Caracteriza����o visual numa amostra infantil em idade pr��-escolar e escolar: o estado da arte num rastreio

Existem cerca de 1 milh��o e 500 mil crian��as cegas e 19 milh��es com algum tipo de defici��ncia visual, abrangendo a faixa et��ria dos 0 aos 14 anos. Os erros refrativos s��o a principal causa de defici��ncia visual nas crian��as, sendo a miopia e o astigmatismo os principais respons��veis por essa situa����o. Estima-se que a preval��ncia de ambliopia na popula����o infantil em Portugal �� de 1 a 2,5%, onde cerca de 20% das crian��as apresentam erros refrativos significativos. O diagn��stico, a referencia����o e o encaminhamento precoces s��o fundamentais na preven����o das defici��ncias visuais de causas evit��veis. Finalidade do estudo: caracteriza����o do estado visual numa amostra infantil em idade escolar e pr��-escolar.

Rendimiento escolar e tipos de errores en la lectura en los ni��os con alteraciones de la funci��n visual

Se desarroll�� un estudio descriptivo con el objetivo de evaluar el rendimiento escolar as�� como tipos de errores en la lectura en ni��os con alteraciones de la funci��n visual. En el estudio participaron 672 ni��os del Municipio de Lisboa (7.69��1.19 a��os): grupo de control (funci��n visual normal=562) y grupo experimental (alteraciones da funci��n visual=110). Se cuestionaron 34 profesores acerca del rendimiento escolar y lectura a trav��s de un cuestionario validado. Para la evaluaci��n en la lectura se emple�� la prueba de lectura de 34 palabras sueltas. Los ni��os con la funci��n visual alterada mostraron niveles m��s bajos de rendimiento escolar. Estaban en el nivel "negativo" del 10,9% de los ni��os con la funci��n visual alterada y s��lo del 5,3% de los ni��os con la funci��n visual normal. Estos ni��os comenten m��s errores en la lectura (p<0,001) con un mayor n��mero de no palabras (3,09��5,20) en comparaci��n con los ni��os con la funci��n visual normal (1,44��3,09). Comenten tambi��n m��s omisiones y adiciones de letras y confusiones de grafema, teniendo dificultades en el an��lisis global de la palabra. Se propone un modelo de orientaci��n para los profesores.

Avalia����o da acuidade visual em crian��as no ACeS D��o Laf��es

O sentido da vis��o �� crucial para o ser humano. As anomalias da fun����o visual associam-se sempre a um impacto na qualidade de vida, com repercuss��es importantes a n��vel individual, familiar e socioecon��mico. Na inf��ncia podem condicionar todo o desenvolvimento da crian��a, com consequ��ncias no desempenho escolar, nas escolhas profissionais e na probabilidade de aceder a um emprego com remunera����o satisfat��ria. Ao nascimento, o sistema visual ainda se encontra em desenvolvimento. Patologias que condicionem altera����es na qualidade e nitidez do est��mulo luminoso que chega �� retina podem alterar o normal desenvolvimento do sistema visual a n��vel cortical, causando diminui����o da capacidade visual potencialmente irrevers��vel ��� ambliopia. Embora exista uma plasticidade neuronal residual do sistema visual at�� cerca dos 10-12 anos, a efetividade de interven����es terap��uticas diminui drasticamente, em geral, a partir dos 6-7 anos. Desta forma, �� consensual que a dete����o e interven����o precoce das patologias oftalmol��gicas na inf��ncia �� fundamental para evitar perda de vis��o irrevers��vel, principalmente em idade pr��-escolar. Assim, o Programa Nacional de Sa��de Infantil e Juvenil integra as principais recomenda����es para avalia����o da fun����o visual em crian��as, desde o nascimento at�� aos 18 anos, onde os Cuidados de Sa��de Prim��rios assumem um papel crucial. A acuidade visual corresponde �� capacidade de vis��o dos detalhes, essencial para muitas tarefas quotidianas, como a leitura. A sua avalia����o �� fundamental e deve ser realizada sistematicamente, sobretudo aos 2-3 anos, aos 5 anos e aos 10 anos de idade da crian��a. Objetivo do estudo: Determinar a propor����o de crian��as (0-10 anos) com registo de acuidade visual nas consultas de vigil��ncia de sa��de infantil e juvenil, entre 2007 e 2015.

Quantitative evaluation of visual function 12 months after bilateral implantation of a diffractive trifocal IOL

PURPOSE: To quantitatively evaluate visual function 12 months after bilateral implantation of the Physiol FineVision�� trifocal intraocular lens (IOL) and to compare these results with those obtained in the first postoperative month. METHODS: In this prospective case series, 20 eyes of 10 consecutive patients were included. Monocular and binocular, uncorrected and corrected visual acuities (distance, near, and intermediate) were measured. Metrovision�� was used to test contrast sensitivity under static and dynamic conditions, both in photopic and low-mesopic settings. The same software was used for pupillometry and glare evaluation. Motion, achromatic, and chromatic contrast discrimination were tested using 2 innovative psychophysical tests. A complete ophthalmologic examination was performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Psychophysical tests were performed 1 month after surgery and repeated 12 months postoperatively. RESULTS: Final distance uncorrected visual acuity (VA) was 0.00 �� 0.08 and distance corrected VA was 0.00 �� 0.05 logMAR. Distance corrected near VA was 0.00 �� 0.09 and distance corrected intermediate VA was 0.00 �� 0.06 logMAR. Glare testing, pupillometry, contrast sensitivity, motion, and chromatic and achromatic contrast discrimination did not differ significantly between the first and last visit (p&gt;0.05) or when compared to an age-matched control group (p&gt;0.05). CONCLUSIONS: The Physiol FineVision�� trifocal IOL provided satisfactory full range of vision and quality of vision parameters 12 months after surgery. Visual acuity and psychophysical tests did not vary significantly between the first and last visit.

Interoperabilidade, processamento e an��lise visual de dados geogr��ficos

Esta disserta����o apresenta uma arquitectura interoper��vel que permite lidar com a obten����o, manipula����o, processamento e an��lise de informa����o geogr��fica. A aplica����o 30, implementada como parte da arquitectura, para al��m de permitir a visualiza����o e manipula����o de dados dentro de um ambiente 30, oferece m��todos que permitem descobrir, aceder e usar geo-processos, dispon��veis atrav��s de servi��os Web. A interac����o com o utilizador �� tamb��m feita atrav��s uma abordagem que quebra a t��pica complexidade que a maioria dos Sistemas de Informa����o Geogr��fica apresenta. O recurso �� programa����o visual reduz a complexidade do sistema, e permite aos operadores tirar proveito da localiza����o e de uma abstrac����o de um processo complexo, onde as unidades de processamento s��o representadas no terreno atrav��s de componentes 30 que podem ser directamente manipuladas e ligadas de modo a criar encandeamentos complexos de processos. Estes processos podem tamb��m ser criados visualmente e disponibilizados online. ABSTRACT; This thesis presents an interoperable architecture mainly designed for manipulation, processing and geographical information analysis. The three-dimensional interface, implemented as part of the architecture, besides allowing the visualization and manipulation of spatial data within a 30 environment, offers methods for discovering, accessing and using geo-processes, available through Web Services. Furthermore, the user interaction is done through an approach that breaks the typical complexity of most Geographic information Systems. This simplicity is in general archived through a visual programming approach that allows operators to take advantage of location, and use processes through abstract representations. Thus, processing units are represented on the terrain through 30 components, which can be directly manipulated and linked to create complex process chains. New processes can also be visually created and deployed online.

Visual programming in a heterogeneous multi-core environment

�� do conhecimento geral de que, hoje em dia, a tecnologia evolui rapidamente. S��o criadas novas arquitecturas para resolver determinadas limita����es ou problemas. Por vezes, essa evolu����o �� pac��fica e n��o requer necessidade de adapta����o e, por outras, essa evolu����o pode Implicar mudan��as. As linguagens de programa����o s��o, desde sempre, o principal elo de comunica����o entre o programador e o computador. Novas linguagens continuam a aparecer e outras est��o sempre em desenvolvimento para se adaptarem a novos conceitos e paradigmas. Isto requer um esfor��o extra para o programador, que tem de estar sempre atento a estas mudan��as. A Programa����o Visual pode ser uma solu����o para este problema. Exprimir fun����es como m��dulos que recebem determinado Input e retomam determinado output poder�� ajudar os programadores espalhados pelo mundo, atrav��s da possibilidade de lhes dar uma margem para se abstra��rem de pormenores de baixo n��vel relacionados com uma arquitectura espec��fica. Esta tese n��o s�� mostra como combinar as capacidades do CeII/B.E. (que tem uma arquitectura multi��processador heterog��nea) com o OpenDX (que tem um ambiente de programa����o visual), como tamb��m demonstra que tal pode ser feito sem grande perda de performance. ABSTRACT; lt is known that nowadays technology develops really fast. New architectures are created ln order to provide new solutions for different technology limitations and problems. Sometimes, this evolution is pacific and there is no need to adapt to new technologies, but things also may require a change every once ln a while. Programming languages have always been the communication bridge between the programmer and the computer. New ones keep coming and other ones keep improving ln order to adapt to new concepts and paradigms. This requires an extra-effort for the programmer, who always needs to be aware of these changes. Visual Programming may be a solution to this problem. Expressing functions as module boxes which receive determined Input and return determined output may help programmers across the world by giving them the possibility to abstract from specific low-level hardware issues. This thesis not only shows how the CeII/B.E. (which has a heterogeneous multi-core architecture) capabilities can be combined with OpenDX (which has a visual programming environment), but also demonstrates that lt can be done without losing much performance.

Reading Performance in Children with Visual Function Anomalies

Aims: To compare reading performance in children with and without visual function anomalies and identify the influence of abnormal visual function and other variables in reading ability. Methods: A cross-sectional study was carried in 110 children of school age (6-11 years) with Abnormal Visual Function (AVF) and 562 children with Normal Visual Function (NVF). An orthoptic assessment (visual acuity, ocular alignment, near point of convergence and accommodation, stereopsis and vergences) and autorefraction was carried out. Oral reading was analyzed (list of 34 words). Number of errors, accuracy (percentage of success) and reading speed (words per minute - wpm) were used as reading indicators. Sociodemographic information from parents (n=670) and teachers (n=34) was obtained. Results: Children with AVF had a higher number of errors (AVF=3.00 errors; NVF=1.00 errors; p<0.001), a lower accuracy (AVF=91.18%; NVF=97.06%; p<0.001) and reading speed (AVF=24.71 wpm; NVF=27.39 wpm; p=0.007). Reading speed in the 3rd school grade was not statistically different between the two groups (AVF=31.41 wpm; NVF=32.54 wpm; p=0.113). Children with uncorrected hyperopia (p=0.003) and astigmatism (p=0.019) had worst reading performance. Children in 2nd, 3rd, or 4th grades presented a lower risk of having reading impairment when compared with the 1st grade. Conclusion: Children with AVF had reading impairment in the first school grade. It seems that reading abilities have a wide variation and this disparity lessens in older children. The slow reading characteristics of the children with AVF are similar to dyslexic children, which suggest the need for an eye evaluation before classifying the children as dyslexic.

Whole-body cortisol increases after direct and visual contact with a predator in zebrafish, Danio rerio

Ornamental fish may be severely affected by a stressful environment. Stressors impair the immune response, reproduction and growth rate; thus, the identification of possible stressors will aid to improve the overall quality of ornamental fish. The aim of this study was to determine whole-body cortisol of adult zebrafish, Danio rerio, following visual or direct contact with a predator species. Zebrafish were distributed in three groups: the first group, which consisted of zebrafish reared completely isolated of the predator, was considered the negative control; the second group, in which the predator, Parachromis managuensis was stocked together with zebrafish, was considered the positive control; the third group consisted of zebrafish stocked in a glass aquarium, with direct visual contact with the predator. The mean whole-body cortisol concentration in zebrafish from the negative control was 6.78 +/- 1.12 ng g(-1), a concentration statistically lower than that found in zebrafish having visual contact with the predator (9.26 +/- 0.88 ng g(-1)) which, in turn, was statistically lower than the mean whole-body cortisol of the positive control group (12.35 +/- 1.59 ng g(-1)). The higher whole-body cortisol concentration found in fish from the positive control can be attributed to the detection, by the zebrafish, of relevant risk situations that may involve a combination of chemical, olfactory and visual cues. One of the functions of elevated cortisol is to mobilize energy from body resources to cope with stress. The elevation of whole-body cortisol in fish subjected to visual contact with the predator involves only the visual cue in the recognition of predation risk. We hypothesized that the zebrafish could recognize predator characteristics in P managuensis, such as length, shape, color and behavior. Nonetheless, the elevation of whole-body cortisol in zebrafish suggested that the visual contact of the predator may elicit a stress response in prey fish. This assertion has a strong practical application concerning the species distribution in ornamental fish markets in which prey species should not be allowed to see predator species. Minimizing visual contact between prey and predator fish may improve the quality, viability and welfare of small fish in ornamental fish markets. (c) 2007 Elsevier B.V. All rights reserved.

Knightly Masculinity, Court Games and Material Culture in Late Medieval Portugal: The case of Constable Afonso (c. 1480���1504)

This article explores the ways in which gender was used in order to transform an exiled and uneducated illegitimate child into a prince. Our study revolves around a member of the royal family, Afonso (c.1480���1504), who was brought up in hiding by peasants and who later, as a teenager, was reincorporated into the court. We argue that the keys to this process of rehabilitation were, on one hand, family politics centred around different configurations and on the other, his introduction into a court environment marked by the ideals of chivalry. Within this dynamic, material culture played a key role, because it gave the prince all the visual attributes of his new status, as well as allowing him the means to create a new self. We shall briefly introduce Afonso and his family context in order to give an insight into his life within changing political and dynastic contexts. Then, we will analyse the expression of manhood in the Portuguese court, using the spectacles at the court as a basis for observation, thus relating gender to material culture in a courtly environment.

Uma Introdu����o �� Sintaxe do C++: C++03 e C++11

A interac����o dos humanos com os computadores envolve uma combina����o das tarefas de programa����o e de utiliza����o. Nem sempre �� expl��cita a diferen��a entre as duas tarefas. Introduzir comandos num programa de desenho assistido por computador �� utiliza����o ou programa����o numa linguagem interpretada? Modificar uma folha de c��lculo com macros �� utiliza����o ou programa����o? Usar um ���Integrated Development Environment��� ou IDE para inserir dados num ficheiro �� utiliza����o (do IDE) ou programa����o? A escrita de um texto usando LaTeX ou HTML �� utiliza����o ou programa����o numa ���markup language���? Recorrer a um programa de computa����o simb��lica �� utiliza����o ou programa����o? Utilizar um processador de texto �� utiliza����o ou programa����o visual? Ao utilizador n��o se exige um conhecimento completo de todos os comandos, todos os menus, todos os s��mbolos do software que utiliza. Nem a memoriza����o da sintaxe e de todos os pormenores de funcionamento de um programa �� um atributo necess��rio ou sequer ��til ao utilizador; a concretiza����o desse conhecimento n��o assegura maior efici��ncia na utiliza����o. Quando se come��a, apenas algumas instru����es elementares s��o recebidas, por vezes de um colega, de um Professor, ou obtidas recorrendo �� pesquisa na Internet. Com a familiariza����o, o utilizador exige mais do Software que usa e de si pr��prio: um manual passa a ser um recurso de grande utilidade. A confian��a conquistada gera, periodicamente, a necessidade de auto-exame e de aumento do ��mbito do conhecimento. Desta forma, quem utiliza computadores acaba por ser confrontado com uma tarefa que, efectivamente, pode ser considerada ou requer programa����o. P��e-se uma quest��o no imediato (se ningu��m decidiu por si) que �� a da selec����o da linguagem de programa����o. A abordagem multiparadigma e longa experi��ncia de utiliza����o do C++ tornam-no atractivo para aplica����es onde a efici��ncia se combina com a disponibilidade de estruturas de dados e algoritmos adoptados pela ind��stria (o que coloquialmente se denomina STL, Standard Template Library, cf. [#breymann, #josuttis], mais geralmente biblioteca Standard). Adicionalmente, linguagens populares como o Java, C# e PHP possuem sintaxes inspiradas e em muitas partes coincidentes com as do C e C++. Por exemplo, um ciclo ���for��� em Java �� parcialmente coincidente com o do C99, que �� um sub-conjunto do ���for��� do C++. S��o os pormenores, a efici��ncia e as capacidades do C++ que permitem a cria����o de software Profissional. Todos os sistemas operativos cl��ssicos (Unix, Microsoft Windows, Linux) disp��em de compiladores, IDE, bibliotecas e s��o em grande parte constru��dos recorrendo a C e C++. Relativamente a outras linguagens, a quantidade de ferramentas dispon��vel e o conhecimento adquirido durante d��cadas �� dif��cil de ignorar. Esse conhecimento faz com que a sintaxe do C++ pare��a muito maior do que o estritamente necess��rio e afaste potenciais interessados. A longa evolu����o do C++ introduziu tamb��m uma diferen��a no estilo muito marcada. C��digo dos anos 80 e 90 do s��culo XX �� frequentemente menos leg��vel do que o que correntemente se produz. Muitos tutoriais dispon��veis online fazem parecer a linguagem menos rigorosa (e mais complexa) do que na realidade ��, j�� que raramente �� apresentado o caso geral da sintaxe. Constata-se que muitos autores ainda usam os cabe��alhos do C, quando j�� n��o s��o necess��rios. Scott Meyers afirma que o C++ �� uma federa����o de linguagens [#scottmeyers] e por esse facto requer perspectivas de abordagem distintas de outras linguagens. Sem alguma sistematiza����o �� dif��cil apreciar a sua compacidade e coer��ncia. Por��m, a forma harmoniosa como as componentes sint��cticas se encaixam �� uma grande mais-valia do C++ s�� constatada com experimenta����o e leitura atenta. A presente monografia dirige-se a quem pretenda utilizar o C++ como ferramenta profissional de Software. Em termos de pr��-requisitos Acad��micos, dir-se-�� que um curso (1�� Ciclo) de Ci��ncia ou de Engenharia aumentar�� o interesse por certos aspectos mais t��cnicos da linguagem mas qualquer indiv��duo com gosto pela experimenta����o tirar�� proveito do conte��do. Este texto n��o busca a exaustividade enciclop��dica na cobertura do tema. Neste texto forne��o, de forma directa, uma introdu����o ao C++ a qual permite come��ar a produzir c��digo sem os custos da dispers��o de fontes e nota����es na recolha de informa����o. Antecipo assim a sua utiliza����o nos Pa��ses de L��ngua Portuguesa, uma vez que os textos que encontrei s��o ora mais exigentes ora menos completos, frequentemente ambos.

Beam Energy Dependence Of Moments Of The Net-charge Multiplicity Distributions In Au+au Collisions At Rhic.

We report the first measurements of the moments--mean (M), variance (��(2)), skewness (S), and kurtosis (��)--of the net-charge multiplicity distributions at midrapidity in Au+Au collisions at seven energies, ranging from sqrt[sNN]=7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, ��(2)/M, S��, and ����(2), with the expectations from Poisson and negative binomial distributions (NBDs). The S�� values deviate from the Poisson baseline and are close to the NBD baseline, while the ����(2) values tend to lie between the two. Within the present uncertainties, our data do not show nonmonotonic behavior as a function of collision energy. These measurements provide a valuable tool to extract the freeze-out parameters in heavy-ion collisions by comparing with theoretical models.

Partitioning The Net Effect Of Host Diversity On An Emerging Amphibian Pathogen.

The 'dilution effect' (DE) hypothesis predicts that diverse host communities will show reduced disease. The underlying causes of pathogen dilution are complex, because they involve non-additive (driven by host interactions and differential habitat use) and additive (controlled by host species composition) mechanisms. Here, we used measures of complementarity and selection traditionally employed in the field of biodiversity-ecosystem function (BEF) to quantify the net effect of host diversity on disease dynamics of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd). Complementarity occurs when average infection load in diverse host assemblages departs from that of each component species in uniform populations. Selection measures the disproportionate impact of a particular species in diverse assemblages compared with its performance in uniform populations, and therefore has strong additive and non-additive properties. We experimentally infected tropical amphibian species of varying life histories, in single- and multi-host treatments, and measured individual Bd infection loads. Host diversity reduced Bd infection in amphibians through a mechanism analogous to complementarity (sensu BEF), potentially by reducing shared habitat use and transmission among hosts. Additionally, the selection component indicated that one particular terrestrial species showed reduced infection loads in diverse assemblages at the expense of neighbouring aquatic hosts becoming heavily infected. By partitioning components of diversity, our findings underscore the importance of additive and non-additive mechanisms underlying the DE.

Visual contrast sensitivity in tonic-clonic epileptic patients

We measured the effects of epilepsy on visual contrast sensitivity to linear and vertical sine-wave gratings. Sixteen female adults, aged 21 to 50 years, comprised the sample in this study, including eight adults with generalized tonic-clonic seizure-type epilepsy and eight age-matched controls without epilepsy. Contrast threshold was measured using a temporal two-alternative forced-choice binocular psychophysical method at a distance of 150 cm from the stimuli, with a mean luminance of 40.1 cd/m��. A one-way analysis of variance (ANOVA) applied to the linear contrast threshold showed significant differences between groups (F[3,188] = 14.829; p < .05). Adults with epilepsy had higher contrast thresholds (1.45, 1.04, and 1.18 times for frequencies of 0.25, 2.0, and 8.0 cycles per degree of visual angle, respectively). The Tukey Honestly Significant Difference post hoc test showed significant differences (p < .05) for all of the tested spatial frequencies. The largest difference between groups was in the lowest spatial frequency. Therefore, epilepsy may cause more damage to the neural pathways that process low spatial frequencies. However, epilepsy probably alters both the magnocellular visual pathway, which processes low spatial frequencies, and the parvocellular visual pathway, which processes high spatial frequencies. The experimental group had lower visual contrast sensitivity to all tested spatial frequencies.

Fracionamento dos carboidratos pelas equa����es do Cornell Net Carbohydrate and Protein System de tr��s cultivares de girassol na presen��a ou n��o de irriga����o

Objetivou-se quantificar as fra����es de carboidratos pelas equa����es do Cornell Net Carbohydrate and Protein System (CNCPS) de tr��s cultivares de girassol (Helianthus annuus L.) cultivados na presen��a ou n��o de irriga����o. A utiliza����o de uma prepara����o fibrosa, denominada parede celular (PC), nas equa����es da CNCPS, em substitui����o �� fibra em detergente neutro (FDN) n��o promoveu diferen��as nas fra����es de carboidratos B1 e C, mas influenciou as fra����es A e B2. Como os valores da fra����o B1, obtidos pelo modelo CNCPS foram menores que os teores de amido e pectina determinados em laborat��rio, sup��e-se que a pectina e outros oligossacar��deos da parede celular, solubilizados pela solu����o de detergente neutro (fibra sol��vel), nunca fizeram parte da fra����o B1, e sim da fra����o A. Apesar de os carboidratos da fibra sol��vel apresentarem elevadas taxas de degrada����o, n��o parece adequada a caracteriza����o da fibra sol��vel na fra����o A. Parece mais adequado que a fibra sol��vel (que inclui a pectina) seja alocada a uma fra����o exclusivamente sua, que pode ser a fra����o B2, e que seja criada uma nova fra����o, a B3, para os carboidratos diger��veis da parede celular. Assim, a fra����o B1 seria composta apenas de amido. A equa����o da fra����o C, que estima os carboidratos indiger��veis da parede celular, pode ser simplificada, relacionando a fra����o indiger��vel ao teor de lignina na mat��ria seca, e n��o �� FDN isenta de cinzas e prote��na, como atualmente utilizado. Esta proposta tem implica����es pr��ticas, uma vez que a fra����o indiger��vel da parede celular tem sido expressa em rela����o �� FDN, e n��o na MS, com base no fato de que os efeitos inibit��rios da lignina ocorrem sobre os componentes fibrosos da parede celular vegetal, e n��o sobre o conte��do celular.

Visual Feedforward Control in Human Locomotion During Avoidance of Obstacles that Change Size

The purpose of the current study was to understand how visual information about an ongoing change in obstacle size is used during obstacle avoidance for both lead and trail limbs. Participants were required to walk in a dark room and to step over an obstacle edged with a special tape visible in the dark. The obstacle's dimensions were manipulated one step before obstacle clearance by increasing or decreasing its size. Two increasing and two decreasing obstacle conditions were combined with seven control static conditions. Results showed that information about the obstacle's size was acquired and used to modulate trail limb trajectory, but had no effect on lead limb trajectory. The adaptive step was influenced by the time available to acquire and process visual information. In conclusion, visual information about obstacle size acquired during lead limb crossing was used in a feedforward manner to modulate trail limb trajectory.