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Introduction: Traumatic brain injury (TBI) is an important public health concern and that may lead to severe neural sequels, such as color vision deficits. Methods: We evaluated the color vision of 10 TBI patients with normal cognitive function using a color discrimination test in a fixed saturation level. We also analyzed computerized tomography scans to identify the local of the brain damages. Results: Four TBI patients that had lesions in brain areas of the ventral visual streams, five TBI patients had lesions inferred in brain areas of the dorsal visual stream, and one TBI patient had lesion in the occipital area. All the patients had cognitive and color vision screened and they had characterized the chromatic discrimination at high and low saturation. All participants had no significant cognitive impairment in the moment of the color vision test. Additionally, they had perfect performance for discrimination of chromatic stimulus at high saturation and similar to controls (n = 37 age-matched participants). Three of four TBI patients with lesions in the ventral brain and one patient with lesion in the occipital area had impairment of the chromatic discrimination at low saturation. All TBI patients with lesions in the dorsal brain had performance similar or slightly worse than the controls. Conclusion: Chromatic discrimination at low saturation was associated to visual damage in the ventral region of the brain and is a potential tool for functional evaluation of brain damage in TBI patients.

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Recent research has proposed new approaches to investigate color vision in Old World Monkeys by measuring suprathreshold chromatic discrimination. In this study, we aimed to extend this approach to New World Monkeys with different color vision genotypes by examining their performance in chromatic discrimination tasks along different fixed chromatic saturation axes. Four tufted capuchin monkeys were included in the study, and their color vision genotypes were one classical protanope, one classical deuteranope, one non-classical protanope, and a normal trichromat. During the experiments, the monkeys were required to perform a chromatic discrimination task using pseudoisochromatic stimuli with varying target saturations of 0.06, 0.04, 0.03, and 0.02 u'v' units. The number of errors made by the monkeys along different chromatic axes was recorded, and their performance was quantified using the binomial probability of their hits during the tests. Our results showed that dichromatic monkeys made more errors near the color confusion lines associated with their specific color vision genotypes, while the trichromatic monkey did not demonstrate any systematic errors. At high chromatic saturation, the trichromatic monkey had significant hits in the chromatic axes around the 180° chromatic axis, whereas the dichromatic monkeys had errors in colors around the color confusion lines. At lower saturation, the performance of the dichromatic monkeys became more challenging to differentiate among the three types, but it was still distinct from that of the trichromatic monkey. In conclusion, our findings suggest that high saturation conditions can be used to identify the color vision dichromatic phenotype of capuchin monkeys, while low chromatic saturation conditions enable the distinction between trichromats and dichromats. These results extend the understanding of color vision in New World Monkeys and highlight the usefulness of suprathreshold chromatic discrimination measures in exploring color vision in non-human primates.

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The giant river prawn, Macrobrachium rosenbergii (de Man, 1879), is a species of great commercial importance. It is farmed under different conditions that translate to a great range of light environments, which impact their behavior and productivity. We present the first study employing both visual modeling and beha vioral data to evaluate the ontogenetic changes in color preferences of juveniles and adults of M. rosenbergii. We offered ten shelters of different colors to juveniles and adults and registered their preferences. Our results show that shelter preference changed with ontogeny: juveniles chose shelters based on chromaticity (preference for blue), while adults based their decisions on brightness (preference for dark grey). This preference adults show for dark colors is probably associated with light avoidance behavior. We recommend providing blue shelters for juveniles and dark shelters for adults.(AU)

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La pérdida no orgánica de la visión o pérdida funcional, es un trastorno en el cual se presenta cierta sintomatología visual, sin que haya causa alguna que pueda justificarlo. Se presenta un caso de una paciente adolescente femenina de 16 años de edad, color de piel blanca, con antecedentes oculares de ptosis palpebral derecha congénita y malos hábitos alimentarios. Su motivo de consulta fue pérdida de la visión de colores no constatada inicialmente; luego, debido a su insistencia, comenzamos a notar una disminución progresiva e incongruente de la visión cromática, con parámetros funcionales visuales normales, defectos en campos visuales computarizados no reproducibles y exámenes de electrofisiología visual normales, con recuperación total de este defecto sin tomarse ninguna conducta terapéutica específica. La pérdida no orgánica de la visión se refiere a cualquier defecto visual en la que no se demuestra alteración de las estructuras que se encuentran entre la córnea y la corteza cerebral occipital. Los trastornos de la vía aferente constituyen la manifestación más frecuente. Puede existir disminución, unilateral o bilateral, de la visión, afectación del campo visual o ambos. La visión de colores es usualmente anormal, pero rara vez, es el motivo de consulta. El origen psicógeno es corriente en niños y es más frecuente en mujeres que en hombres. El déficit adquirido de la visión de colores ocurre a consecuencia de una patología ocular, lesión intracraneal o uso excesivo de algún medicamento y, por lo general, se acompaña de pérdida variable de la agudeza visual(AU)

Non-organic loss of vision or functional loss is a disorder in which certain visual symptomatology is present, without any cause that could justify it. We present a case of a 16-year-old female adolescent patient, white skin color, with ocular history of congenital right palpebral ptosis and bad eating habits. Her reason for consultation was loss of color vision not initially detected; then, due to her insistence, we began to notice a progressive and incongruent decrease in color vision, with normal visual functional parameters, defects in non-reproducible computerized visual fields and normal visual electrophysiology tests, with total recovery of this defect without any specific therapeutic behavior. Non-organic vision loss refers to any visual defect in which no alteration of the structures between the cornea and the occipital cerebral cortex is demonstrated. Disorders of the afferent pathway constitute the most frequent manifestation. There may be unilateral or bilateral decreased vision, visual field impairment, or both. Color vision is usually abnormal, but rarely, it is the reason for consultation. Psychogenic origin is common in children and is more frequent in women than in men. Acquired color vision deficits occur as a consequence of an ocular pathology, intracranial injury or excessive use of medication and are usually accompanied by variable loss of visual acuity(AU)

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Con la técnica de aerografía sobre madera, se crea la obra "Daltonismo Racional", composición planteada en orden cartesiano, iniciando en el plano izquierdo superior con el panel rojo de línea totalmente quebrada, en constante zigzag, seguido a la derecha por el panel verde con gráfico de cigarrillo humeante; luego, en el sector izquierdo debajo del panel rojo encontramos el panel verde con la botella de licor y, finalmente, en la zona derecha inferior hallamos el panel con el gráfico del monitor rojo y línea blanca horizontal. Respecto a sus dimensiones, corresponde a un políptico conformado por cuatro módulos cuadrados, de 36 cm x 36 cm x 7 cm de profundidad. Entre los módulos hay un espacio de 20 cm, lo cual permite la formación de una cruz, por los dos espacios cruzados perpendicularmente. La obra tiene un carácter contestatario, frente a la manera como se pretende financiar la salud pública, debido a que los impuestos generados por la venta y consumo de alcohol y cigarrillos, se destinan para la salud, lo que nos lleva a una paradoja: ¿es razonable pensar que a través del detrimento de la salud de las personas que consumen licores y cigarrillos, se intente solucionar los problemas de salud?, ¿no es acaso la prevención y el no consumo de estas sustancias, lo que nos permite cultivar un mejor estado de salud?

With the technique of airbrushing on wood, the work "Rational Daltonism" is created. This is laid out in Cartesian order, starting on the upper left plane with the red panel with a totally broken line, in constant zigzag, followed to the right by the green panel with a graphic of a smoking cigarette; then, in the left sector below the red panel we find the green panel with the liquor bottle and, finally, in the lower right area we find the panel with the red monitor graphic and horizontal white line. Regarding its dimensions, it corresponds to a polyptych made up of four square modules, 36 cm x 36 cm x 7 cm deep. Between the modules there is a space of 20 cm, which allows the formation of a cross, by the two spaces crossed perpendicularly. The work has an anti-establishment character, as opposed to the way in which public health is intended to be financed, because the taxes generated by the sale and consumption of alcohol and cigarettes are destined for health, which leads us to a paradox: Is it reasonable to think that there is an attempt to solve health problems through the health detriment of the people who consume liquor and cigarettes? Is not prevention and not consuming these substances what allows us to cultivate a better health condition?

Com a técnica de aerografia sobre madeira, é criada a obra Daltonismo Racional. Esta está disposta em ordem cartesiana, iniciando no plano superior esquerdo com o painel vermelho com uma linha totalmente quebrada, em constante ziguezague, seguido à direita pelo painel verde com o gráfico de um cigarro fumando; em seguida, no setor esquerdo abaixo do painel vermelho encontramos o painel verde com a garrafa de licor e, finalmente, na área inferior direita encontramos o painel com o gráfico do monitor vermelho e linha branca horizontal. Quanto às suas dimensões, corresponde a um políptico composto por quatro módulos quadrados, com 36 cm x 36 cm x 7 cm de profundidade. Entre os módulos existe um espaço de 20 cm, que permite a formação de uma cruz, pelos dois espaços cruzados perpendicularmente. La obra tiene un carácter contestatario, frente a la manera como se pretende financiar la salud pública, debido a que los impuestos generados por la venta y consumo de alcohol y cigarrillos, se destinan para la salud, lo que nos lleva a una paradoja: es razonable pensar que a través del detrimento de la salud de las personas que consumen licores y cigarrillos, se intente solucionar los problemas de salud?, no es acaso la prevención y el no consumo de estas sustancias, lo que nos permite cultivar un mejor Estado de saúde?

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Chronic tobacco consumption, identified as Tobacco Use Disorder (TUD), is a public health problem. We present a case report of a 37-year-old Brazilian male diagnosed with TUD at age 26, with no comorbidities, that presented visual improvements (i.e., lower thresholds and better discrimination) after nicotine gum administration. Here, we assessed contrast sensitivity and chromatic discrimination using the Metropsis and the Cambridge Colour Test, respectively. Results showed lower thresholds for both visual tasks after the use of nicotine gum. Even considering this is a single case report, our intent is to open new avenues for research involving smoking, addiction and the use of nicotine gum as a replacement tool or adjuvant tool for improvement of visual and/or cognitive processing. It is well known that nicotine gum has protective effects for some diseases, and improves some cognitive functions. However, unclear were its effects on visual processing of people with TUD.

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Introduction: Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in developed countries and one of the leading causes of blindness. In this work, we evaluated color vision and the pupil light reflex (PLR) to assess visual function in patients with early and neovascular AMD (NVAMD) compared with the control group. Methods: We recruited 34 early patients with dry AMD and classified them into two groups following AREDS: 13 patients with NVAMD and 24 healthy controls. Controls and patients with early dry AMD had visual acuity (VA) best or equal to 20/25 (0.098 logMAR). Color vision was assessed in controls and patients with early dry AMD using the Cambridge Color Test (CCT) 2.0 through the Trivector protocol. The PLR was evaluated using a Ganzfeld, controlled by the RETI-port system. The stimuli consisted of 1s blue (470 nm) and red (631 nm) light flashes presented alternately at 2-min intervals. To assess the cone contribution, we used a red flash at 2.4 log cd.m-2, with a blue background at 0.78 log cd.m-2. For rods, we used 470-nm flashes at -3 log cd.m-2, and for the melanopsin function of ipRGCs, we used 470 nm at 2.4 log cd.m-2. Results: Patients with early dry AMD had reduced color discrimination in all three axes: protan (p = 0.0087), deutan (p = 0.0180), and tritan (p = 0.0095) when compared with the control group. The PLR has also been affected in patients with early dry AMD and patients with NVAMD. The amplitude for the melanopsin-driven response was smaller in patients with early dry AMD (p = 0.0485) and NVAMD (p = 0.0035) than in the control group. The melanopsin function was lower in patients with NVAMD (p = 0.0290) than the control group. For the rod-driven response, the latency was lower in the NVAMD group (p = 0.0041) than in the control group. No changes were found in cone-driven responses between the control and AMD groups. Conclusion: Patients with early dry AMD present diffusely acquired color vision alteration detected by CCT. Rods and melanopsin contributions for PLR are affected in NVAMD. The CCT and the PLR may be considered sensitive tests to evaluate and monitor functional changes in patients with AMD.

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Color vision deficiency (CVD) is a frequent condition that alters color perception to such an extent that many people encounter serious difficulties on their everyday lives. In this work, we present a strategy to analyze the effectiveness of light filters aimed to improve color discriminability of persons with CVD. The calculations are based on a simple model of color discrimination which has been successfully applied to several animal species. We first tested the calculations on three well-known commercial lenses designed for persons with CVD. In agreement with results of clinical studies, the calculations show that the highly colored lenses (VINO® and X-Chrom®) enhance chromaticity contrasts between problematic colors, whereas the more neutral Enchroma® do not provide any benefit. Also, we predict that two light filters proposed in recent works for novel lenses would not improve the performance of the commercial ones. Since the mathematical approach presented in this work enables predictive filter assessment, it opens the door to future research on the design of more effective lenses to improve color discriminability of persons with CVD. The calculations allow for large-scale screening of numerous light filters and different colored stimuli, CVD conditions, light sources, etc.

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In primates, the advantage of trichromacy (i.e., color vision expressed by most humans) over dichromacy (i.e., color vision expressed by many colorblind humans) has been linked to the detection of yellowish/reddish targets against a background of mature green leaves. Nevertheless, mostly because of studies conducted in humans, we know that achromatic cues might also play an important role in object identification, particularly when camouflage is involved. For instance, dichromacy favors the detection of camouflaged targets by exploitation of shape cues. The present study sought to evaluate the relative importance of color and shape cues on the detection of food targets by female and male marmosets (Callithrix jacchus). Animals were observed with respect to their foraging behavior and the number of food targets captured. We confirmed that females are advantageous in detecting conspicuous food against a green background and revealed that females and males rely on shape cues to segregate cryptic food. Unexpectedly, males outperformed females in cryptic food foraging, while camouflage improved males' (but not females') performance. Here we show that dichromats could potentially benefit from a better segregation of green natural targets (e.g., immature fruits, green insects, and gum trees) when viewed against a green dappled background.

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A tail of conspicuous coloration is hypothesized to be an advantageous trait for many species of lizards. Predator attacks would be directed to a non-vital, and autotomizable, body part, increasing the chance of survival. However, as body size increases it also increases the signaling area that could attract predators from greater distances, increasing the overall chance of predation. Here, we test the hypothesis that there is a trade-off between tail color and size, affecting predation probabilities. We used plasticine replicas of lizards to study the predation patterns of small and large lizards with red and blue tails. In a natural environment, we exposed six hundred replicas to the attacks of free-ranging predators. Large red-tailed replicas were more attacked by birds. Mammals and unidentified predators showed no preference for any size or colors. The attacks were not primarily directed to conspicuous tails when compared to the bodies/heads of our replicas. Our study suggests that red color signals in large lizards could enhance their detection by visually oriented predators (i.e., birds). The efficacy of conspicuous tails as a decoy may rely on associated behavioral displays, which are hard to test with static replicas.

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