To assess the effectiveness of a kindergarten vision screening program by randomly assigning schools to receive or not receive vision screening, then following up 1.5 years later. Fifty high-needs elementary schools were randomly assigned to participate or not in a vision screening program for children in senior kindergarten (SK; age 5‒6 years). When the children were in Grade 2 (age 6‒7 years), vision screening was conducted at all 50 schools. Contrary to expectations, screened and non-screened schools did not differ in the prevalence of suspected amblyopia in Grade 2 (8.6

BACKGROUND:Visual problems can negatively affect visual development and learning but often go undetected. We assessed the feasibility of scaling up a school-based screening program to identify and treat kindergarten children with visual problems. METHODS:We conducted a prospective cohort study offering vision screening to junior (JK) and senior kindergarten (SK) children attending 43 schools in 15 Ontario communities. Screening comprised photoscreeners and tests of visual acuity, stereoacuity and eye alignment. Children who failed any test were referred for a comprehensive eye examination, with treatment as needed (e.g., glasses). RESULTS:Using a passive consent model, 89% of children were screened compared with 62% using an active consent model (p < 0.001). Referral rates to an optometrist varied across schools (mean referral rate for children in JK 53%, range 25%-83%; mean referral rate for children in SK 34%, range 12%-61%). Among 4811 children who were screened, a visual problem was detected in 516 (10.7%), including 164 (3.4%) with amblyopia and 324 (6.7%) with clinically significant refractive errors. For 347 (67.2%) of the children with a visual problem, this was their first eye examination. Rescreening in Year 2 did not lead to detection of additional problems among children who passed screening in Year 1. Regardless of location (child's school or optometrist's office), 1563 (68.9%) of children attended the follow-up optometry examination. Most of the children who were surveyed (291 of 322, 90.4%) indicated that they enjoyed vision screening. INTERPRETATION:Many children in Ontario with a visual problem were not being identified by the status quo in 2015-2017. We found that in-school vision screening with follow-up eye examinations is an effective strategy for identifying at-risk children and placing them in eye care before grade 1.

Vision impairment has a significant impact on quality of life. Seventy percent of existing vision impairment in Canada is estimated to be correctable with prescription glasses. The sizeable proportion of correctable vision impairment appears related to the barriers to access to vision care in Canada. The objective of this scoping review is to determine gaps in the understanding of barriers to accessing vision care for vulnerable populations in Canada. The Arksey and O'Malley methodological framework was adopted. Studies published in English between 2005 and September 2017 on access to primary vision care by vulnerable populations in Canada were reviewed. Electronic databases used included Ovid MEDLINE, Ovid EMBASE, SCOPUS, ProQuest, and CINAHL. The Behavioural Model of Health Services Use was used to elucidate gaps in the literature. To develop relevant policies around vision care, efforts should be made to assess all dimensions of access for vulnerable populations across Canada.

Objectives To assess the diagnostic accuracy of five vision screening tools used in a school setting using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Design We compared the results of the five best evidence-based screening tools available in 2014 to the results of a comprehensive eye exam with cycloplegic refraction by a licenced optometrist. Screening included Cambridge Crowded Acuity Cards, Plusoptix S12 and Spot photoscreeners, Preschool Randot Stereoacuity Test and the Pediatric Vision Scanner (PVS). Referral criteria followed AAPOS (2013) guidelines and published norms. Setting A large school in Toronto, Canada, with 25 split classrooms of junior kindergarten (JK: 4 year olds) and senior kindergarten (SK: 5 year olds) children. Participants Over 2 years, 1132 eligible children were enrolled at the school. After obtaining parental consent, 832 children were screened. Subsequently, 709 children had complete screening and optometry exam data. Main outcome measures The presence/absence of a visual problem based on optometrist's assessment: amblyopia, amblyopia risk factors (reduced stereoacuity, strabismus and clinically significant refractive errors) and any other ocular problem (eg, nystagmus). Results Overall, 26.5% of the screened children had a visual problem, including 5.9% with amblyopia. Using all five tools, screening sensitivity=84% (95% CI 78 to 89), specificity=49% (95%CI 44 to 53), PPV=37% (95% CI 33 to 42), and NPV=90% (95% CI 86 to 93). The odds of having a correct screening result in SK (mean age=68.2 months) was 1.5 times those in JK (mean age=55.6 months; 95%CI 1.1 to 2.1), with sensitivity improved to 89% (95% CI 80 to 96) and specificity improved to 57% (95% CI 50 to 64) among SK children. Conclusions A school-based screening programme correctly identified 84% of those kindergarten children who were found to have a visual problem by a cyclopleged optometry exam. Additional analyses revealed how accuracy varies with different combinations of screening tools and referral criteria.

Memory functioning undergoes dynamic changes between childhood and adulthood. Spontaneous use of elaborative strategies, which can enhance the recall of information, expands with age and contributes to age-associated improvement in memory functioning. Findings from lesion and neuroimaging studies suggest that the ability to use elaborative strategies is dependent upon intact functioning of the prefrontal cortex (PFC), particularly the dorsolateral PFC region. Because the PFC undergoes protracted maturation, we examined whether age difference in the structure of the PFC is correlated with age-associated increase in strategy use. Here, we investigated the relationship between PFC volume and spontaneous strategy use in a sample of 120 participants aged 5-25 years. We assessed semantic clustering during recall with a standardized word-list recall task (California Verbal Learning Task children's version, CVLT-C) and computed PFC regional volumes from participants' structural brain images. We observed an age-associated increase in the use of semantic clustering and an age-associated decrease in volumes of the PFC. Further, we found that smaller PFC volume was linked to increased use of semantic clustering. Importantly, the volume of the right dorsolateral PFC partially explained the relation between age and the use of semantic clustering. These findings suggest that PFC maturation supports the development of strategy use and lends further support for the notion that brain-behavior relations change across development.

An individual's socioeconomic status (SES) is often viewed as a proxy for a host of environmental influences. SES disparities have been linked to variance in brain structures particularly the hippocampus, a neural substrate of learning and memory. However, it is unclear whether the association between SES and hippocampal volume is similar in children and adults. We investigated the relationship between hippocampal volume and SES in a group of children (n = 31, age 8-12 years) and a group of young adults (n = 32, age 18-25 years). SES was assessed with four indicators that loaded on a single factor, therefore a composite SES scores was used in the main analyses. Hippocampal volume was measured using manual demarcation on high resolution structural images. SES was associated with hippocampal volume in the children, but not in adults, suggesting that in childhood, but not adulthood, SES-related environmental factors influence hippocampal volume. In addition, hippocampal volume, but not SES, was associated with scores on a memory task, suggesting that net effects of postnatal environmental factors, captured by SES, are more distal determinants of memory performance than hippocampal volume. Longitudinal investigation of the association between SES, hippocampal volume and cognitive functioning may further our understanding of the putative neural mechanisms underlying SES-related environmental effects on cognitive development.

Faces are adaptively coded relative to visual norms that are updated by experience, and this adaptive coding is linked to face recognition ability. Here we investigated whether adaptive coding of faces is disrupted in individuals (adolescents and adults) who experience face recognition difficulties following visual deprivation from congenital cataracts in infancy. We measured adaptive coding using face identity aftereffects, where smaller aftereffects indicate less adaptive updating of face-coding mechanisms by experience. We also examined whether the aftereffects increase with adaptor identity strength, consistent with norm-based coding of identity, as in typical populations, or whether they show a different pattern indicating some more fundamental disruption of face-coding mechanisms. Cataract-reversal patients showed significantly smaller face identity aftereffects than did controls (Experiments 1 and 2). However, their aftereffects increased significantly with adaptor strength, consistent with norm-based coding (Experiment 2). Thus we found reduced adaptability but no fundamental disruption of norm-based face-coding mechanisms in cataract-reversal patients. Our results suggest that early visual experience is important for the normal development of adaptive face-coding mechanisms.

Although object perception involves encoding a wide variety of object properties (e.g., size, color, viewpoint), some properties are irrelevant for identifying the object. The key to successful object recognition is having an internal representation of the object identity that is insensitive to these properties while accurately representing important diagnostic features. Behavioral evidence indicates that the formation of these kinds of invariant object representations takes many years to develop. However, little research has investigated the developmental emergence of invariant object representations in the ventral visual processing stream, particularly in the lateral occipital complex (LOC) that is implicated in object processing in adults. Here, we used an fMR adaptation paradigm to evaluate age-related changes in the neural representation of objects within LOC across variations in size and viewpoint from childhood through early adulthood. We found a dissociation between the neural encoding of object size and object viewpoint within LOC: by age of 5-10 years, area LOC demonstrates adaptation across changes in size, but not viewpoint, suggesting that LOC responses are invariant to size variations, but that adaptation across changes in view is observed in LOC much later in development. Furthermore, activation in LOC was correlated with behavioral indicators of view invariance across the entire sample, such that greater adaptation was correlated with better recognition of objects across changes in viewpoint. We did not observe similar developmental differences within early visual cortex. These results indicate that LOC acquires the capacity to compute invariance specific to different sources of information at different time points over the course of development.

Previous studies have shown that by age 5-8 years, the lateral occipital complex (LOC) shows adult-like responses when contrasting images of objects versus scrambled objects. Here, we selected complex novel shapes and manipulated both size and viewpoint of these shapes in an adaptation paradigm to assess the neural profile in LOC in children (5-10 years), adolescents (11-16 years), and adults (18-27 years). Observers were shown blocks in which the same object was shown repeatedly, the same object was shown in different sizes/views, or different objects were shown.Hidden formatting deleted. Delete this text! yes"> The results showed that all 3 age groups demonstrated size-invariance, showing a reduced neural response to the same-object-same-size condition and the same-object-different-sizes conditions. However, only adults showed evidence of view-invariance. Adolescents and children showed a similar neural response to the same object different views condition and the different objects condition.Hidden formatting deleted. Delete this text! yes"> The results suggest that size-invariance develops early but the neural mechanisms underlying view-invariant object recognition is not yet mature even in adolescents. Meeting abstract presented at VSS 2013

We investigated the effects of early visual deprivation on the underlying representation of the six basic emotions. Using multi-dimensional scaling (MDS), we compared the similarity judgments of adults who had missed early visual input because of bilateral congenital cataracts to control adults with normal vision. Participants made similarity judgments of the six basic emotional expressions, plus neutral, at three different intensities. Consistent with previous studies, the similarity judgments of typical adults could be modeled with four underlying dimensions, which can be interpreted as representing pleasure, arousal, potency and intensity of expressions. As a group, cataract-reversal patients showed a systematic structure with dimensions representing pleasure, potency, and intensity. However, an arousal dimension was not obvious in the patient group's judgments. Hierarchical clustering analysis revealed a pattern in patients seen in typical 7-year-olds but not typical 14-year-olds or adults. There was also more variability among the patients than among the controls, as evidenced by higher stress values for the MDS fit to the patients' data and more dispersed weightings on the four dimensions. The findings suggest an important role for early visual experience in shaping the later development of the representations of emotions. Since the normal underlying structure for emotion emerges postnatally and continues to be refined until late childhood, the altered representation of emotion in adult patients suggests a sleeper effect.

Cortical reorganization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood.

Anecdotal reports obtained from three individuals with prosopagnosia, all of whom have participated in an investigation, capture the essence of their impairment. This article focuses on the contrast between two prominent forms of prosopagnosia, one of which results from an acquired brain insult in an otherwise premorbidly normal individual and a second which appears to be lifelong and occurs in the absence of any obvious brain damage, at least as evident on conventional brain imaging. It reviews two central issues: the first concerns the similarities and differences in the psychological representations of faces in acquired prosopagnosia (AP) and congenital prosopagnosia (CP), and the second concerns the nature of the underlying neural representations of faces in these two populations. Some well-established overlapping behavioral characteristics are identified.

Research investigating the neural correlates of face processing has emphasized differences in neural activity when participants view faces versus other stimulus categories (e.g., houses). Much less is known about the neural mechanisms underlying the discrimination among individual faces. Using a large number of female faces, here we show that the amplitude of the face-sensitive N170 electrocortical component is related to a range of facial characteristics. The right N170 amplitude was related to eye color and face width. The left N170 amplitude was related to eye shape and face proportions, suggesting a functional dissociation between hemispheres. In contrast, the amplitude of the P100 and N250 components was largely unaffected by these facial characteristics. Consistent with recent findings in non-human primates, we identify for the first time evidence of human electrocortical brain potentials that are sensitive to variations in specific facial characteristics, a prerequisite for recognizing the identity of individual faces.

Adapting to a face shifts the perceived identity of a subsequent face in the direction opposite to the adapting face, a phenomenon known as a face identity aftereffect. In the present study, we examined the temporal dynamics of such aftereffects in children at an age when face processing abilities are not yet adult-like. We hypothesized that children's difficulties in face processing may stem from an unstable mental representation of facial identity, which may be especially prone to adaptation aftereffects. Using a novel procedure designed especially for children, we show that both 8-year-olds and adults demonstrate identity aftereffects of similarly small size after just one second of viewing the adapting face, and that the strength of the aftereffect increases logarithmically and similarly with longer adapting durations for both age groups. The findings suggest that the mental representation of facial identity in 8-year-olds is no more malleable than that of adults, at least in response to short-term adaptation.

A useful framework for understanding the mental representation of facial identity is face-space (Valentine, 1991), a multi-dimensional cognitive map in which individual faces are coded relative to the average of previously encountered faces, and in which the distance among faces represents their perceived similarity. We examined whether individuals with prosopagnosia, a disorder characterized by an inability to recognize familiar faces despite normal visual acuity and intellectual abilities, evince behavior consistent with this underlying representational schema. To do so, we compared the performance of 6 individuals with congenital prosopagnosia (CP), with a group of age- and gender-matched control participants in a series of experiments involving judgments of facial identity. We used digital images of male and female faces and morphed them to varying degrees relative to an average face, to create caricatures, anti-caricatures, and anti-faces (i.e. faces of the opposite identity). Across 5 behavioral tasks, CP individuals' performance was similar to that of the control group and consistent with the face-space framework. As a test of the sensitivity of our measures in revealing face processing abnormalities, we also tested a single acquired prosopagnosic (AP) individual, whose performance on the same tasks deviated significantly from the control and CP groups. The findings suggest that, despite an inability to recognize individual identities, CPs perceive faces in a manner consistent with norm-based coding of facial identity, although their representation is likely supported by a feature-based strategy. We suggest that the apparently normal posterior cortical regions, including the fusiform face area, serve as the neural substrate for at least a coarse, feature-based face-space map in CP and that their face recognition impairment arises from the disconnection between these regions and more anterior cortical sites.

Recognizing a face from a novel viewpoint requires processing the structural properties of the face that are reliable cues to identity and view-invariant. One such property may be second-order relations (e.g., spacing between eyes and mouth). In Experiment 1, we investigated whether 10-year-old children's and adults' recognition of faces across changes in viewpoint could be improved through training, and whether training results were correlated with sensitivity to second-order relations. Over two one-hour sessions 10-year-olds and adults (n = 10) were trained to make same/different judgments about facial identity between faces seen from different viewpoints. Consistent with previous studies (e.g. Mondloch et al., 2003), 10-year-olds were worse overall than adults. However, both groups improved at a similar rate during training, with 10-year-olds' final accuracy being comparable to adults' accuracy prior to training. There was no correlation between performance on the viewpoint training task and sensitivity to second-order relations either before or after training in either age group, perhaps because observers may have learned to match specific views of the training faces and not a general skill. In Experiment 2, we investigated whether training adults (n = 12) would be more effective if novel faces were introduced as training progressed over the two-day period. Improvement in matching faces across changes in viewpoint transferred from the first 7 facial identities to the next 7 identities, a result suggesting that training improved a general skill in view-invariant recognition. However, improvement failed to transfer to the third set of 7 identities and was not correlated with sensitivity to second-order relations, results suggesting that the learning also involved the linking of view-specific exemplars. Collectively, the results indicate that improvements in recognizing faces across changes in viewpoint involve both view-specific and view-independent processes, and are not directly related to sensitivity to second-order relations.

The neuropsychological disorder, known as visual agnosia, refers to the impairment in deriving the meaning of a visually presented stimulus, in spite of the affected individual having intact sensory and low-level vision, and normal language and semantic function. This type of disorder is intriguing both clinically and scientifically, and vision scientists have studied visual agnosia as a means of shedding light on how the normal visual system functions. Considerable progress has been made in this domain, in parallel with detailed behavioral and neural investigations of the visual system of neurologically intact individuals and of nonhuman primates. Here, we focus specifically on the neuropsychological studies and provide a broad overview of the wide range of impairments that fall under the label 'visual agnosia', including those acquired following brain damage in premorbidly normal individuals, those that appear to have been present since birth, and those whose onset is late in life and is associated with neurodegeneration. We also outline the different subtypes of visual agnosia, including those that affect primarily the recognition of faces, words, or objects, and we lay out some of the key questions currently being addressed by researchers in this domain. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

Early visual deprivation caused by bilateral congenital cataracts produces deficits in discriminating faces that differ in the spacing of features, but not in feature shape (Le Grand et al. [2001] Nature 410: 810). We investigated whether these deficits are specific to human faces by testing patients' ability to discriminate between stimuli differing only in feature spacing in human and monkey faces (Experiment 1) and in houses (Experiment 2). Patients, as a group, showed deficits on only one task: they had lower accuracy than normal in discriminating feature spacing in human faces. In contrast, they were normal in discriminating feature spacing in monkey faces and in houses. The results suggest that early visual experience is necessary to set up (or preserve) the neural architecture used for processing human faces, but not for processing objects in general. (C) 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 775-781, 2010.