Yes / Motion-in-depth can be detected by using two different types of binocular cues: change of disparity (CD) and inter-ocular velocity differences (IOVD). To investigate the underlying detection mechanisms, stimuli can be constructed that isolate these cues or contain both (FULL cue). Two different methods to isolate the IOVD cue can be employed: anti-correlated (aIOVD) and de-correlated (dIOVD) motion signals. While both types of stimuli have been used in studies investigating the perception of motion-in-depth, for the first time, we explore whether both stimuli isolate the same mechanism and how they differ in their relative efficacy. Here, we set out to directly compare aIOVD and dIOVD sensitivity by measuring motion coherence thresholds. In accordance with previous results by Czuba et al. (2010), we found that motion coherence thresholds were similar for aIOVD and FULL cue stimuli for most participants. Thresholds for dIOVD stimuli, however, differed consistently from thresholds for the two other cues, suggesting that aIOVD and dIOVD stimuli could be driving different visual mechanisms.

Yes / Motion in depth (MID) can be cued by high-resolution changes in binocular disparity over time (CD), and low-resolution interocular velocity differences (IOVD). Computational differences between these two mechanisms suggest that they may be implemented in visual pathways with different spatial and temporal resolutions. Here, we used fMRI to examine how achromatic and S-cone signals contribute to human MID perception. Both CD and IOVD stimuli evoked responses in a widespread network that included early visual areas, parts of the dorsal and ventral streams, and motion-selective area hMT+. Crucially, however, we measured an interaction between MID type and chromaticity. fMRI CD responses were largely driven by achromatic stimuli, but IOVD responses were better driven by isoluminant S-cone inputs. In our psychophysical experiments, when S-cone and achromatic stimuli were matched for perceived contrast, participants were equally sensitive to the MID in achromatic and S-cone IOVD stimuli. In comparison, they were relatively insensitive to S-cone CD. These findings provide evidence that MID mechanisms asymmetrically draw on information in precortical pathways. An early opponent motion signal optimally conveyed by the S-cone pathway may provide a substantial contribution to the IOVD mechanism. / Supported by the Biotechnology and Biological Sciences Research Council Grants BB/M002543/1 (to A.R.W.), BB/M001660/1 (to J.M.H.), and BB/M001210/1 (to M.B.). / Research Development Fund Publication Prize Award winner, May 2019.

Impairment of stereoacuity is common in the elderly population and is found to be a risk factor for falls. The purpose of these experiments was to extend knowledge regarding impairment of binocular vision and adaptive gait. Firstly using a 3D motion analysis system to measure how impairment of stereopsis affected adaptive gait during a negotiation of a step, secondly by determining which clinical stereotest was the most reliable for measuring stereoacuity in elderly subjects and finally investigating how manipulating the perceived height of a step in both binocular and monocular conditions affected negotiation of a step. In conditions of impaired stereopsis induced by acutely presented monocular blur, both young and elderly subjects adopted a safety strategy of increasing toe clearance of the step edge, even at low levels of monocular blur (+0.50DS) and the effect was greater when the dominant eye was blurred. The same adaptation was not found for individuals with chronic monocular blur, where vertical toe clearance did not change but variability of toe clearance increased compared to full binocular correction. Findings indicate stereopsis is important for accurately judging the height of a step, and offers support to epidemiological findings that impaired stereoacuity is a risk for falls. Poor agreement was found between clinical stereotests. The Frisby test was found to have the best repeatability. Finally, a visual illusion that caused a step to be perceived as taller led to increased toe elevation. This demonstrates a potential way of increasing toe clearance when stepping up and hence increase safety on stairs. / The Study data files are unavailable online.

No / Purpose To determine the test-retest reproducibility of accommodation measurements gathered in an unselected sample of primary school children. Methods Monocular and binocular amplitudes of accommodation (AA) were collected by five different Testers using the push-up method in an unselected sample of school children (n=137, age: 8.1±2.1-years). Testing was conducted on three occasions (average testing interval: 8-days) in 91.2% of the children. Results The median AA was 19.1D, the variation due to the identity of the Tester was 3.1D (p<0.001) and the within-subject variation (which takes the variation due to Tester identity into account) was 5.2D. Around 75-79% of children exhibited monocular AAs-12D when tested on the first occasion, but more than 90% exhibited an AA-12D when subsequently tested. Around 74-80% of those with an AA<12D on the first occasion had values-12D on subsequent testing even though no treatment had been undertaken. Poorer initial AA measurements were less likely to improve on repeat testing. Conclusions Our results reveal substantial intra-individual variation in AA measurements, raising questions about the usefulness of this test in children aged 4-12-years. We suggest that AA assessment may prove most useful in children in this age range as a pass/fail check for substantially reduced AA, for example, where the AA is <12D. Our sample would suggest that the prevalence of persistently reduced AA may be around 3.2% when tested under binocular conditions and 4-6.4% when tested monocularly.

INTRODUÇÃO: Aproximadamente 20% das crianças brasileiras em idade escolar apresentam algum problema oftalmológico e cerca de 95% dos distúrbios poderiam ser evitados ou minorados com promoção de saúde e assistência. A triagem visual é realizada por agentes comunitários de saúde, professores e alfabetizadores. Apesar do treinamento que os professores recebem, muitas crianças são dispensadas na triagem realizada nos serviços especializados e ainda existe um alto índice de absenteísmo, evidenciando-se a necessidade de melhorar a gestão dos recursos humanos e financeiros envolvidos no rastreamento visual e refrativo de escolares do ensino fundamental. OBJETIVOS: O estudo buscou comparar o rastreamento visual com corte de acuidade visual monocular, sem correção, <= 0,7, corte <= 0,6, medida de acuidade visual binocular e corte <= 0,7 e rastreamento refrativo com Spot Vision ScreeningTM PediaVision (SPOT). O segundo objetivo deste estudo foi avaliar a performance do SPOT como auto-refrator. MÉTODOS: Durante o Projeto Visão do Futuro, ocorrido em 2012, no HCFMUSP, avaliamos 1554 crianças, que preencheram os critérios de inclusão do estudo e destas, 148 foram submetidas ao photoscreening. RESULTADOS: A adoção de corte <= 0,6 no rastreamento visual monocular reduziria em 29% o número de crianças encaminhadas para avaliação oftalmológica e a triagem binocular com corte <= 0,7 em 41,1%, porém 61 casos de ambliopia deixariam de ser diagnosticados. O SPOT apresentou sensibilidade em detectar erro refracional com necessidade de prescrição de 73,3% e especificidade de 93,18% e, em média, a diferença da refração do Spot com a refração clínica subjetiva foi de + 0,63 DE com -0,33 DC no eixo de 4°, para o olho direito de cada paciente. CONCLUSÕES: As mudanças de corte para 0,6 e binocular 0,7 reduzem consideravelmente o número de avaliações, porém, a última deixa de diagnosticar parcela importante das crianças amblíopes. O SPOT apresentou bons índices de sensibilidade e especificidade no rastreamento refrativo em escolares e os valores de refração obtidos com este equipamento assemelham-se clinicamente aos valores de refração clínica subjetiva / BACKGROUND: Approximately 20% of brazilian children of school age have some eye problem and about 95% of the disorders could be prevented or reduced with health promotion and care. The visual screening is performed by community health agent and teachers. Despite training that teachers receive, many children are over-referred and also there\'s a high index of absence students, highlighting the need to improve the management of human and financial resources involved in visual and refractive screening of elementary school. PURPOSES: The present study aimed to compare visual screening by monocular visual acuity with cut-off of 0,7, 0,6, binocular visual acuity and cut-off 0,7 and photoscreening by Spot Vision ScreeningTM PediaVision (SPOT). The second objective of this study was to evaluate the performance of the Spot as auto-refractor. METHODS: During the Program \"Visão do Futuro\", in 2012, at HCFMUSP, 1554 children that met the inclusion criteria were examined, 148 of these were photoscreened. RESULTS: The adoption of cut-off <= 0.6 in monocular visual screening would reduce by 29% the number of children referred for ophthalmic evaluation and binocular screening with cutting <= 0.7 to 41.1%, however 61 cases of amblyopia would not be diagnosticated. SPOT had a sensitivity to detect refractive error requiring prescription of 73.3% and specificity of 93.18%. The mean difference between refraction obtained by Spot and clinical subjective refraction was of +0.63 SD combined with -0,33 CD in the 4° axis for right eye of each patient. CONCLUSIONS: Reducing cut-off in monocular visual acuity to 0.6 or 0.7 binocular considerably reduce the number of evaluations, however, the last leaves to diagnose significant portion of amblyopic children. The SPOT showed good levels of sensitivity and specificity in refractive screening of school children and refraction values obtained with this equipment are clinically similar to the values of subjective clinical refraction

INTRODUÇÃO: O relacionamento com o mundo exterior é feito fundamentalmente através da visão, de modo que qualquer anormalidade na função visual das crianças pré-escolares pode levar à dificuldade no aprendizado e no relacionamento social, assim como queda de rendimento nas atividades físicas e intelectuais. O Sistema Único de Saúde ainda não se estruturou para o atendimento oftalmológico do pré-escolar e os rastreamentos visuais realizados nas escolas são, às vezes, a única chance de detecção dos problemas visuais nesta população. OBJETIVOS: Detectar erros de refração não corrigidos e fatores causadores de ambliopia em uma população de préescolares com 4 - 6 anos de idade, por meio de rastreamento visual (medida da AV com a tabela de Snellen) e refrativo (medida do erro refrativo sem e com cicloplegia com o Spot(TM) Vision Screener). MÉTODOS: 97 crianças préescolares matriculadas em creches municipais e estaduais foram submetidas a rastreamento visual (ponto de corte: AV monocular <= 0,7 e/ou diferença duas linhas de Snellen entre os olhos) e rastreamento refrativo (ponto de corte: hipermetropia >= 3,00 D, miopia >= 0,75 D e astigmatismo >= 0,75 D). Todas as crianças foram submetidas a exame oftalmológico completo e mensuração do erro refrativo com cicloplegia com o refrator automático Topcon KR 8000. RESULTADOS: O método de rastreamento visual com tabela optométrica de Snellen apresentou valores de sensibilidade e especificidade, respectivamente, 58,6% e 64,7%. O método de rastreamento refrativo com Spot(TM) Vision Screener apresentou valores de sensibilidade e especificidade, respectivamente, 92,8% e 35,2% (sem cicloplegia) e 96,4% e 29,4% (com cicloplegia). Os percentuais estimados do não encaminhamento para exame oftalmológico completo das crianças com erros de refração acima do ponto de corte estabelecido foram: 46,4% para o rastreamento visual, 17,9% para o rastreamento refrativo com Spot(TM) sem cicloplegia e de 3,6% com o Spot(TM) com cicloplegia. CONCLUSÃO: Na população avaliada, o método de triagem refrativa pelo Spot(TM) Vision Screener com cicloplegia foi o mais efetivo / BACKGROUND: Contacting the outside world is fundamentally made through vision, so that any abnormalities in visual function of preschool children can lead to difficulty in learning and social networking, as well as income decline in physical and intellectual activities. Brazilian Health System (SUS) has not yet structured to preschool eye care and visual scans performed in schools are sometimes the only chance of detection of visual problems in this population. PURPOSES: Detect uncorrected refractive errors and factors that lead to ambliopia in a population of preschool children 4-6 years of age by visual screening (as visual acuity with the Snellen chart) and refractive (measurement of refractive error, without cicloplegia and under cicloplegia, by photoscreener Spot(TM) Vision Screener). METHODS: 97 preschool children enrolled in state and municipal schools were subjected to visual screening (cut-off: monocular visual acuity <= 0.7 and / or difference of two lines in Snellen chart between both eyes) and refractive screening (cut-off: hyperopia >= 3.00 D, myopia >= 0.75 D and astigmatism >= 0.75 D). All children underwent complete eye examination and measurement of refractive errors under cycloplegia with auto-refractor Topcon KR 8000. RESULTS: Visual screening method using chart Snellen had values of sensitivity and specificity, respectively, 58.6% and 64.7%. Refractive screening method using photoscreener Spot(TM) Vision Screener showed values of sensitivity and specificity, respectively, 92.8% and 35.2% (without cycloplegia), and 96.4% and 29.4% (under cycloplegia). The estimated percentage of non-referral to complete ophthalmologic examination of children with refractive errors above the cut-off point were 46.4% for the visual screening, 17.9% for the refractive screening with Spot(TM) without cycloplegia and 3.6 % with Spot(TM) under cycloplegia. CONCLUSION: In this population, the refractive screening method by Spot(TM) Vision Screener under cycloplegia was the most effective

INTRODUÇÃO: O relacionamento com o mundo exterior é feito fundamentalmente através da visão, de modo que qualquer anormalidade na função visual das crianças pré-escolares pode levar à dificuldade no aprendizado e no relacionamento social, assim como queda de rendimento nas atividades físicas e intelectuais. O Sistema Único de Saúde ainda não se estruturou para o atendimento oftalmológico do pré-escolar e os rastreamentos visuais realizados nas escolas são, às vezes, a única chance de detecção dos problemas visuais nesta população. OBJETIVOS: Detectar erros de refração não corrigidos e fatores causadores de ambliopia em uma população de préescolares com 4 - 6 anos de idade, por meio de rastreamento visual (medida da AV com a tabela de Snellen) e refrativo (medida do erro refrativo sem e com cicloplegia com o Spot(TM) Vision Screener). MÉTODOS: 97 crianças préescolares matriculadas em creches municipais e estaduais foram submetidas a rastreamento visual (ponto de corte: AV monocular <= 0,7 e/ou diferença duas linhas de Snellen entre os olhos) e rastreamento refrativo (ponto de corte: hipermetropia >= 3,00 D, miopia >= 0,75 D e astigmatismo >= 0,75 D). Todas as crianças foram submetidas a exame oftalmológico completo e mensuração do erro refrativo com cicloplegia com o refrator automático Topcon KR 8000. RESULTADOS: O método de rastreamento visual com tabela optométrica de Snellen apresentou valores de sensibilidade e especificidade, respectivamente, 58,6% e 64,7%. O método de rastreamento refrativo com Spot(TM) Vision Screener apresentou valores de sensibilidade e especificidade, respectivamente, 92,8% e 35,2% (sem cicloplegia) e 96,4% e 29,4% (com cicloplegia). Os percentuais estimados do não encaminhamento para exame oftalmológico completo das crianças com erros de refração acima do ponto de corte estabelecido foram: 46,4% para o rastreamento visual, 17,9% para o rastreamento refrativo com Spot(TM) sem cicloplegia e de 3,6% com o Spot(TM) com cicloplegia. CONCLUSÃO: Na população avaliada, o método de triagem refrativa pelo Spot(TM) Vision Screener com cicloplegia foi o mais efetivo / BACKGROUND: Contacting the outside world is fundamentally made through vision, so that any abnormalities in visual function of preschool children can lead to difficulty in learning and social networking, as well as income decline in physical and intellectual activities. Brazilian Health System (SUS) has not yet structured to preschool eye care and visual scans performed in schools are sometimes the only chance of detection of visual problems in this population. PURPOSES: Detect uncorrected refractive errors and factors that lead to ambliopia in a population of preschool children 4-6 years of age by visual screening (as visual acuity with the Snellen chart) and refractive (measurement of refractive error, without cicloplegia and under cicloplegia, by photoscreener Spot(TM) Vision Screener). METHODS: 97 preschool children enrolled in state and municipal schools were subjected to visual screening (cut-off: monocular visual acuity <= 0.7 and / or difference of two lines in Snellen chart between both eyes) and refractive screening (cut-off: hyperopia >= 3.00 D, myopia >= 0.75 D and astigmatism >= 0.75 D). All children underwent complete eye examination and measurement of refractive errors under cycloplegia with auto-refractor Topcon KR 8000. RESULTS: Visual screening method using chart Snellen had values of sensitivity and specificity, respectively, 58.6% and 64.7%. Refractive screening method using photoscreener Spot(TM) Vision Screener showed values of sensitivity and specificity, respectively, 92.8% and 35.2% (without cycloplegia), and 96.4% and 29.4% (under cycloplegia). The estimated percentage of non-referral to complete ophthalmologic examination of children with refractive errors above the cut-off point were 46.4% for the visual screening, 17.9% for the refractive screening with Spot(TM) without cycloplegia and 3.6 % with Spot(TM) under cycloplegia. CONCLUSION: In this population, the refractive screening method by Spot(TM) Vision Screener under cycloplegia was the most effective

INTRODUÇÃO: Aproximadamente 20% das crianças brasileiras em idade escolar apresentam algum problema oftalmológico e cerca de 95% dos distúrbios poderiam ser evitados ou minorados com promoção de saúde e assistência. A triagem visual é realizada por agentes comunitários de saúde, professores e alfabetizadores. Apesar do treinamento que os professores recebem, muitas crianças são dispensadas na triagem realizada nos serviços especializados e ainda existe um alto índice de absenteísmo, evidenciando-se a necessidade de melhorar a gestão dos recursos humanos e financeiros envolvidos no rastreamento visual e refrativo de escolares do ensino fundamental. OBJETIVOS: O estudo buscou comparar o rastreamento visual com corte de acuidade visual monocular, sem correção, <= 0,7, corte <= 0,6, medida de acuidade visual binocular e corte <= 0,7 e rastreamento refrativo com Spot Vision ScreeningTM PediaVision (SPOT). O segundo objetivo deste estudo foi avaliar a performance do SPOT como auto-refrator. MÉTODOS: Durante o Projeto Visão do Futuro, ocorrido em 2012, no HCFMUSP, avaliamos 1554 crianças, que preencheram os critérios de inclusão do estudo e destas, 148 foram submetidas ao photoscreening. RESULTADOS: A adoção de corte <= 0,6 no rastreamento visual monocular reduziria em 29% o número de crianças encaminhadas para avaliação oftalmológica e a triagem binocular com corte <= 0,7 em 41,1%, porém 61 casos de ambliopia deixariam de ser diagnosticados. O SPOT apresentou sensibilidade em detectar erro refracional com necessidade de prescrição de 73,3% e especificidade de 93,18% e, em média, a diferença da refração do Spot com a refração clínica subjetiva foi de + 0,63 DE com -0,33 DC no eixo de 4°, para o olho direito de cada paciente. CONCLUSÕES: As mudanças de corte para 0,6 e binocular 0,7 reduzem consideravelmente o número de avaliações, porém, a última deixa de diagnosticar parcela importante das crianças amblíopes. O SPOT apresentou bons índices de sensibilidade e especificidade no rastreamento refrativo em escolares e os valores de refração obtidos com este equipamento assemelham-se clinicamente aos valores de refração clínica subjetiva / BACKGROUND: Approximately 20% of brazilian children of school age have some eye problem and about 95% of the disorders could be prevented or reduced with health promotion and care. The visual screening is performed by community health agent and teachers. Despite training that teachers receive, many children are over-referred and also there\'s a high index of absence students, highlighting the need to improve the management of human and financial resources involved in visual and refractive screening of elementary school. PURPOSES: The present study aimed to compare visual screening by monocular visual acuity with cut-off of 0,7, 0,6, binocular visual acuity and cut-off 0,7 and photoscreening by Spot Vision ScreeningTM PediaVision (SPOT). The second objective of this study was to evaluate the performance of the Spot as auto-refractor. METHODS: During the Program \"Visão do Futuro\", in 2012, at HCFMUSP, 1554 children that met the inclusion criteria were examined, 148 of these were photoscreened. RESULTS: The adoption of cut-off <= 0.6 in monocular visual screening would reduce by 29% the number of children referred for ophthalmic evaluation and binocular screening with cutting <= 0.7 to 41.1%, however 61 cases of amblyopia would not be diagnosticated. SPOT had a sensitivity to detect refractive error requiring prescription of 73.3% and specificity of 93.18%. The mean difference between refraction obtained by Spot and clinical subjective refraction was of +0.63 SD combined with -0,33 CD in the 4° axis for right eye of each patient. CONCLUSIONS: Reducing cut-off in monocular visual acuity to 0.6 or 0.7 binocular considerably reduce the number of evaluations, however, the last leaves to diagnose significant portion of amblyopic children. The SPOT showed good levels of sensitivity and specificity in refractive screening of school children and refraction values obtained with this equipment are clinically similar to the values of subjective clinical refraction

Impairment of stereoacuity is common in the elderly population and is found to be a risk factor for falls. The purpose of these experiments was to extend knowledge regarding impairment of binocular vision and adaptive gait. Firstly using a 3D motion analysis system to measure how impairment of stereopsis affected adaptive gait during a negotiation of a step, secondly by determining which clinical stereotest was the most reliable for measuring stereoacuity in elderly subjects and finally investigating how manipulating the perceived height of a step in both binocular and monocular conditions affected negotiation of a step. In conditions of impaired stereopsis induced by acutely presented monocular blur, both young and elderly subjects adopted a safety strategy of increasing toe clearance of the step edge, even at low levels of monocular blur (+0.50DS) and the effect was greater when the dominant eye was blurred. The same adaptation was not found for individuals with chronic monocular blur, where vertical toe clearance did not change but variability of toe clearance increased compared to full binocular correction. Findings indicate stereopsis is important for accurately judging the height of a step, and offers support to epidemiological findings that impaired stereoacuity is a risk for falls. Poor agreement was found between clinical stereotests. The Frisby test was found to have the best repeatability. Finally, a visual illusion that caused a step to be perceived as taller led to increased toe elevation. This demonstrates a potential way of increasing toe clearance when stepping up and hence increase safety on stairs.

The dissertation examines the problem of temporally uneven information processing in the nervous system. We chose binocular rivalry and ambiguous figure perception for our research, as these phenomena are pronounced examples of cyclical processes in perception. Binocular rivalry and ambiguous figure perception are cases in perception, when the subjective perception every few seconds vacillates between alternative interpretations, while the physical stimulation remains constant. Our research examines the relationship between these perception alterations and millisecond-order cycles of information processing in the nervous system. We created special equipment to present visual stimuli intermittently (flickering) and examined, whether the flickering rate of the stimuli influences the temporal characteristics (mean dominance duration) of binocular rivalry and ambiguous figure perception. The results confirmed the relationship, but also highlighted the temporal instability of binocular rivalry dominance durations. / Disertacijoje nagrinėjama informacijos apdorojimo procesų nervų sistemoje laikinio netolygumo problema. Tyrimui pasirinkti akių konkurencijos ir dviprasmių figūrų suvokimo reiškiniai, ryškiai atspindintys suvokimo procesų cikliškumą. Akių konkurencija ir dviprasmių figūrų suvokimas yra reiškiniai, kuomet fiziniam stimului nesikeičiant, subjektyvus suvokimas kas kelias sekundes kaitaliojasi tarp alternatyvių interpretacijų. Tyrime nagrinėjamas šių sekundinių suvokimo ciklų ryšys su milisekundžių eilės informacijos apdorojimo ciklais. Sukurta speciali aparatūra, kuria stimulai į akis buvo pateikti mirksintys nustatytu dažniu, ir tikrinta, ar stimulų mirksėjimo dažnis lemia akių konkurencijos ir dviprasmių figūrų suvokimo laikines savybes (vidutinę dominavimo trukmę). Rezultatai patvirtino šį ryšį, tačiau taip pat nustatyta, kad akių konkurencijos vidutinei dominavimo trukmei yra būdingas laikinis nestabilumas – dominavimo trukmė gana didele amplitude kinta kelių minučių, valandos ir kelių parų eigoje.