flexible, odourless and robust. They are instructive and can be used in tutorials, examinations and seminars. PMID:16551016

  13. "They Think They Know What's Best for Me": An Interpretative Phenomenological Analysis of the Experience of Inclusion and Support in High School for Vision-Impaired Students with Albinism

    ERIC Educational Resources Information Center

    Thurston, Mhairi

    2014-01-01

    The challenges of social inclusion and access to the curriculum facing students with visual impairment in schools are well documented. The refreshed UK Vision Strategy (2013) seeks to improve education for students with vision impairment. In order to do this, it is important to understand how students with visual impairment experience education.…

  14. Applications of Colour Processing In Optical Inspection

    NASA Astrophysics Data System (ADS)

    Thomas, W. V.; Connolly, C.

    1986-11-01

    Humans are endowed with the facility to perceive colour. This not only provides an additional aesthetic dimension but also helps perform visual tasks efficiently. There are many occupations, including inspection, not open to those with defective colour vision. Todays machine vision systems are virtually all colour-blind. Yet there are applications where colour is intrinsic. Consider for example the inspection and grading of fruit, vegetables, biscuits and other food products. Consider also the widespread use of colour coding for wiring and components in the electrical and electronic industries. Automatic optical inspection of such things cannot be done without relating to colour. There are other applications where colour is not directly relevant but the additional information provided can help simplify and speed up the processing task. This paper reviews the nature of colour, relating the psychophysical aspects of colour perception and the physical properties of available sensors to the needs of an automatic inspection system. The theory of colour perception is based on the tri-stimulus theory which says that any colour may be matched using appropriate proportions of three primary colours. Although later experiments have suggested human colour perception is more complex, most electronic video sensors employ a three colour system. Usually the red, green and blue primary components are derived and may be used directly as sensory inputs to a vision system. However the primary representation of colour is not the most efficient means of encoding nor is it the most useful basis for interpretive processing. The R,G and B primary signals may be simply transformed into a new coordinate system where one of the axes represents true object colour or hue. Using this new colour space simplifies processing. These ideas are illustrated by an inspection example. The colour coded wires of a European power cable are identified to ensure that a power plug is safely wired. For this

  15. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians. PMID:23664831

  16. The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

    ERIC Educational Resources Information Center

    Emmorey, Karen; Korpics, Franco; Petronio, Karen

    2009-01-01

    The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf…

  17. Extending Our Vision: Access to Inclusive Dance Education for People with Visual Impairment

    ERIC Educational Resources Information Center

    Seham, Jenny; Yeo, Anna J.

    2015-01-01

    Environmental, organizational and attitudinal obstacles continue to prevent people with vision loss from meaningfully engaging in dance education and performance. This article addresses the societal disabilities that handicap access to dance education for the blind. Although much of traditional dance instruction relies upon visual cuing and…

  18. Changes in Quality of Life in Visually Impaired Patients after Low-Vision Rehabilitation

    ERIC Educational Resources Information Center

    Renieri, Giulia; Pitz, Susanne; Pfeiffer, Norbert; Beutel, Manfred E.; Zwerenz, Rudiger

    2013-01-01

    The objective of the study was to assess the impact of low-vision aids on quality of life. Interviews included a modified version of the National Eye Institute Visual Functioning Questionnaire (Modified German NEI VFQ-25), the Hospital Anxiety and Depression Scale, the Mini-Mental State Examination Blind, and Indicators of the Rehabilitation…

  19. Visualizing without Vision at the Microscale: Students with Visual Impairments Explore Cells with Touch

    ERIC Educational Resources Information Center

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-01-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This…

  20. Visualizing Without Vision at the Microscale: Students With Visual Impairments Explore Cells With Touch

    NASA Astrophysics Data System (ADS)

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-12-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This study explored the efficacy of new haptic (simulated tactile feedback and kinesthetics) instructional technology for teaching cell morphology and function to middle and high school students with visual impairments. The study examined students' prior experiences learning about the cell and cell functions in classroom instruction, as well as how haptic feedback technology impacted students' awareness of the 3-D nature of an animal cell, the morphology and function of cell organelles, and students' interest in the haptic technology as an instructional tool. Twenty-one students with visual impairment participated in the study. Students explored a tactile model of the cell with a haptic point probe that allowed them to feel the cell and its organelles. Results showed that students made significant gains in their ability to identify cell organelles and found the technology to be highly interesting as an instructional tool. The need for additional adaptive technology for students with visual impairments is discussed.

  1. Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness

    PubMed Central

    Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B.; Franklin, Anna

    2016-01-01

    The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d’) and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object’s stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain. PMID:27023274

  2. Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness.

    PubMed

    Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B; Franklin, Anna

    2016-01-01

    The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d') and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain. PMID:27023274

  3. Vision Impairs the Abilities of Bats to Avoid Colliding with Stationary Obstacles

    PubMed Central

    Orbach, Dara N.; Fenton, Brock

    2010-01-01

    Background Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as “distress calls” of other bats, contributed to probabilities of collision. Methodology/Principal Findings To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions. Conclusions/Significance Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments. PMID:21085481

  4. Model Vision Project-Outreach Phase for Severely Handicapped Children and Youth with Visual Impairment. July 1, 1978 to September 30, 1981. Final Report.

    ERIC Educational Resources Information Center

    Harley, Randall K.; And Others

    The document presents the final report of the Model Vision Project (MVP) Outreach Phase, funded to demonstrate appropriate educational, diagnostic, training, and other services to severely multihandicapped, visually impaired children. Roles of various staff are reviewed, and individuals serving as consultants are listed. Summarized are the goals…

  5. The Sound of Vision Project: On the Feasibility of an Audio-Haptic Representation of the Environment, for the Visually Impaired.

    PubMed

    Jóhannesson, Ómar I; Balan, Oana; Unnthorsson, Runar; Moldoveanu, Alin; Kristjánsson, Árni

    2016-01-01

    The Sound of Vision project involves developing a sensory substitution device that is aimed at creating and conveying a rich auditory representation of the surrounding environment to the visually impaired. However, the feasibility of such an approach is strongly constrained by neural flexibility, possibilities of sensory substitution and adaptation to changed sensory input. We review evidence for such flexibility from various perspectives. We discuss neuroplasticity of the adult brain with an emphasis on functional changes in the visually impaired compared to sighted people. We discuss effects of adaptation on brain activity, in particular short-term and long-term effects of repeated exposure to particular stimuli. We then discuss evidence for sensory substitution such as Sound of Vision involves, while finally discussing evidence for adaptation to changes in the auditory environment. We conclude that sensory substitution enterprises such as Sound of Vision are quite feasible in light of the available evidence, which is encouraging regarding such projects. PMID:27355966

  6. Auditory localization and precedence effect: an exploratory study in infants and toddlers with visual impairment and normal vision.

    PubMed

    Hüg, Mercedes X; Arias, Claudia; Tommasini, Fabián C; Ramos, Oscar A

    2014-09-01

    The precedence effect is a spatial hearing phenomenon implicated in sound localization on reverberant environments. It occurs when a pair of sounds, with a brief delay between them, is presented from different directions; listeners give greater perceptual weight to localization cues coming from the first-arriving sound, called lead, and suppress localization cues from the later-arriving reflection, called lag. Developmental studies with sighted infants show that the first responses to precedence effect stimuli are observed at 4-5 months of life. In this exploratory study, we use the minimum audible angle (MAA) paradigm in conjunction with the observer-based psychophysical procedure to test the ability of infants and toddlers, with visual impairment and normal vision, to discriminate changes in the azimuthal position of sounds configured under precedence effect conditions. The results indicated that similar and, in some conditions, higher performances were obtained by blind toddlers when compared to sighted children of similar age, and revealed that the observer-based psychophysical procedure is a valuable method to measure auditory localization acuity in infants and toddlers with visual impairment. The video records showed auditory orienting behaviors specific of the blind children group. PMID:24864055

  7. Construction of an Evaluating System of Tactile Walking Surface Indicators for Persons with Vision Impairments

    NASA Astrophysics Data System (ADS)

    Sueda, Osamu; Fujisawa, Shoichiro; Xin, Wang

    An experiment to evaluate a tactile walking surface indicator for visually impaired persons was usually carried out in the outdoor environment, and the weather and the seasons affected on the schedule and the result. We constructed the evaluation system within the building so we could conduct walking experiments that were unaffected by the weather regardless of the four seasons. The subjects of this system were not only a visually impaired person and a sighted deaf person but also general person. The laboratory provided a soundproof and shaded structure consisting of the walls and the ceiling. External sound and light were blocked. The hue could be adjusted by three-color fluorescent lamps, and the light could be adjusted from daytime brightness to a dim moon light. Research into the walking of visually impaired persons at nighttime is a pressing problem as the barrier-free transportation law has been enacted in Japan. An international standard has been discussed, and a scientific basis for that standard is now required.

  8. Can Hooke's Law and the Airy Disk First Zero Radius Formulation Predict That Education and Work Environment Visual Task Excesses Lead to Vision Impairment?

    NASA Astrophysics Data System (ADS)

    McLeod, Douglas M.; McLeod, Roger D.

    2002-10-01

    DMM found that a distant, single church steeple, which appeared "twin-like" after extended studying episodes, could then be brought into correct visual register by a conscious effort. Similar anecdotal events are repeatable by attentive students or workers in the early stages of educationally or work environmentally induced repetitive vision impairment. RDM proposes that his model for vision and its repair utilizes sequentially applied vision improvement stages that are the equivalent of DMM's experience. Such visual events involve feedback signals generated during the crystalline lens's minor dioptric oscillations that are generated by the blinking reflex, empowered by the Airy radius proportional to wavelength times focal length divided by pupil aperture. This implies some conscious control of feedback mechanisms, which can self-regulate vision protecting processes. Continued visual effort under duress invokes Hooke's "stress proportional to strain." Exceeding extrinsic eye muscles' elastic limits overrides spontaneous feedback repair mechanisms.

  9. Association of Co-Existing Impairments in Cognition and Self-Rated Vision and Hearing With Health Outcomes in Older Adults

    PubMed Central

    Liu, Phillip L.; Cohen, Harvey Jay; Fillenbaum, Gerda G.; Burchett, Bruce M.; Whitson, Heather E.

    2015-01-01

    OBJECTIVES To assess the relationship of disability (activities of daily living (ADL) and instrumental ADL (IADL)), self-rated health (SRH), and 6-year mortality with co-existing impairments in vision (self-rated), hearing (self-rated) and/or cognition (Short Portable Mental Status Questionnaire) in older adults. METHODS The study sample was comprised of 3871 participants from the North Carolina Established Populations for Epidemiologic Studies of the Elderly study (NC EPESE). RESULTS Persons with all three impairments had increased odds of ADL/IADL disability, and low SRH. Participants with combined visual and cognitive impairments had increased odds of mortality. While sensory impairments were associated with poor SRH, cognitive impairment was not unless both sensory impairments were present. DISCUSSION Co-existent sensory and cognitive impairments were associated with higher risk of impaired functional status. Self-rated auditory impairment alone was not associated with higher odds of death, but mortality was linked to visual, and particularly cognitive impairment, alone or combined. PMID:27054148

  10. Colour detection thresholds in faces and colour patches.

    PubMed

    Tan, Kok Wei; Stephen, Ian D

    2013-01-01

    Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status. PMID:24344549

  11. Integrated vision-based robotic arm interface for operators with upper limb mobility impairments.

    PubMed

    Jiang, Hairong; Wachs, Juan P; Duerstock, Bradley S

    2013-06-01

    An integrated, computer vision-based system was developed to operate a commercial wheelchair-mounted robotic manipulator (WMRM). In this paper, a gesture recognition interface system developed specifically for individuals with upper-level spinal cord injuries (SCIs) was combined with object tracking and face recognition systems to be an efficient, hands-free WMRM controller. In this test system, two Kinect cameras were used synergistically to perform a variety of simple object retrieval tasks. One camera was used to interpret the hand gestures to send as commands to control the WMRM and locate the operator's face for object positioning. The other sensor was used to automatically recognize different daily living objects for test subjects to select. The gesture recognition interface incorporated hand detection, tracking and recognition algorithms to obtain a high recognition accuracy of 97.5% for an eight-gesture lexicon. An object recognition module employing Speeded Up Robust Features (SURF) algorithm was performed and recognition results were sent as a command for "coarse positioning" of the robotic arm near the selected daily living object. Automatic face detection was also provided as a shortcut for the subjects to position the objects to the face by using a WMRM. Completion time tasks were conducted to compare manual (gestures only) and semi-manual (gestures, automatic face detection and object recognition) WMRM control modes. The use of automatic face and object detection significantly increased the completion times for retrieving a variety of daily living objects. PMID:24187264

  12. Applying colour science in colour design

    NASA Astrophysics Data System (ADS)

    Luo, Ming Ronnier

    2006-06-01

    Although colour science has been widely used in a variety of industries over the years, it has not been fully explored in the field of product design. This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling. By integrating these advanced colour technologies together with modern colour imaging devices such as display, camera, scanner and printer, some computer systems have been recently developed to assist designers for designing colour palettes through colour selection by means of a number of widely used colour order systems, for creating harmonised colour schemes via a categorical colour system, for generating emotion colours using various colour emotional scales and for facilitating colour naming via a colour-name library. All systems are also capable of providing accurate colour representation on displays and output to different imaging devices such as printers.

  13. Inhibitory neuron transplantation into adult visual cortex creates a new critical period that rescues impaired vision

    PubMed Central

    Davis, Melissa F.; Figueroa Velez, Dario X.; Guevarra, Roblen P.; Yang, Michael C.; Habeeb, Mariyam; Carathedathu, Mathew C.; Gandhi, Sunil P.

    2015-01-01

    The maturation of inhibitory circuits in the juvenile cortex triggers a critical period of plasticity in visual system development. Although several manipulations of inhibition can alter its timing, none have reactivated critical period plasticity in adulthood. We developed a transplantation method to reactivate critical period plasticity in the adult visual cortex. Transplanted embryonic inhibitory neurons from the medial ganglionic eminence reinstate ocular dominance plasticity in adult recipients. Transplanted inhibitory cells develop cell-type appropriate molecular characteristics and visually evoked responses. In adult mice impaired by deprivation during the juvenile critical period, transplantation also recovers both visual cortical responses and performance on a behavioral test of visual acuity. Plasticity and recovery are induced when the critical period would have occurred in the donor animal. These results reveal that the focal reactivation of visual cortical plasticity using inhibitory cell transplantation creates a new critical period that restores visual perception after childhood deprivation. PMID:25937171

  14. A model clinical program for patients with diabetes and vision impairment.

    PubMed

    Bernbaum, M; Albert, S G; Brusca, S R; Drimmer, A; Duckro, P N; Cohen, J D; Trindade, M C; Silverberg, A B

    1989-01-01

    A program was developed to improve independence, self-esteem, and glycemic control in patients with diabetes and blindness. Twenty-nine individuals with both insulin-dependent and noninsulin-dependent diabetes mellitus entered 12-week programs that included education focusing on diabetes self-management skills for the visually impaired, monitored exercise sessions, and group support. Glycated hemoglobin values fell from 13.0% +/- 0.6% (SEM) to 11.4% +/- 0.5% (P = .001). Exercise tolerance in a 12-minute walk test improved from 0.48 +/- 0.04 to 0.64 +/- 0.05 miles (P = .001). Marked improvements occurred in psychosocial indices, demonstrated through changes in the Rand Mental Health Index from 155 +/- 6 to 174 +/- 5 (P = .0001), the Rosenberg Self-Esteem Scale from 22 +/- 1 to 19 +/- 1 (P = .001), the Zung Depression Scale from 0.50 +/- 0.02 to 0.44 +/- 0.02 (P = .001), and the Diabetes Self-Reliance Test from 60 +/- 3 to 74 +/- 2 (P = .0001). PMID:2791859

  15. A Navigation System for the Visually Impaired: A Fusion of Vision and Depth Sensor.

    PubMed

    Kanwal, Nadia; Bostanci, Erkan; Currie, Keith; Clark, Adrian F

    2015-01-01

    For a number of years, scientists have been trying to develop aids that can make visually impaired people more independent and aware of their surroundings. Computer-based automatic navigation tools are one example of this, motivated by the increasing miniaturization of electronics and the improvement in processing power and sensing capabilities. This paper presents a complete navigation system based on low cost and physically unobtrusive sensors such as a camera and an infrared sensor. The system is based around corners and depth values from Kinect's infrared sensor. Obstacles are found in images from a camera using corner detection, while input from the depth sensor provides the corresponding distance. The combination is both efficient and robust. The system not only identifies hurdles but also suggests a safe path (if available) to the left or right side and tells the user to stop, move left, or move right. The system has been tested in real time by both blindfolded and blind people at different indoor and outdoor locations, demonstrating that it operates adequately. PMID:27057135

  16. A Navigation System for the Visually Impaired: A Fusion of Vision and Depth Sensor

    PubMed Central

    Kanwal, Nadia; Bostanci, Erkan; Currie, Keith; Clark, Adrian F.

    2015-01-01

    For a number of years, scientists have been trying to develop aids that can make visually impaired people more independent and aware of their surroundings. Computer-based automatic navigation tools are one example of this, motivated by the increasing miniaturization of electronics and the improvement in processing power and sensing capabilities. This paper presents a complete navigation system based on low cost and physically unobtrusive sensors such as a camera and an infrared sensor. The system is based around corners and depth values from Kinect's infrared sensor. Obstacles are found in images from a camera using corner detection, while input from the depth sensor provides the corresponding distance. The combination is both efficient and robust. The system not only identifies hurdles but also suggests a safe path (if available) to the left or right side and tells the user to stop, move left, or move right. The system has been tested in real time by both blindfolded and blind people at different indoor and outdoor locations, demonstrating that it operates adequately. PMID:27057135

  17. Monitor, a vibrotactile aid for environmental perception: a field evaluation by four people with severe hearing and vision impairment.

    PubMed

    Ranjbar, Parivash; Stenström, Ingeborg

    2013-01-01

    Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44-54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%-97% and 58%-95% with the directional microphone. The corresponding values in traffic were 29%-100% and 65%-100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds. PMID:23861651

  18. The “voice” has it: screen reader adoption and switching behavior among vision impaired persons in India

    PubMed Central

    Pal, Joyojeet; Cutrell, Edward

    2013-01-01

    We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, TTS “voice” quality, particularly a “human-sounding voice” as one of the key features differentiating free/open source (FOSS) products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives – first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior. PMID:24620705

  19. Monitor, a Vibrotactile Aid for Environmental Perception: A Field Evaluation by Four People with Severe Hearing and Vision Impairment

    PubMed Central

    Stenström, Ingeborg

    2013-01-01

    Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44–54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%–97% and 58%–95% with the directional microphone. The corresponding values in traffic were 29%–100% and 65%–100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds. PMID:23861651

  20. Pseudoisochromatic test plate colour representation dependence on printing technology

    NASA Astrophysics Data System (ADS)

    Luse, K.; Fomins, S.; Ozolinsh, M.

    2012-08-01

    The aim of the study is to determine best printing technology for creation of colour vision deficiency tests. Valid tests for protanopia and deuteranopia were created from perceived colour matching experiments from printed colour samples by colour deficient individuals. Calibrated EpsonStylus Pro 7800 printer for ink prints and Noritsu HD 3701 digital printer for photographic prints were used. Multispectral imagery (by tunable liquid crystal filters system CRI Nuance Vis 07) data analysis show that in case of ink prints, the measured pixel colour coordinate dispersion (in the CIExy colour diagram) of similar colour arrays is smaller than in case of photographic printing. The print quality in terms of colour coordinate dispersion for printing methods used is much higher than in case of commercially available colour vision deficiency tests.

  1. Low vision due to cerebral visual impairment: differentiating between acquired and genetic causes

    PubMed Central

    2014-01-01

    Background To gain more insight into genetic causes of cerebral visual impairment (CVI) in children and to compare ophthalmological findings between genetic and acquired forms of CVI. Methods The clinical data of 309 individuals (mainly children) with CVI, and a visual acuity ≤0.3 were analyzed for etiology and ocular variables. A differentiation was made between acquired and genetic causes. However, in persons with West syndrome or hydrocephalus, it might be impossible to unravel whether CVI is caused by the seizure disorder or increased intracranial pressure or by the underlying disorder (that in itself can be acquired or genetic). In two subgroups, individuals with ‘purely’ acquired CVI and with ‘purely’ genetic CVI, the ocular variables (such as strabismus, pale optic disc and visual field defects) were compared. Results It was possible to identify a putative cause for CVI in 60% (184/309) of the cohort. In the remaining 40% the etiology could not be determined. A ‘purely’ acquired cause was identified in 80 of the patients (26%). West syndrome and/or hydrocephalus was identified in 21 patients (7%), and in 17 patients (6%) both an acquired cause and West and/or hydrocephalus was present. In 66 patients (21%) a genetic diagnosis was obtained, of which 38 (12%) had other possible risk factor (acquired, preterm birth, West syndrome or hydrocephalus), making differentiation between acquired and genetic not possible. In the remaining 28 patients (9%) a ‘purely’ genetic cause was identified. CVI was identified for the first time in several genetic syndromes, such as ATR-X, Mowat-Wilson, and Pitt Hopkins syndrome. In the subgroup with ‘purely’ acquired causes (N = 80) strabismus (88% versus 64%), pale optic discs (65% versus 27%) and visual field defects (72% versus 30%) could be observed more frequent than in the subgroup with ‘purely’ genetic disorders (N = 28). Conclusions We conclude that CVI can be part of a genetic syndrome and

  2. Hardware Implementation of a Spline-Based Genetic Algorithm for Embedded Stereo Vision Sensor Providing Real-Time Visual Guidance to the Visually Impaired

    NASA Astrophysics Data System (ADS)

    Lee, Dah-Jye; Anderson, Jonathan D.; Archibald, James K.

    2008-12-01

    Many image and signal processing techniques have been applied to medical and health care applications in recent years. In this paper, we present a robust signal processing approach that can be used to solve the correspondence problem for an embedded stereo vision sensor to provide real-time visual guidance to the visually impaired. This approach is based on our new one-dimensional (1D) spline-based genetic algorithm to match signals. The algorithm processes image data lines as 1D signals to generate a dense disparity map, from which 3D information can be extracted. With recent advances in electronics technology, this 1D signal matching technique can be implemented and executed in parallel in hardware such as field-programmable gate arrays (FPGAs) to provide real-time feedback about the environment to the user. In order to complement (not replace) traditional aids for the visually impaired such as canes and Seeing Eyes dogs, vision systems that provide guidance to the visually impaired must be affordable, easy to use, compact, and free from attributes that are awkward or embarrassing to the user. "Seeing Eye Glasses," an embedded stereo vision system utilizing our new algorithm, meets all these requirements.

  3. Prevalences and causes of vision impairment in elderly Chinese: a socioeconomic perspective of a comparative report nested in Jiangsu Eye Study

    PubMed Central

    Zhu, Rong-Rong; Shi, Jian; Yang, Mei; Guan, Huai-Jin

    2016-01-01

    AIM To survey the prevalence and causes of visual impairment/blindness among elderly Chinese from different socioeconomic status in community-based design. METHODS Cluster-sampling randomly selected residents from Binhu and Funing District, two areas representing different socioeconomic levels in China with Binhu in an advanced status and Funing in less-developed area. The participants subjected to ophthalmic examination. The presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were recorded. Visual impairment and blindness were defined according to World Health Organization criteria. The causes of visual impairment/blindness were identified by ophthalmic examination and/or questionnaire. The socioeconomic status included the per capita gross domestic product, numbers of hospital with ophthalmic service and the number of ophthalmologists per 1 million residents. RESULTS We successfully included 12 867 participants form 2 areas in this study. The prevalence of PVA impairment (<20/63 to ≥20/400) in the better eye was 5.4% in Binhu and 23.6% in Funing, while the prevalence of blindness (<20/400) was 0.9% in Binhu and 2.3% in Funing. With BCVA, the prevalence of visual impairment was 2.4% in Binhu and 6.4% in Funing, while the prevalence of blindness was 0.8% in Binhu and 1.6% in Funing. The participants with older age and female gender had higher prevalence in visual impairment and blindness. The highest prevalences of vision impairment and blindness evaluated by BCVA at >80y age group reached 20.4% and 6.3% respectively. The prevalences of vision impairment and blindness evaluated by BCVA were 3.5% and 1.0% in male and 5.0% and 1.3% in female. The above differences were statistically significant (P<0.05). The predominant causes of visual impairment and blindness were cataract, retinal disorders and uncorrected refractive error in both areas. The socioeconomic status was associated with visual impairment and blindness. CONCLUSION This community

  4. 'Flight of colours' in lesions of the visual system.

    PubMed

    Feldman, M; Todman, L; Bender, M B

    1974-11-01

    A bright pocket flashlight was directed into one eye for 10 seconds; the subject then closed the eyelids and reported the sequence of after-image colours observed. Lesions of the visual system which compromised bilateral central colour vision also reduced or abolished the `flight of colours'. This simple bedside test of each eye independently is of value in detecting mild defects of central vision. PMID:4457619

  5. Vision Changes in Space

    NASA Video Gallery

    This Human Research Program 'Research to Outreach' video featuring NASA Clinical Translational Scientist Jennifer Fogarty explains the risk of vision impairment both during and after spaceflight, i...

  6. Present Vision--Future Vision.

    ERIC Educational Resources Information Center

    Fitterman, L. Jeffrey

    This paper addresses issues of current and future technology use for and by individuals with visual impairments and blindness in Florida. Present technology applications used in vision programs in Florida are individually described, including video enlarging, speech output, large inkprint, braille print, paperless braille, and tactual output…

  7. Influence of retinopathy on the achromatic and chromatic vision of patients with type 2 diabetes

    PubMed Central

    2014-01-01

    Background Luminance contrast sensitivity and colour vision are considered to have great predictive value in the evaluation of type 2 diabetic retinopathy. However, these two visual characteristics have seldom been investigated in the same group of patients. In the present study we measured contrast sensitivity and colour vision in a group of patients with type 2 diabetes and correlated the results with estimates of common metabolic markers for the disease. A subgroup of the patients had no clinical signs of retinopathy. Methods The vision of 27 patients (n = 50 eyes) with type 2 diabetes, with retinopathy (n = 20 eyes), or without retinopathy (n = 30 eyes) were evaluated using two psychophysical tests, the Farnsworth–Munsell 100 hue test (FM 100), and measurements of the luminance contrast sensitivity at 11 spatial frequencies. The results were compared with measurements obtained from an age-matched control group (n = 32), and were correlated with the level of glycated haemoglobin, glycaemic level, and time of disease onset. Signs of retinopathy were identified during the ophthalmological examinations. Results Contrast sensitivity and colour vision impairments were present at different levels in diabetes patients. Eyes with retinopathy showed more severe vision loss than eyes without retinopathy. The FM 100 test was more sensitive for separation of patients from controls. Colour vision loss had no colour axes preference. The contrast sensitivity test appeared to have some advantage in differentiating patients with retinopathy from patients without retinopathy. Conclusions Both methods can be useful to follow the visual function of diabetic patients and should be used together to discriminate patients from controls, as well as to identify early signs of retinal damage. PMID:25174264

  8. X-linked cone dystrophy and colour vision deficiency arising from a missense mutation in a hybrid L/M cone opsin gene

    PubMed Central

    McClements, Michelle; Davies, Wayne I L; Michaelides, Michel; Carroll, Joseph; Rha, Jungate; Mollon, John D; Neitz, Maureen; MacLaren, Robert E; Moore, Anthony T; Hunt, David M

    2013-01-01

    In this report, we describe a male subject who presents with a complex phenotype of myopia associated with cone dysfunction and a protan vision deficiency. Retinal imaging demonstrates extensive cone disruption, including the presence of non-waveguiding cones, an overall thinning of the retina, and an irregular mottled appearance of the hyper reflective band associated with the inner segment ellipsoid portion of the photoreceptor. Mutation screening revealed a novel p.Glu41Lys missense mutation in a hybrid L/M opsin gene. Spectral analysis shows that the mutant opsin fails to form a pigment in vitro and fails to be trafficked to the cell membrane in transfected Neuro2a cells. Extensive sequence and quantitative PCR analysis identifies this mutant gene as the only gene present in the affected subject’s L/M opsin gene array, yet the presence of protanopia indicates that the mutant opsin must retain some activity in vivo. To account for this apparent contradiction, we propose that a limited amount of functional pigment is formed within the normal cellular environment of the intact photoreceptor, and that this requires the presence of chaperone proteins that promote stability and normal folding of the mutant protein. PMID:23337435

  9. Modelling memory colour region for preference colour reproduction

    NASA Astrophysics Data System (ADS)

    Zeng, Huanzhao; Luo, Ronnier

    2010-01-01

    Colour preference adjustment is an essential step for colour image enhancement and perceptual gamut mapping. In colour reproduction for pictorial images, properly shifting colours away from their colorimetric originals may produce more preferred colour reproduction result. Memory colours, as a portion of the colour regions for colour preference adjustment, are especially important for preference colour reproduction. Identifying memory colours or modelling the memory colour region is a basic step to study preferred memory colour enhancement. In this study, we first created gamut for each memory colour region represented as a convex hull, and then used the convex hull to guide mathematical modelling to formulate the colour region for colour enhancement.

  10. Improving the Well-Being of Vision-Impaired Older Adults through Orientation and Mobility Training and Rehabilitation: An Evaluation.

    ERIC Educational Resources Information Center

    Engel, Rafael J.; Welsh, Richard L.; Lewis, Laura J.

    2000-01-01

    A study examined the short-term outcomes achieved by 70 older people with visual impairments who received rehabilitation services. Results found rehabilitation services were associated with reduction in the use of medical doctors, reduction in the use of in-home professionals, and increased confidence and increased ease of use in public…

  11. In the Palm of Your Hand: A Vision of the Future of Technology for People with Visual Impairments.

    ERIC Educational Resources Information Center

    Fruchterman, James R.

    2003-01-01

    This article discusses future directions for wireless cell phones, including personal computer capabilities, multiple input and output modalities, and open source platforms, and the benefits for people with visual impairments. The use of cell phones for increased accessibility of the Internet and for electronic books is also discussed. (Contains…

  12. Synaesthesia and colour constancy.

    PubMed

    Erskine, Holly; Mattingley, Jason B; Arnold, Derek H

    2013-04-01

    Grapheme-colour synaesthesia is an atypical condition characterized by the perception of colours when reading achromatic text. We investigated the level of colour processing responsible for these experiences. To do so, we tapped a central characteristic of colour perception. In different lighting conditions the same wavelength of light can prompt the perception of different colours. This helps humans recognize distinctive coloured objects despite changes in illumination. We wanted to see if synaesthetic colours were generated at a neural locus that was susceptible to colour constancy analyses. We used colour matching and naming tasks to examine interactions between simulated coloured illuminants and synaesthetic colours. Neither synaesthetic colour matching or naming was impacted. This contrasted with non-synaesthetic control participants, who performed the colour-matching task with graphemes physically coloured to mimic synaesthesia. Our data suggest that synaesthetic colour signals are not generated at lower-levels of colour processing, but are introduced at higher levels of analysis and are therefore not impacted by the processes responsible for perceptual constancy. PMID:22487049

  13. Light Vision Color

    NASA Astrophysics Data System (ADS)

    Valberg, Arne

    2005-04-01

    Light Vision Color takes a well-balanced, interdisciplinary approach to our most important sensory system. The book successfully combines basics in vision sciences with recent developments from different areas such as neuroscience, biophysics, sensory psychology and philosophy. Originally published in 1998 this edition has been extensively revised and updated to include new chapters on clinical problems and eye diseases, low vision rehabilitation and the basic molecular biology and genetics of colour vision. Takes a broad interdisciplinary approach combining basics in vision sciences with the most recent developments in the area Includes an extensive list of technical terms and explanations to encourage student understanding Successfully brings together the most important areas of the subject in to one volume

  14. Why do seals have cones? Behavioural evidence for colour-blindness in harbour seals.

    PubMed

    Scholtyssek, Christine; Kelber, Almut; Dehnhardt, Guido

    2015-03-01

    All seals and cetaceans have lost at least one of two ancestral cone classes and should therefore be colour-blind. Nevertheless, earlier studies showed that these marine mammals can discriminate colours and a colour vision mechanism has been proposed which contrasts signals from cones and rods. However, these earlier studies underestimated the brightness discrimination abilities of these animals, so that they could have discriminated colours using brightness only. Using a psychophysical discrimination experiment, we showed that a harbour seal can solve a colour discrimination task by means of brightness discrimination alone. Performing a series of experiments in which two harbour seals had to discriminate the brightness of colours, we also found strong evidence for purely scotopic (rod-based) vision at light levels that lead to mesopic (rod-cone-based) vision in other mammals. This finding speaks against rod-cone-based colour vision in harbour seals. To test for colour-blindness, we used a cognitive approach involving a harbour seal trained to use a concept of same and different. We tested this seal with pairs of isoluminant stimuli that were either same or different in colour. If the seal had perceived colour, it would have responded to colour differences between stimuli. However, the seal responded with "same", providing strong evidence for colour-blindness. PMID:25452008

  15. Rethinking Colour Constancy

    PubMed Central

    Logvinenko, Alexander D.; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching’s effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions—metamer mismatching and colour constancy—must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy’s false premise that colour is an intrinsic attribute of an object. PMID:26356217

  16. Rethinking Colour Constancy.

    PubMed

    Logvinenko, Alexander D; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching's effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions-metamer mismatching and colour constancy-must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy's false premise that colour is an intrinsic attribute of an object. PMID:26356217

  17. Vision Deficits in Adults with Down Syndrome

    PubMed Central

    Krinsky-McHale, Sharon J.; Silverman, Wayne; Gordon, James; Devenny, Darlynne A.; Oley, Nancy; Abramov, Israel

    2013-01-01

    Background In individuals with Down syndrome virtually all structures of the eye have some abnormality which likely diminishes vision. We examined basic vision functions in adults with Down syndrome. Materials and Methods Participants completed a battery of psychophysical tests which probed a comprehensive array of visual functions. The performance of adults with Down syndrome was compared to younger and older adults without intellectual disability. Results Adults with Down syndrome had significant vision deficits; reduced sensitivity across spatial frequencies and temporal modulation rates, reduced stereopsis, impaired vernier acuity, and anomalies in colour discrimination. The pattern of deficits observed was similar to those seen by researchers examining adults with Alzheimer’s disease. Conclusions Our findings suggest that a common mechanism may be responsible for the pattern of deficits observed, possibly the presence of Alzheimer’s disease neuropathology in the visual association cortex. We also showed that individuals with mild to moderate intellectual disability are capable of participating in studies employing state-of-the-art psychophysical procedures. This has wider implications in terms of their ability to participate in research that use similar techniques. PMID:23784802

  18. Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population.

    PubMed

    Mandas, Antonella; Mereu, Rosa Maria; Catte, Olga; Saba, Antonio; Serchisu, Luca; Costaggiu, Diego; Peiretti, Enrico; Caminiti, Giulia; Vinci, Michela; Casu, Maura; Piludu, Stefania; Fossarello, Maurizio; Manconi, Paolo Emilio; Dessí, Sandra

    2014-01-01

    Neurological disorders (Alzheimer's disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65 years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer's disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer's disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer's disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision disorders but

  19. Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population

    PubMed Central

    Mandas, Antonella; Mereu, Rosa Maria; Catte, Olga; Saba, Antonio; Serchisu, Luca; Costaggiu, Diego; Peiretti, Enrico; Caminiti, Giulia; Vinci, Michela; Casu, Maura; Piludu, Stefania; Fossarello, Maurizio; Manconi, Paolo Emilio; Dessí, Sandra

    2014-01-01

    Neurological disorders (Alzheimer’s disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65 years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer’s disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer’s disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer’s disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision

  20. Older adults coping with vision loss.

    PubMed

    Weber, Joseph A; Wong, Karen B

    2010-07-01

    Age-related vision loss is one of the most commonly cited disabling impairments of adult life. Stressors presented by vision loss can create barriers, threatening the well-being of the individual. This qualitative study of 30 older adults (65 to 95 years of age) investigated vision loss and coping strategies. All participants experienced unexpected sight loss during their adult years. The Adaptation to Age-Related Vision Loss (AVL) Scale was used in this study to examine psychosocial adaptation to vision impairment. The coping strategies of vision impairment were assessed by collecting self-reported reflections toward vision loss and how the change impacted the participant's life. Given the correct balance of support, confidence, and acceptance, older adults can confront the existing barriers and focus on the ability to optimize function with vision loss. Health care service providers and practitioners can provide needed assistance and a helpful guide to assist older adults in successfully coping with vision impairment. PMID:20845173

  1. Does Colour Preference Have a Role in Colour Term Acquisition?

    ERIC Educational Resources Information Center

    Pitchford, Nicola J.; Davis, Emma E.; Scerif, Gaia

    2009-01-01

    A developmental association exists between colour preference and emerging colour term acquisition in young children. Colour preference might influence colour term acquisition by directing attention towards or away from a particular colour, making it more or less memorable. To investigate the role that colour preference may have in the acquisition…

  2. Topographic Mapping of Residual Vision by Computer

    ERIC Educational Resources Information Center

    MacKeben, Manfred

    2008-01-01

    Many persons with low vision have diseases that damage the retina only in selected areas, which can lead to scotomas (blind spots) in perception. The most frequent of these diseases is age-related macular degeneration (AMD), in which foveal vision is often impaired by a central scotoma that impairs vision of fine detail and causes problems with…

  3. Increased Burden of Vision Impairment and Eye Diseases in Persons with Chronic Kidney Disease — A Population-Based Study

    PubMed Central

    Wong, Chee Wai; Lamoureux, Ecosse L.; Cheng, Ching-Yu; Cheung, Gemmy Chui Ming; Tai, E. Shyong; Wong, Tien Y.; Sabanayagam, Charumathi

    2016-01-01

    Background Chronic kidney disease (CKD) has been shown to be associated with diabetic retinopathy (DR) and age-related macular degeneration (AMD), leading causes of blindness in elderly adults in previous studies. However, the association of CKD with visual impairment (VI) is not clear. We aimed to examine the association of CKD with VI and other age-related ocular diseases in a population-based sample of Asian adults. Methods We analyzed data from 10,033 adults aged 40–80 years who participated in the Singapore Epidemiology of Eye Diseases (SEED, 2004–11) Study. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 from serum creatinine. VI was defined as best-corrected visual acuity < 20/40 in the better eye. Cataract, retinopathy, DR, glaucoma and AMD were assessed using standardized ocular examination, retinal photography and visual field assessments. The associations of CKD with VI and ocular conditions were examined using logistic regression models adjusted for age, sex, race, smoking, alcohol intake, education status, body mass index, systolic blood pressure, diabetes mellitus, cholesterol levels and cardiovascular disease. Findings The prevalence of VI and ocular disease were significantly higher in participants with CKD (36.1% and 84.7%) than in those without (12.9% and 54.3%, both p < 0.001). In multivariable models, CKD was significantly associated with VI (odds ratio [95% confidence interval] = 1.34 [1.14–1.58]), any ocular disease (1.28 [1.03–1.61]), cataract (1.24 [1.01–1.52]), any retinopathy (1.77 [1.45–2.15]), and DR (1.94 [1.47–2.54]). Interpretation The burden of VI and eye diseases is high among persons with CKD. Our findings suggest that it may be useful to screen for ocular disease and VI in persons with CKD. PMID:27077127

  4. Colour and lighting in hospital design

    NASA Astrophysics Data System (ADS)

    Dalke, Hilary; Little, Jenny; Niemann, Elga; Camgoz, Nilgun; Steadman, Guillaume; Hill, Sarah; Stott, Laura

    2006-06-01

    Little information or guidance has been available to assist the development of a hospital's visual environment. A report on lighting and colour design schemes, accessible to non professionals with responsibility for refurbishment strategies, was required by NHS Estates. Firstly, 20 hospitals were audited to establish a picture of current practice and to identify key issues where colour design could broadly enhance the environment for patients, staff and visitors. Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired. Provision of staff relaxation rooms that are different in terms of colour and lux levels from immediate work spaces, or thoughtfully designed areas for patients awaiting intensive treatment, have been shown to have some beneficial effects on a sense of well being. Colour and design have not been established as a definite cure for sickness and ill health, but certainly monotony and poor conditions in premises that have not been refurbished with any care, have had a detrimental affect on recovery rates and staff morale. The realisation that a well balanced and attractive environment is of major importance to patients' health is, in no way new; Florence Nightingale observed that 'a variety of form and brilliance of colour in the objects presented to patients are an actual means of recovery'.

  5. Minimum Perceptible Differences in the Colour Reproduction of Photographic Prints.

    NASA Astrophysics Data System (ADS)

    Wood, Carol Ann

    Available from UMI in association with The British Library. Electronic simulations of the Macbeth Color Checker Chart were prepared such that each of the eighteen colour patches could be varied independently from the rest of the chart. The output was in the form of photographic colour prints which comprised a ring-around set of 168 prints for each of the colour patches, where each print was a colour perturbation from a standard print. Twelve observers, with normal colour vision, judged the prints in each set to be perceptibly different or not perceptibly different from the standard print, for each patch. The experimental results, in the form of hue-orientated and non hue-orientated ellipses, were compared with MacAdam type ellipses, CIELAB unit ellipses and ellipses derived from the CMC(1:c) colour difference formula: the comparisons were made in the 1976 CIELAB colour space. Colour reproduction indices were calculated for the end points of the semi-major and semi-minor axes of the CMC ellipses, for each of the eighteen colour patches. The coefficient of variation was very small for the combined hue index, the combined chroma index and the overall combined index, indicating that the mean values for these indices could be assigned to any of the ellipses as a measure of the minimum perceptible difference in terms of colour appearance.

  6. Optimality of the basic colour categories for classification

    PubMed Central

    Griffin, Lewis D

    2005-01-01

    Categorization of colour has been widely studied as a window into human language and cognition, and quite separately has been used pragmatically in image-database retrieval systems. This suggests the hypothesis that the best category system for pragmatic purposes coincides with human categories (i.e. the basic colours). We have tested this hypothesis by assessing the performance of different category systems in a machine-vision task. The task was the identification of the odd-one-out from triples of images obtained using a web-based image-search service. In each triple, two of the images had been retrieved using the same search term, the other a different term. The terms were simple concrete nouns. The results were as follows: (i) the odd-one-out task can be performed better than chance using colour alone; (ii) basic colour categorization performs better than random systems of categories; (iii) a category system that performs better than the basic colours could not be found; and (iv) it is not just the general layout of the basic colours that is important, but also the detail. We conclude that (i) the results support the plausibility of an explanation for the basic colours as a result of a pressure-to-optimality and (ii) the basic colours are good categories for machine vision image-retrieval systems. PMID:16849219

  7. Rockpool Gobies Change Colour for Camouflage

    PubMed Central

    Stevens, Martin; Lown, Alice E.; Denton, Alexander M.

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  8. Rockpool gobies change colour for camouflage.

    PubMed

    Stevens, Martin; Lown, Alice E; Denton, Alexander M

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  9. Trends in the Prevalence of Autism Spectrum Disorder, Cerebral Palsy, Hearing Loss, Intellectual Disability, and Vision Impairment, Metropolitan Atlanta, 1991–2010

    PubMed Central

    Van Naarden Braun, Kim; Christensen, Deborah; Doernberg, Nancy; Schieve, Laura; Rice, Catherine; Wiggins, Lisa; Schendel, Diana; Yeargin-Allsopp, Marshalyn

    2015-01-01

    This study examined the prevalence and characteristics of autism spectrum disorder (ASD), cerebral palsy (CP), hearing loss (HL), intellectual disability (ID), and vision impairment (VI) over a 15–20 year time period, with specific focus on concurrent changes in ASD and ID prevalence. We used data from a population-based developmental disabilities surveillance program for 8-year-olds in metropolitan Atlanta. From 1991–2010, prevalence estimates of ID and HL were stable with slight increases in VI prevalence. CP prevalence was constant from 1993–2010. The average annual increase in ASD prevalence was 9.3% per year from 1996–2010, with a 269% increase from 4.2 per 1,000 in 1996 to 15.5 per 1,000 in 2010. From 2000–2010, the prevalence of ID without ASD was stable; during the same time, the prevalence of ASD with and without co-occurring ID increased by an average of 6.6% and 9.6% per year, respectively. ASD prevalence increases were found among both males and females, and among nearly all racial/ethnic subgroups and levels of intellectual ability. Average annual prevalence estimates from 1991–2010 underscore the significant community resources needed to provide early intervention and ongoing supports for children with ID (13.0 per 1,000), CP, (3.5 per 1,000), HL (1.4 per 1,000) and VI (1.3 in 1,000), with a growing urgency for children with ASD. PMID:25923140

  10. The colour preference control based on two-colour combinations

    NASA Astrophysics Data System (ADS)

    Hong, Ji Young; Kwak, Youngshin; Park, Du-Sik; Kim, Chang Yeong

    2008-02-01

    This paper proposes a framework of colour preference control to satisfy the consumer's colour related emotion. A colour harmony algorithm based on two-colour combinations is developed for displaying the images with several complementary colour pairs as the relationship of two-colour combination. The colours of pixels belonging to complementary colour areas in HSV colour space are shifted toward the target hue colours and there is no colour change for the other pixels. According to the developed technique, dynamic emotions by the proposed hue conversion can be improved and the controlled output image shows improved colour emotions in the preference of the human viewer. The psychophysical experiments are conducted to investigate the optimal model parameters to produce the most pleasant image to the users in the respect of colour emotions.

  11. Colour contribution to children's wayfinding in school environments

    NASA Astrophysics Data System (ADS)

    Helvacıoǧlu, Elif; Olguntürk, Nilgün

    2011-03-01

    The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled 100 primary school children aged seven and eight years old. The study was conducted in four phases. In the first phase, the participants were tested for familiarity with the experiment site and also for colour vision deficiencies by using Ishihara's tests for colour-blindness. In the second phase, they were escorted on the experiment route by the tester one by one, from one starting point to one end point and were asked to lead the tester to the end point by the same route. In the third phase, they were asked to describe verbally the route. In the final phase, they were asked to remember the specific colours at their correct locations. It was found that colour has a significant effect on children's wayfinding performances in school environments. However, there were no differences between different colours in terms of their remembrances in route finding tasks. In addition, the correct identifications of specific colours and landmarks were dependent on their specific locations. Contrary to the literature, gender differences were not found to be significant in the accuracy of route learning performances.

  12. (Computer) Vision without Sight

    PubMed Central

    Manduchi, Roberto; Coughlan, James

    2012-01-01

    Computer vision holds great promise for helping persons with blindness or visual impairments (VI) to interpret and explore the visual world. To this end, it is worthwhile to assess the situation critically by understanding the actual needs of the VI population and which of these needs might be addressed by computer vision. This article reviews the types of assistive technology application areas that have already been developed for VI, and the possible roles that computer vision can play in facilitating these applications. We discuss how appropriate user interfaces are designed to translate the output of computer vision algorithms into information that the user can quickly and safely act upon, and how system-level characteristics affect the overall usability of an assistive technology. Finally, we conclude by highlighting a few novel and intriguing areas of application of computer vision to assistive technology. PMID:22815563

  13. (Computer) Vision without Sight.

    PubMed

    Manduchi, Roberto; Coughlan, James

    2012-01-01

    Computer vision holds great promise for helping persons with blindness or visual impairments (VI) to interpret and explore the visual world. To this end, it is worthwhile to assess the situation critically by understanding the actual needs of the VI population and which of these needs might be addressed by computer vision. This article reviews the types of assistive technology application areas that have already been developed for VI, and the possible roles that computer vision can play in facilitating these applications. We discuss how appropriate user interfaces are designed to translate the output of computer vision algorithms into information that the user can quickly and safely act upon, and how system-level characteristics affect the overall usability of an assistive technology. Finally, we conclude by highlighting a few novel and intriguing areas of application of computer vision to assistive technology. PMID:22815563

  14. Vision and Driving

    PubMed Central

    Owsley, Cynthia; McGwin, Gerald

    2010-01-01

    Driving is the primary means of personal travel in many countries and is relies heavily on vision for its successful execution. Research over the past few decades has addressed the role of vision in driver safety (motor vehicle collision involvement) and in driver performance (both on-road and using interactive simulators in the laboratory). Here we critically review what is currently known about the role of various aspects of visual function in driving. We also discuss translational research issues on vision screening for licensure and re-licensure and rehabilitation of visually impaired persons who want to drive. PMID:20580907

  15. Evidence for a role of action in colour perception.

    PubMed

    Bompas, Aline; O'Regan, J Kevin

    2006-01-01

    Action is not usually considered to play a role in colour perception. However, sensorimotor theories of perception (eg O'Regan and Noë, 2001 Behavior and Brain Science 24 939-1011) suggest that, on the contrary, the transformations created by action in the sensory input are a necessary condition for all perception. In the case of colour vision, eye movements may explain how a retina with significant irregularities in resolution and cone arrangement (Roorda and Williams, 1999 Nature 397 520-522) could permit the perception of a richly coloured world (Clark and O'Regan, 2000 15th International Conference on Pattern Recognition volume 2: Pattern Recognition and Neural Networks pp 503-506; Skaff et al, 2002 16th International Conference on Pattern Recognition volume 2, pp 681-684). We provide evidence that perception of colour is modified when an artificial coupling is introduced linking eye movements and colour changes. After 40 min of wearing left-field-blue/right-field-yellow spectacles, observers' colour vision adapts so that, after removing the spectacles, white patches seem to become bluer when the eyes move rightwards and yellower when the eyes move leftwards. This induced dependence of colour perception on the direction of eye saccade is shown to be related to the amount of eye movements during exposure. This result, which cannot be explained either by retinal adaptation, or by a conditioned association between colour and side, constitutes first clear evidence for a role of eye movements in perceived colour and argues for the involvement in colour perception of neural mechanisms continuously tuned to sensorimotor contingencies. PMID:16491709

  16. Vision problems

    MedlinePlus

    ... which nothing can be seen) Vision loss and blindness are the most severe vision problems. Causes Vision ... that look faded. The most common cause of blindness in people over age 60. Eye infection, inflammation, ...

  17. The unsuitability of html-based colour charts for estimating animal colours – a comment on Berggren and Merilä (2004)

    PubMed Central

    Stevens, Martin; Cuthill, Innes C

    2005-01-01

    Background A variety of techniques are used to study the colours of animal signals, including the use of visual matching to colour charts. This paper aims to highlight why they are generally an unsatisfactory tool for the measurement and classification of animal colours and why colour codes based on HTML (really RGB) standards, as advocated in a recent paper, are particularly inappropriate. There are many theoretical arguments against the use of colour charts, not least that human colour vision differs markedly from that of most other animals. However, the focus of this paper is the concern that, even when applied to humans, there is no simple 1:1 mapping from an RGB colour space to the perceived colours in a chart (the results are both printer- and illumination-dependent). We support our criticisms with data from colour matching experiments with humans, involving self-made, printed colour charts. Results Colour matching experiments with printed charts involving 11 subjects showed that the choices made by individuals were significantly different between charts that had exactly the same RGB values, but were produced from different printers. Furthermore, individual matches tended to vary under different lighting conditions. Spectrophotometry of the colour charts showed that the reflectance spectra of the charts varied greatly between printers and that equal steps in RGB space were often far from equal in terms of reflectance on the printed charts. Conclusion In addition to outlining theoretical criticisms of the use of colour charts, our empirical results show that: individuals vary in their perception of colours, that different printers produce strikingly different results when reproducing what should be the same chart, and that the characteristics of the light irradiating the surface do affect colour perception. Therefore, we urge great caution in the use of colour charts to study animal colour signals. They should be used only as a last resort and in full

  18. Effects of memory colour on colour constancy for unknown coloured objects

    PubMed Central

    Granzier, Jeroen J M; Gegenfurtner, Karl R

    2012-01-01

    The perception of an object's colour remains constant despite large variations in the chromaticity of the illumination—colour constancy. Hering suggested that memory colours, the typical colours of objects, could help in estimating the illuminant's colour and therefore be an important factor in establishing colour constancy. Here we test whether the presence of objects with diagnostical colours (fruits, vegetables, etc) within a scene influence colour constancy for unknown coloured objects in the scene. Subjects matched one of four Munsell papers placed in a scene illuminated under either a reddish or a greenish lamp with the Munsell book of colour illuminated by a neutral lamp. The Munsell papers were embedded in four different scenes—one scene containing diagnostically coloured objects, one scene containing incongruent coloured objects, a third scene with geometrical objects of the same colour as the diagnostically coloured objects, and one scene containing non-diagnostically coloured objects (eg, a yellow coffee mug). All objects were placed against a black background. Colour constancy was on average significantly higher for the scene containing the diagnostically coloured objects compared with the other scenes tested. We conclude that the colours of familiar objects help in obtaining colour constancy for unknown objects. PMID:23145282

  19. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica

    PubMed Central

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  20. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica.

    PubMed

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  1. Vision Changes, Intelligence, and Aging: Part 2.

    ERIC Educational Resources Information Center

    Bennett, Edward S.; Eklund, Susan J.

    1983-01-01

    Reviews the effects of vision changes on intelligence and explains how intellectual performance may be improved by attempting to compensate for vision loss. Suggests that vision factors can't be ignored when assessing intellectual changes and may account for a large portion of mental impairment previously ascribed to other factors. (JAC)

  2. The Development of Low Vision Therapist Certification.

    ERIC Educational Resources Information Center

    Watson, Gale R.; Quillman, R. Dee; Flax, Marshall; Gerritsen, Bryan

    1999-01-01

    Discusses the development and implementation of the low-vision-therapist certification through the Association for Education and Rehabilitation of the Blind and Visually Impaired. Credentials for professionals in low vision are described, along with required written examination, and the role of the low-vision therapist. (CR)

  3. Colour Mixing Based on Daylight

    ERIC Educational Resources Information Center

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large…

  4. Plasmonic colour laser printing

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil; Mortensen, N. Asger; Kristensen, Anders

    2016-04-01

    Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel.

  5. Colour processing in complex environments: insights from the visual system of bees

    PubMed Central

    Dyer, Adrian G.; Paulk, Angelique C.; Reser, David H.

    2011-01-01

    Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours. PMID:21147796

  6. Colour processing in complex environments: insights from the visual system of bees.

    PubMed

    Dyer, Adrian G; Paulk, Angelique C; Reser, David H

    2011-03-22

    Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours. PMID:21147796

  7. Quantitative studies of animal colour constancy: using the chicken as model.

    PubMed

    Olsson, Peter; Wilby, David; Kelber, Almut

    2016-05-11

    Colour constancy is the capacity of visual systems to keep colour perception constant despite changes in the illumination spectrum. Colour constancy has been tested extensively in humans and has also been described in many animals. In humans, colour constancy is often studied quantitatively, but besides humans, this has only been done for the goldfish and the honeybee. In this study, we quantified colour constancy in the chicken by training the birds in a colour discrimination task and testing them in changed illumination spectra to find the largest illumination change in which they were able to remain colour-constant. We used the receptor noise limited model for animal colour vision to quantify the illumination changes, and found that colour constancy performance depended on the difference between the colours used in the discrimination task, the training procedure and the time the chickens were allowed to adapt to a new illumination before making a choice. We analysed literature data on goldfish and honeybee colour constancy with the same method and found that chickens can compensate for larger illumination changes than both. We suggest that future studies on colour constancy in non-human animals could use a similar approach to allow for comparison between species and populations. PMID:27170714

  8. Ultrasonic colour flow imaging.

    PubMed

    Wells, P N

    1994-12-01

    Real-time ultrasonic colour flow imaging, which was first demonstrated to be feasible only about a decade ago, has come into widespread clinical use. Ultrasound is scattered by ensembles of red blood cells. The ultrasonic frequency that gives the best signal-to-noise ratio for backscattering from blood depends on the required penetration. The frequency of ultrasound backscattered from flowing blood is shifted by the Doppler effect. The direction of flow can be determined by phase quadrature detection, and range selectivity can be provided by pulse-echo time-delay measurements. The Doppler frequency spectrum can be determined by Fourier analysis. Early two- and three-dimensional flow-imaging systems used slow manual scanning; velocity colour coding was introduced. Real-time colour flow imaging first became feasible when autocorrelation detection was used to extract the Doppler signal. Time-domain processing, which is a broad-band technique, was also soon shown to be practicable, for analysing both radio-frequency pulse-echo wavetrains and two-dimensional image speckle. Frequency- and time-domain processing both require effective cancellation of stationary echoes. The time-domain approach seems to have advantages in relation to both aliasing and the effects of attenuation in overlying tissues. Colour-coding schemes that can be interpreted without the need to refer to keys have been adopted, for both velocity and flow disturbance. Colour coding according to signal power has also been reintroduced. Three-dimensional display has been demonstrated. In interpreting colour flow images, it is important to understand the functions of critical system controls and the origins of artifacts. Various strategies can be adopted to increase the image frame rate. The problems of performance measurement and safety need to be kept under review. There are numerous opportunities for further development of ultrasonic colour flow imaging, including improvements in system design, methods of

  9. Reading aids for adults with low vision

    PubMed Central

    Virgili, Gianni; Acosta, Ruthy; Grover, Lori L; Bentley, Sharon A; Giacomelli, Giovanni

    2014-01-01

    Background The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual-vision and low-vision aids, which range from simple optical magnifiers to high-magnification video magnifiers. Objectives To assess the effects of reading aids for adults with low vision. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to January 2013), EMBASE (January 1980 to January 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2013), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov/) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 31 January 2013. We searched the reference lists of relevant articles and used the Science Citation Index to find articles that cited the included studies and contacted investigators and manufacturers of low-vision aids. We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991. Selection criteria This review includes randomised and quasi-randomised trials in which any device or aid used for reading had been compared to another device or aid in people aged 16 or over with low vision as defined by the study investigators. Data collection and analysis At least two authors independently

  10. Gene therapy for red-green colour blindness in adult primates.

    PubMed

    Mancuso, Katherine; Hauswirth, William W; Li, Qiuhong; Connor, Thomas B; Kuchenbecker, James A; Mauck, Matthew C; Neitz, Jay; Neitz, Maureen

    2009-10-01

    Red-green colour blindness, which results from the absence of either the long- (L) or the middle- (M) wavelength-sensitive visual photopigments, is the most common single locus genetic disorder. Here we explore the possibility of curing colour blindness using gene therapy in experiments on adult monkeys that had been colour blind since birth. A third type of cone pigment was added to dichromatic retinas, providing the receptoral basis for trichromatic colour vision. This opened a new avenue to explore the requirements for establishing the neural circuits for a new dimension of colour sensation. Classic visual deprivation experiments have led to the expectation that neural connections established during development would not appropriately process an input that was not present from birth. Therefore, it was believed that the treatment of congenital vision disorders would be ineffective unless administered to the very young. However, here we show that the addition of a third opsin in adult red-green colour-deficient primates was sufficient to produce trichromatic colour vision behaviour. Thus, trichromacy can arise from a single addition of a third cone class and it does not require an early developmental process. This provides a positive outlook for the potential of gene therapy to cure adult vision disorders. PMID:19759534

  11. Low Vision

    MedlinePlus

    ... Cases of Low Vision (in thousands) by Age, Gender, and Race/Ethnicity Table for 2010 U.S. Prevalent ... Cases of Low Vision (in thousands) by Age, Gender, and Race/Ethnicity Table for 2000 U.S. Prevalent ...

  12. Colour in flux: describing and printing colour in art

    NASA Astrophysics Data System (ADS)

    Parraman, Carinna

    2008-01-01

    This presentation will describe artists, practitioners and scientists, who were interested in developing a deeper psychological, emotional and practical understanding of the human visual system who were working with wavelength, paint and other materials. From a selection of prints at The Prints and Drawings Department at Tate London, the presentation will refer to artists who were motivated by issues relating to how colour pigment was mixed and printed, to interrogate and explain colour perception and colour science, and in art, how artists have used colour to challenge the viewer and how a viewer might describe their experience of colour. The title Colour in Flux refers, not only to the perceptual effect of the juxtaposition of one colour pigment with another, but also to the changes and challenges for the print industry. In the light of screenprinted examples from the 60s and 70s, the presentation will discuss 21 st century ideas on colour and how these notions have informed the Centre for Fine Print Research's (CFPR) practical research in colour printing. The latter part of this presentation will discuss the implications for the need to change methods in mixing inks that moves away from existing colour spaces, from non intuitive colour mixing to bespoke ink sets, colour mixing approaches and colour mixing methods that are not reliant on RGB or CMYK.

  13. Low Vision Enhancement System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    NASA's Technology Transfer Office at Stennis Space Center worked with the Johns Hopkins Wilmer Eye Institute in Baltimore, Md., to incorporate NASA software originally developed by NASA to process satellite images into the Low Vision Enhancement System (LVES). The LVES, referred to as 'ELVIS' by its users, is a portable image processing system that could make it possible to improve a person's vision by enhancing and altering images to compensate for impaired eyesight. The system consists of two orientation cameras, a zoom camera, and a video projection system. The headset and hand-held control weigh about two pounds each. Pictured is Jacob Webb, the first Mississippian to use the LVES.

  14. Can Impaired Vision be Easily, Quickly and Safely Restored toward Health and Maintained Wellness, Using McLeod's Patent Pending Naturoptics Methods?

    NASA Astrophysics Data System (ADS)

    Courtmanche, Amanda; McLeod, Roger; McLeod, David

    2006-10-01

    A healthy eye has its large set of diffraction patterns, generated by the viewed scene, spread across the visible spectrum. Only the two of these simultaneously coincident with foveal cones, and rods, or with extra-foveal cones, are visually useful. This fact and pupil diameter changes with illumination, which cause proportional wavelength changes, drives the healthy visual state. A quasi-monochromatic interval is coincident with foveal cones, and rods. A shorter, partially overlapping interval aligns with extrafoveal cones, with about twenty nanometers separation. Wavelengths follow the Airy disk radius formula. An unhealthy eye is an eyeball deformed by self- induced vision abuse. Incorrect and effectively static stresses in the large external eye muscles displace and distort the patterns. Rebalancing the proper vision and muscle state are safely, quickly and rapidly restored by mimicking natural eye and head movements with naturoptics.

  15. Colour image segmentation using unsupervised clustering technique for acute leukemia images

    NASA Astrophysics Data System (ADS)

    Halim, N. H. Abd; Mashor, M. Y.; Nasir, A. S. Abdul; Mustafa, N.; Hassan, R.

    2015-05-01

    Colour image segmentation has becoming more popular for computer vision due to its important process in most medical analysis tasks. This paper proposes comparison between different colour components of RGB(red, green, blue) and HSI (hue, saturation, intensity) colour models that will be used in order to segment the acute leukemia images. First, partial contrast stretching is applied on leukemia images to increase the visual aspect of the blast cells. Then, an unsupervised moving k-means clustering algorithm is applied on the various colour components of RGB and HSI colour models for the purpose of segmentation of blast cells from the red blood cells and background regions in leukemia image. Different colour components of RGB and HSI colour models have been analyzed in order to identify the colour component that can give the good segmentation performance. The segmented images are then processed using median filter and region growing technique to reduce noise and smooth the images. The results show that segmentation using saturation component of HSI colour model has proven to be the best in segmenting nucleus of the blast cells in acute leukemia image as compared to the other colour components of RGB and HSI colour models.

  16. Fun with Colour

    ERIC Educational Resources Information Center

    Rennie, Richard

    2015-01-01

    The Australian Curriculum: Science for Year 5 includes "recognising that the colour of an object depends on the properties of the object and the color of the light source". This article shows how much more can be done with color in the science laboratory. Activities include using a prism to explore white light, using a hand lens to…

  17. Specifying colour and maintaining colour accuracy for 3D printing

    NASA Astrophysics Data System (ADS)

    Parraman, Carinna; Walters, Peter; Reid, Brendan; Huson, David

    2008-02-01

    Advances in rapid prototyping technologies have led to the emergence of three-dimensional printers which can fabricate physical artefacts, including the application of surface colours. In light of these developments, this paper asserts that the need to print colour accurately is just as important for designers using three-dimensional colour printing as it is for two-dimensional inkjet printing. Parallels can be made with two-dimensional digital Inkjet printing and 2D common problems include: on screen previsualisation, colour management methods, colour gamut and maintaining colour accuracy. However, for three dimensional colour printed objects, there are more variables that will affect the finished colour. These are: the powder and process inks, unevenness of the surface, wax post-processing and other infiltration media and procedures. Furthermore, in some 3D printers, the K channel is replaced by the binder and so the printer is only using the cyan, magenta and yellow channels. The paper will suggest methods for improving pre-visualisation and accurate pre-viewing of the colours through the manufacture of three-dimensional colour charts as a reference guide for designers so that they can make accurate coloured artefacts. A series of case studies will be demonstrated.

  18. False-colour palette generation using a reference colour gamut

    NASA Astrophysics Data System (ADS)

    Green, Phil

    2015-01-01

    Monochrome images are often converted to false-colour images, in which arbitrary colours are assigned to regions of the image to aid recognition of features within the image. Criteria for selection of colour palettes vary according to the application, but may include distinctiveness, extensibility, consistency, preference, meaningfulness and universality. A method for defining a palette from colours on the surface of a reference gamut is described, which ensures that all colours in the palette have the maximum chroma available for the given hue angle in the reference gamut. The palette can be re-targeted to a reproduction medium as needed using colour management, and this method ensures consistency between cross-media colour reproductions using the palette.

  19. Low Vision FAQs

    MedlinePlus

    ... Jobs Home > Low Vision > Low Vision FAQs Healthy Vision Diabetes Diabetes Home How Much Do You Know? ... los Ojos Cómo hablarle a su oculista Low Vision FAQs What is low vision? Low vision is ...

  20. Living with vision loss

    MedlinePlus

    Diabetes - vision loss; Retinopathy - vision loss; Low vision; Blindness - vision loss ... Low vision is a visual disability. Wearing regular glasses or contacts does not help. People with low vision have ...

  1. Present problems of food colours.

    PubMed

    Kläui, H

    1980-01-01

    Food colours belong to those food additives which have been most carefully evaluated toxicologically. The colours which are accepted today by international bodies, like the FAO/WHO and Codex Alimentarius, offer an extraordinary high degree of safety. Within these toxicologically accepted colours, the group of colours which naturally occur in foods (for long periods of time) deserves special attention: such colours combine in an ideal way a very long practical human experience with scientific examination under experimental and animal test conditions, and they offer, therefore, a maximum degree of safety. Colours which naturally occur in foods and which are also of industrial importance are: caramel, carotenoids, grape skin extracts and some colouring spices. PMID:7447918

  2. Colouration in crab spiders: substrate choice and prey attraction.

    PubMed

    Heiling, Astrid M; Chittka, Lars; Cheng, Ken; Herberstein, Marie E

    2005-05-01

    Australian crab spiders Thomisus spectabilis ambush pollinating insects, such as honeybees (Apis mellifera) on flowers, and can change their body colour between yellow and white. It is traditionally assumed that the spiders change their colour to match the flower colour, thus rendering them cryptic to insect prey. Here, we test this assumption combining state-of-the-art knowledge of bee vision and behavioural experiments. In the field, yellow spiders are only found on yellow daisies (Chrysanthemum frutescens), whereas white spiders are found on yellow and white daisies. These field patterns were confirmed in the laboratory. When given the choice between white and yellow daisies, yellow spiders preferred yellow daisies, whereas white spiders showed only a slight but non-significant preference for white flowers. Thus, T. spectabilis select background colours according to their own body colour. When viewed from a distance, bees use an achromatic signal produced by their green receptors for target detection. Through this visual channel, white spiders on white flowers, and yellow spiders on yellow flowers are virtually undetectable. From a closer distance of a few centimetres, when bees evaluate colour contrast, the combination of spider colour against different flower backgrounds affected the response of honeybees, but not in ways predicted by a classical crypsis/conspicuousness interpretation. Yellow spiders on yellow flowers are not perfectly matched when interpreted through the colour vision of a honeybee. Nevertheless, honeybees showed indifference to the presence of a spider, equally landing on vacant or spider-occupied flowers. Likewise, white spiders are poorly hidden on white flowers, as white spiders reflect ultraviolet light strongly, while white flowers do not. Surprisingly, bees are attracted to this contrast, and significantly more honeybees preferred white flowers occupied by white spiders. White spiders on yellow flowers produce the highest colour

  3. Leading Vision

    ERIC Educational Resources Information Center

    Fawcett, Gay

    2004-01-01

    The current educational landscape makes it imperative that a vision statement become more than a fine-sounding statement that is laminated, hung on the wall, and quickly forgotten. If educators do not have a clear image of the future they wish to create, then someone will be ready to create it for them. But with a clear vision of the future, a…

  4. Learning Visions.

    ERIC Educational Resources Information Center

    Phelps, Margaret S.; And Others

    This paper describes LEARNing Visions, a K-12 intervention program for at-risk youth in Jackson County, Tennessee, involving a partnership between the schools, local businesses, Tennessee Technological University, and Visions Five (a private company). Jackson County is characterized by an undereducated population, a high employment rate, and a low…

  5. Colour based fire detection method with temporal intensity variation filtration

    NASA Astrophysics Data System (ADS)

    Trambitckii, K.; Anding, K.; Musalimov, V.; Linß, G.

    2015-02-01

    Development of video, computing technologies and computer vision gives a possibility of automatic fire detection on video information. Under that project different algorithms was implemented to find more efficient way of fire detection. In that article colour based fire detection algorithm is described. But it is not enough to use only colour information to detect fire properly. The main reason of this is that in the shooting conditions may be a lot of things having colour similar to fire. A temporary intensity variation of pixels is used to separate them from the fire. These variations are averaged over the series of several frames. This algorithm shows robust work and was realised as a computer program by using of the OpenCV library.

  6. Computational vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1981-01-01

    The range of fundamental computational principles underlying human vision that equally apply to artificial and natural systems is surveyed. There emerges from research a view of the structuring of vision systems as a sequence of levels of representation, with the initial levels being primarily iconic (edges, regions, gradients) and the highest symbolic (surfaces, objects, scenes). Intermediate levels are constrained by information made available by preceding levels and information required by subsequent levels. In particular, it appears that physical and three-dimensional surface characteristics provide a critical transition from iconic to symbolic representations. A plausible vision system design incorporating these principles is outlined, and its key computational processes are elaborated.

  7. Computer vision

    NASA Technical Reports Server (NTRS)

    Gennery, D.; Cunningham, R.; Saund, E.; High, J.; Ruoff, C.

    1981-01-01

    The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed.

  8. A Low Vision Reading Comprehension Test.

    ERIC Educational Resources Information Center

    Watson, G. R.; And Others

    1996-01-01

    Fifty adults (ages 28-86) with macular degeneration were given the Low Vision Reading Comprehension Assessment (LVRCA) to test its reliability and validity in evaluating the reading comprehension of those with vision impairments. The LVRCA was found to take only nine minutes to administer and was a valid and reliable tool. (CR)

  9. Efficacy of a Low Vision Patient Consultation

    ERIC Educational Resources Information Center

    Siemsen, Dennis W.; Bergstrom, A. Ren?e; Hathaway, Julie C.

    2005-01-01

    A variety of obstacles can prevent persons or individuals with low vision from deriving the greatest possible benefit from the rehabilitation process, including inadequate understanding of their visual impairment, lack of knowledge about available services, and misconceptions about low vision devices. This study explores the use of a…

  10. Color Vision Deficits and Literacy Acquisition.

    ERIC Educational Resources Information Center

    Hurley, Sandra Rollins

    1994-01-01

    Shows that color blindness, whether partial or total, inhibits literacy acquisition. Offers a case study of a third grader with impaired color vision. Presents a review of literature on the topic. Notes that people with color vision deficits are often unaware of the handicap. (RS)

  11. Social Work in a Low Vision Program.

    ERIC Educational Resources Information Center

    Lanning, William A.; McClelland, Gus

    1995-01-01

    The Department of Veterans Affairs VICTORS (Vision Impairment Center To Optimize Remaining Sight) Program emphasizes individual independence through the use of low vision devices and training. The social worker's role combines traditional counseling with administrative responsibilities, such as interviewing the patient to identify needs and…

  12. Complementary colours for a physicist

    NASA Astrophysics Data System (ADS)

    Babič, Vitomir; Čepič, Mojca

    2009-07-01

    This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing colours and their physically exact complements using cellophane is presented. The origin of the colours lies in the transmission of polarized light through the birefringent cellophane, and therefore the optics of birefringent materials is briefly presented. A set-up which will be described in the following can be used in a laboratory experiment at an undergraduate level.

  13. Distinctive convergence in Australian floral colours seen through the eyes of Australian birds

    PubMed Central

    Burd, Martin; Stayton, C. Tristan; Shrestha, Mani; Dyer, Adrian G.

    2014-01-01

    We used a colour-space model of avian vision to assess whether a distinctive bird pollination syndrome exists for floral colour among Australian angiosperms. We also used a novel phylogenetically based method to assess whether such a syndrome represents a significant degree of convergent evolution. About half of the 80 species in our sample that attract nectarivorous birds had floral colours in a small, isolated region of colour space characterized by an emphasis on long-wavelength reflection. The distinctiveness of this ‘red arm’ region was much greater when colours were modelled for violet-sensitive (VS) avian vision than for the ultraviolet-sensitive visual system. Honeyeaters (Meliphagidae) are the dominant avian nectarivores in Australia and have VS vision. Ancestral state reconstructions suggest that 31 lineages evolved into the red arm region, whereas simulations indicate that an average of five or six lineages and a maximum of 22 are likely to have entered in the absence of selection. Thus, significant evolutionary convergence on a distinctive floral colour syndrome for bird pollination has occurred in Australia, although only a subset of bird-pollinated taxa belongs to this syndrome. The visual system of honeyeaters has been the apparent driver of this convergence. PMID:24573847

  14. Across light: through colour

    NASA Astrophysics Data System (ADS)

    Azevedo, Isabel; Richardson, Martin; Bernardo, Luis Miguel

    2012-03-01

    The speed at which our world is changing is reflected in the shifting way artistic images are created and produced. Holography can be used as a medium to express the perception of space with light and colour and to make the material and the immaterial experiments with optical and digital holography. This paper intends to be a reflection on the final product of that process surrounding a debate of ideas for new experimental methodologies applied to holographic images. Holography is a time-based medium and the irretrievable linear flow of time is responsible for a drama, unique to traditional cinematography. If the viewers move to left or right, they see glimpses of the next scene or the previous one perceived a second ago. This interaction of synthetic space arises questions such as: can we see, in "reality", two forms in the same space? Trying to answer this question, a series of works has been created. These concepts are embryonic to a series of digital art holograms and lenticulars technique's titled "Across Light: Through Colour". They required some technical research and comparison between effects from different camera types, using Canon IS3 and Sony HDR CX105.

  15. Improving Vision

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Many people are familiar with the popular science fiction series Star Trek: The Next Generation, a show featuring a blind character named Geordi La Forge, whose visor-like glasses enable him to see. What many people do not know is that a product very similar to Geordi's glasses is available to assist people with vision conditions, and a NASA engineer's expertise contributed to its development. The JORDY(trademark) (Joint Optical Reflective Display) device, designed and manufactured by a privately-held medical device company known as Enhanced Vision, enables people with low vision to read, write, and watch television. Low vision, which includes macular degeneration, diabetic retinopathy, and glaucoma, describes eyesight that is 20/70 or worse, and cannot be fully corrected with conventional glasses.

  16. Vision problems

    MedlinePlus

    ... in dealing with eye emergencies if: You experience partial or complete blindness in one or both eyes, ... a family history of diabetes Eye itching or discharge Vision changes that seem related to medication (DO ...

  17. Vision Underwater.

    ERIC Educational Resources Information Center

    Levine, Joseph S.

    1980-01-01

    Provides information regarding underwater vision. Includes a discussion of optically important interfaces, increased eye size of organisms at greater depths, visual peculiarities regarding the habitat of the coastal environment, and various pigment visual systems. (CS)

  18. Colour invariant target recognition in multiple camera CCTV surveillance

    NASA Astrophysics Data System (ADS)

    Soori, Umair; Yuen, P. W. T.; Ibrahim, I.; Han, J.; Tsitiridis, A.; Hong, K.; Chen, T.; Jackman, J.; James, D.; Richardson, M.

    2011-11-01

    People tracking in crowded scene have been a popular, and at the same time a very difficult topic in computer vision. It is mainly because of the difficulty for the acquisition of intrinsic signatures of targets from a single view of the scene. Many factors, such as variable illumination conditions and viewing angles, will induce illusive modification of intrinsic signatures of targets. The objective of this paper is to verify if colour constancy (CC) approach really helps people tracking in CCTV network system. We have testified a number of CC algorithms together with various colour descriptors, to assess the efficiencies of people recognitions from multi-camera i-LIDS data set via receiver operation characteristics (ROC). It is found that when CC is applied together with some form of colour restoration mechanisms such as colour transfer, it does improve people recognition by at least a factor of 2. An elementary luminance based CC coupled with a pixel based colour transfer algorithm have been developed and it is reported in this paper.

  19. Class Separation Improvements in Pixel Classification Using Colour Injection

    PubMed Central

    Blanco, Edward; Mazo, Manuel; Bergasa, Luis; Palazuelos, Sira; Rodríguez, Jose; Losada, Cristina; Martín, Jose

    2010-01-01

    This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required. PMID:22163628

  20. Texture variations suppress suprathreshold brightness and colour variations.

    PubMed

    Schofield, Andrew J; Kingdom, Frederick A A

    2014-01-01

    Discriminating material changes from illumination changes is a key function of early vision. Luminance cues are ambiguous in this regard, but can be disambiguated by co-incident changes in colour and texture. Thus, colour and texture are likely to be given greater prominence than luminance for object segmentation, and better segmentation should in turn produce stronger grouping. We sought to measure the relative strengths of combined luminance, colour and texture contrast using a suprathreshhold, psychophysical grouping task. Stimuli comprised diagonal grids of circular patches bordered by a thin black line and contained combinations of luminance decrements with either violet, red, or texture increments. There were two tasks. In the Separate task the different cues were presented separately in a two-interval design, and participants indicated which interval contained the stronger orientation structure. In the Combined task the cues were combined to produce competing orientation structure in a single image. Participants had to indicate which orientation, and therefore which cue was dominant. Thus we established the relative grouping strength of each cue pair presented separately, and compared this to their relative grouping strength when combined. In this way we observed suprathreshold interactions between cues and were able to assess cue dominance at ecologically relevant signal levels. Participants required significantly more luminance and colour compared to texture contrast in the Combined compared to Separate conditions (contrast ratios differed by about 0.1 log units), showing that suprathreshold texture dominates colour and luminance when the different cues are presented in combination. PMID:25502555

  1. Digital colour management system for colour parameters reconstruction

    NASA Astrophysics Data System (ADS)

    Grudzinski, Karol; Lasmanowicz, Piotr; Assis, Lucas M. N.; Pawlicka, Agnieszka; Januszko, Adam

    2013-10-01

    Digital Colour Management System (DCMS) and its application to new adaptive camouflage system are presented in this paper. The DCMS is a digital colour rendering method which would allow for transformation of a real image into a set of colour pixels displayed on a computer monitor. Consequently, it can analyse pixels' colour which comprise images of the environment such as desert, semi-desert, jungle, farmland or rocky mountain in order to prepare an adaptive camouflage pattern most suited for the terrain. This system is described in present work as well as the use the subtractive colours mixing method to construct the real time colour changing electrochromic window/pixel (ECD) for camouflage purpose. The ECD with glass/ITO/Prussian Blue(PB)/electrolyte/CeO2-TiO2/ITO/glass configuration was assembled and characterized. The ECD switched between green and yellow after +/-1.5 V application and the colours have been controlled by Digital Colour Management System and described by CIE LAB parameters.

  2. Grey leaves in an alpine plant: a cryptic colouration to avoid attack?

    PubMed

    Niu, Yang; Chen, Gao; Peng, De-Li; Song, Bo; Yang, Yang; Li, Zhi-Min; Sun, Hang

    2014-08-01

    Cryptic colouration is a common predation-avoidance strategy in animals that is postulated to occur in plants, but few experimental studies have rigorously tested this hypothesis. We investigated the colouration of Corydalis benecincta, an alpine plant with remarkably dimorphic leaf colours (grey and green), based on a cost-benefit analysis. First we tested the premise that herbivores (Parnassius butterflies) cannot distinguish grey leaves from a scree background by spectrographic measurements and by estimating discriminability between leaves and scree using a butterfly colour vision model. Then we estimated the potential costs of inconspicuousness by comparing the photosynthetic performance and visual attractiveness to flower visitors of the two colour morphs. Finally, we examined the potential benefits of inconspicuousness by comparing damage, survivorship and female reproductive success. It is difficult for herbivores to distinguish grey-coloured morphs against the background. This grey colour originates in a combination of anthocyanins and chlorophylls. The two colour morphs had similar photosynthetic performance, visual attractiveness and female reproductive success. However, grey morphs had significantly lower herbivore damage and higher survivorship. Grey leaves benefit C. benecincta by reducing herbivory with low investment in anthocyanin synthesis, and little cost on photosynthesis and mating opportunity. This cryptic colouration may have evolved through selection pressure imposed by visually foraging herbivores. PMID:24800901

  3. Linguistic determinants of word colouring in grapheme-colour synaesthesia.

    PubMed

    Simner, Julia; Glover, Louise; Mowat, Alice

    2006-02-01

    Previous studies of grapheme-colour synaesthesia have suggested that words tend to be coloured by their initial letter or initial vowel (e.g., Baron-Cohen et al., 1993; Ward et al., 2005). We examine this assumption in two ways. First, we show that letter position and syllable stress have been confounded, such that the initial letters of a word are often in stressed position (e.g., 'wo-man, 'ta-ble, 'ha-ppy). With participant JW, we separate these factors (e.g., with stress homographs such as 'con-vict vs. con-'vict) and show that the primary determinant of word colour is syllable stress, with only a secondary influence of letter position. We show that this effect derives from conceptual rather than perceptual stress, and that the effect is more prominent for synaesthetes whose words are coloured by vowels than by consonants. We examine, too, the time course of word colour generation. Slower colour naming occurs for spoken versus written stimuli, as we might expect from the additional requirement of grapheme conversion in the former. Reaction time data provide evidence, too, of incremental processing, since word colour is generated faster when the dominant grapheme is flagged early rather than late in the spoken word. Finally, we examine the role of non-dominant graphemes in word colouring and show faster colour naming when later graphemes match the dominant grapheme (e.g., ether) compared to when they do not (e.g., ethos). Taken together, our findings suggest that words are coloured incrementally by a process of competition between constituent graphemes, in which stressed graphemes and word-initial graphemes are disproportionately weighted. PMID:16683502

  4. The effects of the visual environment on responses to colour by domestic chicks.

    PubMed

    Miklósi, A; Gonda, Zs; Osorio, D; Farzin, A

    2002-03-01

    It is well known that development of vision is affected by experience, but there are few studies of environmental effects on colour vision. Natural scenes contain predominantly a restricted range of reflectance spectra, so such effects might be important, perhaps biasing visual mechanisms towards common colours. We investigated how the visual environment affects colour preferences of domestic chicks ( Gallus gallus), by training week-old birds to select small food containers distinguished from an achromatic alternative either by an orange or by a greenish-blue colour. Chicks that had been raised in control conditions, with long-wavelength-dominated reflectance spectra, responded more readily to orange than to blue. This was not due to avoidance of blue, as increasing saturation enhanced the chicks' preference for the same hue. The advantage of orange was, however, reduced or abolished for chicks raised in an environment dominated by blue objects. This indicates that responses to coloured food are affected by experience of non-food objects. If colours of ordinary objects in the environment do influence responses to specialised visual signals this might help explain why biological signals directed at birds are often coloured yellow, orange or red; long-wavelength-dominated spectra being more prevalent than short-wavelength-dominated spectra. PMID:11919694

  5. Reversible colour change in Arthropoda.

    PubMed

    Umbers, Kate D L; Fabricant, Scott A; Gawryszewski, Felipe M; Seago, Ainsley E; Herberstein, Marie E

    2014-11-01

    The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry. PMID:24495279

  6. Characterization of Caramel Colour IV.

    PubMed

    Licht, B H; Shaw, K; Smith, C; Mendoza, M; Orr, J; Myers, D V

    1992-05-01

    A large number of commercial Caramel Colour IV samples were characterized in order to assess the uniformity of the class and to provide data to be used in specifications development. Owing to the chemical and physical complexity of caramel colour it was not feasible to perform detailed analysis of all constituents for assessment of uniformity. Instead, selected parameters were evaluated and judgements were made with respect to compositional uniformity based on the similarities of these parameters among the various samples. As Caramel Colour IV is required by the food industry in a range of colour intensities, there must be a range of properties that differ from sample to sample, but that are sufficiently similar for the material to still be considered as part of the Caramel Colour IV class. Fractions as well as whole caramel were analysed using selected spectrophotometric, chromatographic and chemical techniques. Samples were fractionated based on molecular weight and polarity. The data presented here provide evidence for the uniformity in composition of Caramel Colour IV with respect to molecular weight distribution, to nitrogen and sulphur content and their distribution throughout the fractions, to absorbance properties and to specific low molecular weight compounds. Thus, it can be concluded that Caramel Colour IV exhibits compositional uniformity within the range of colour intensity required by the food industry worldwide. PMID:1644377

  7. Complementary Colours for a Physicist

    ERIC Educational Resources Information Center

    Babic, Vitomir; Cepic, Mojca

    2009-01-01

    This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing…

  8. Ecological importance of trichromatic vision to primates.

    PubMed

    Dominy, N J; Lucas, P W

    2001-03-15

    Trichromatic colour vision, characterized by three retinal photopigments tuned to peak wavelengths of approximately 430 nm, approximately 535 nm and approximately 562 nm (refs 1, 2), has evolved convergently in catarrhine primates and one genus of New World monkey, the howlers (genus Alouatta). This uniform capacity to discriminate red-green colours, which is not found in other mammals, has been proposed as advantageous for the long-range detection of either ripe fruits or young leaves (which frequently flush red in the tropics) against a background of mature foliage. Here we show that four trichromatic primate species in Kibale Forest, Uganda, eat leaves that are colour discriminated only by red-greenness, a colour axis correlated with high protein levels and low toughness. Despite their divergent digestive systems, these primates have no significant interspecific differences in leaf colour selection. In contrast, eaten fruits were generally discriminated from mature leaves on both red-green and yellow-blue channels and also by their luminance, with a significant difference between chimpanzees and monkeys in fruit colour choice. Our results implicate leaf consumption, a critical food resource when fruit is scarce, as having unique value in maintaining trichromacy in catarrhines. PMID:11268211

  9. Cone opsins, colour blindness and cone dystrophy: Genotype-phenotype correlations.

    PubMed

    Gardner, J C; Michaelides, M; Hardcastle, A J

    2016-01-01

    X-linked cone photoreceptor disorders caused by mutations in the OPN1LW (L) and OPN1MW (M) cone opsin genes on chromosome Xq28 include a range of conditions from mild stable red-green colour vision deficiencies to severe cone dystrophies causing progressive loss of vision and blindness. Advances in molecular genotyping and functional analyses of causative variants, combined with deep retinal phenotyping, are unravelling genetic mechanisms underlying the variability of cone opsin disorders. PMID:27245533

  10. Generating colour and texture verniers.

    PubMed

    Brelstaff, G J; Wilson, J B

    1994-05-01

    This paper describes computer graphics techniques for presenting visual stimuli in a vernier format composed out of coloured texture patterns. Such stimuli can be used to investigate the performance at the task of localising boundaries mediated by changes in colour and/or texture. We summarise the contents as follows: (1) Techniques for presenting visual stimuli are reviewed with a view to how they might be used to present colour and texture verniers. (2) The design of the vernier stimuli for the localisation task is considered. (3) Significant elements of this design are: (a) the use of non-isoplanatic textures to avoid interference effects at boundaries, (b) the modulation of the texture patterns along axes in MacLeod-Boynton colour space so that relative retinal cone contributions are controlled, and (c) the use of double-buffering, colour map manipulation, and contrast randomisation techniques to avoid problems commonly encountered when presenting computer graphics stimuli on colour monitors. (4) Results of a psychophysical experiment that presents colour and texture verniers are reported elsewhere. PMID:8089039

  11. The Effect of an On-Site Vision Examination on Adherence to Vision Screening Recommendations

    ERIC Educational Resources Information Center

    Chu, Raymond; Huang, Kristine; Barnhardt, Carmen; Chen, Angela

    2015-01-01

    Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening…

  12. The Need for a Uniform Method of Recording and Reporting Functional Vision Assessments

    ERIC Educational Resources Information Center

    Shaw, Rona; Russotti, Joanne; Strauss-Schwartz, Judy; Vail, Helen; Kahn, Ronda

    2009-01-01

    The use of functional vision by school-age students who have visual impairments, including those with additional disabilities, is typically reported by teachers of students with visual impairments. Functional vision assessments determine how well a student uses his or her vision to perform tasks throughout the school day. The information that is…

  13. Colour Reconnection in WW Events

    NASA Astrophysics Data System (ADS)

    D'Hondt, J.

    2003-07-01

    Preliminary results are presented for a measurement of the κ parameter used in the JETSET SK-I model of Colour Reconnection in {W}+{W}^- -> qbar {q}'bar {q}q^' events at LEP2. An update on the investigation of Colour Reconnection effects in hadronic decays of W pairs, using the particle flow in DELPHI is presented. A second method is based on the observation that two different mW estimators have different sensitivity to the parametrised Colour Reconnection effect. Hence the difference between them is an observable with information content about κ.

  14. Can colours be used to segment words when reading?

    PubMed

    Perea, Manuel; Tejero, Pilar; Winskel, Heather

    2015-07-01

    Rayner, Fischer, and Pollatsek (1998, Vision Research) demonstrated that reading unspaced text in Indo-European languages produces a substantial reading cost in word identification (as deduced from an increased word-frequency effect on target words embedded in the unspaced vs. spaced sentences) and in eye movement guidance (as deduced from landing sites closer to the beginning of the words in unspaced sentences). However, the addition of spaces between words comes with a cost: nearby words may fall outside high-acuity central vision, thus reducing the potential benefits of parafoveal processing. In the present experiment, we introduced a salient visual cue intended to facilitate the process of word segmentation without compromising visual acuity: each alternating word was printed in a different colour (i.e., ). Results only revealed a small reading cost of unspaced alternating colour sentences relative to the spaced sentences. Thus, present data are a demonstration that colour can be useful to segment words for readers of spaced orthographies. PMID:26002618

  15. Presidential Visions.

    ERIC Educational Resources Information Center

    Gallin, Alice, Ed.

    1992-01-01

    This journal issue is devoted to the theme of university presidents and their visions of the future. It presents the inaugural addresses and speeches of 16 Catholic college and university presidents focusing on their goals, ambitions, and reasons for choosing to become higher education leaders at this particular time in the history of education in…

  16. Visions 2001.

    ERIC Educational Resources Information Center

    Rivero, Victor; Norman, Michele

    2001-01-01

    Reports on the views of 18 educational leaders regarding their vision on the future of education in an information age. Topics include people's diverse needs; relationships between morality, ethics, values, and technology; leadership; parental involvement; online courses from multiple higher education institutions; teachers' role; technology…

  17. Training Visions

    ERIC Educational Resources Information Center

    Training, 2011

    2011-01-01

    In this article, "Training" asks the 2011 winners to give their predictions for what training--either in general or specifically at their companies--will look like in the next five to 10 years. Perhaps their "training visions" will spark some ideas in one's organization--or at least help prepare for what might be coming in the next decade or so.

  18. Agrarian Visions.

    ERIC Educational Resources Information Center

    Theobald, Paul

    A new feature in "Country Teacher,""Agrarian Visions" reminds rural teachers that they can do something about rural decline. Like to populism of the 1890s, the "new populism" advocates rural living. Current attempts to address rural decline are contrary to agrarianism because: (1) telecommunications experts seek to solve problems of rural…

  19. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence.

    PubMed

    Moreno-Martínez, F Javier; Rodríguez-Rojo, Inmaculada C

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing. PMID:26074675

  20. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence

    PubMed Central

    Moreno-Martínez, F. Javier; Rodríguez-Rojo, Inmaculada C.

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing. PMID:26074675

  1. Vision Loss, Sudden

    MedlinePlus

    ... of age-related macular degeneration. Spotlight on Aging: Vision Loss in Older People Most commonly, vision loss ... Some Causes and Features of Sudden Loss of Vision Cause Common Features* Tests Sudden loss of vision ...

  2. Blindness and vision loss

    MedlinePlus

    ... eye ( chemical burns or sports injuries) Diabetes Glaucoma Macular degeneration The type of partial vision loss may differ, ... tunnel vision and missing areas of vision With macular degeneration, the side vision is normal but the central ...

  3. The Gradual Transformation of Historical Situations: Understanding "Change and Continuity" through Colours and Timelines

    ERIC Educational Resources Information Center

    Vella, Yosanne

    2011-01-01

    The small-scale research that Yosanne Vella reports in this article was driven by concern to help pupils develop "big picture" visions of the past and to engage effectively with the idea of change as a process rather than an event. The strategy that she adopts--asking groups of students to colour in a timeline recording their judgement in response…

  4. What Colour Is a Shadow?

    ERIC Educational Resources Information Center

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

  5. The Role of Organizations in Reaching Older Adults about Vision Loss

    ERIC Educational Resources Information Center

    Sussman-Skalka, Carol J.; Cimarolli, Verena R.; Stuen, Cynthia

    2006-01-01

    Vision impairment affects approximately 17% of Americans age 45 and older. Yet, 94% of adults with self-reported vision loss did not receive any type of vision rehabilitation services to help them retain independence. These findings underscore the need for promoting awareness about what can be done when vision fails. A national dissemination…

  6. Colour discrimination learning in black-handed tamarin ( Saguinus midas niger).

    PubMed

    Pessoa, Daniel M A; Araujo, Mariana F P; Tomaz, Carlos; Pessoa, Valdir F

    2003-10-01

    Colour is one cue that monkeys use for perceptual segregation of targets and to identify food resources. For fruit-eating primates such as Saguinus, an accurate colour perception would be advantageous to help find ripe fruits at distance. The colour vision abilities of black-handed tamarins ( Saguinus midas niger) were assessed through a discrimination learning paradigm using Munsell colour chips as stimuli. Pairs of chips were chosen from an early experiment with protan and deutan humans. The monkeys (three males and one female) were tested with stimuli of the same hue, but different brightness values, in order to make sure that discriminations were based on colour rather than brightness cues. The results showed that the female, but not the males, presented an above-chance performance for stimuli resembling hue conditions under which tamarins forage (oranges vs greens). Colour vision in S. m. niger is discussed according to the advantages and disadvantages of dichromatism in daily search for food as well as to aspects regarding polymorphism in New World monkeys. PMID:14593516

  7. Applied machine vision

    SciTech Connect

    Not Available

    1984-01-01

    This book presents the papers given at a conference on robot vision. Topics considered at the conference included the link between fixed and flexible automation, general applications of machine vision, the development of a specification for a machine vision system, machine vision technology, machine vision non-contact gaging, and vision in electronics manufacturing.

  8. Evaluating the Visually Impaired: Neuropsychological Techniques.

    ERIC Educational Resources Information Center

    Price, J. R.; And Others

    1987-01-01

    Assessment of nonvisual neuropsychological impairments in visually impaired persons can be achieved through modification of existing intelligence, memory, sensory-motor, personality, language, and achievement tests so that they do not require vision or penalize visually impaired persons. The Halstead-Reitan and Luria-Nebraska neuropsychological…

  9. Computer vision

    SciTech Connect

    Not Available

    1982-01-01

    This paper discusses material from areas such as artificial intelligence, psychology, computer graphics, and image processing. The intent is to assemble a selection of this material in a form that will serve both as a senior/graduate-level academic text and as a useful reference to those building vision systems. This book has a strong artificial intelligence flavour, emphasising the belief that both the intrinsic image information and the internal model of the world are important in successful vision systems. The book is organised into four parts, based on descriptions of objects at four different levels of abstraction. These are: generalised images-images and image-like entities; segmented images-images organised into subimages that are likely to correspond to interesting objects; geometric structures-quantitative models of image and world structures; relational structures-complex symbolic descriptions of image and world structures. The book contains author and subject indexes.

  10. Pleiades Visions

    NASA Astrophysics Data System (ADS)

    Whitehouse, M.

    2016-01-01

    Pleiades Visions (2012) is my new musical composition for organ that takes inspiration from traditional lore and music associated with the Pleiades (Seven Sisters) star cluster from Australian Aboriginal, Native American, and Native Hawaiian cultures. It is based on my doctoral dissertation research incorporating techniques from the fields of ethnomusicology and cultural astronomy; this research likely represents a new area of inquiry for both fields. This large-scale work employs the organ's vast sonic resources to evoke the majesty of the night sky and the expansive landscapes of the homelands of the above-mentioned peoples. Other important themes in Pleiades Visions are those of place, origins, cosmology, and the creation of the world.

  11. Lambda Vision

    NASA Astrophysics Data System (ADS)

    Czajkowski, Michael

    2014-06-01

    There is an explosion in the quantity and quality of IMINT data being captured in Intelligence Surveillance and Reconnaissance (ISR) today. While automated exploitation techniques involving computer vision are arriving, only a few architectures can manage both the storage and bandwidth of large volumes of IMINT data and also present results to analysts quickly. Lockheed Martin Advanced Technology Laboratories (ATL) has been actively researching in the area of applying Big Data cloud computing techniques to computer vision applications. This paper presents the results of this work in adopting a Lambda Architecture to process and disseminate IMINT data using computer vision algorithms. The approach embodies an end-to-end solution by processing IMINT data from sensors to serving information products quickly to analysts, independent of the size of the data. The solution lies in dividing up the architecture into a speed layer for low-latent processing and a batch layer for higher quality answers at the expense of time, but in a robust and fault-tolerant way. This approach was evaluated using a large corpus of IMINT data collected by a C-130 Shadow Harvest sensor over Afghanistan from 2010 through 2012. The evaluation data corpus included full motion video from both narrow and wide area field-of-views. The evaluation was done on a scaled-out cloud infrastructure that is similar in composition to those found in the Intelligence Community. The paper shows experimental results to prove the scalability of the architecture and precision of its results using a computer vision algorithm designed to identify man-made objects in sparse data terrain.

  12. Poor Vision and Dangerous Falls Plague Many U.S. Seniors

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_158679.html Poor Vision and Dangerous Falls Plague Many U.S. Seniors Year- ... HealthDay News) -- Millions of American seniors have severe vision impairment, and with it comes the risk of ...

  13. The effect of an on-site vision examination on adherence to vision screening recommendations.

    PubMed

    Chu, Raymond; Huang, Kristine; Barnhardt, Carmen; Chen, Angela

    2015-04-01

    Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening recommendations by providing the eye examination at the students' school and at no cost. Of the 1,306 students screened, 382 (29.2%) were identified with possible visual impairment. Parental consent for examination was obtained for 198 (51.8%) students. Our vision screening and examination program yielded similar adherence to follow-up as stand-alone vision screening programs. Future program considerations should address perceptual barriers that may be contributing to parental nonadherence to vision screening recommendations. PMID:24574183

  14. Differentiating Biological Colours with Few and Many Sensors: Spectral Reconstruction with RGB and Hyperspectral Cameras

    PubMed Central

    Garcia, Jair E.; Girard, Madeline B.; Kasumovic, Michael; Petersen, Phred; Wilksch, Philip A.; Dyer, Adrian G.

    2015-01-01

    Background The ability to discriminate between two similar or progressively dissimilar colours is important for many animals as it allows for accurately interpreting visual signals produced by key target stimuli or distractor information. Spectrophotometry objectively measures the spectral characteristics of these signals, but is often limited to point samples that could underestimate spectral variability within a single sample. Algorithms for RGB images and digital imaging devices with many more than three channels, hyperspectral cameras, have been recently developed to produce image spectrophotometers to recover reflectance spectra at individual pixel locations. We compare a linearised RGB and a hyperspectral camera in terms of their individual capacities to discriminate between colour targets of varying perceptual similarity for a human observer. Main Findings (1) The colour discrimination power of the RGB device is dependent on colour similarity between the samples whilst the hyperspectral device enables the reconstruction of a unique spectrum for each sampled pixel location independently from their chromatic appearance. (2) Uncertainty associated with spectral reconstruction from RGB responses results from the joint effect of metamerism and spectral variability within a single sample. Conclusion (1) RGB devices give a valuable insight into the limitations of colour discrimination with a low number of photoreceptors, as the principles involved in the interpretation of photoreceptor signals in trichromatic animals also apply to RGB camera responses. (2) The hyperspectral camera architecture provides means to explore other important aspects of colour vision like the perception of certain types of camouflage and colour constancy where multiple, narrow-band sensors increase resolution. PMID:25965264

  15. The colour of an avifauna: A quantitative analysis of the colour of Australian birds

    PubMed Central

    Delhey, Kaspar

    2015-01-01

    Animal coloration is a poorly-understood aspect of phenotypic variability. Here I expand initial studies of the colour gamut of birds by providing the first quantitative description of the colour variation of an entire avifauna: Australian landbirds (555 species). The colour of Australian birds occupies a small fraction (19%) of the entire possible colour space and colour variation is extremely uneven. Most colours are unsaturated, concentrated in the centre of colour space and based on the deposition of melanins. Other mechanisms of colour production are less common but account for larger portions of colour space and for most saturated colours. Male colours occupy 45–25% more colour space than female colours, indicating that sexual dichromatism translates into a broader range of male colours. Male-exclusive colours are often saturated, at the edge of chromatic space, and have most likely evolved for signalling. While most clades of birds occupy expected or lower-than-expected colour volumes, parrots and cockatoos (Order Psittaciformes) occupy a much larger volume than expected. This uneven distribution of colour variation across mechanisms of colour production, sexes and clades is probably shared by avifaunas in other parts of the world, but this remains to be tested with comparable data. PMID:26679370

  16. The colour of an avifauna: A quantitative analysis of the colour of Australian birds.

    PubMed

    Delhey, Kaspar

    2015-01-01

    Animal coloration is a poorly-understood aspect of phenotypic variability. Here I expand initial studies of the colour gamut of birds by providing the first quantitative description of the colour variation of an entire avifauna: Australian landbirds (555 species). The colour of Australian birds occupies a small fraction (19%) of the entire possible colour space and colour variation is extremely uneven. Most colours are unsaturated, concentrated in the centre of colour space and based on the deposition of melanins. Other mechanisms of colour production are less common but account for larger portions of colour space and for most saturated colours. Male colours occupy 45-25% more colour space than female colours, indicating that sexual dichromatism translates into a broader range of male colours. Male-exclusive colours are often saturated, at the edge of chromatic space, and have most likely evolved for signalling. While most clades of birds occupy expected or lower-than-expected colour volumes, parrots and cockatoos (Order Psittaciformes) occupy a much larger volume than expected. This uneven distribution of colour variation across mechanisms of colour production, sexes and clades is probably shared by avifaunas in other parts of the world, but this remains to be tested with comparable data. PMID:26679370

  17. Pediatric Low Vision

    MedlinePlus

    ... Asked Questions Español Condiciones Chinese Conditions Pediatric Low Vision What is Low Vision? Partial vision loss that cannot be corrected causes ... and play. What are the signs of Low Vision? Some signs of low vision include difficulty recognizing ...

  18. Vision Therapy News Backgrounder.

    ERIC Educational Resources Information Center

    American Optometric Association, St. Louis, MO.

    The booklet provides an overview on vision therapy to aid writers, editors, and broadcasters help parents, teachers, older adults, and all consumers learn more about vision therapy. Following a description of vision therapy or vision training, information is provided on how and why vision therapy works. Additional sections address providers of…

  19. Vision Loss in Older Adults.

    PubMed

    Pelletier, Allen L; Rojas-Roldan, Ledy; Coffin, Janis

    2016-08-01

    Vision loss affects 37 million Americans older than 50 years and one in four who are older than 80 years. The U.S. Preventive Services Task Force concludes that current evidence is insufficient to assess the balance of benefits and harms of screening for impaired visual acuity in adults older than 65 years. However, family physicians play a critical role in identifying persons who are at risk of vision loss, counseling patients, and referring patients for disease-specific treatment. The conditions that cause most cases of vision loss in older patients are age-related macular degeneration, glaucoma, ocular complications of diabetes mellitus, and age-related cataracts. Vitamin supplements can delay the progression of age-related macular degeneration. Intravitreal injection of a vascular endothelial growth factor inhibitor can preserve vision in the neovascular form of macular degeneration. Medicated eye drops reduce intraocular pressure and can delay the progression of vision loss in patients with glaucoma, but adherence to treatment is poor. Laser trabeculoplasty also lowers intraocular pressure and preserves vision in patients with primary open-angle glaucoma, but long-term studies are needed to identify who is most likely to benefit from surgery. Tight glycemic control in adults with diabetes slows the progression of diabetic retinopathy, but must be balanced against the risks of hypoglycemia and death in older adults. Fenofibrate also slows progression of diabetic retinopathy. Panretinal photocoagulation is the mainstay of treatment for diabetic retinopathy, whereas vascular endothelial growth factor inhibitors slow vision loss resulting from diabetic macular edema. Preoperative testing before cataract surgery does not improve outcomes and is not recommended. PMID:27479624

  20. Measuring grinding surface roughness based on the sharpness evaluation of colour images

    NASA Astrophysics Data System (ADS)

    Huaian, Y. I.; Jian, L. I. U.; Enhui, L. U.; Peng, A. O.

    2016-02-01

    Current machine vision-based detection methods for metal surface roughness mainly use the grey values of images for statistical analysis but do not make full use of the colour information and ignore the subjective judgment of the human vision system. To address these problems, this paper proposes a method to measure surface roughness through the sharpness evaluation of colour images. Based on the difference in sharpness of virtual images of colour blocks that are formed on grinding surfaces with different roughness, an algorithm for evaluating the sharpness of colour images that is based on the difference of the RGB colour space was used to develop a correlation model between the sharpness and the surface roughness. The correlation model was analysed under two conditions: constant illumination and varying illumination. The effect of the surface textures of the grinding samples on the image sharpness was also considered, demonstrating the feasibility of the detection method. The results show that the sharpness is strongly correlated with the surface roughness; when the illumination and the surface texture have the same orientation, the sharpness clearly decreases with increasing surface roughness. Under varying illumination, this correlation between the sharpness and surface roughness was highly robust, and the sharpness of each virtual image increased linearly with the illumination. Relative to the detection method for surface roughness using gray level co-occurrence matrix or artificial neural network, the proposed method is convenient, highly accurate and has a wide measurement range.

  1. Floral colours in a world without birds and bees: the plants of Macquarie Island.

    PubMed

    Shrestha, M; Lunau, K; Dorin, A; Schulze, B; Bischoff, M; Burd, M; Dyer, A G

    2016-09-01

    We studied biotically pollinated angiosperms on Macquarie Island, a remote site in the Southern Ocean with a predominately or exclusively dipteran pollinator fauna, in an effort to understand how flower colour affects community assembly. We compared a distinctive group of cream-green Macquarie Island flowers to the flora of likely source pools of immigrants and to a continental flora from a high latitude in the northern hemisphere. We used both dipteran and hymenopteran colour models and phylogenetically informed analyses to explore the chromatic component of community assembly. The species with cream-green flowers are very restricted in colour space models of both fly vision and bee vision and represent a distinct group that plays a very minor role in other communities. It is unlikely that such a community could form through random immigration from continental source pools. Our findings suggest that fly pollination has imposed a strong ecological filter on Macquarie Island, favouring floral colours that are rare in continental floras. This is one of the strongest demonstrations that plant-pollinator interactions play an important role in plant community assembly. Future work exploring colour choices by dipteran flower visitors would be valuable. PMID:27016399

  2. Retinal Detachment Vision Simulator

    MedlinePlus

    ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment Vision Simulator Mar. 01, 2016 How does a detached or torn retina affect your vision? If a retinal tear is occurring, you may ...

  3. Structural colour in Chondrus crispus

    NASA Astrophysics Data System (ADS)

    Chandler, Chris J.; Wilts, Bodo D.; Vignolini, Silvia; Brodie, Juliet; Steiner, Ullrich; Rudall, Paula J.; Glover, Beverley J.; Gregory, Thomas; Walker, Rachel H.

    2015-07-01

    The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector.

  4. Structural colour in Chondrus crispus.

    PubMed

    Chandler, Chris J; Wilts, Bodo D; Vignolini, Silvia; Brodie, Juliet; Steiner, Ullrich; Rudall, Paula J; Glover, Beverley J; Gregory, Thomas; Walker, Rachel H

    2015-01-01

    The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector. PMID:26139470

  5. String formation beyond leading colour

    NASA Astrophysics Data System (ADS)

    Christiansen, Jesper R.; Skands, Peter Z.

    2015-08-01

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N C are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In e + e -collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/ N {/C 2} suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important < p ⊥> ( n charged) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p ⊥ spectra remains challenging to explain.

  6. Colour Reconnection at LEP2

    NASA Astrophysics Data System (ADS)

    Abreu, P.

    2002-03-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, Aleph, Delphi, L3 and Opal, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method1, are yet inconclusive.

  7. An RGB approach to prismatic colours

    NASA Astrophysics Data System (ADS)

    Theilmann, Florian; Grusche, Sascha

    2013-11-01

    Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of ‘differently refrangible’ coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well saturated colours of simple edge spectra. Besides, the connection of physical wavelength and colour remains obscure—after all, colour and wavelength are not equivalent. In this paper, we suggest that teachers demonstrate these impressive experiments in the classroom by using a video projector and a prism to disperse black-and-white slit images. We introduce experimental and diagrammatic methods for establishing the connection between the original slit image and the wavelength composition of the resulting spectrum. From this (or any other given) wavelength composition, students can systematically derive the colours with a simple RGB approach, thus gaining a more accurate picture of the relation between wavelength and colour.

  8. Filtering and polychromatic vision in mantis shrimps: themes in visible and ultraviolet vision

    PubMed Central

    Cronin, Thomas W.; Bok, Michael J.; Marshall, N. Justin; Caldwell, Roy L.

    2014-01-01

    Stomatopod crustaceans have the most complex and diverse assortment of retinal photoreceptors of any animals, with 16 functional classes. The receptor classes are subdivided into sets responsible for ultraviolet vision, spatial vision, colour vision and polarization vision. Many of these receptor classes are spectrally tuned by filtering pigments located in photoreceptors or overlying optical elements. At visible wavelengths, carotenoproteins or similar substances are packed into vesicles used either as serial, intrarhabdomal filters or lateral filters. A single retina may contain a diversity of these filtering pigments paired with specific photoreceptors, and the pigments used vary between and within species both taxonomically and ecologically. Ultraviolet-filtering pigments in the crystalline cones serve to tune ultraviolet vision in these animals as well, and some ultraviolet receptors themselves act as birefringent filters to enable circular polarization vision. Stomatopods have reached an evolutionary extreme in their use of filter mechanisms to tune photoreception to habitat and behaviour, allowing them to extend the spectral range of their vision both deeper into the ultraviolet and further into the red. PMID:24395960

  9. Filtering and polychromatic vision in mantis shrimps: themes in visible and ultraviolet vision.

    PubMed

    Cronin, Thomas W; Bok, Michael J; Marshall, N Justin; Caldwell, Roy L

    2014-01-01

    Stomatopod crustaceans have the most complex and diverse assortment of retinal photoreceptors of any animals, with 16 functional classes. The receptor classes are subdivided into sets responsible for ultraviolet vision, spatial vision, colour vision and polarization vision. Many of these receptor classes are spectrally tuned by filtering pigments located in photoreceptors or overlying optical elements. At visible wavelengths, carotenoproteins or similar substances are packed into vesicles used either as serial, intrarhabdomal filters or lateral filters. A single retina may contain a diversity of these filtering pigments paired with specific photoreceptors, and the pigments used vary between and within species both taxonomically and ecologically. Ultraviolet-filtering pigments in the crystalline cones serve to tune ultraviolet vision in these animals as well, and some ultraviolet receptors themselves act as birefringent filters to enable circular polarization vision. Stomatopods have reached an evolutionary extreme in their use of filter mechanisms to tune photoreception to habitat and behaviour, allowing them to extend the spectral range of their vision both deeper into the ultraviolet and further into the red. PMID:24395960

  10. Binocular Vision

    PubMed Central

    Blake, Randolph; Wilson, Hugh

    2010-01-01

    This essay reviews major developments –empirical and theoretical –in the field of binocular vision during the last 25 years. We limit our survey primarily to work on human stereopsis, binocular rivalry and binocular contrast summation, with discussion where relevant of single-unit neurophysiology and human brain imaging. We identify several key controversies that have stimulated important work on these problems. In the case of stereopsis those controversies include position versus phase encoding of disparity, dependence of disparity limits on spatial scale, role of occlusion in binocular depth and surface perception, and motion in 3D. In the case of binocular rivalry, controversies include eye versus stimulus rivalry, role of “top-down” influences on rivalry dynamics, and the interaction of binocular rivalry and stereopsis. Concerning binocular contrast summation, the essay focuses on two representative models that highlight the evolving complexity in this field of study. PMID:20951722

  11. Vision Screening

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Visi Screen OSS-C, marketed by Vision Research Corporation, incorporates image processing technology originally developed by Marshall Space Flight Center. Its advantage in eye screening is speed. Because it requires no response from a subject, it can be used to detect eye problems in very young children. An electronic flash from a 35 millimeter camera sends light into a child's eyes, which is reflected back to the camera lens. The photorefractor then analyzes the retinal reflexes generated and produces an image of the child's eyes, which enables a trained observer to identify any defects. The device is used by pediatricians, day care centers and civic organizations that concentrate on children with special needs.

  12. Robot Vision

    NASA Technical Reports Server (NTRS)

    Sutro, L. L.; Lerman, J. B.

    1973-01-01

    The operation of a system is described that is built both to model the vision of primate animals, including man, and serve as a pre-prototype of possible object recognition system. It was employed in a series of experiments to determine the practicability of matching left and right images of a scene to determine the range and form of objects. The experiments started with computer generated random-dot stereograms as inputs and progressed through random square stereograms to a real scene. The major problems were the elimination of spurious matches, between the left and right views, and the interpretation of ambiguous regions, on the left side of an object that can be viewed only by the left camera, and on the right side of an object that can be viewed only by the right camera.

  13. Low Vision Aids and Low Vision Rehabilitation

    MedlinePlus

    ... The future will offer even more solutions. Newer technology for low vision aids While low vision devices ... magnifiers have long been the standard in assistive technology, advances in consumer electronics are also improving quality ...

  14. Colour as a signal for entraining the mammalian circadian clock.

    PubMed

    Walmsley, Lauren; Hanna, Lydia; Mouland, Josh; Martial, Franck; West, Alexander; Smedley, Andrew R; Bechtold, David A; Webb, Ann R; Lucas, Robert J; Brown, Timothy M

    2015-04-01

    Twilight is characterised by changes in both quantity ("irradiance") and quality ("colour") of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue-yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision. PMID:25884537

  15. An RGB Approach to Prismatic Colours

    ERIC Educational Resources Information Center

    Theilmann, Florian; Grusche, Sascha

    2013-01-01

    Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well…

  16. Biological Components of Colour Preference in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

    2010-01-01

    Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in…

  17. Bullying in German Adolescents: Attending Special School for Students with Visual Impairment

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2011-01-01

    The present study analysed bullying in German adolescents with and without visual impairment. Ninety-eight adolescents with vision loss from schools for students with visual impairment, of whom 31 were blind and 67 had low vision, were compared with 98 sighted peers using a matched-pair design. Students with low vision reported higher levels of…

  18. Physiology and Psychology of Vision and Its Disorders: A Review

    PubMed Central

    Moschos, Marilita M

    2014-01-01

    The purpose of this review is to bring together to the physiology and psychology of vision and to analyze, based on our own data and on the available literature, the relationship between sight loss and individual reactions. As recent treatments for depression are often effective and have few side-effects, ophthalmologists should consider referral for treatment of depression in patients suffering from vision impairment. For this reason, vision rehabilitation should be more readily available and recommended. PMID:25741524

  19. Colour annealing - a toy model of colour reconnections

    SciTech Connect

    Sandhoff, Marisa; Skands, Peter; /Fermilab

    2005-12-01

    We present a simple toy model for colour reconnections at the nonperturbative level. The model resembles an annealing-type algorithm and is applicable to any collider and process type, though we argue for a possible enhancement of the effect in hadron-hadron collisions. We present a simple application and study of the consequences for semileptonic t{bar t} events at the Tevatron.

  20. Prentice Medal Lecture 2013: Visual Accessibility: A Challenge for Low-Vision Research

    PubMed Central

    Legge, Gordon E.

    2014-01-01

    Low vision may be defined as any chronic form of vision impairment, not correctable by glasses or contact lenses, that adversely affects everyday function. Visual accessibility refers to factors that make an environment, device or display usable by vision. In this article, I discuss the concept of visual accessibility with special reference to low vision. What role can vision science play in enhancing visual accessibility for people with low vision? I propose that greater efforts to embed low-vision research in real-world contexts and collaboration with other disciplines will accelerate progress. I describe examples from my current research projects on architectural accessibility and reading accessibility. PMID:24978657

  1. Adolescents with Low Vision: Perceptions of Driving and Nondriving

    ERIC Educational Resources Information Center

    Sacks, Sharon Zell; Rosenblum, L. Penny

    2006-01-01

    Two studies examined how adolescents with low vision perceive their ability to drive. The results of both studies indicated similarities in the participants' responses with respect to knowledge of visual impairment, information about options for driving with low vision, frustrations and obstacles imposed by not being able to drive, and independent…

  2. Visual Memory for Objects Following Foveal Vision Loss

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Herbik, Anne; Hofmüller, Wolfram; Hoffmann, Michael B.; Pollmann, Stefan

    2015-01-01

    Allocation of visual attention is crucial for encoding items into visual long-term memory. In free vision, attention is closely linked to the center of gaze, raising the question whether foveal vision loss entails suboptimal deployment of attention and subsequent impairment of object encoding. To investigate this question, we examined visual…

  3. Are Brazilian Conferences and Internship Arrangements, Involving McLeod's Patent Pending Naturoptic Method for Restoring Healthy Vision, for Visually Impaired Professional Americas' Students, an Effective Mechanism to Teach and Implement Desired Changes?

    NASA Astrophysics Data System (ADS)

    Ataide, Italanei; Ataide, Jade; McLeod, Roger

    2006-10-01

    We have initiated investigations and procedures that we hope can be applied, perhaps first in Brazil, and also possibly in countries like Chile, Paraguay, Peru and Venezuela, or elsewhere in the Americas, to propagate favorably Naturoptic Vision Improvement methods. Could the countries involved serve as conference locations that would determine whether it is feasible and possible to transfer this applied physics process rapidly, economically and effectively? The methods and the practical theory involved are easily transmitted, as we hope to demonstrate. This approach is easiest of all to use with well- sighted youth or other individuals, and can be extended to them appropriately to maintain fine vision throughout their lives. Perhaps there should be Naturoptic Vision Maintenance conferences, also!

  4. Characterisation of the n-colour printing process using the spot colour overprint model.

    PubMed

    Deshpande, Kiran; Green, Phil; Pointer, Michael R

    2014-12-29

    This paper is aimed at reproducing the solid spot colours using the n-colour separation. A simplified numerical method, called as the spot colour overprint (SCOP) model, was used for characterising the n-colour printing process. This model was originally developed for estimating the spot colour overprints. It was extended to be used as a generic forward characterisation model for the n-colour printing process. The inverse printer model based on the look-up table was implemented to obtain the colour separation for n-colour printing process. Finally the real-world spot colours were reproduced using 7-colour separation on lithographic offset printing process. The colours printed with 7 inks were compared against the original spot colours to evaluate the accuracy. The results show good accuracy with the mean CIEDE2000 value between the target colours and the printed colours of 2.06. The proposed method can be used successfully to reproduce the spot colours, which can potentially save significant time and cost in the printing and packaging industry. PMID:25607147

  5. Printing colour at the optical diffraction limit.

    PubMed

    Kumar, Karthik; Duan, Huigao; Hegde, Ravi S; Koh, Samuel C W; Wei, Jennifer N; Yang, Joel K W

    2012-09-01

    The highest possible resolution for printed colour images is determined by the diffraction limit of visible light. To achieve this limit, individual colour elements (or pixels) with a pitch of 250 nm are required, translating into printed images at a resolution of ∼100,000 dots per inch (d.p.i.). However, methods for dispensing multiple colourants or fabricating structural colour through plasmonic structures have insufficient resolution and limited scalability. Here, we present a non-colourant method that achieves bright-field colour prints with resolutions up to the optical diffraction limit. Colour information is encoded in the dimensional parameters of metal nanostructures, so that tuning their plasmon resonance determines the colours of the individual pixels. Our colour-mapping strategy produces images with both sharp colour changes and fine tonal variations, is amenable to large-volume colour printing via nanoimprint lithography, and could be useful in making microimages for security, steganography, nanoscale optical filters and high-density spectrally encoded optical data storage. PMID:22886173

  6. Carotenoids need structural colours to shine.

    PubMed

    Shawkey, Matthew D; Hill, Geoffrey E

    2005-06-22

    The bright colours of feathers are among the most striking displays in nature and are frequently used as sexual signals. Feathers can be coloured by pigments or by ordered tissue, and these mechanisms have traditionally been treated as distinct modes of display. Here we show that some yellow plumage colour is created both by reflection of light from white structural tissue and absorption of light by carotenoids. Thus, structural components of feathers contribute substantially to yellow 'carotenoid' displays, but the effect of variation in structural components on variation in colour displays is, to our knowledge, unstudied. The presence of structural colour in some carotenoid-based colour displays will have to be considered in studies of colour signalling. PMID:17148144

  7. International computer vision directory

    SciTech Connect

    Flora, P.C.

    1986-01-01

    This book contains information on: computerized automation technologies. State-of-the-art computer vision systems for many areas of industrial use are covered. Other topics discussed include the following automated inspection systems; robot/vision systems; vision process control; cameras (vidicon and solid state); vision peripherals and components; and pattern processor.

  8. Ultraviolet Light: Some Considerations for Vision Stimulation.

    ERIC Educational Resources Information Center

    Knowlton, Marie

    1986-01-01

    The article examines evidence of visual impairment caused by excessive amounts of ultraviolet (UV) light. Among considerations when using a source of UV light for vision stimulation are the position of the child and teacher, use of window glass filters or protective glasses, and careful recordkeeping of all UV stimulation. (Author/JW)[

  9. Low Vision: Assessment and Training for Mobility.

    ERIC Educational Resources Information Center

    Dodds, Allan G.; Davis, Denis P.

    1987-01-01

    To develop a battery of tasks to predict and improve mobility performance, a series of functional vision tasks (texural shearing, degraded images, embedded figures, and parafoveal attention) were generated by a microcomputer. Sixty visually impaired subjects given either computerized task training or real-life training improved their low vision…

  10. Neurological Vision Rehabilitation: Description and Case Study

    ERIC Educational Resources Information Center

    Kingston, John; Katsaros, Jennifer; Vu, Yurika; Goodrich, Gregory L.

    2010-01-01

    The wars in Afghanistan and Iraq have been notable for the high rates of traumatic brain injury (TBI) that have been incurred by the troops. Visual impairments often occur following TBI and present new challenges for rehabilitation. We describe a neurological vision rehabilitation therapy that addresses the unique needs of patients with vision…

  11. Raven's Coloured Progressive Matrices as a Measure of Cognitive Functioning in Cerebral Palsy

    ERIC Educational Resources Information Center

    Pueyo, R.; Junque, C.; Vendrell, P.; Narberhaus, A.; Segarra, D.

    2008-01-01

    Background: Cognitive dysfunction is frequent in Cerebral Palsy (CP). CP motor impairment and associated speech deficits often hinder cognitive assessment, with the result being that not all CP studies consider cognitive dysfunction. Raven's Coloured Progressive Matrices is a simple, rapid test which can be used in persons with severe motor…

  12. Visual modelling suggests a weak relationship between the evolution of ultraviolet vision and plumage coloration in birds.

    PubMed

    Lind, O; Delhey, K

    2015-03-01

    Birds have sophisticated colour vision mediated by four cone types that cover a wide visual spectrum including ultraviolet (UV) wavelengths. Many birds have modest UV sensitivity provided by violet-sensitive (VS) cones with sensitivity maxima between 400 and 425 nm. However, some birds have evolved higher UV sensitivity and a larger visual spectrum given by UV-sensitive (UVS) cones maximally sensitive at 360-370 nm. The reasons for VS-UVS transitions and their relationship to visual ecology remain unclear. It has been hypothesized that the evolution of UVS-cone vision is linked to plumage colours so that visual sensitivity and feather coloration are 'matched'. This leads to the specific prediction that UVS-cone vision enhances the discrimination of plumage colours of UVS birds while such an advantage is absent or less pronounced for VS-bird coloration. We test this hypothesis using knowledge of the complex distribution of UVS cones among birds combined with mathematical modelling of colour discrimination during different viewing conditions. We find no support for the hypothesis, which, combined with previous studies, suggests only a weak relationship between UVS-cone vision and plumage colour evolution. Instead, we suggest that UVS-cone vision generally favours colour discrimination, which creates a nonspecific selection pressure for the evolution of UVS cones. PMID:25664902

  13. HEALTH-RELATED QUALITY OF LIFE AND VISUAL AND COGNTIVE IMPAIRMENT AMONG NURSING HOME RESIDENTS

    PubMed Central

    Elliott, Amanda F.; McGwin, Gerald; Owsley, Cynthia

    2009-01-01

    Aim To examine whether the relationship between vision impairment and health-related quality of life (HRQoL) in nursing home residents is impacted by co-existing cognitive impairment. Methods This cross-sectional study involved a total of 382 English-speaking older adults (>55 years of age) with ≥13 on the Mini Mental State Exam (MMSE) from seventeen nursing homes in Birmingham, AL. Assessments were taken of visual acuity (Lighthouse Near Visual Acuity Test), cognition (MMSE), and health-related quality of life (Nursing Home Vision-Targeted Health-Related Quality of Life Questionnaire, VF-14, and the SF-36). Results A greater portion of participants had both vision and cognitive impairments (38.5%) as compared to those with neither impairment (21.5%), vision impairment alone (13.4%), and cognitive impairment alone (26.7%). Cognitive impairment did not modify the impact of vision impairment on HRQoL. The reduction in HRQoL associated with vision impairment was similar for those with and without cognitive impairment. Conclusion The deleterious impact of vision impairment on HRQoL in nursing home residents was not exacerbated by the co-occurrence of cognitive impairment. Aging-related visual impairment in nursing home residents is often reversible through treatment leading to improved HRQoL, and thus it is clinically important to know that cognitive impairment is unlikely to interfere with this benefit. PMID:18971236

  14. (Computer vision and robotics)

    SciTech Connect

    Jones, J.P.

    1989-02-13

    The traveler attended the Fourth Aalborg International Symposium on Computer Vision at Aalborg University, Aalborg, Denmark. The traveler presented three invited lectures entitled, Concurrent Computer Vision on a Hypercube Multicomputer'', The Butterfly Accumulator and its Application in Concurrent Computer Vision on Hypercube Multicomputers'', and Concurrency in Mobile Robotics at ORNL'', and a ten-minute editorial entitled, It Concurrency an Issue in Computer Vision.'' The traveler obtained information on current R D efforts elsewhere in concurrent computer vision.

  15. Put on that colour, it fits your emotion: Colour appropriateness as a function of expressed emotion.

    PubMed

    Dael, Nele; Perseguers, Marie-Noëlle; Marchand, Cynthia; Antonietti, Jean-Philippe; Mohr, Christine

    2016-01-01

    People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have particularly strong affective connotations. To test whether colour choices can be driven by emotion, we investigated whether and how colour hue, brightness, and saturation are systematically associated with bodily expressions of positive (joy) and negative (fear) emotions. Twenty-five non-colour-blind participants viewed videos of these expressions and selected for each video the most appropriate colour using colour sliders providing values for hue, brightness, and saturation. The overall colour choices were congruent with the expressed emotion--that is, participants selected brighter and more saturated colours for joy expressions than for fear expressions. Also, colours along the red-yellow spectrum were deemed more appropriate for joy expressions and cyan-bluish hues for fear expressions. The current study adds further support to the role of emotion in colour choices by (a) showing that emotional information is spontaneously used in an unconstrained choice setting, (b) extending to ecologically valid stimuli occurring in everyday encounters (dressed bodies), and PMID:26339950

  16. Colour and odour drive fruit selection and seed dispersal by mouse lemurs

    PubMed Central

    Valenta, Kim; Burke, Ryan J.; Styler, Sarah A.; Jackson, Derek A.; Melin, Amanda D.; Lehman, Shawn M.

    2013-01-01

    Animals and fruiting plants are involved in a complex set of interactions, with animals relying on fruiting trees as food resources, and fruiting trees relying on animals for seed dispersal. This interdependence shapes fruit signals such as colour and odour, to increase fruit detectability, and animal sensory systems, such as colour vision and olfaction to facilitate food identification and selection. Despite the ecological and evolutionary importance of plant-animal interactions for shaping animal sensory adaptations and plant characteristics, the details of the relationship are poorly understood. Here we examine the role of fruit chromaticity, luminance and odour on seed dispersal by mouse lemurs. We show that both fruit colour and odour significantly predict fruit consumption and seed dispersal by Microcebus ravelobensis and M. murinus. Our study is the first to quantify and examine the role of bimodal fruit signals on seed dispersal in light of the sensory abilities of the disperser. PMID:23939534

  17. The Physical Environment and the Visually Impaired.

    ERIC Educational Resources Information Center

    Braf, Per-Gunnar

    Reported are results of a project carried out at the Swedish Institute for the Handicapped to determine needs of the visually impaired in the planning and adaptation of buildings and other forms of physical environment. Chapter 1 considers implications of impaired vision and includes definitions, statistics, and problems of the visually impaired…

  18. The original colours of fossil beetles

    PubMed Central

    McNamara, Maria E.; Briggs, Derek E. G.; Orr, Patrick J.; Noh, Heeso; Cao, Hui

    2012-01-01

    Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group. PMID:21957131

  19. Structural colour: Colour mixing in wing scales of a butterfly

    NASA Astrophysics Data System (ADS)

    Vukusic, P.; Sambles, J. R.; Lawrence, C. R.

    2000-03-01

    Green coloration in the animal kingdom, as seen in birds' feathers and reptile integument, is often an additive mixture of structurally effected blue and pigmentary yellow. Here we investigate the origin of the bright green coloration of the wing scales of the Indonesian male Papilio palinurus butterfly, the microstructure of which generates an extraordinary combination of both yellow and blue iridescence. The dual colour arises from a modulation imposed on the multilayer, producing the blue component as a result of a previously undiscovered retro-reflection process.

  20. How Bees Discriminate a Pattern of Two Colours from Its Mirror Image

    PubMed Central

    Horridge, Adrian

    2015-01-01

    A century ago, in his study of colour vision in the honeybee (Apis mellifera), Karl von Frisch showed that bees distinguish between a disc that is half yellow, half blue, and a mirror image of the same. Although his inference of colour vision in this example has been accepted, some discrepancies have prompted a new investigation of the detection of polarity in coloured patterns. In new experiments, bees restricted to their blue and green receptors by exclusion of ultraviolet could learn patterns of this type if they displayed a difference in green contrast between the two colours. Patterns with no green contrast required an additional vertical black line as a landmark. Tests of the trained bees revealed that they had learned two inputs; a measure and the retinotopic position of blue with large field tonic detectors, and the measure and position of a vertical edge or line with small-field phasic green detectors. The angle between these two was measured. This simple combination was detected wherever it occurred in many patterns, fitting the definition of an algorithm, which is defined as a method of processing data. As long as they excited blue receptors, colours could be any colour to human eyes, even white. The blue area cue could be separated from the green receptor modulation by as much as 50°. When some blue content was not available, the bees learned two measures of the modulation of the green receptors at widely separated vertical edges, and the angle between them. There was no evidence that the bees reconstructed the lay-out of the pattern or detected a tonic input to the green receptors. PMID:25617892

  1. Quantifying Plant Colour and Colour Difference as Perceived by Humans Using Digital Images

    PubMed Central

    Kendal, Dave; Hauser, Cindy E.; Garrard, Georgia E.; Jellinek, Sacha; Giljohann, Katherine M.; Moore, Joslin L.

    2013-01-01

    Human perception of plant leaf and flower colour can influence species management. Colour and colour contrast may influence the detectability of invasive or rare species during surveys. Quantitative, repeatable measures of plant colour are required for comparison across studies and generalisation across species. We present a standard method for measuring plant leaf and flower colour traits using images taken with digital cameras. We demonstrate the method by quantifying the colour of and colour difference between the flowers of eleven grassland species near Falls Creek, Australia, as part of an invasive species detection experiment. The reliability of the method was tested by measuring the leaf colour of five residential garden shrub species in Ballarat, Australia using five different types of digital camera. Flowers and leaves had overlapping but distinct colour distributions. Calculated colour differences corresponded well with qualitative comparisons. Estimates of proportional cover of yellow flowers identified using colour measurements correlated well with estimates obtained by measuring and counting individual flowers. Digital SLR and mirrorless cameras were superior to phone cameras and point-and-shoot cameras for producing reliable measurements, particularly under variable lighting conditions. The analysis of digital images taken with digital cameras is a practicable method for quantifying plant flower and leaf colour in the field or lab. Quantitative, repeatable measurements allow for comparisons between species and generalisations across species and studies. This allows plant colour to be related to human perception and preferences and, ultimately, species management. PMID:23977275

  2. Quantifying plant colour and colour difference as perceived by humans using digital images.

    PubMed

    Kendal, Dave; Hauser, Cindy E; Garrard, Georgia E; Jellinek, Sacha; Giljohann, Katherine M; Moore, Joslin L

    2013-01-01

    Human perception of plant leaf and flower colour can influence species management. Colour and colour contrast may influence the detectability of invasive or rare species during surveys. Quantitative, repeatable measures of plant colour are required for comparison across studies and generalisation across species. We present a standard method for measuring plant leaf and flower colour traits using images taken with digital cameras. We demonstrate the method by quantifying the colour of and colour difference between the flowers of eleven grassland species near Falls Creek, Australia, as part of an invasive species detection experiment. The reliability of the method was tested by measuring the leaf colour of five residential garden shrub species in Ballarat, Australia using five different types of digital camera. Flowers and leaves had overlapping but distinct colour distributions. Calculated colour differences corresponded well with qualitative comparisons. Estimates of proportional cover of yellow flowers identified using colour measurements correlated well with estimates obtained by measuring and counting individual flowers. Digital SLR and mirrorless cameras were superior to phone cameras and point-and-shoot cameras for producing reliable measurements, particularly under variable lighting conditions. The analysis of digital images taken with digital cameras is a practicable method for quantifying plant flower and leaf colour in the field or lab. Quantitative, repeatable measurements allow for comparisons between species and generalisations across species and studies. This allows plant colour to be related to human perception and preferences and, ultimately, species management. PMID:23977275

  3. Colour Consideration for Waiting areas in hospitals

    NASA Astrophysics Data System (ADS)

    Zraati, Parisa

    2012-08-01

    Colour is one the most important factors in the nature that can have some affects on human behaviour. Many years ago, it was proven that using colour in public place can have some affect on the users. Depend of the darkness and lightness; it can be vary from positive to negative. The research will mainly focus on the colour and psychological influences and physical factors. The statement of problem in this research is what is impact of colour usually applied to waiting area? The overall aim of the study is to explore the visual environment of hospitals and to manage the colour psychological effect of the hospital users in the waiting area by creating a comfortable, pleasant and cozy environment for users while spend their time in waiting areas. The analysisconcentrate on satisfaction and their interesting regarding applied colour in two private hospital waiting area in Malaysia.

  4. Molecular tests for coat colours in horses.

    PubMed

    Rieder, Stefan

    2009-12-01

    Colour phenotypes may have played a major role during early domestication events and initial selection among domestic animal species. As coat colours mostly follow a relatively simple mode of Mendelian inheritance, they have been among the first traits to be systematically analysed at the molecular level. As a result of the number of genetic tools developed during the past decade, horse coat colour tests have been designed and are now commercially available for some of the basic phenotypes. These tests enable breeders to verify segregation within particular pedigrees, to select specific colour phenotypes according to market demand or studbook policies and to avoid complex inherited diseases associated with some of the colour patterns. This paper reviews the relevance of the topic, describes all currently available tests for coat colours in horses and addresses also ongoing research in this field. PMID:19912415

  5. [On a binocular vision testing in concomitant strabismus].

    PubMed

    Seleznev, A V; Vakurin, E A; Kashchenko, T P

    2011-01-01

    Character of vision in 105 children with strabismus (with regular eye position) was tested using four dot test on different distance (5.0, 2.5, 1.0 m) and "Phorbis" device comprising phoropter and a set of light filters, that let us perform examination in the conditions of colour, polaroid and bitmapped division of visual fields. Stereoscopic vision was examined using original method based on anaglyph haploscopy. Binocular vision in strabismus was found to become more frequent as the distance and dissociating effect of light-filters decrease, and turned to be maximal in near testing in conditions of bitmapped haploscopy. Visual stereoscopic acuity in children with concomitant strabismus even on reaching regular eye position and binocular vision is significantly lower compared with healthy children of the same age. PMID:21800722

  6. The multiple disguises of spiders: web colour and decorations, body colour and movement

    PubMed Central

    Théry, Marc; Casas, Jérôme

    2008-01-01

    Diverse functions have been assigned to the visual appearance of webs, spiders and web decorations, including prey attraction, predator deterrence and camouflage. Here, we review the pertinent literature, focusing on potential camouflage and mimicry. Webs are often difficult to detect in a heterogeneous visual environment. Static and dynamic web distortions are used to escape visual detection by prey, although particular silk may also attract prey. Recent work using physiological models of vision taking into account visual environments rarely supports the hypothesis of spider camouflage by decorations, but most often the prey attraction and predator confusion hypotheses. Similarly, visual modelling shows that spider coloration is effective in attracting prey but not in conveying camouflage. Camouflage through colour change might be used by particular crab spiders to hide from predator or prey on flowers of different coloration. However, results obtained on a non-cryptic crab spider suggest that an alternative function of pigmentation may be to avoid UV photodamage through the transparent cuticle. Numerous species are clearly efficient locomotory mimics of ants, particularly in the eyes of their predators. We close our paper by highlighting gaps in our knowledge. PMID:18990672

  7. Cryptic differences in colour among Müllerian mimics: how can the visual capacities of predators and prey shape the evolution of wing colours?

    PubMed

    Llaurens, V; Joron, M; Théry, M

    2014-03-01

    Antagonistic interactions between predators and prey often lead to co-evolution. In the case of toxic prey, aposematic colours act as warning signals for predators and play a protective role. Evolutionary convergence in colour patterns among toxic prey evolves due to positive density-dependent selection and the benefits of mutual resemblance in spreading the mortality cost of educating predators over a larger prey assemblage. Comimetic species evolve highly similar colour patterns, but such convergence may interfere with intraspecific signalling and recognition in the prey community, especially for species involved in polymorphic mimicry. Using spectrophotometry measures, we investigated the variation in wing coloration among comimetic butterflies from distantly related lineages. We focused on seven morphs of the polymorphic species Heliconius numata and the seven corresponding comimetic species from the genus Melinaea. Significant differences in the yellow, orange and black patches of the wing were detected between genera. Perceptions of these cryptic differences by bird and butterfly observers were then estimated using models of animal vision based on physiological data. Our results showed that the most strikingly perceived differences were obtained for the contrast of yellow against a black background. The capacity to discriminate between comimetic genera based on this colour contrast was also evaluated to be higher for butterflies than for birds, suggesting that this variation in colour, likely undetectable to birds, might be used by butterflies for distinguishing mating partners without losing the benefits of mimicry. The evolution of wing colour in mimetic butterflies might thus be shaped by the opposite selective pressures exerted by predation and species recognition. PMID:24444083

  8. Eyeglasses for Vision Correction

    MedlinePlus

    ... Stories Español Eye Health / Glasses & Contacts Eyeglasses for Vision Correction Dec. 12, 2015 Wearing eyeglasses is an easy way to correct refractive errors. Improving your vision with eyeglasses offers the opportunity to select from ...

  9. Chemicals Industry Vision

    SciTech Connect

    none,

    1996-12-01

    Chemical industry leaders articulated a long-term vision for the industry, its markets, and its technology in the groundbreaking 1996 document Technology Vision 2020 - The U.S. Chemical Industry. (PDF 310 KB).

  10. Color vision test

    MedlinePlus

    ... from birth) color vision problems: Achromatopsia -- complete color blindness , seeing only shades of gray Deuteranopia -- difficulty telling ... test -- color; Ishihara color vision test Images Color blindness tests References Adams AJ, Verdon WA, Spivey BE. ...

  11. Ultraviolet vision and foraging in dip and plunge diving birds.

    PubMed

    Håstad, Olle; Ernstdotter, Emma; Odeen, Anders

    2005-09-22

    Many fishes are sensitive to ultraviolet (UV) light and display UV markings during courtship. As UV scatters more than longer wavelengths of light, these signals are only effective at short distances, reducing the risk of detection by swimming predators. Such underwater scattering will be insignificant for dip and plunge diving birds, which prey on fishes just below the water surface. One could therefore expect to find adaptations in the eyes of dip and plunge diving birds that tune colour reception to UV signals. We used a molecular method to survey the colour vision tuning of five families of dip or plunge divers and compared the results with those from sister taxa of other foraging methods. We found evidence of extended UV vision only in gulls (Laridae). Based on available evidence, it is more probable that this trait is associated with their terrestrial foraging habits rather than piscivory. PMID:17148194

  12. 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…

  13. Colour measurements of all ceramic crown systems.

    PubMed

    Rosenstiel, S F; Porter, S S; Johnston, W M

    1989-09-01

    The objectives of this study were: (i) to determine variability among colour parameters of five different ceramic crown systems; and (ii) to measure the effect of using coloured luting agents on restoration colour. The crown systems studied were Cerestore, Dicor, Hi-Ceram, Renaissance, and Vitadur-N. Five crowns for each system were made according to manufacturer's instructions with the same nominal shade (Vita Lumin Vacuum A2) to fit an Ivorine central incisor tooth. Restoration thickness was adjusted to within +/- 0.1 mm (+/- 0.05 mm in the mid-facial area where colour measurements were to be made) with the aid of a dial calliper prior to glazing or, in the case of Dicor, surface staining. Where a core was part of the system this was fabricated to the minimum recommended thickness. The crowns were cemented using luting agents of five different colours in a randomly chosen sequence. The colour of each restoration/cement combination was measured three times using a small-area colorimeter (Minolta CR-121). The variance of each colour parameter (L*, a*, b*) was statistically compared for each crown system using an analysis of variance procedure, as was the effect of the cement. Observed differences were related to visual perception by using the colour difference formula. There were statistically significant differences among the variances of the crown systems and the cements, with significant interactions between crown systems and direction of colour and between cement and direction of colour. Restorations made with different ceramic crown systems had noticeably different colour despite having the same nominal shade. Changing the shade of the luting agent had a perceivable effect on Dicor crowns and, to a lesser extent, on Vitadur-N crowns but not on the other systems due, presumably, to the opacity of their core materials. PMID:2809851

  14. Robot Vision Library

    NASA Technical Reports Server (NTRS)

    Howard, Andrew B.; Ansar, Adnan I.; Litwin, Todd E.; Goldberg, Steven B.

    2009-01-01

    The JPL Robot Vision Library (JPLV) provides real-time robot vision algorithms for developers who are not vision specialists. The package includes algorithms for stereo ranging, visual odometry and unsurveyed camera calibration, and has unique support for very wideangle lenses

  15. The visually impaired child.

    PubMed

    Thompson, Lisa; Kaufman, Lawrence M

    2003-02-01

    This article discusses the causes of childhood blindness and how the primary care provider may begin the appropriate steps toward diagnosing and managing the visually impaired child. Community resources (see Box 3) and low-vision programs in schools should be used so that parents do not need to reinvent strategies to raise a blind child. Worldwide, childhood blindness, which places is a tremendous burden on families and communities of the third world, is mostly preventable with improved hygiene, diet, and immunization. PMID:12713115

  16. Development of specifications for caramel colours.

    PubMed

    Licht, B H; Shaw, K; Smith, C; Mendoza, M; Orr, J; Myers, D V

    1992-05-01

    Specifications have been developed to define each of the four classes of caramel colour. The specifications were based on analysis of a large database generated during the course of characterization studies of each of the classes. A series of simple and practical tests was developed for the analysis of caramel colour samples to ensure conformity to the specifications. PMID:1644379

  17. A novel colour-sensitive CMOS detector

    NASA Astrophysics Data System (ADS)

    Langfelder, G.; Longoni, A.; Zaraga, F.

    2009-10-01

    A novel colour-sensitive semiconductor detector is proposed. The device (named Transverse Field Detector (TFD)) can be used to measure the colour of the incident light without any colour filter. The device is completely compatible with standard CMOS processes and is suitable to be integrated in a pixel array for imaging purposes. The working principle is based on the capability of this device to collect at different superficial junctions the carriers, generated at different depths, by means of suitable transverse electric fields. The transverse components of the electric field are generated inside the depleted region by a suitable bias of the superficial junctions. Thanks to the differences in the light absorption coefficients at different wavelengths, the device performs colour separation. Among the advantages of this approach are the capability of an active tuning of the pixel colour response, which can be obtained just by changing the biasing values of collecting junctions, and foreseen higher colour fidelity, thanks to the easy extension to four colour pixels. First test structures of three colours TFD pixels were designed and built in a standard CMOS 90 nm technology. Operative principles of the device and first experimental results are presented.

  18. Application of graph colouring to biological networks.

    PubMed

    Khor, S

    2010-05-01

    The author explores the application of graph colouring to biological networks, specifically protein-protein interaction (PPI) networks. First, the author finds that given similar conditions (i.e. graph size, degree distribution and clustering), fewer colours are needed to colour disassortative than assortative networks. Fewer colours create fewer independent sets which in turn imply higher concurrency potential for a network. Since PPI networks tend to be disassortative, the author suggests that in addition to functional specificity and stability proposed previously by Maslov and Sneppen (Science, 296, 2002), the disassortative nature of PPI networks may promote the ability of cells to perform multiple, crucial and functionally diverse tasks concurrently. Second, because graph colouring is closely related to the presence of cliques in a graph, the significance of node colouring information to the problem of identifying protein complexes (dense subgraphs in PPI networks), is investigated. The author finds that for PPI networks where 1-11% of nodes participate in at least one identified protein complex, such as H. sapien, DSATUR (a well-known complete graph colouring algorithm) node colouring information can improve the quality (homogeneity and separation) of initial candidate complexes. This finding may help improve existing protein complex detection methods, and/or suggest new methods. [Includes supplementary material]. PMID:20499999

  19. Representing Object Colour in Language Comprehension

    ERIC Educational Resources Information Center

    Connell, Louise

    2007-01-01

    Embodied theories of cognition hold that mentally representing something "red" engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task…

  20. Colour mathematics: with graphs and numbers

    NASA Astrophysics Data System (ADS)

    Lo Presto, Michael C.

    2009-07-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just attempting to memorize them.

  1. Colour Mathematics: With Graphs and Numbers

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2009-01-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just…

  2. Brilliant Colours from a White Snow Cover

    ERIC Educational Resources Information Center

    Vollmer, Michael; Shaw, Joseph A

    2013-01-01

    Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not…

  3. Microwave vision for robots

    NASA Technical Reports Server (NTRS)

    Lewandowski, Leon; Struckman, Keith

    1994-01-01

    Microwave Vision (MV), a concept originally developed in 1985, could play a significant role in the solution to robotic vision problems. Originally our Microwave Vision concept was based on a pattern matching approach employing computer based stored replica correlation processing. Artificial Neural Network (ANN) processor technology offers an attractive alternative to the correlation processing approach, namely the ability to learn and to adapt to changing environments. This paper describes the Microwave Vision concept, some initial ANN-MV experiments, and the design of an ANN-MV system that has led to a second patent disclosure in the robotic vision field.

  4. Programming parallel vision algorithms

    SciTech Connect

    Shapiro, L.G.

    1988-01-01

    Computer vision requires the processing of large volumes of data and requires parallel architectures and algorithms to be useful in real-time, industrial applications. The INSIGHT dataflow language was designed to allow encoding of vision algorithms at all levels of the computer vision paradigm. INSIGHT programs, which are relational in nature, can be translated into a graph structure that represents an architecture for solving a particular vision problem or a configuration of a reconfigurable computational network. The authors consider here INSIGHT programs that produce a parallel net architecture for solving low-, mid-, and high-level vision tasks.

  5. Computational approaches to vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1986-01-01

    Vision is examined in terms of a computational process, and the competence, structure, and control of computer vision systems are analyzed. Theoretical and experimental data on the formation of a computer vision system are discussed. Consideration is given to early vision, the recovery of intrinsic surface characteristics, higher levels of interpretation, and system integration and control. A computational visual processing model is proposed and its architecture and operation are described. Examples of state-of-the-art vision systems, which include some of the levels of representation and processing mechanisms, are presented.

  6. Principles of modern low vision rehabilitation.

    PubMed

    Markowitz, Samuel N

    2006-06-01

    Low vision rehabilitation is a new emerging subspecialty drawing from the traditional fields of ophthalmology, optometry, occupational therapy, and sociology, with an ever-increasing impact on our customary concepts of research, education, and services for the visually impaired patient. A multidisciplinary approach and coordinated effort are necessary to take advantage of new scientific advances and achieve optimal results for the patient. Accordingly, the intent of this paper is to outline the principles and details of a modern low vision rehabilitation service. All rehabilitation attempts must start with a first hand interview (the intake) for assessing functionality and priority tasks for rehabilitation, as well as assessing the patient's all-important cognitive skills. The assessment of residual visual functions follows the intake and offers a unique opportunity to measure, evaluate, and document accurately the extent of functional loss sustained by the patient from disease. An accurate assessment of residual visual functions includes assessment of visual acuity, contrast sensitivity, binocularity, refractive errors, perimetry, oculomotor functions, cortical visual integration, and light characteristics affecting visual functions. Functional vision assessment in low vision rehabilitation measures how well one uses residual visual functions to perform routine tasks, using different items under various conditions, throughout the day. Of the many functional vision skills known, reading skills is an obligatory item for all low vision rehabilitation assessments. Results of assessment guide rehabilitation professionals in developing rehabilitation plans for the individual and recommending appropriate low vision devices. The outcome from assessing residual visual functions is detection of visual functions that can be improved with the use of optical devices. Methods for prescribing devices such as image relocation with prisms to a preferred retinal locus, field

  7. Colour in insect thermoregulation: empirical and theoretical tests in the colour-changing grasshopper, Kosciuscola tristis.

    PubMed

    Umbers, K D L; Herberstein, M E; Madin, J S

    2013-01-01

    Body colours can result in different internal body temperatures, but evidence for the biological significance of colour-induced temperature differences is inconsistent. We investigated the relationship between body colour and temperature in a model insect species that rapidly changes colour. We used an empirical approach and constructed a heat budget model to quantify whether a colour change from black to turquoise has a role in thermoregulation for the chameleon grasshopper (Kosciuscola tristis). Our study shows that colour change in K. tristis provides relatively small temperature differences that vary greatly with wind speed (0.55 °C at ms(-1) to 0.05 °C at 10 ms(-1)). The biological significance of this difference is unclear and we discuss the requirement for more studies that directly test hypotheses regarding the fitness effects of colour in manipulating body temperature. PMID:23108152

  8. Measurement and prediction of pork colour.

    PubMed

    Van Oeckel, M J; Warnants, N; Boucqué, C V

    1999-08-01

    The extent to which instrumental colour determinations by FOPu (light scattering), Göfo (reflectance) and Labscan II (CIE L*, CIE a* and CIE b*, hue and chroma) are related to the Japanese colour grades was studied. Additionally, four on-line methods: pH1, FOP1, PQM1 (conductivity) and DDLT (Double Density Light Transmission, analogous to Capteur Gras/Maigre), were evaluated for their ability to predict subjectively and objectively colour. One hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were analysed. Of the instrumental colour determinations, CIE L* (r=-0.82), FOPu (r=-0.70) and Göfo (r=0.70) were best correlated with the Japanese colour scores. The Japanese colour grades could be predicted by the on-line instruments, pH1, FOP1, PQM1 and DDLT, with determination coefficients between 15 and 28%. Ultimate meat colour, determined by Japanese colour standards, FOPu, Göfo and CIE L*, was better predicted by DDLT than by the classic on-line instruments: FOP1, pH1 and PQM1, although the standard error of the estimate was similar for all instruments. This means that DDLT, although originally designed for estimating lean meat percentage, can additionally give information about meat quality, in particular colour. However, it must be stressed that the colour estimate by DDLT refers to a population of animals, rather than to individual pigs, because of the number of erroneously assigned samples. PMID:22062695

  9. Physicochemical and physiological basis of dichromatic colour

    NASA Astrophysics Data System (ADS)

    Kreft, Samo; Kreft, Marko

    2007-11-01

    Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum.

  10. Physicochemical and physiological basis of dichromatic colour.

    PubMed

    Kreft, Samo; Kreft, Marko

    2007-11-01

    Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum. PMID:17534588

  11. Artificial selection for food colour preferences

    PubMed Central

    Cole, Gemma L.; Endler, John A.

    2015-01-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection. PMID:25740894

  12. Artificial selection for food colour preferences.

    PubMed

    Cole, Gemma L; Endler, John A

    2015-04-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection. PMID:25740894

  13. Colouration and colour changes of the fiddler crab, Uca capricornis: a descriptive study.

    PubMed

    Detto, Tanya; Hemmi, Jan M; Backwell, Patricia R Y

    2008-01-01

    Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition. PMID:18286186

  14. Colouration and Colour Changes of the Fiddler Crab, Uca capricornis: A Descriptive Study

    PubMed Central

    Detto, Tanya; Hemmi, Jan M.; Backwell, Patricia R. Y.

    2008-01-01

    Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition. PMID:18286186

  15. Improving Access to Vision Care for People Who are Homeless through Eyeglasses Recycling.

    PubMed

    Lam, Janna; Robertson, Kirstin; Robertson, Wesley; Bernstein, Rebecca

    2015-11-01

    Visual impairment disproportionately affects the health and function of people who are homeless. A common and correctable cause of visual impairment is refractive error. However, eyeglasses remain an unmet need for the poor and underinsured. This report describes eyeglasses recycling and vision screening to reduce the burden of correctable visual impairment. PMID:26548683

  16. Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range.

    PubMed

    Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M; Althaus, Betty; Anil, Selin; Dael, Nele

    2016-01-01

    Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally. PMID:27022909

  17. Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range

    PubMed Central

    Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M.; Althaus, Betty; Anil, Selin; Dael, Nele

    2016-01-01

    Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally. PMID:27022909

  18. The colour wheels of art, perception, science and physiology

    NASA Astrophysics Data System (ADS)

    Harkness, Nick

    2006-06-01

    Colour is not the domain of any one discipline be it art, philosophy, psychology or science. Each discipline has its own colour wheel and this presentation examines the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology (after image) with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell. The paper analyses and discusses the differences between the four colour wheels using the Natural Colour System® notation as the reference for hue (the position of colours within each of the colour wheels). Examination of the colour wheels shows the dominance of blue in the wheels of art, science and physiology particularly at the expense of green. This paper does not consider the three-dimensionality of colour space its goal was to review the hue of a colour with regard to its position on the respective colour wheels.

  19. Drug-induced hair colour changes.

    PubMed

    Bublin, J G; Thompson, D F

    1992-10-01

    Drug-induced hair colour changes are not a common adverse effect from medications. A wide variety of drugs have been implicated in causing hair colour changes but very few have data to support a true relationship. Of the drugs reported, chloroquine and cancer chemotherapeutic agents have the best evidence to support an association. Other drugs, such as p-aminobenzoic acid, calcium pantothenate, anthralin, chinoform, mephenesin, minoxidil, propofol, valproic acid, and verapamil await confirmatory data. Drug-induced causes should be considered in any patient with unexplained hair colour changes. PMID:1464633

  20. Mathematical leadership vision.

    PubMed

    Hamburger, Y A

    2000-11-01

    This article is an analysis of a new type of leadership vision, the kind of vision that is becoming increasingly pervasive among leaders in the modern world. This vision appears to offer a new horizon, whereas, in fact it delivers to its target audience a finely tuned version of the already existing ambitions and aspirations of the target audience. The leader, with advisors, has examined the target audience and has used the results of extensive research and statistical methods concerning the group to form a picture of its members' lifestyles and values. On the basis of this information, the leader has built a "vision." The vision is intended to create an impression of a charismatic and transformational leader when, in fact, it is merely a response. The systemic, arithmetic, and statistical methods employed in this operation have led to the coining of the terms mathematical leader and mathematical vision. PMID:11092414

  1. FPGA Vision Data Architecture

    NASA Technical Reports Server (NTRS)

    Morfopoulos, Arin C.; Pham, Thang D.

    2013-01-01

    JPL has produced a series of FPGA (field programmable gate array) vision algorithms that were written with custom interfaces to get data in and out of each vision module. Each module has unique requirements on the data interface, and further vision modules are continually being developed, each with their own custom interfaces. Each memory module had also been designed for direct access to memory or to another memory module.

  2. Vision and falls in older people: risk factors and intervention strategies.

    PubMed

    Lord, Stephen R; Smith, Stuart T; Menant, Jasmine C

    2010-11-01

    Poor vision impairs balance and increases the risk of falls and fractures in older people. Multifocal glasses can add to this risk by impairing contrast sensitivity, depth perception, and ability to negotiate obstacles. Vision assessment and provision of new spectacles may not reduce, and may even increase, the risk of falls. Restriction of the use of multifocal glasses may reduce falls in active older people. Other effective fall prevention strategies include maximizing vision through cataract surgery and occupational therapy interventions in visually impaired older people. PMID:20934611

  3. Cortical Visual Impairment: New Directions

    PubMed Central

    Good, William V.

    2009-01-01

    Cortical visual impairment is the leading cause of bilateral low vision in children in the U.S., yet very little research is being done to find new diagnostic measures and treatments. Dr. Velma Dobson's pioneering work on visual assessments of developmentally delayed children stands out as highly significant in this field. Future research will assess new diagnostic measures, including advanced imaging techniques. In addition, research will evaluate methods to prevent, treat, and rehabilitate infants and children afflicted with this condition. PMID:19417710

  4. Why colour in subterranean vertebrates? Exploring the evolution of colour patterns in caecilian amphibians.

    PubMed

    Wollenberg, K C; Measey, C John

    2009-05-01

    The proximate functions of animal skin colour are difficult to assign as they can result from natural selection, sexual selection or neutral evolution under genetic drift. Most often colour patterns are thought to signal visual stimuli; so,their presence in subterranean taxa is perplexing. We evaluate the adaptive nature of colour patterns in nearly a third of all known species of caecilians, an order of amphibians most of which live in tropical soils and leaf litter. We found that certain colour pattern elements in caecilians can be explained based on characteristics concerning above-ground movement. Our study implies that certain caecilian colour patterns have convergently evolved under selection and we hypothesize their function most likely to be a synergy of aposematism and crypsis, related to periods when individuals move overground. In a wider context, our results suggest that very little exposure to daylight is required to evolve and maintain a varied array of colour patterns in animal skin. PMID:21462404

  5. Artificial human vision camera

    NASA Astrophysics Data System (ADS)

    Goudou, J.-F.; Maggio, S.; Fagno, M.

    2014-10-01

    In this paper we present a real-time vision system modeling the human vision system. Our purpose is to inspire from human vision bio-mechanics to improve robotic capabilities for tasks such as objects detection and tracking. This work describes first the bio-mechanical discrepancies between human vision and classic cameras and the retinal processing stage that takes place in the eye, before the optic nerve. The second part describes our implementation of these principles on a 3-camera optical, mechanical and software model of the human eyes and associated bio-inspired attention model.

  6. The Social Lives of Canadian Youths with Visual Impairments

    ERIC Educational Resources Information Center

    Gold, Deborah; Shaw, Alexander; Wolffe, Karen

    2010-01-01

    This survey of the social and leisure experiences of Canadian youths with visual impairments found that, in general, youths with low vision experienced more social challenges than did their peers who were blind. Levels of social support were not found to differ on the basis of level of vision, sex, or age. (Contains 1 figure and 1 table.)

  7. A Roadmap for Interpreting the Literature on Vision and Driving

    PubMed Central

    Owsley, Cynthia; Wood, Joanne M.; McGwin, Gerald

    2015-01-01

    Over the past several decades there has been a sharp increase in the number of studies focused on the relationship between vision and driving. The intensified scientific attention to this topic has most likely been stimulated by the lack of an evidence-basis for determining vision standards for driving licensure and a poor understanding about how vision impairment impacts driver safety and performance. Clinicians depend on the scientific literature on vision and driving as a resource to appropriately advise visually impaired patients about driving fitness. Policy makers also depend on the scientific literature in order to develop guidelines that are evidence-based and are thus fair to persons who are visually impaired. Thus it is important for clinicians and policy makers alike to understand how various study designs and measurement methods should be appropriately interpreted so that the conclusions and recommendations they make based on this literature are not overly broad, too narrowly constrained, or even misguided. In this overview, based on our 25 years of experience in this field, we offer a methodological framework to guide interpretations of studies on vision and driving, which can also serve as a heuristic for researchers in the area. Here we discuss research designs and general measurement methods for the study of vision as they relate to driver safety, driver performance, and driver-centered (self-reported) outcomes. PMID:25753389

  8. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  9. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  10. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  11. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  12. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  13. Plants and colour: Flowers and pollination

    NASA Astrophysics Data System (ADS)

    Miller, Renee; Owens, Simon J.; Rørslett, Bjørn

    2011-03-01

    While there is a range of colours found in plants the predominant colour is green. Pigments in plants have several roles e.g. photosynthesis and signalling. If colour is to be used as a signal then it must stand out from green. However, one should be aware that there are also coloured compounds where we have not yet fully investigated the role of colour in their functions—they may have roles in, for example, defence or heat exchange. In this paper, we will describe the basic chemistry of the major pigments found in plants and especially floral pigments. We will then discuss their locations in parts of the flower (such as sepals, petals, pollen and nectar), the cells in which they are found and their sub-cellular locations. Floral pigments have a large role to play in pollination of flowers by animals. They can and are modified in many ways during the development of flowers in nature, for example, at emergence and post-pollination. There are a range of biochemical mechanisms of colour change both within flowers and in isolated pigments. Some of the factors influencing colour are temperature, co-pigments, pH, metals, sugars, anthocyanin stacking and cell shape. There is a renewed interest in analysing floral pigments and how they are modified partly because of advances in recombinant DNA technologies, but also because of pollinators and their significance to biodiversity and for evolutionary studies. There is continued strong interest from the horticultural industry for the introduction of new colours e.g. the blue rose and for the exploitation of natural dyes. Funding in this area may impact future research in a potentially beneficial way but it must not deflect us from science-based conservation.

  14. Caramel colours--a historical introduction.

    PubMed

    Chappel, C I; Howell, J C

    1992-05-01

    Caramel colours used in the manufacture of a wide variety of foods and beverages have been an item of commerce for more than one hundred years. The regulatory history of these additives in the US, the UK, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the EC is reviewed, and an introduction to the safety studies of caramel colours in this issue of Food and Chemical Toxicology is provided. PMID:1644375

  15. Colour preferences of juvenile turbot (Scophthalmus maximus).

    PubMed

    Li, Xian; Chi, Liang; Tian, Huiqin; Meng, Lingjie; Zheng, Jimeng; Gao, Xiaolong; Liu, Ying

    2016-03-15

    The background colour of aquaculture tanks is normally chosen based on practical experience and/or observations of fish behaviour and the growth rates achieved. However, some farmed species, including turbot, are sentient and can show a preference for a particular environment. In the current study, a self-referent colour preference device was developed and the self-referent colour preference of farmed fish investigated. In experiment 1, the background colour preference of juvenile turbot cultured under a grey background for >3months post-incubation was evaluated. Based on these results, in experiment 2, juvenile turbot were adapted to blue, pink, white, or black backgrounds for 50days and their preferences established. Meanwhile, the growth rates, feed intake, and metabolic rates (including oxygen consumption rate, and ammonia excretion rate) of the turbot were evaluated. The results showed that turbot farmed under a grey background, or after long-term white, blue, pink and black colour adaptation, always displayed a preference for a white background and a dislike for black, red, or brown backgrounds, although their body colour was greyish. Long-term adaptation influenced the frequency of juveniles selecting white, black, pink or blue backgrounds. They showed the highest growth rate, feed intake, and metabolic rates under blue and white backgrounds, and the lowest under a black background in accordance with their preferences shown in experiment 1. Although it is unclear how turbot determine their self-referent colour preferences over such a short period of time, these results indicate that dark colours are unsuitable for the aquaculture of turbot culture in terms of the welfare of the fish. PMID:26792527

  16. THE COLOUR GLASS CONDENSATE: AN INTRODUCTION

    SciTech Connect

    IANCU,E.; LEONIDOV,A.; MCLERRAN,L.

    2001-08-06

    In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory.

  17. Composition of a Vision Screen for Servicemembers With Traumatic Brain Injury: Consensus Using a Modified Nominal Group Technique

    PubMed Central

    Finkelstein, Marsha; Llanos, Imelda; Scheiman, Mitchell; Wagener, Sharon Gowdy

    2014-01-01

    Vision impairment is common in the first year after traumatic brain injury (TBI), including among service members whose brain injuries occurred during deployment in Iraq and Afghanistan. Occupational therapy practitioners provide routine vision screening to inform treatment planning and referral to vision specialists, but existing methods are lacking because many tests were developed for children and do not screen for vision dysfunction typical of TBI. An expert panel was charged with specifying the composition of a vision screening protocol for servicemembers with TBI. A modified nominal group technique fostered discussion and objective determinations of consensus. After considering 29 vision tests, the panel recommended a nine-test vision screening that examines functional performance, self-reported problems, far–near acuity, reading, accommodation, convergence, eye alignment and binocular vision, saccades, pursuits, and visual fields. Research is needed to develop reliable, valid, and clinically feasible vision screening protocols to identify TBI-related vision disorders in adults. PMID:25005505

  18. Not so colourful after all: eggshell pigments constrain avian eggshell colour space.

    PubMed

    Hanley, Daniel; Grim, Tomáš; Cassey, Phillip; Hauber, Mark E

    2015-05-01

    Birds' eggshells are renowned for their striking colours and varied patterns. Although often considered exceptionally diverse, we report that avian eggshell coloration, sampled here across the full phylogenetic diversity of birds, occupies only 0.08-0.10% of the avian perceivable colour space. The concentrations of the two known tetrapyrrole eggshell pigments (protoporphyrin and biliverdin) are generally poor predictors of colour, both intra- and interspecifically. Here, we show that the constrained diversity of eggshell coloration can be accurately predicted by colour mixing models based on the relative contribution of both pigments and we demonstrate that the models' predictions can be improved by accounting for the reflectance of the eggshell's calcium carbonate matrix. The establishment of these proximate links between pigmentation and colour will enable future tests of hypotheses on the functions of perceived avian eggshell colours that depend on eggshell chemistry. More generally, colour mixing models are not limited to avian eggshell colours but apply to any natural colour. Our approach illustrates how modelling can aid the understanding of constraints on phenotypic diversity. PMID:25994009

  19. Not so colourful after all: eggshell pigments constrain avian eggshell colour space

    PubMed Central

    Hanley, Daniel; Grim, Tomáš; Cassey, Phillip; Hauber, Mark E.

    2015-01-01

    Birds' eggshells are renowned for their striking colours and varied patterns. Although often considered exceptionally diverse, we report that avian eggshell coloration, sampled here across the full phylogenetic diversity of birds, occupies only 0.08–0.10% of the avian perceivable colour space. The concentrations of the two known tetrapyrrole eggshell pigments (protoporphyrin and biliverdin) are generally poor predictors of colour, both intra- and interspecifically. Here, we show that the constrained diversity of eggshell coloration can be accurately predicted by colour mixing models based on the relative contribution of both pigments and we demonstrate that the models' predictions can be improved by accounting for the reflectance of the eggshell's calcium carbonate matrix. The establishment of these proximate links between pigmentation and colour will enable future tests of hypotheses on the functions of perceived avian eggshell colours that depend on eggshell chemistry. More generally, colour mixing models are not limited to avian eggshell colours but apply to any natural colour. Our approach illustrates how modelling can aid the understanding of constraints on phenotypic diversity. PMID:25994009

  20. Understanding WCAG2.0 Colour Contrast Requirements Through 3D Colour Space Visualisation.

    PubMed

    Sandnes, Frode Eika

    2016-01-01

    Sufficient contrast between text and background is needed to achieve sufficient readability. WCAG2.0 provides a specific definition of sufficient contrast on the web. However, the definition is hard to understand and most designers thus use contrast calculators to validate their colour choices. Often, such checks are performed after design and this may be too late. This paper proposes a colour selection approach based on three-dimensional visualisation of the colour space. The complex non-linear relationships between the colour components become comprehendible when viewed in 3D. The method visualises the available colours in an intuitive manner and allows designers to check a colour against the set of other valid colours. Unlike the contrast calculators, the proposed method is proactive and fun to use. A colour space builder was developed and the resulting models were viewed with a point cloud viewer. The technique can be used as both a design tool and a pedagogical aid to teach colour theory and design. PMID:27534328

  1. Low vision goggles: optical design studies

    NASA Astrophysics Data System (ADS)

    Levy, Ofer; Apter, Boris; Efron, Uzi

    2006-08-01

    Low Vision (LV) due to Age Related Macular Degeneration (AMD), Glaucoma or Retinitis Pigmentosa (RP) is a growing problem, which will affect more than 15 million people in the U.S alone in 2010. Low Vision Aid Goggles (LVG) have been under development at Ben-Gurion University and the Holon Institute of Technology. The device is based on a unique Image Transceiver Device (ITD), combining both functions of imaging and Display in a single chip. Using the ITD-based goggles, specifically designed for the visually impaired, our aim is to develop a head-mounted device that will allow the capture of the ambient scenery, perform the necessary image enhancement and processing, and re-direct it to the healthy part of the patient's retina. This design methodology will allow the Goggles to be mobile, multi-task and environmental-adaptive. In this paper we present the optical design considerations of the Goggles, including a preliminary performance analysis. Common vision deficiencies of LV patients are usually divided into two main categories: peripheral vision loss (PVL) and central vision loss (CVL), each requiring different Goggles design. A set of design principles had been defined for each category. Four main optical designs are presented and compared according to the design principles. Each of the designs is presented in two main optical configurations: See-through system and Video imaging system. The use of a full-color ITD-Based Goggles is also discussed.

  2. Monozygotic twins' colour-number association: a case study.

    PubMed

    Hancock, Peter

    2006-02-01

    A case study of a pair of monozygotic twins, both of whom show a strong and enduring colour-number association, is reported. The origin of the colours, in a jigsaw puzzle, is known. Neither reports conscious photisms typical of synaesthesia, but a Stroop task of naming the colours of digits shows an interference effect with incongruent colours. PMID:16683487

  3. Salience of Primary and Secondary Colours in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Pitchford, Nicola; Hart, Lynsey; Davies, Ian R. L.; Clausse, Samantha; Jennings, Siobhan

    2008-01-01

    Primary colour terms ("black", "white", "red", "green", "yellow", and "blue") are more fundamental in colour language than secondary colour terms ("pink", "purple", "orange", "brown", and "grey"). Here, we assess whether this distinction exists in the absence of language, by investigating whether primary colours attract and sustain preverbal…

  4. Vision and vision-related outcome measures in multiple sclerosis

    PubMed Central

    Balcer, Laura J.; Miller, David H.; Reingold, Stephen C.

    2015-01-01

    Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis. PMID:25433914

  5. Vision and vision-related outcome measures in multiple sclerosis.

    PubMed

    Balcer, Laura J; Miller, David H; Reingold, Stephen C; Cohen, Jeffrey A

    2015-01-01

    Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis. PMID:25433914

  6. [What do you actually see? Visual impairments and their simulation for well-seeing subjects].

    PubMed

    de Jong, P T

    2003-12-20

    Most physicians know little about how persons with limited vision perceive something. Sometimes, simple technical aids can make it possible to get an idea as to what a visual disorder means to the person involved. Examples of this are the wearing of glasses of varying positive power and light transmittance, or the study of case histories, paintings and photographic simulations. Among the latter are a woman who painted what she 'saw' with her removed eye, an anophthalmic man who painted from memory, and the painting of a protanopic artist who chose colours by reading the labels on the paint tubes. Thus one may gain insight in disturbances such as phantom images, diminished visual acuity and visual field loss, metamorphopsia, diplopia, dazzling, and visual agnosia. And also in disturbed image fusion, in depth and stereoscopic vision, dark adaptation and colour vision, as well as diminishing visual functions at high age. This article contains colour illustrations that simulate the disturbances. PMID:14735855

  7. Positive emotion can protect against source memory impairment.

    PubMed

    MacKenzie, Graham; Powell, Tim F; Donaldson, David I

    2015-01-01

    Despite widespread belief that memory is enhanced by emotion, evidence also suggests that emotion can impair memory. Here we test predictions inspired by object-based binding theory, which states that memory enhancement or impairment depends on the nature of the information to be retrieved. We investigated emotional memory in the context of source retrieval, using images of scenes that were negative, neutral or positive in valence. At study each scene was paired with a colour and during retrieval participants reported the source colour for recognised scenes. Critically, we isolated effects of valence by equating stimulus arousal across conditions. In Experiment 1 colour borders surrounded scenes at study: memory impairment was found for both negative and positive scenes. Experiment 2 used colours superimposed over scenes at study: valence affected source retrieval, with memory impairment for negative scenes only. These findings challenge current theories of emotional memory by showing that emotion can impair memory for both intrinsic and extrinsic source information, even when arousal is equated between emotional and neutral stimuli, and by dissociating the effects of positive and negative emotion on episodic memory retrieval. PMID:24784151

  8. Color vision deficiencies

    NASA Astrophysics Data System (ADS)

    Vannorren, D.

    1982-04-01

    Congenital and acquired color vision defects are described in the context of physiological data. Light sources, photometry, color systems and test methods are described. A list of medicines is also presented. The practical social consequences of color vision deficiencies are discussed.

  9. Home vision tests

    MedlinePlus

    ... peripheral vision. All the lines, both vertical and horizontal, should appear straight and unbroken. They should meet ... You need a well-lit area at least 10 feet long for the distance vision test, and the following: Measuring tape or a ...

  10. Overview of computer vision

    SciTech Connect

    Gevarter, W.B.

    1982-09-01

    An overview of computer vision is provided. Image understanding and scene analysis are emphasized, and pertinent aspects of pattern recognition are treated. The basic approach to computer vision systems, the techniques utilized, applications, the current existing systems and state-of-the-art issues and research requirements, who is doing it and who is funding it, and future trends and expectations are reviewed.

  11. Synthesized night vision goggle

    NASA Astrophysics Data System (ADS)

    Zhou, Haixian

    2000-06-01

    A Synthesized Night Vision Goggle that will be described int his paper is a new type of night vision goggle with multiple functions. It consists of three parts: main observing system, picture--superimposed system (or Cathode Ray Tube system) and Charge-Coupled Device system.

  12. INSIGHT: Vision & Leadership, 2002.

    ERIC Educational Resources Information Center

    McGraw, Tammy, Ed.

    2002-01-01

    This publication focuses on promising new and emerging technologies and what they might mean to the future of K-12 schools. Half of the volume contains articles devoted in some way to "Vision," and articles in the other half are under the heading of "Leadership." Contents in the "Vision" section include: "The Future of Reading and Learning To…

  13. New Term, New Vision?

    ERIC Educational Resources Information Center

    Ravenhall, Mark

    2011-01-01

    During the affluent noughties it was sometimes said of government that it had "more visions than Mystic Meg and more pilots than British Airways". In 2011, the pilots, the pathfinders, the new initiatives are largely gone--implementation is the name of the game--but the visions remain. The latest one, as it affects adult learners, is in the…

  14. A Handheld LED Coloured-Light Mixer for Students to Learn Collaboratively the Primary Colours of Light

    ERIC Educational Resources Information Center

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

    2009-01-01

    To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny…

  15. Taking Care of Your Vision

    MedlinePlus

    ... a Friend Who Cuts? Taking Care of Your Vision KidsHealth > For Teens > Taking Care of Your Vision ... are important parts of keeping your peepers perfect. Vision Basics One of the best things you can ...

  16. Clinical Trials in Vision Research

    MedlinePlus

    ... Clinical Trials in Vision Research Clinical Trials in Vision Research Clinical studies depend on people who volunteer. ... about the treatment. How are clinical trials in vision different from other clinical trials? Eyes are one ...

  17. Panoramic stereo sphere vision

    NASA Astrophysics Data System (ADS)

    Feng, Weijia; Zhang, Baofeng; Röning, Juha; Zong, Xiaoning; Yi, Tian

    2013-01-01

    Conventional stereo vision systems have a small field of view (FOV) which limits their usefulness for certain applications. While panorama vision is able to "see" in all directions of the observation space, scene depth information is missed because of the mapping from 3D reference coordinates to 2D panoramic image. In this paper, we present an innovative vision system which builds by a special combined fish-eye lenses module, and is capable of producing 3D coordinate information from the whole global observation space and acquiring no blind area 360°×360° panoramic image simultaneously just using single vision equipment with one time static shooting. It is called Panoramic Stereo Sphere Vision (PSSV). We proposed the geometric model, mathematic model and parameters calibration method in this paper. Specifically, video surveillance, robotic autonomous navigation, virtual reality, driving assistance, multiple maneuvering target tracking, automatic mapping of environments and attitude estimation are some of the applications which will benefit from PSSV.

  18. A handheld LED coloured-light mixer for students to learn collaboratively the primary colours of light

    NASA Astrophysics Data System (ADS)

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

    2009-03-01

    To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny light-emitting diodes (LEDs) producing primary colours are combined with green intensity varying circuitry to generate the standard colour-triangle secondary colours and various shades ranging from yellow to orange and pale blue to cyan. In the laboratory, students worked collaboratively, predicting, observing and explaining, and finally discussing until there was a consensus.

  19. Machine vision is not computer vision

    NASA Astrophysics Data System (ADS)

    Batchelor, Bruce G.; Charlier, Jean-Ray

    1998-10-01

    The identity of Machine Vision as an academic and practical subject of study is asserted. In particular, the distinction between Machine Vision on the one hand and Computer Vision, Digital Image Processing, Pattern Recognition and Artificial Intelligence on the other is emphasized. The article demonstrates through four cases studies that the active involvement of a person who is sensitive to the broad aspects of vision system design can avoid disaster and can often achieve a successful machine that would not otherwise have been possible. This article is a transcript of the key- note address presented at the conference. Since the proceedings are prepared and printed before the conference, it is not possible to include a record of the response to this paper made by the delegates during the round-table discussion. It is hoped to collate and disseminate these via the World Wide Web after the event. (A link will be provided at http://bruce.cs.cf.ac.uk/bruce/index.html.).

  20. Near Vision Test for Adults

    MedlinePlus

    ... Eyes Education Series Online Training and Certification Patient Education Materials Star Pupils ... Test for Adults Testing Near Vision and Distance Vision Prevent Blindness does NOT recommend that you ...

  1. Sequential colour mapping system of brain potentials.

    PubMed

    Giard, M H; Peronnet, F; Pernier, J; Mauguiere, F; Bertrand, O

    1985-05-01

    We present a colour mapping system for the visualization of both the spatial scalp distribution and the temporal evolution of brain potentials. The system is applicable to recordings of auditory, visual and somatosensory potentials. It uses a Tektronix 4113 colour terminal connected to a Solar 16 (SEMS) mini-computer. The brain potentials are recorded on up to 16 scalp electrodes. The gain and the baseline are corrected separately on each channel. At each point of the scalp the potential is reconstructed by a linear interpolation of the measured potentials of the four nearest electrodes. Simultaneously n2 (1 less than n less than 8) colour maps can be presented on the screen. This allows the study of the temporal evolution of full scalp evoked potentials. The user chooses the two extreme latencies defining the time window to be explored and the latencies of the maps are regularly time-spaced within this window. In a typical case, in which four maps are desired, the latencies of the maps can be chosen independently. The 16-colour palette is predetermined but the user has three possibilities to establish the correspondence between the electrical potential and the colours. Examples are shown in the visual and somatosensory stimulation modalities. The advantages and limitations of such a representation are discussed. PMID:3849381

  2. Paramagnetism in colour superconductivity and compact stars

    NASA Astrophysics Data System (ADS)

    Ferrer, Efrain J.; de la Incera, Vivian

    2007-06-01

    It is quite plausible that colour superconductivity occurs in the inner regions of neutron stars. At the same time, it is known that strong magnetic fields exist in the interior of these compact objects. In this paper we discuss some important effects that can occur in the colour superconducting core of compact stars due to the presence of the stars' magnetic field. In particular, we consider the modification of the gluon dynamics for a colour superconductor with three massless quark flavours in the presence of an external magnetic field. We show that the long-range component of the external magnetic field that penetrates the colour-flavour locked phase produces an instability for field values larger than the charged gluons' Meissner mass. As a consequence, the ground state is restructured forming a vortex state characterized by the condensation of charged gluons and the creation of magnetic flux tubes. In the vortex state the magnetic field outside the flux tubes is equal to the applied one, while inside the tubes its strength increases by an amount that depends on the amplitude of the gluon condensate. This paramagnetic behaviour of the colour superconductor can be relevant for the physics of compact stars.

  3. A four-colour optical detector circuit

    NASA Astrophysics Data System (ADS)

    Yohannes, Israel; Assaad, Maher

    2013-02-01

    In this article, a new architecture for a four-colour optical detector circuit is presented. The proposed detector uses a photodiode as its basic light transducing element and a mixed signal readout circuit for signal processing and decision making. The readout circuit requires only two comparators, two multiplexers and a few logic gates to produce a digital 4 bit output that represents the right colour detected. The proposed detector is advantageous because the number of required components is fixed even if the number of detected colours is increased. The feature of having a fixed number of elements while increasing the number of detected colours is important especially in component count (i.e. low cost) and low power consumption. The proposed detector can be used as an autonomous and portable real-time pH monitoring applications. The objective of this article is to present a validation of a novel four colour sensor architecture using simulation and experiment as a proof of concept for a future implementation as a CMOS integrated circuit using the Austria Microsystems 350 nm technology.

  4. Colour inputs to random-dot stereopsis.

    PubMed

    Stuart, G W; Edwards, M; Cook, M L

    1992-01-01

    Recently it has been claimed by Livingstone and Hubel that, of three anatomically and functionally distinct visual channels (the magnocellular, parvocellular interblob, and blob channels), only the magnocellular channel is involved in the processing of stereoscopic depth. Since the magnocellular system shows little overt colour opponency, the reported loss of the ability to resolve random-dot stereograms defined only by colour contrast seems consistent with this view. However, Julesz observed that reversed-contrast stereograms could be fused if correlated colour information was added. In the present study, 'noise' (non-corresponding) pixels were injected into random-dot stereograms in order to increase fusion time. All six subjects tested were able to achieve stereopsis in less than three minutes when there was only correspondence in colour and not in luminance, and three when luminance contrast was completely reversed. This ability depends on information about the direction of colour contrast, not just the presence of chromatic borders. When luminance and chromatic contrast are defined in terms of signal-to-noise ratios at the photoreceptor mosaic, chromatic information plays at least as important a role in stereopsis as does luminance information, suggesting that the magnocellular channel is not uniquely involved. PMID:1297976

  5. Spelling Performance of Visually Impaired Adults

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos S.; Arvaniti, Evmorfia K.; Dimitriadi, Despina I.; Gkoutsioudi, Vasiliki G.; Zantali, Christina I.

    2009-01-01

    Visual processes undoubtedly play an important role in print reading as well as in spelling. In the present study we intend to compare the spelling performance of visually impaired individuals (both individuals who are blind and individuals with low vision) with that of their fully sighted peers. An analysis of errors (misspelled words and…

  6. Scalable, full-colour and controllable chromotropic plasmonic printing.

    PubMed

    Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

    2015-01-01

    Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates controllable chromotropic capability, that is, the ability of reversible colour transformations. This chromotropic capability affords enormous potentials in building functionalized prints for anticounterfeiting, special label, and high-density data encryption storage. With such excellent performances in functional colour applications, this colour-printing approach could pave the way for plasmonic colour printing in real-world commercial utilization. PMID:26567803

  7. Information Limits on Identification of Natural Surfaces by Apparent Colour

    PubMed Central

    Foster, David H.; Nascimento, Sérgio M. C.; Amano, Kinjiro

    2007-01-01

    By adaptational and other mechanisms, the visual system can compensate for moderate changes in the colour of the illumination on a scene. Although the colours of most surfaces are perceived to be constant (“colour constancy”), some are not. The effect of these residual colour changes on the ability of observers to identify surfaces by their apparent colour was determined theoretically from high-resolution hyperspectral images of natural scenes under different daylights with correlated colour temperatures 4300 K, 6500 K, and 25000 K. Perceived differences between colours were estimated with an approximately uniform colour-distance measure. The information preserved under illuminant changes increased with the number of surfaces in the sample, but was limited to a relatively low asymptotic value, indicating the importance of physical factors in constraining identification by apparent colour. PMID:16178155

  8. Scalable, full-colour and controllable chromotropic plasmonic printing

    PubMed Central

    Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

    2015-01-01

    Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates controllable chromotropic capability, that is, the ability of reversible colour transformations. This chromotropic capability affords enormous potentials in building functionalized prints for anticounterfeiting, special label, and high-density data encryption storage. With such excellent performances in functional colour applications, this colour-printing approach could pave the way for plasmonic colour printing in real-world commercial utilization. PMID:26567803

  9. Stereo vision and strabismus

    PubMed Central

    Read, J C A

    2015-01-01

    Binocular stereopsis, or stereo vision, is the ability to derive information about how far away objects are, based solely on the relative positions of the object in the two eyes. It depends on both sensory and motor abilities. In this review, I briefly outline some of the neuronal mechanisms supporting stereo vision, and discuss how these are disrupted in strabismus. I explain, in some detail, current methods of assessing stereo vision and their pros and cons. Finally, I review the evidence supporting the clinical importance of such measurements. PMID:25475234

  10. Stereo vision and strabismus.

    PubMed

    Read, J C A

    2015-02-01

    Binocular stereopsis, or stereo vision, is the ability to derive information about how far away objects are, based solely on the relative positions of the object in the two eyes. It depends on both sensory and motor abilities. In this review, I briefly outline some of the neuronal mechanisms supporting stereo vision, and discuss how these are disrupted in strabismus. I explain, in some detail, current methods of assessing stereo vision and their pros and cons. Finally, I review the evidence supporting the clinical importance of such measurements. PMID:25475234

  11. Knowledge and Use of Low Vision Services Among Persons with Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Casten, Robin J.; Maloney, Eileen K.; Rovner, Barry W.

    2005-01-01

    Visual impairment (blindness or low vision) is a leading cause of disability among older adults and is most often due to age-related macular degeneration (AMD). It is predicted that 2.95 million people will have AMD by 2020 (Eye Diseases Prevalence Research Group, 2004). Unfortunately, there is no cure for AMD, nor can lost vision be restored.…

  12. The Greatest Generation Meets Its Greatest Challenge: Vision Loss and Depression in Older Adults

    ERIC Educational Resources Information Center

    O'Donnell, Coleen

    2005-01-01

    Having lived through the Great Depression and World War II, older adults now face the challenge of vision loss in record numbers. Depression is closely associated with functional loss and social isolation in late-life vision loss. The principles of assisting those who are aging will also benefit those who are aging with a visual impairment. They…

  13. Use of a Noncycloplegic Autorefractor to Perform Vision Screening in Preschools

    ERIC Educational Resources Information Center

    Clarke, Noreen; Shacks, Janice; Kerr, Amanda R. E.; Bottrell, Christine L.; Poulsen, Marie Kanne; Yin, Larry

    2008-01-01

    Early detection and treatment of vision disorders in children are important to avoid lifelong visual impairment; however, preschool vision-screening rates are low. Traditional methods of screening lack the precision of objective tests and are difficult to administer in preschoolers. This study adopted a method using school nurses to conduct vision…

  14. Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Pollmann, Stefan

    2015-01-01

    Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental…

  15. Capturing natural-colour 3D models of insects for species discovery and diagnostics.

    PubMed

    Nguyen, Chuong V; Lovell, David R; Adcock, Matt; La Salle, John

    2014-01-01

    Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity-past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research

  16. Why simulations of colour for CVD observers might not be what they seem

    NASA Astrophysics Data System (ADS)

    Green, Phil

    2015-01-01

    A common task in universal design is to create a 'simulation' of the appearance of a colour image as it appears to a CVD observer. Although such simulations are useful in illustrating the particular problems that a CVD observer has in discriminating between colours in an image, it may not be reasonable to assume that such a simulation accurately conveys the experience of the CVD observer to an observer with normal vision. Two problems with this assumption are discussed here. First, it risks confusing appearance with sensation. A colour appearance model can more or less accurately predict the change in appearance of a colour when it is viewed under different conditions, but does not define the actual sensation. Such a sensation cannot be directly communicated but merely located on a scale with other related sensations. In practice we avoid this epistemological problem by asking observers to judge colour matches, relations and differences, none of which requires examination of the sensation itself. Since we do not truly know what sensation a normal observer experiences, it seems unscientific to suppose that we can do so for CVD observers. Secondly, and following from the above, the relation between stimulus and corresponding sensation is established as part of neural development during infancy, and while we can determine the stimulus we cannot readily determine what sensation the stimulus is mapped to, or what the available range of sensations is for a given observer. It is suggested that a similar range of sensations could be available to CVD observers as to normal observers.

  17. A Computerized System for Workplace Design for Visually Impaired Workers.

    ERIC Educational Resources Information Center

    Chen, J-G; Hou, C-A

    1991-01-01

    VITAL (Vision Impaired Task and Assignment Lexicon) is an integrated computerized system that performs workplace design tasks for visually impaired workers. VITAL consists of three modules: ergonomics consultation, disability index, and work measurement. Evaluation indicated that VITAL could be used as a tool to help nonprofessional vocational…

  18. Identity Development in German Adolescents with and without Visual Impairments

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2013-01-01

    Introduction: The study reported here assessed the exploration of identity and commitment to an identity in German adolescents with and without visual impairments. Methods: In total, 178 adolescents with visual impairments (blindness or low vision) and 526 sighted adolescents completed the Ego Identity Process Questionnaire. Results: The levels of…

  19. Factors Affecting the Reading Media Used by Visually Impaired Adults

    ERIC Educational Resources Information Center

    Goudiras, Dimitrios B.; Papadopoulos, Konstantinos S.; Koutsoklenis, Athanasios Ch.; Papageorgiou, Virginia E.; Stergiou, Maria S.

    2009-01-01

    The aim of this study was to examine reading media (braille, cassettes, screen-reader, screen-magnifier, large print, low vision aids, CCTV) used by visually impaired adults. This article reports the results of a research project involving 100 people with visual impairment. The participants were interviewed and asked to fill in a questionnaire to…

  20. The effect of expectation on facilitation of colour/form conjunction tasks by TMS over area V5.

    PubMed

    Ellison, Amanda; Battelli, Lorella; Cowey, Alan; Walsh, Vincent

    2003-01-01

    In an earlier paper, we reported task-specific impairments and improvements caused by applying TMS over cortical visual area V5 [Proceedings of the Royal Society of London B 265 (1998) 537]. The phenomenon is further investigated in the present study using two of the previous tasks: a motion/form conjunction in which TMS impaired performance and a colour/form conjunction in which performance was enhanced with TMS. In the earlier experiment, subjects were presented with blocks of trials of one task type perhaps allowing some of the observed effects to arise from knowing the type of stimulus to be discriminated. When blocks of trials consisted of randomly mixed moving/form and colour/form conjunction tasks, TMS over V5 still impaired target-present responses for the moving/form conjunction, but the facilitation seen for colour/form conjunction target-present responses disappeared. We suggest that the competitive inhibition postulated between visual movement areas and colour areas in the brain, in our previous paper, are subject to expectation or knowledge of forthcoming stimulus type. PMID:14527542

  1. Photonic-crystal full-colour displays

    NASA Astrophysics Data System (ADS)

    Arsenault, André C.; Puzzo, Daniel P.; Manners, Ian; Ozin, Geoffrey A.

    2007-08-01

    In our information-rich world, it is becoming increasingly important to develop technologies capable of displaying dynamic and changeable data, for reasons ranging from value-added advertising to environmental sustainability. There is an intense drive at the moment towards paper-like displays, devices having a high reflectivity and contrast to provide viewability in a variety of environments, particularly in sunlight where emissive or backlit devices perform very poorly. The list of possible technologies is extensive, including electrophoretic, cholesteric liquid crystalline, electrochromic, electrodewetting, interferometric and more. Despite tremendous advances, the key drawback of all these existing display options relates to colour. As soon as an RGB (red, green and blue) colour filter or spatially modulated colour scheme is implemented, substantial light losses are inevitable even if the intrinsic reflectivity of the material is very good.

  2. Are all the coloured galaxias the same?

    NASA Astrophysics Data System (ADS)

    Hidalgo-Gámez, A. M.; Miranda-Pérez, B. E.; Vega-Acevedo, I.; Castañeda, H.; Saviane, I.

    2016-06-01

    The coloured galaxies were recently discovered in the data-base of the SDSS. They are all compact and show unsual colours in the gri composite image. The most studied so far are those called "green peas" because of their green colour but there are bright blue, purple, red, orange, grey and pink. The green, purple and blue also share a large equivalent width in the oxygen forbbiden line [OIII]5007, larger than 200 Å, being more intense than Hα. This is quite unsual even for star forming galaxies. Although some authors have concluded that all three are the same kind of galaxies, we have studied them carefully and found out that there are important differences among the properties, including the scaling relations.

  3. Multi-colour detection of gravitational arcs

    NASA Astrophysics Data System (ADS)

    Maturi, Matteo; Mizera, Sebastian; Seidel, Gregor

    2014-07-01

    Strong gravitational lensing provides fundamental insights into the understanding of the dark matter distribution in massive galaxies, galaxy clusters, and the background cosmology. Despite their importance, few gravitational arcs have been discovered so far. The urge for more complete, large samples and unbiased methods of selecting candidates increases. Several methods for the automatic detection of arcs have been proposed in the literature, but large amounts of spurious detections retrieved by these methods force observers to visually inspect thousands of candidates per square degree to clean the samples. This approach is largely subjective and requires a huge amount of checking by eye, especially considering the actual and upcoming wide-field surveys, which will cover thousands of square degrees. In this paper we study the statistical properties of the colours of gravitational arcs detected in the 37 deg2 of the CFHTLS-Archive-Research Survey (CARS). Most of them lie in a relatively small region of the (g' - r', r' - i') colour-colour diagram. To explain this property, we provide a model that includes the lensing optical depth expected in a ΛCDM cosmology that, in combination with the sources' redshift distribution of a given survey, in our case CARS, peaks for sources at redshift z ~ 1. By furthermore modelling the colours derived from the spectral energy distribution of the galaxies that dominate the population at that redshift, the model reproduces the observed colours well. By taking advantage of the colour selection suggested by both data and model, we automatically detected 24 objects out of 90 detected by eye checking. Compared with the single-band arcfinder, this multi-band filtering returns a sample complete to 83% and a contamination reduced by a factor of ~6.5. New gravitational arc candidates are also proposed.

  4. OCoc- from Ocean Colour to Organic Carbon

    NASA Astrophysics Data System (ADS)

    Heim, B.; Overduin, P. P.; Schirrmeister, L.; Lantuit, H.; Doerffer, R.

    2009-12-01

    Enhanced permafrost warming and increased arctic river discharges have heightened concern about the input of terrigenous matter into Arctic coastal waters. The ‘OCoc-from Ocean Colour to Organic Carbon’ project (IPY-project 1176), funded by the German Research Foundation (DFG), is an Ocean Colour study joined with the Arctic Coastal Dynamics ACD network and Arctic Circum-polar Coastal Observatory Network ACCO-Net (IPY-project 90). OCoc uses Ocean Colour satellite data for synoptical monitoring of organic matter fluxes from fluvial and coastal sources. Initial results from German-Russian expeditions at the southeastern Laptev Sea Coast (Arctic Siberia, Russia) in August 2008 and August 2009 are presented. Large parts of this coastal zone are characterized by highly erosive organic-rich material. Ocean Colour MERIS Reduced Resolution (RR)-LIB data of the have been processed towards optical aquatic parameters using Beam-Visat4.2 and the MERIS case2 regional processor for coastal application (C2R). Calculated aquatic parameters are absorption and backscattering coefficients, apparent optical properties such as the first attenuation depth (‘Z90’) and calculated concentrations of chlorophyll, total suspended matter and coloured dissolved organic matter absorption from the water leaving reflectances. Initial comparisons with expedition data (Secchi depths, cDOM) show that the MERIS-C2R optical parameters ’total absorption’ and the first attenuation depth, ’Z90’, seem adequately to represent true conditions. High attenuation values in the spectral blue wavelength range may serve as tracer for the organic-rich terrigenous input. The synoptic information of Ocean Colour products will provide valuable spatial and dynamical information on the Organic Carbon and sediment fluxes from the Siberian permafrost coast.

  5. Artificial Vision: Vision of a Newcomer

    NASA Astrophysics Data System (ADS)

    Fujikado, Takashi; Sawai, Hajime; Tano, Yasuo

    The Japanese Consortium for an Artificial Retina has developed a new stimulating method named Suprachoroidal-Transretinal Stimulation (STS). Using STS, electrically evoked potentials (EEPs) were effectively elicited in Royal College of Surgeons (RCS) rats and in rabbits and cats with normal vision, using relatively small stimulus currents, such that the spatial resolution appeared to be adequate for a visual prosthesis. The histological analysis showed no damage to the rabbit retina when electrical currents sufficient to elicit distinct EEPs were applied. It was also shown that transcorneal electrical stimulation (TES) to the retina prevented the death of retinal ganglion cells (RGCs). STS, which is less invasive than other retinal prostheses, could be one choice to achieve artificial vision, and the optimal parameters of electrical stimulation may also be effective for the neuroprotection of residual RGCs.

  6. Home vision tests

    MedlinePlus

    ... testing. AMSLER GRID TEST This test helps detect macular degeneration . This is a disease that causes blurred vision, ... eye exam. People who are at risk of macular degeneration may be told by their ophthalmologist to perform ...

  7. Blindness and vision loss

    MedlinePlus

    ... cause: With cataracts , vision may be cloudy or fuzzy, and bright light may cause glare With diabetes, ... used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed ...

  8. Living with vision loss

    MedlinePlus

    ... EH, Katz PR, Malone ML, eds. Practice of Geriatrics . 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap ... Shega JW. Vision loss. In: Wachtel TJ, ed. Geriatric Clinical Advisor: Instant diagnosis and treatment . Philadelphia, PA: ...

  9. Vision and Motion Pictures.

    ERIC Educational Resources Information Center

    Grambo, Gregory

    1998-01-01

    Presents activities on persistence of vision that involve students in a hands-on approach to the study of early methods of creating motion pictures. Students construct flip books, a Zoetrope, and an early movie machine. (DDR)

  10. Pitfalls in colour photography of choroidal tumours

    PubMed Central

    Schalenbourg, A; Zografos, L

    2013-01-01

    Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown. PMID:23238442

  11. Consumer exposures to anthocyanins from colour additives, colouring foodstuffs and from natural occurrence in foods.

    PubMed

    Tennant, David R; Klingenberg, Andreas

    2016-06-01

    Anthocyanins are responsible for the red/blue colour of grapes, currants, and other fruits and vegetables. They may also be extracted for use as colour additives (E163) or concentrated for use as colouring foods. Consumer exposures have been assessed using data on natural occurrence, use levels and frequencies from food manufacturers and European food consumption data. Intakes from natural occurrence can be up to 4 mg kg bw(-1) day(-1) at the mean and up to 17 mg kg bw(-1) day(-1) for children who are high level consumers of red/black berries and small fruits. High-level intakes for children from food colour and colouring food applications lie in the range 0.3-6.3 mg kg bw(-1) day(-1) and for adults at 0.6-2.8 mg kg bw(-1) day(-1). Exposures from food colour use and colouring foods separately or combined are therefore lower than those from natural occurrence in foods. PMID:27094402

  12. Colour-temperature correspondences: when reactions to thermal stimuli are influenced by colour.

    PubMed

    Ho, Hsin-Ni; Van Doorn, George H; Kawabe, Takahiro; Watanabe, Junji; Spence, Charles

    2014-01-01

    In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant's responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented. PMID:24618675

  13. Synthetic Vision Systems

    NASA Technical Reports Server (NTRS)

    Prinzel, L.J.; Kramer, L.J.

    2009-01-01

    A synthetic vision system is an aircraft cockpit display technology that presents the visual environment external to the aircraft using computer-generated imagery in a manner analogous to how it would appear to the pilot if forward visibility were not restricted. The purpose of this chapter is to review the state of synthetic vision systems, and discuss selected human factors issues that should be considered when designing such displays.

  14. Employment Retention after Vision Loss: Intensive Case Studies.

    ERIC Educational Resources Information Center

    Crudden, Adele; Fireison, Cara K.

    This study examined the lives of 10 individuals with blindness or severe visual impairment who maintained competitive employment despite their vision loss. The study was designed to provide information regarding the personal characteristics and current practices related to work environment alterations which enhance competitive employment…

  15. Making Choices in Functional Vision Evaluations: "Noodles, Needles, and Haystacks."

    ERIC Educational Resources Information Center

    Bishop, V. E.

    1988-01-01

    An approach to functional vision evaluations clarifies the types of data collection and suggests protocols for three broad categories of visually handicapped children: "normal" school-age students, "normal" preschoolers, and multiply handicapped pupils. Visually impaired infants are classified with multiply handicapped pupils because evaluation…

  16. The Need for Vision in Teaching Orientation and Mobility.

    ERIC Educational Resources Information Center

    Wiener, W. R.; And Others

    1992-01-01

    Three experiments examined the ability of blind individuals and individuals simulating the visual acuity of 20/400 to monitor the behaviors of a cane traveler in various environments and at distances between 10 feet and 25 feet. Results suggested that at least some vision is needed for instructors monitoring visually impaired individuals learning…

  17. Emotion-Induced Trade-Offs in Spatiotemporal Vision

    ERIC Educational Resources Information Center

    Bocanegra, Bruno R.; Zeelenberg, Rene

    2011-01-01

    It is generally assumed that emotion facilitates human vision in order to promote adaptive responses to a potential threat in the environment. Surprisingly, we recently found that emotion in some cases impairs the perception of elementary visual features (Bocanegra & Zeelenberg, 2009b). Here, we demonstrate that emotion improves fast temporal…

  18. The Impact of Vision Loss on Personality Traits

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos S.; Koustriava, Eleni; Charalampidou, Maria; Gerapostolou, Ioanna

    2013-01-01

    The aim of this study is to explore the differences in personality traits amongst adults with blindness, adults with low vision and sighted adults. Moreover, the relationship between the four scales of Eysenck's personality questionnaire and the demographic characteristics of participants with visual impairments was examined. There are no…

  19. Biofeedback for Better Vision

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Biofeedtrac, Inc.'s Accommotrac Vision Trainer, invented by Dr. Joseph Trachtman, is based on vision research performed by Ames Research Center and a special optometer developed for the Ames program by Stanford Research Institute. In the United States, about 150 million people are myopes (nearsighted), who tend to overfocus when they look at distant objects causing blurry distant vision, or hyperopes (farsighted), whose vision blurs when they look at close objects because they tend to underfocus. The Accommotrac system is an optical/electronic system used by a doctor as an aid in teaching a patient how to contract and relax the ciliary body, the focusing muscle. The key is biofeedback, wherein the patient learns to control a bodily process or function he is not normally aware of. Trachtman claims a 90 percent success rate for correcting, improving or stopping focusing problems. The Vision Trainer has also proved effective in treating other eye problems such as eye oscillation, cross eyes, and lazy eye and in professional sports to improve athletes' peripheral vision and reaction time.

  20. Agile automated vision

    NASA Astrophysics Data System (ADS)

    Fandrich, Juergen; Schmitt, Lorenz A.

    1994-11-01

    The microelectronic industry is a protagonist in driving automated vision to new paradigms. Today semiconductor manufacturers use vision systems quite frequently in their fabs in the front-end process. In fact, the process depends on reliable image processing systems. In the back-end process, where ICs are assembled and packaged, today vision systems are only partly used. But in the next years automated vision will become compulsory for the back-end process as well. Vision will be fully integrated into every IC package production machine to increase yields and reduce costs. Modem high-speed material processing requires dedicated and efficient concepts in image processing. But the integration of various equipment in a production plant leads to unifying handling of data flow and interfaces. Only agile vision systems can act with these contradictions: fast, reliable, adaptable, scalable and comprehensive. A powerful hardware platform is a unneglectable requirement for the use of advanced and reliable, but unfortunately computing intensive image processing algorithms. The massively parallel SIMD hardware product LANTERN/VME supplies a powerful platform for existing and new functionality. LANTERN/VME is used with a new optical sensor for IC package lead inspection. This is done in 3D, including horizontal and coplanarity inspection. The appropriate software is designed for lead inspection, alignment and control tasks in IC package production and handling equipment, like Trim&Form, Tape&Reel and Pick&Place machines.

  1. Automaticity and localisation of concurrents predicts colour area activity in grapheme-colour synaesthesia.

    PubMed

    Gould van Praag, Cassandra D; Garfinkel, Sarah; Ward, Jamie; Bor, Daniel; Seth, Anil K

    2016-07-29

    In grapheme-colour synaesthesia (GCS), the presentation of letters or numbers induces an additional 'concurrent' experience of colour. Early functional MRI (fMRI) investigations of GCS reported activation in colour-selective area V4 during the concurrent experience. However, others have failed to replicate this key finding. We reasoned that individual differences in synaesthetic phenomenology might explain this inconsistency in the literature. To test this hypothesis, we examined fMRI BOLD responses in a group of grapheme-colour synaesthetes (n=20) and matched controls (n=20) while characterising the individual phenomenology of the synaesthetes along dimensions of 'automaticity' and 'localisation'. We used an independent functional localiser to identify colour-selective areas in both groups. Activations in these areas were then assessed during achromatic synaesthesia-inducing, and non-inducing conditions; we also explored whole brain activations, where we sought to replicate the existing literature regarding synaesthesia effects. Controls showed no significant activations in the contrast of inducing > non-inducing synaesthetic stimuli, in colour-selective ROIs or at the whole brain level. In the synaesthete group, we correlated activation within colour-selective ROIs with individual differences in phenomenology using the Coloured Letters and Numbers (CLaN) questionnaire which measures, amongst other attributes, the subjective automaticity/attention in synaesthetic concurrents, and their spatial localisation. Supporting our hypothesis, we found significant correlations between individual measures of synaesthetic phenomenology and BOLD responses in colour-selective areas, when contrasting inducing against non-inducing stimuli. Specifically, left-hemisphere colour area responses were stronger for synaesthetes scoring high on phenomenological localisation and automaticity/attention, while right-hemisphere colour area responses showed a relationship with localisation

  2. Temporal analysis of the chromatic flash VEP--separate colour and luminance contrast components.

    PubMed

    Klistorner, A; Crewther, D P; Crewther, S G

    1998-12-01

    Temporal analysis of the chromatic flash visual evoked potential (VEP) was studied in human subjects with normal and anomalous colour vision using a deterministic pseudo-random binary stimulus (VERIS). Five experiments were carried out on four normal subjects investigating heterochromatic red-green exchange and single colour/achromatic (either red/grey or green/grey) exchange over a wide range of luminance ratios for the two stimuli, the effects of lowered mean luminance on the chromatic VEP and the effects of colour desaturation at constant mean luminance and constant luminance contrast. Finally, the performance of three dichromats, a protanope and two deuteranopes, on heterochromatic exchange VEP and on colour desaturation were investigated. In contrast to the chromatic electroretinogram, which shows great symmetry with respect to luminance ratio on opposite sides of the isoluminant point, the chromatic VEP demonstrated a distinct asymmetry when the colours exchanged included red. On the red side of isoluminance (red more luminant than green), a wave with longer latency and altered waveform became dominant. The effects of green stimulation were indistinguishable from those of achromatic stimulation at the same luminance contrast over the whole range of chromatic contrast and for all levels of desaturation studied. Desaturation of red with constant luminance contrast (desaturated red/grey stimulation) resulted in a systematic alteration in the evoked waveform. Subtraction of the achromatic first- and second-order responses from responses recorded in the red desaturation series resulted in remarkably uniform waveforms, with peak amplitudes growing linearly with saturation. The absence of interaction between achromatic and coloured components for all (including the most intense colour) stimulus parameters used suggests that the generators of these components are separate. Recordings from the dichromats showed that the contrast response minimum shifted from the point

  3. Federal regulation of vision enhancement devices for normal and abnormal vision

    NASA Astrophysics Data System (ADS)

    Drum, Bruce

    2006-09-01

    The Food and Drug Administration (FDA) evaluates the safety and effectiveness of medical devices and biological products as well as food and drugs. The FDA defines a device as a product that is intended, by physical means, to diagnose, treat, or prevent disease, or to affect the structure or function of the body. All vision enhancement devices fulfill this definition because they are intended to affect a function (vision) of the body. In practice, however, FDA historically has drawn a distinction between devices that are intended to enhance low vision as opposed to normal vision. Most low vision aids are therapeutic devices intended to compensate for visual impairment, and are actively regulated according to their level of risk to the patient. The risk level is usually low (e.g. Class I, exempt from 510(k) submission requirements for magnifiers that do not touch the eye), but can be as high as Class III (requiring a clinical trial and Premarket Approval (PMA) application) for certain implanted and prosthetic devices (e.g. intraocular telescopes and prosthetic retinal implants). In contrast, the FDA usually does not actively enforce its regulations for devices that are intended to enhance normal vision, are low risk, and do not have a medical intended use. However, if an implanted or prosthetic device were developed for enhancing normal vision, the FDA would likely decide to regulate it actively, because its intended use would entail a substantial medical risk to the user. Companies developing such devices should contact the FDA at an early stage to clarify their regulatory status.

  4. Hearing Impairments

    NASA Astrophysics Data System (ADS)

    Cavender, Anna; Ladner, Richard E.

    For many people with hearing impairments, the degree of hearing loss is only a small aspect of their disability and does not necessarily determine the types of accessibility solutions or accommodations that may be required. For some people, the ability to adjust the audio volume may be sufficient. For others, translation to a signed language may be more appropriate. For still others, access to text alternatives may be the best solution. Because of these differences, it is important for researchers in Web accessibility to understand that people with hearing impairments may have very different cultural-linguistic traditions and personal backgrounds.

  5. Ploidy analysis of azalea flower colour sports.

    PubMed

    De Schepper, S; De Loose, M; Van Bockstaele, E; Debergh, P

    2001-01-01

    Flower colour variegation is not only a phenomenon of importance to horticulture, the phenotype involved is also often used as a scientific model system for the study of complex gene regulation processes. In the course of such studies on azalea, we observed a correlation between flower colour patterns, flower morphology and somatic polyploidy. Using high-resolution flow cytometry of nuclear DNA, the ploidy level was determined in flowers of different azalea sport families. Sports exhibiting variegated flowers with broad (> 7mm), differently coloured, petal edges (picotee type) proved to be tetraploid in the petal edge while diploid in the rest of the flower tissue. Neither flower colour pattern nor ploidy differences are chimeral in origin, but seem to be correlated with the topographic location of the cells within the flower tissue, i.e. the margin of the petals. The possible role of gene dosage effects and cell size involved in the remarkable correlation between somatic polyploidy, (flavonoid) gene expression and the flower morphology is discussed. PMID:15954634

  6. Colour octet extension of 2HDM

    NASA Astrophysics Data System (ADS)

    Valencia, German

    2016-07-01

    In this paper we consider some aspects of the Manohar-Wise extension of the SM with a colour-octet electroweak-doublet scalar applied to 2HDM. We present theoretical constraints on the parameters of this extension to both the SM and the 2HDM and discuss related phenomenology at LHC.

  7. New Evidence for Infant Colour Categories

    ERIC Educational Resources Information Center

    Franklin, Anna; Davies, Ian R. L.

    2004-01-01

    Bornstein, Kessen, and Weiskopf (1976) reported that pre-linguistic infants perceive colour categorically for primary boundaries: Following habituation, dishabituation only occurred if the test stimulus was from a different adult category to the original. Here, we replicated this important study and extended it to include secondary boundaries,…

  8. Genetics of human iris colour and patterns.

    PubMed

    Sturm, Richard A; Larsson, Mats

    2009-10-01

    The presence of melanin pigment within the iris is responsible for the visual impression of human eye colouration with complex patterns also evident in this tissue, including Fuchs' crypts, nevi, Wolfflin nodules and contraction furrows. The genetic basis underlying the determination and inheritance of these traits has been the subject of debate and research from the very beginning of quantitative trait studies in humans. Although segregation of blue-brown eye colour has been described using a simple Mendelian dominant-recessive gene model this is too simplistic, and a new molecular genetic perspective is needed to fully understand the biological complexities of this process as a polygenic trait. Nevertheless, it has been estimated that 74% of the variance in human eye colour can be explained by one interval on chromosome 15 that contains the OCA2 gene. Fine mapping of this region has identified a single base change rs12913832 T/C within intron 86 of the upstream HERC2 locus that explains almost all of this association with blue-brown eye colour. A model is presented whereby this SNP, serving as a target site for the SWI/SNF family member HLTF, acts as part of a highly evolutionary conserved regulatory element required for OCA2 gene activation through chromatin remodelling. Major candidate genes possibly effecting iris patterns are also discussed, including MITF and PAX6. PMID:19619260

  9. Advanced colour processing for mobile devices

    NASA Astrophysics Data System (ADS)

    Gillich, Eugen; Dörksen, Helene; Lohweg, Volker

    2015-02-01

    Mobile devices such as smartphones are going to play an important role in professionally image processing tasks. However, mobile systems were not designed for such applications, especially in terms of image processing requirements like stability and robustness. One major drawback is the automatic white balance, which comes with the devices. It is necessary for many applications, but of no use when applied to shiny surfaces. Such an issue appears when image acquisition takes place in differently coloured illuminations caused by different environments. This results in inhomogeneous appearances of the same subject. In our paper we show a new approach for handling the complex task of generating a low-noise and sharp image without spatial filtering. Our method is based on the fact that we analyze the spectral and saturation distribution of the channels. Furthermore, the RGB space is transformed into a more convenient space, a particular HSI space. We generate the greyscale image by a control procedure that takes into account the colour channels. This leads in an adaptive colour mixing model with reduced noise. The results of the optimized images are used to show how, e. g., image classification benefits from our colour adaptation approach.

  10. Colour thresholding and objective quantification in bioimaging

    NASA Technical Reports Server (NTRS)

    Fermin, C. D.; Gerber, M. A.; Torre-Bueno, J. R.

    1992-01-01

    Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples.

  11. Teaching Pronunciation with the Vowel Colour Chart.

    ERIC Educational Resources Information Center

    Finger, Julianne

    1985-01-01

    Explains the composition of the Vowel Colour Chart, a system for teaching Canadian English vowels in which each sound is represented by a color, the color word being the key word for that vowel sound. Suggests practical ways to use the chart with learners of English as a second language. (SED)

  12. Structural colour: elusive iridescence strategies brought to light.

    PubMed

    Vukusic, Pete

    2011-03-01

    Understanding structural colours in nature requires the right set of optical experiments: this is illustrated by a new study on iridescent bird of paradise feathers, which suggests the potential behavioural importance of dynamic colour changes. PMID:21377094

  13. Colour preferences influences odour learning in the hawkmoth, Macroglossum stellatarum

    NASA Astrophysics Data System (ADS)

    Balkenius, Anna; Kelber, Almut

    2006-05-01

    The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed.

  14. Establishment of comprehensive low vision services in Michigan.

    PubMed

    Gormezano, S R; Raznik, P

    1993-01-01

    The AOA Low Vision Section presented its distinguished service award to the Michigan Commission for the Blind during the Section's 10th anniversary celebration at the 95th AOA Congress in Montreal. A progressive low vision service delivery system has evolved in Michigan over the past 22 years with optometry identified as the provider of clinical low vision care. The development of this system is described as the relationship between the Michigan Optometric Association, Michigan Commission for the Blind, and other multidisciplinary agencies is explained. Strategies for serving the visually impaired pediatric, career/vocationally aged, elderly and multiply handicapped populations in Michigan are highlighted. This historical review offers ideas for future planning as optometric low vision services are integrated into other state programs. PMID:8454826

  15. Testing the AUDI2000 colour-difference formula for solid colours using some visual datasets with usefulness to automotive industry

    NASA Astrophysics Data System (ADS)

    Martínez-García, Juan; Melgosa, Manuel; Gómez-Robledo, Luis; Li, Changjun; Huang, Min; Liu, Haoxue; Cui, Guihua; Luo, M. Ronnier; Dauser, Thomas

    2013-11-01

    Colour-difference formulas are tools employed in colour industries for objective pass/fail decisions of manufactured products. These objective decisions are based on instrumental colour measurements which must reliably predict the subjective colour-difference evaluations performed by observers' panels. In a previous paper we have tested the performance of different colour-difference formulas using the datasets employed at the development of the last CIErecommended colour-difference formula CIEDE2000, and we found that the AUDI2000 colour-difference formula for solid (homogeneous) colours performed reasonably well, despite the colour pairs in these datasets were not similar to those typically employed in the automotive industry (CIE Publication x038:2013, 465-469). Here we have tested again AUDI2000 together with 11 advanced colour-difference formulas (CIELUV, CIELAB, CMC, BFD, CIE94, CIEDE2000, CAM02-UCS, CAM02-SCD, DIN99d, DIN99b, OSA-GP-Euclidean) for three visual datasets we may consider particularly useful to the automotive industry because of different reasons: 1) 828 metallic colour pairs used to develop the highly reliable RIT-DuPont dataset (Color Res. Appl. 35, 274-283, 2010); 2) printed samples conforming 893 colour pairs with threshold colour differences (J. Opt. Soc. Am. A 29, 883-891, 2012); 3) 150 colour pairs in a tolerance dataset proposed by AUDI. To measure the relative merits of the different tested colour-difference formulas, we employed the STRESS index (J. Opt. Soc. Am. A 24, 1823-1829, 2007), assuming a 95% confidence level. For datasets 1) and 2), AUDI2000 was in the group of the best colour-difference formulas with no significant differences with respect to CIE94, CIEDE2000, CAM02-UCS, DIN99b and DIN99d formulas. For dataset 3) AUDI2000 provided the best results, being statistically significantly better than all other tested colour-difference formulas.

  16. Flower colour and cytochromes P450†

    PubMed Central

    Tanaka, Yoshikazu; Brugliera, Filippa

    2013-01-01

    Cytochromes P450 play important roles in biosynthesis of flavonoids and their coloured class of compounds, anthocyanins, both of which are major floral pigments. The number of hydroxyl groups on the B-ring of anthocyanidins (the chromophores and precursors of anthocyanins) impact the anthocyanin colour, the more the bluer. The hydroxylation pattern is determined by two cytochromes P450, flavonoid 3′-hydroxylase (F3′H) and flavonoid 3′,5′-hydroxylase (F3′5′H) and thus they play a crucial role in the determination of flower colour. F3′H and F3′5′H mostly belong to CYP75B and CYP75A, respectively, except for the F3′5′Hs in Compositae that were derived from gene duplication of CYP75B and neofunctionalization. Roses and carnations lack blue/violet flower colours owing to the deficiency of F3′5′H and therefore lack the B-ring-trihydroxylated anthocyanins based upon delphinidin. Successful redirection of the anthocyanin biosynthesis pathway to delphinidin was achieved by expressing F3′5′H coding regions resulting in carnations and roses with novel blue hues that have been commercialized. Suppression of F3′5′H and F3′H in delphinidin-producing plants reduced the number of hydroxyl groups on the anthocyanidin B-ring resulting in the production of monohydroxylated anthocyanins based on pelargonidin with a shift in flower colour to orange/red. Pelargonidin biosynthesis is enhanced by additional expression of a dihydroflavonol 4-reductase that can use the monohydroxylated dihydrokaempferol (the pelargonidin precursor). Flavone synthase II (FNSII)-catalysing flavone biosynthesis from flavanones is also a P450 (CYP93B) and contributes to flower colour, because flavones act as co-pigments to anthocyanins and can cause blueing and darkening of colour. However, transgenic plants expression of a FNSII gene yielded paler flowers owing to a reduction of anthocyanins because flavanones are precursors of anthocyanins and flavones. PMID:23297355

  17. Visual impairment.

    PubMed

    Ellenberger, Carl

    2016-01-01

    This chapter can guide the use of imaging in the evaluation of common visual syndromes: transient visual disturbance, including migraine and amaurosis fugax; acute optic neuropathy complicating multiple sclerosis, neuromyelitis optica spectrum disorder, Leber hereditary optic neuropathy, and Susac syndrome; papilledema and pseudotumor cerebri syndrome; cerebral disturbances of vision, including posterior cerebral arterial occlusion, posterior reversible encephalopathy, hemianopia after anterior temporal lobe resection, posterior cortical atrophy, and conversion blindness. Finally, practical efforts in visual rehabilitation by sensory substitution for blind patients can improve their lives and disclose new information about the brain. PMID:27430448

  18. Colour-scent associations in a tropical orchid: three colours but two odours.

    PubMed

    Delle-Vedove, Roxane; Juillet, Nicolas; Bessière, Jean-Marie; Grison, Claude; Barthes, Nicolas; Pailler, Thierry; Dormont, Laurent; Schatz, Bertrand

    2011-06-01

    Colour and scent are the major pollinator attractants to flowers, and their production may be linked by shared biosynthetic pathways. Species with polymorphic floral traits are particularly relevant to study the joint evolution of floral traits. We used in this study the tropical orchid Calanthe sylvatica from Réunion Island. Three distinct colour varieties are observed, presenting lilac, white or purple flowers, and named respectively C. sylvaticavar.lilacina (hereafter referred as var. lilacina), C. sylvaticavar. alba (var. alba) and C. sylvatica var. purpurea (var. purpurea). We investigated the composition of the floral scent produced by these colour varieties using the non-invasive SPME technique in the wild. Scent emissions are dominated by aromatic compounds. Nevertheless, the presence of the terpenoid (E)-4,8-dimethylnona-1,3,7-triène (DMNT) is diagnostic of var. purpurea, with the volatile organic compounds (VOC) produced by some individuals containing up to 60% of DMNT. We evidence specific colour-scent associations in C. sylvatica, with two distinct scent profiles in the three colour varieties: the lilacina-like profile containing no or very little DMNT (<2%) and the purpurea-like profile containing DMNT (>2%). Calanthe sylvatica var. alba individuals group with one or the other scent profile independently of their population of origin. We suggest that white-flowered individuals have evolved at least twice, once from var. lilacina and at least once from var. purpurea after the colonisation of la Réunion. White-flowered individuals may have been favoured by the particular pollinator fauna characterising the island. These flowering varieties of C. sylvatica, which display three colours but two scents profiles prove that colour is not always a good indicator of odour and that colour-scent associations may be complex, depending on pollination ecology of the populations concerned. PMID:21377705

  19. Colour-the-INSight: combining a direct view rifle sight with fused intensified and thermal imagery

    NASA Astrophysics Data System (ADS)

    Hogervorst, M. A.; Jansen, C.; Toet, A.; Bijl, P.; Bakker, P.; Hiddema, A. C.; van Vliet, S. F.

    2012-06-01

    We present the design and evaluation of a new demonstrator rifle sight viewing system containing direct view, red aim point and fusion of an (uncooled, LWIR) thermal sensor with a digital image intensifier. Our goal is to create a system that performs well under a wide variety of (weather) conditions during daytime and nighttime and combines the advantages of the various sensor systems. A real-time colour image with salient hot targets is obtained from the night vision sensors by implementing the Colour-the-Night fusion method (Hogervorst & Toet, 2010) on the on-board processor. The prototype system was evaluated in a series of field trials with military observers performing detection and identification tasks. The tests showed that during daytime the addition of a thermal image to direct vision is advantageous, e.g. for the detection of hot targets. At nighttime, the fusion of thermal and image intensified imagery results in increased situational awareness and improved detection of (hot) targets. For identification of small (handheld) objects, the technology needs to be further refined.

  20. Insect vision as model for machine vision

    NASA Astrophysics Data System (ADS)

    Osorio, D.; Sobey, Peter J.

    1992-11-01

    The neural architecture, neurophysiology and behavioral abilities of insect vision are described, and compared with that of mammals. Insects have a hardwired neural architecture of highly differentiated neurons, quite different from the cerebral cortex, yet their behavioral abilities are in important respects similar to those of mammals. These observations challenge the view that the key to the power of biological neural computation is distributed processing by a plastic, highly interconnected, network of individually undifferentiated and unreliable neurons that has been a dominant picture of biological computation since Pitts and McCulloch's seminal work in the 1940's.

  1. [Quality system Vision 2000].

    PubMed

    Pasini, Evasio; Pitocchi, Oreste; de Luca, Italo; Ferrari, Roberto

    2002-12-01

    A recent document of the Italian Ministry of Health points out that all structures which provide services to the National Health System should implement a Quality System according to the ISO 9000 standards. Vision 2000 is the new version of the ISO standard. Vision 2000 is less bureaucratic than the old version. The specific requests of the Vision 2000 are: a) to identify, to monitor and to analyze the processes of the structure, b) to measure the results of the processes so as to ensure that they are effective, d) to implement actions necessary to achieve the planned results and the continual improvement of these processes, e) to identify customer requests and to measure customer satisfaction. Specific attention should be also dedicated to the competence and training of the personnel involved in the processes. The principles of the Vision 2000 agree with the principles of total quality management. The present article illustrates the Vision 2000 standard and provides practical examples of the implementation of this standard in cardiological departments. PMID:12611210

  2. Teaching the Absorption of Light Colours Using an Artificial Rainbow

    ERIC Educational Resources Information Center

    Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

    2015-01-01

    This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

  3. An Interaction of Screen Colour and Lesson Task in CAL

    ERIC Educational Resources Information Center

    Clariana, Roy B.

    2004-01-01

    Colour is a common feature in computer-aided learning (CAL), though the instructional effects of screen colour are not well understood. This investigation considers the effects of different CAL study tasks with feedback on posttest performance and on posttest memory of the lesson colour scheme. Graduate students (n=68) completed a computer-based…

  4. Characters with Visual Impairment: Looking at Books for Young Adults through Their Eyes.

    ERIC Educational Resources Information Center

    Carroll, Pamela S.; Rosenblum, L. Penny

    A study that joined the fields of young adult literature and vision impairment explored the questions: How are characters who have visual impairment presented by young adult books?; and How do readers respond to those characters? Only a few books were found (13) that feature characters with visual impairments, and the portrayal of characters…

  5. Low Cost Night Vision System for Intruder Detection

    NASA Astrophysics Data System (ADS)

    Ng, Liang S.; Yusoff, Wan Azhar Wan; R, Dhinesh; Sak, J. S.

    2016-02-01

    The growth in production of Android devices has resulted in greater functionalities as well as lower costs. This has made previously more expensive systems such as night vision affordable for more businesses and end users. We designed and implemented robust and low cost night vision systems based on red-green-blue (RGB) colour histogram for a static camera as well as a camera on an unmanned aerial vehicle (UAV), using OpenCV library on Intel compatible notebook computers, running Ubuntu Linux operating system, with less than 8GB of RAM. They were tested against human intruders under low light conditions (indoor, outdoor, night time) and were shown to have successfully detected the intruders.

  6. Adaptation to Low Vision Caused by Age-Related Macular Degeneration: A Case Study

    ERIC Educational Resources Information Center

    Smith, Theresa Marie

    2008-01-01

    One in eight Americans aged 65 and older has an eye disease resulting in low vision, and more women than men are visually impaired, mainly because women live longer. Age-related visual impairments are an indicator of a decline in activities of daily living and self-help skills. The top eye conditions that affect older adults are macular…

  7. Piaget's Water-Level Task: The Impact of Vision on Performance

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni

    2011-01-01

    In the present study, the aim was to examine the differences in performance between children and adolescents with visual impairment and sighted peers in the water-level task. Twenty-eight individuals with visual impairments, 14 individuals with blindness and 14 individuals with low vision, and 28 sighted individuals participated in the present…

  8. Periodontium bestows vision!!

    PubMed Central

    Gulati, Minkle; Salaria, Sanjeev Kumar; Anand, Vishal; Jain, Nikil; Pandey, Suraj

    2016-01-01

    The role of periodontium in supporting the tooth structures is well-known. However, less is known about its contribution to the field of ophthalmology. Corneal diseases are among major causes of blindness affecting millions of people worldwide, for which synthetic keratoprosthesis was considered the last resort to restore vision. Yet, these synthetic keratoprosthesis suffered from serious limitations, especially the foreign body reactions invoked by them resulting in extrusion of the whole prosthesis from the eye. To overcome these shortcomings, an autologous osteo-odonto keratoprosthesis utilizing intraoral entities was introduced that could positively restore vision even in cases of severely damaged eyes. The successful functioning of this prosthesis, however, predominantly depended on the presence of a healthy periodontium for grafting. Therefore, the following short communication aims to acknowledge this lesser-known role of the periodontium and other oral structures in bestowing vision to the blind patients.

  9. Overview of sports vision

    NASA Astrophysics Data System (ADS)

    Moore, Linda A.; Ferreira, Jannie T.

    2003-03-01

    Sports vision encompasses the visual assessment and provision of sports-specific visual performance enhancement and ocular protection for athletes of all ages, genders and levels of participation. In recent years, sports vision has been identified as one of the key performance indicators in sport. It is built on four main cornerstones: corrective eyewear, protective eyewear, visual skills enhancement and performance enhancement. Although clinically well established in the US, it is still a relatively new area of optometric specialisation elsewhere in the world and is gaining increasing popularity with eyecare practitioners and researchers. This research is often multi-disciplinary and involves input from a variety of subject disciplines, mainly those of optometry, medicine, physiology, psychology, physics, chemistry, computer science and engineering. Collaborative research projects are currently underway between staff of the Schools of Physics and Computing (DIT) and the Academy of Sports Vision (RAU).

  10. Periodontium bestows vision!!

    PubMed

    Gulati, Minkle; Salaria, Sanjeev Kumar; Anand, Vishal; Jain, Nikil; Pandey, Suraj

    2016-01-01

    The role of periodontium in supporting the tooth structures is well-known. However, less is known about its contribution to the field of ophthalmology. Corneal diseases are among major causes of blindness affecting millions of people worldwide, for which synthetic keratoprosthesis was considered the last resort to restore vision. Yet, these synthetic keratoprosthesis suffered from serious limitations, especially the foreign body reactions invoked by them resulting in extrusion of the whole prosthesis from the eye. To overcome these shortcomings, an autologous osteo-odonto keratoprosthesis utilizing intraoral entities was introduced that could positively restore vision even in cases of severely damaged eyes. The successful functioning of this prosthesis, however, predominantly depended on the presence of a healthy periodontium for grafting. Therefore, the following short communication aims to acknowledge this lesser-known role of the periodontium and other oral structures in bestowing vision to the blind patients. PMID:27563213

  11. Integrating National Space Visions

    NASA Technical Reports Server (NTRS)

    Sherwood, Brent

    2006-01-01

    This paper examines value proposition assumptions for various models nations may use to justify, shape, and guide their space programs. Nations organize major societal investments like space programs to actualize national visions represented by leaders as investments in the public good. The paper defines nine 'vision drivers' that circumscribe the motivations evidently underpinning national space programs. It then describes 19 fundamental space activity objectives (eight extant and eleven prospective) that nations already do or could in the future use to actualize the visions they select. Finally the paper presents four contrasting models of engagement among nations, and compares these models to assess realistic pounds on the pace of human progress in space over the coming decades. The conclusion is that orthogonal engagement, albeit unlikely because it is unprecedented, would yield the most robust and rapid global progress.

  12. Bio-inspired vision

    NASA Astrophysics Data System (ADS)

    Posch, C.

    2012-01-01

    Nature still outperforms the most powerful computers in routine functions involving perception, sensing and actuation like vision, audition, and motion control, and is, most strikingly, orders of magnitude more energy-efficient than its artificial competitors. The reasons for the superior performance of biological systems are subject to diverse investigations, but it is clear that the form of hardware and the style of computation in nervous systems are fundamentally different from what is used in artificial synchronous information processing systems. Very generally speaking, biological neural systems rely on a large number of relatively simple, slow and unreliable processing elements and obtain performance and robustness from a massively parallel principle of operation and a high level of redundancy where the failure of single elements usually does not induce any observable system performance degradation. In the late 1980`s, Carver Mead demonstrated that silicon VLSI technology can be employed in implementing ``neuromorphic'' circuits that mimic neural functions and fabricating building blocks that work like their biological role models. Neuromorphic systems, as the biological systems they model, are adaptive, fault-tolerant and scalable, and process information using energy-efficient, asynchronous, event-driven methods. In this paper, some basics of neuromorphic electronic engineering and its impact on recent developments in optical sensing and artificial vision are presented. It is demonstrated that bio-inspired vision systems have the potential to outperform conventional, frame-based vision acquisition and processing systems in many application fields and to establish new benchmarks in terms of redundancy suppression/data compression, dynamic range, temporal resolution and power efficiency to realize advanced functionality like 3D vision, object tracking, motor control, visual feedback loops, etc. in real-time. It is argued that future artificial vision systems

  13. Vision in elasmobranchs and their relatives: 21st century advances.

    PubMed

    Lisney, T J; Theiss, S M; Collin, S P; Hart, N S

    2012-04-01

    This review identifies a number of exciting new developments in the understanding of vision in cartilaginous fishes that have been made since the turn of the century. These include the results of studies on various aspects of the visual system including eye size, visual fields, eye design and the optical system, retinal topography and spatial resolving power, visual pigments, spectral sensitivity and the potential for colour vision. A number of these studies have covered a broad range of species, thereby providing valuable information on how the visual systems of these fishes are adapted to different environmental conditions. For example, oceanic and deep-sea sharks have the largest eyes amongst elasmobranchs and presumably rely more heavily on vision than coastal and benthic species, while interspecific variation in the ratio of rod and cone photoreceptors, the topographic distribution of the photoreceptors and retinal ganglion cells in the retina and the spatial resolving power of the eye all appear to be closely related to differences in habitat and lifestyle. Multiple, spectrally distinct cone photoreceptor visual pigments have been found in some batoid species, raising the possibility that at least some elasmobranchs are capable of seeing colour, and there is some evidence that multiple cone visual pigments may also be present in holocephalans. In contrast, sharks appear to have only one cone visual pigment. There is evidence that ontogenetic changes in the visual system, such as changes in the spectral transmission properties of the lens, lens shape, focal ratio, visual pigments and spatial resolving power, allow elasmobranchs to adapt to environmental changes imposed by habitat shifts and niche expansion. There are, however, many aspects of vision in these fishes that are not well understood, particularly in the holocephalans. Therefore, this review also serves to highlight and stimulate new research in areas that still require significant attention. PMID

  14. Genetic analyses of the human eye colours using a novel objective method for eye colour classification.

    PubMed

    Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; Sørensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; Børsting, Claus; Morling, Niels

    2013-09-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p<10(-6)) in the PIE-scores of the individuals typed as HERC2 rs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of

  15. Night Vision Camera

    NASA Technical Reports Server (NTRS)

    1996-01-01

    PixelVision, Inc. developed the Night Video NV652 Back-illuminated CCD Camera, based on the expertise of a former Jet Propulsion Laboratory employee and a former employee of Scientific Imaging Technologies, Inc. The camera operates without an image intensifier, using back-illuminated and thinned CCD technology to achieve extremely low light level imaging performance. The advantages of PixelVision's system over conventional cameras include greater resolution and better target identification under low light conditions, lower cost and a longer lifetime. It is used commercially for research and aviation.

  16. Telescopic vision contact lens

    NASA Astrophysics Data System (ADS)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  17. The Colour of the Young Universe

    NASA Astrophysics Data System (ADS)

    2003-12-01

    VLT study gives insight on the evolution of the star formation rate Summary An international team of astronomers [1] has determined the colour of the Universe when it was very young. While the Universe is now kind of beige, it was much bluer in the distant past , at a time when it was only 2,500 million years old. This is the outcome of an extensive and thorough analysis of more than 300 galaxies seen within a small southern sky area, the so-called Hubble Deep Field South. The main goal of this advanced study was to understand how the stellar content of the Universe was assembled and has changed over time. Dutch astronomer Marijn Franx , a team member from the Leiden Observatory (The Netherlands), explains: "The blue colour of the early Universe is caused by the predominantly blue light from young stars in the galaxies. The redder colour of the Universe today is caused by the relatively larger number of older, redder stars." The team leader, Gregory Rudnick from the Max-Planck Institut für Astrophysics (Garching, Germany) adds: "Since the total amount of light in the Universe in the past was about the same as today and a young blue star emits much more light than an old red star, there must have been significantly fewer stars in the young Universe than there is now. Our new findings imply that the majority of stars in the Universe were formed comparatively late, not so long before our Sun was born, at a moment when the Universe was around 7,000 million years old." These new results are based on unique data collected during more than 100 hours of observations with the ISAAC multi-mode instrument at ESO's Very Large Telescope (VLT), as part of a major research project, the Faint InfraRed Extragalactic Survey (FIRES) . The distances to the galaxies were estimated from their brightness in different optical near-infrared wavelength bands. PR Photo 34/03 : The Evolving Colour of the Universe . Observing the early Universe It is now well known that the Sun was formed

  18. Machine vision - Automated visual inspection and robot vision

    NASA Astrophysics Data System (ADS)

    Vernon, David

    The subject of machine vision is treated with emphasis on fundamental tools for image acquisition, processing, and analysis. Topics discussed include an introduction to computer vision, illumination and sensors, image acquisition and representation, fundamentals of digital image processing, the segmentation problem, and image analysis. The book also covers techniques for shape description, robot programming and robot vision, and an introduction to image understanding.

  19. Grounding Our Vision: Brain Research and Strategic Vision

    ERIC Educational Resources Information Center

    Walker, Mike

    2011-01-01

    While recognizing the value of "vision," it could be argued that vision alone--at least in schools--is not enough to rally the financial and emotional support required to translate an idea into reality. A compelling vision needs to reflect substantive, research-based knowledge if it is to spark the kind of strategic thinking and insight capable of…

  20. Uropygial gland and bib colouration in the house sparrow.

    PubMed

    Moreno-Rueda, Gregorio

    2016-01-01

    Birds frequently signal different qualities by plumage colouration, mainly during mating. However, plumage colouration is determined during the moult, and therefore it would indicate the quality of individual birds during the moult, not its current quality. Recent studies, however, suggest that birds could modify plumage colouration by using cosmetic preen oil produced by the uropygial gland. In this study, I show that bib colouration is related to uropygial gland size and body condition in male house sparrows (Passer domesticus). Moreover, I conducted an experiment in which a group of sparrows were inoculated with an antigen, mimicking an illness. In control birds, short-term changes in bib colouration were related to both body condition and change in uropygial gland size. Therefore, birds that reduced uropygial gland size showed a greater colouration change. However, bib colouration did not change with the change in uropygial gland size in experimental birds inoculated with the antigen. Given that the experiment did not affect preen oil production or consumption, this finding tentatively suggests that the immune challenge provoked a change in the composition of preen oil, affecting its cosmetic properties. In short, the results of this study suggest that (1) male house sparrows produce cosmetic preen oil that alters the colouration of their bibs; (2) the more change in uropygial gland size, the more change in bib colouration; and (3) in this way, bib colouration has the potential to signal current health status, since less healthy birds showed less capacity to change bib colouration. PMID:27280079