A lack of vision: evidence for poor communication of visual problems and support needs in education statements/plans for children with SEN.

OBJECTIVE: Visual dysfunction is more common in children with neurological impairments and previous studies have recommended such children receive visual and refractive assessment. In the UK, children with neurological impairment often have educational statementing for Special Educational Needs (SEN) and the statement should detail all health care and support needs to ensure the child's needs are met during school life. STUDY DESIGN: This study examined the representation of visual information in statements of SEN and compared this to orthoptic visual information from school visual assessments for children in a special school in Northern Ireland, UK. METHODS: The parents of 115 school children in a special school were informed about the study via written information. Participation involved parents permitting the researchers to access their child's SEN educational statement and orthoptic clinical records. RESULTS: Statement information was accessed for 28 participants aged between four and 19 years; 25 contained visual information. Two participants were identified in their statements as having a certification of visual impairment. An additional 10 children had visual acuity ≥ 0.3 logMAR. This visual deficit was not reported in statements in eight out of these 12 cases (67%). 11 participants had significant refractive error and wore spectacles, but only five (45%) had this requirement recorded in their statement. Overall, 10 participants (55%) had either reduced visual acuity or significant refractive error which was not recorded in their statement. CONCLUSIONS: Despite additional visual needs being common, and described in clinical records, the majority of those with reduced vision and/or spectacle requirements did not have this information included in their statement. If visual limitations are not recognized by educational services, the child's needs may not be met during school life. More comprehensive eye care services, embedded with stakeholder communication and links to education are necessary to improve understanding of vision for children with neurological impairments.

In-school eyecare in special education settings has measurable benefits for children's vision and behaviour.

OBJECTIVES: To determine whether implementation of comprehensive in-school eyecare results in measurable benefits for children and young people in terms of visual status, classroom behaviours and how well their visual needs are met. DESIGN: School-based observational study. PARTICIPANTS & METHODS: 200 pupils [mean age 10 years 9 months, 70% male, majority moderate (40%) or severe (35%) learning difficulty] of a special education school in the UK. A sector-agreed in-school eyecare framework including full eye examination and cycloplegic refraction, dispensing of spectacles (as appropriate) and written reporting of outcomes to parents/teachers was applied. Classroom behaviours were observed and recorded prior to, and after, the in-school eyecare. Surveys were employed to obtain visual histories from parents/teachers. School records and statutory documents were reviewed for diagnostic and learning disability classifications. Visual function and ocular health were profiled at baseline and significant visual deficits identified. Where such deficits were previously unrecognised, untreated or not compensated for (e.g. correction of refractive error, enlargement of educational material) they were recorded as 'unmet visual need'. At follow-up, 2-5 months after initial (baseline) measures, eye examinations, parent/teacher surveys and behaviour observations were repeated. Follow-up measures were used to determine if measurable improvements were evident in visual function, ocular health, the level of unmet need and classroom behaviour following implementation of in-school eyecare. RESULTS: 199 participants completed baseline and follow-up measures. 122 (61%) participants presented with at least one significant visual or ocular health deficit and 90 (45%) participants had at least one unmet visual need. Younger pupils and those with no previous history of eyecare were more likely to demonstrate unmet visual needs at baseline (OR 1.12 95% CI 1.03 to 1.21) p = 0.012; (OR 4.44 95% CI 1.38 to 14.29 p = 0.007 respectively). On follow-up, the number of pupils with unmet visual needs dropped significantly to 36 (18%) (McNemar's test p<0.001). Visual and behavioural metrics of participants without significant visual deficits or whose visual needs were adequately addressed at baseline remained relatively unchanged between baseline and follow-up (Wilcoxon signed rank p>0.05). Where significant refractive deficits were corrected at follow-up, near visual acuity improved significantly (Wilcoxon signed rank p = 0.013), however, poor spectacle compliance was a persistent cause of unmet visual need. Off-task behaviour reduced significantly after actions to address unmet visual needs were communicated to parents and teachers (Wilcoxon signed rank p = 0.035). CONCLUSIONS: The present study demonstrates for the first time measurable visual and behaviour benefits to children in special education settings when they receive comprehensive in-school eye examinations, on-site spectacle dispensing and jargon-free reporting of outcomes to teachers and parents.

Correction: In-school eyecare in special education settings has measurable benefits for children's vision and behaviour.

[This corrects the article DOI: 10.1371/journal.pone.0220480.].

Reduced accommodation in children with Down syndrome.

PURPOSE: To examine the accommodative accuracy and amplitude in children with Down syndrome. Accommodation is usually assumed to be good in children and is rarely measured. METHODS: A dynamic retinoscopy technique was developed that allows rapid and reliable measures of accuracy and amplitude of accommodation in infants and children. RESULTS: Use of the dynamic technique with a small sample of schoolchildren with Down syndrome shows that 80% have reduced amplitude of accommodation, in comparison to a control group of developmentally normal children. CONCLUSIONS: Optometric management of children with Down syndrome should include consideration of accommodation.

Accommodation and refractive error in children with Down syndrome: cross-sectional and longitudinal studies.

PURPOSE: To examine the relationship between defective accommodation and refractive errors in children with Down syndrome. METHODS: Children with Down syndrome aged 4 to 85 months were seen at their homes as part of an ongoing study of visual development. Seventy-five children contributed cross-sectional data and 69 children longitudinal data. Accommodation was measured using a modification of Nott dynamic retinoscopy technique, and refractive error measurements were obtained using Mohindra retinoscopy. RESULTS: Accommodation was poor, regardless of the refractive error present. The total accommodation produced by the children was related to the refractive error at the time of the test, with the degree of accommodation deficit increasing with the amount of positive refractive error. The longitudinal results showed that although children with Down syndrome did not accommodate accurately, the amount of accommodation elicited did not reflect their maximum amplitude of accommodation. Each child showed a consistent degree of underaccommodation for a given stimulus. Spectacles to correct hypermetropia did not improve the accommodative response. CONCLUSIONS: In children with Down syndrome, underaccommodation is substantial, even when there is no, or a fully corrected, refractive error. The accommodation system of children with Down syndrome may have the physical capacity to respond to a given stimulus, but the neural control of the system has an anomalous set point. Spectacles do not remedy the situation. This has important implications, especially for children in a learning environment, because near vision is consistently out of focus.

The effect of age, size of target, and cognitive factors on accommodative responses of children with Down syndrome.

PURPOSE: To investigate possible factors that may be implicated in the poor accommodative responses of individuals with Down syndrome. This article evaluates the effect of age, angular size of target, and cognitive factors on accommodation. METHODS: Seventy-seven children with Down syndrome who are participating in an ongoing study of visual development were assessed. One hundred thirty-one developmentally normal children took part in a previous study and provided control data. Accommodation was measured using a modified Nott dynamic retinoscopy technique. RESULTS: Children with Down syndrome showed considerably poorer accommodative responses than normally developing children. No target used in the present study produced an improved response in children with Down syndrome. Age, angular subtense of target, and cognitive factors could not fully account for the poor accommodation in children with Down syndrome. CONCLUSIONS: Poor accommodation is a common feature of Down syndrome, regardless of the target used. The etiology of the deficit has yet to be established. It is imperative that educators and clinicians are aware that near vision is out of focus for these children.

Early refractive development in humans.

Over recent years much interest has been directed toward understanding the process by which refractive errors develop, how this is controlled and the effect of refractive errors on subsequent visual status. There are obvious difficulties in studying such mechanisms in human subjects and for this reason many studies have employed animal models. The present paper compiles the evidence available from human subjects, examining the significance of different aspects of refractive status, normal and abnormal patterns of development and their significance in the development of normal binocular function.

Emmetropisation in human infancy: rate of change is related to initial refractive error.

Animal studies show that the rate of recovery from experimentally induced refractive errors is related to the level of ametropia induced. The present study examined the rate of emmetropisation occurring in a sample of 22 human infants refracted by near retinoscopy during the first six months of life and then again between 12 and 17 months old. None of the subjects were myopic. Regression analysis revealed that emmetropisation occurred more rapidly in the presence of high refractive errors (P < 0.005 and P = 0.001 for hyperopia and astigmatism respectively). These data confirm the findings of the animal studies and suggest that non-reducing hyperopia and astigmatism in the second year of life may require correction.

Emmetropisation following preterm birth.

BACKGROUND/AIMS: Even in the absence of retinopathy of prematurity (ROP), premature birth signals increased risk for abnormal refractive development. The present study examined the relation between clinical risk factors and refractive development among preterm infants without ROP. METHODS: Cycloplegic refraction was measured at birth, term, 6, 12, and 48 months corrected age in a cohort of 59 preterm infants. Detailed perinatal history and cranial ultrasound data were collected. 40 full term (plus or minus 2 weeks) subjects were tested at birth, 6, and 12 months old. RESULTS: Myopia and anisometropia were associated with prematurity (p<0.05). More variation in astigmatic axis was found among preterm infants (p<0.05) and a trend for more astigmatism (p<0.1). Emmetropisation occurred in the preterm infants so that at term age they did not differ from the fullterm group in astigmatism or anisometropia. However, preterm infants remained more myopic (less hyperopic) than the fullterm group at term (p<0.05) and those infants born <1500 g remained more anisometropic than their peers until 6 months (p<0.05). Infants with abnormal cranial ultrasound were at risk for higher hyperopia (p<0.05). Other clinical risk factors were not associated with differences in refractive development. At 4 years of age 19% of the preterm group had clinically significant refractive errors. CONCLUSION: Preterm infants without ROP had high rates of refractive error. The early emmetropisation process differed from that of the fullterm group but neither clinical risk factors nor measures of early refractive error were predictive of refractive outcome at 4 years.

Long-term stability of equivalence relations in the absence of training or practice.

An adult male with mild mental retardation, whose laboratory history included training in a match-to-sample task on 16 arbitrary relations among 16 visual stimuli and 2 auditory stimuli, had performances that showed the development of 112 additional arbitrary relations that had never been reinforced. In the presented study on 2-year and 3-year follow-up tests for these derived relations, his performances remained stable despite the absence of opportunities to practice these relations between the tests and the absence of explicit feedback during the tests. The similarity to the long-term stability of language was discussed.

Generalized identity matching of two-dimensional forms by individuals with moderate to profound mental retardation.

The classic literature suggests that individuals with MAs of less than 5 years may fail tasks that require same/different judgments. In Study 1 we used an assessment procedure that provided minimal instructional programming to determine whether 17 adults with MAs ranging from 2 years, 5 months to 4 years, 11 months would show accurate identity matching-to-sample. Stimuli were letter-like nonsense forms. Eight participants showed highly accurate matching. Eight of the 9 who failed were available for further study. Of these, 5 ultimately demonstrated highly accurate matching after training with standard fading procedures. These data suggest that a greater proportion of individuals with low MAs can exhibit generalized identity matching than previously documented in the literature.

Conditional versus trial-unique delayed matching-to-sample.

We compared performance on conditional and trial-unique delayed identity matching-to-sample procedures. In Experiment 1, participants with moderate to severe mental retardation were exposed to both procedures under a single, brief delay value. Three of 5 subjects showed higher accuracy in the trial-unique sessions. In Experiment 2, participants with mild mental retardation were exposed to delay values of 0, 2, 4, 8, and 16 seconds, randomized within each session. For 3 of 4 subjects, accuracy was highest with trial-unique, and lowest on the conditional matching-to-sample, at longer delays. Across the two studies, 6 of 9 subjects showed lower delayed matching accuracy when fewer rather than more stimuli were included in a session.

Naming in conditional discrimination and stimulus equivalence.

Using a matching-to-sample procedure, McIntire, Cleary, and Thompson (1987) taught monkeys the conditional relations A1-R1-A1-R1, A2-R2-A2-R2, A1-R1-B1-R1, A2-R2-B2-R2, B1-R1-C1-R1, and B2-R2-C2-R2, where the first and third terms in each relation refer to the sample and comparison stimuli, respectively, and the second and last terms refer to the emission of a distinctive pattern of responding. The subjects were then tested for the emergent relations A-C, C-A, B-A, C-B, and B-B, with the differential response produced by a given stimulus during training also emitted on test trials (e.g., A1-R1-C1-R1). The performances of both subjects were as accurate on the tested relations as they had been on the trained relations. The new relations were characterized as demonstrations of stimulus equivalence. However, the conditional discrimination literature shows that such training procedures generate control of comparison selection by the differential response patterns. Therefore, no emergent relations were demonstrated because all of the trained response-stimulus relations were preserved on test trials. This paper suggests that these procedures do not provide an appropriate analogy for the kind of emergent stimulus-stimulus relations exhibited by human subjects in equivalence studies and outlines a paradigm for assessing the relative influence of stimulus-stimulus and response-stimulus relations.

Conditional discrimination in mentally retarded subjects: programming acquisition and learning set.

In Experiment 1, 3 subjects with retardation were exposed to two visual-visual arbitrary matching-to-sample problems each day. One conditional discrimination was presented under trial-and-error conditions, and the other was presented under a component training procedure. The latter began by establishing the comparison discrimination and its rapid reversal. The successive discrimination between the sample stimuli was established through differential naming. Then, sample naming was maintained in conditional discrimination sessions in which the same sample was presented in blocks of consecutive trials. Block size was decreased across sessions until sample presentation was randomized as in trial-and-error training (but with naming maintained). Two subjects initially learned only with component training. The performance of the 3rd subject was inconsistent across conditional discriminations. One of the successful subjects ultimately learned rapidly and consistently with trial-and-error procedures. Experiment 2 sought to demonstrate learning set in the other 2 subjects. Elements of the component training procedure were withdrawn over successive conditional discriminations. Ultimately, 1 subject nearly always learned under trial-and-error conditions, and the other learned under trial-and-error conditions combined with differential sample naming.

Conditional discrimination in mentally retarded adults: the development of generalized skills.

The development of generalized conditional discrimination skills was examined in adults with retardation. Two subjects with histories of failure to acquire arbitrary matching under trial-and-error procedures were successful under procedures that trained one or more prerequisite skills. The successive discrimination between the sample stimuli was established by training the subjects to name the stimuli. The simultaneous discrimination between the comparison stimuli was established using either (a) standard simple discrimination training with reversals or (b) a procedure in which each of the two sample-comparison relations in the conditional discrimination was presented in blocks of trials, with the size of the blocks decreasing gradually until sample presentation was randomized. The amount of prerequisite training required varied across subjects and across successive conditional discriminations. After acquiring either two or three conditional discriminations with component training, both subjects learned new conditional discriminations under trial-and-error procedures. In general, each successive conditional discrimination was acquired more rapidly. Tests showed that conditional responding had become a generalized skill. Symmetry was shown for almost all trained relations. Symmetry trial samples were ultimately named the same as the stimuli to which they were related in training.

Conditional discrimination in mentally retarded adults: the effect of training the component simple discriminations.

Two subjects with retardation who exhibited generalized identity matching, but who had extensive histories of failure to acquire arbitrary matching, were exposed to a series of conditions designed to train separately the components of a two-choice conditional discrimination. First, the successive discrimination between the sample stimuli was established by programming a different schedule of reinforcement in the presence of each sample stimulus. Schedule performance was acquired and maintained by both subjects, but neither acquired arbitrary matching. To train the simultaneous discrimination between the comparison stimuli, 1 subject was then exposed to a series of simple discrimination reversals and subsequently failed to acquire arbitrary matching. Both subjects acquired arbitrary matching under a procedure that maintained both the sample and the comparison discrimination by first presenting entire sessions composed of one sample-comparison relation and then gradually reducing the number of consecutive trials with the same sample until sample presentation was randomized (schedule performance was maintained). Removal of the schedule requirement had no effect on arbitrary matching accuracy. Both subjects subsequently demonstrated control by relations symmetric to the trained relations.

Do parakeets exhibit derived stimulus control? Some thoughts on experimental control procedures.

Breaking new ground in the study of emergent stimulus control in nonverbal subjects may require innovation in procedures. A recent study of parakeets is exemplary. This study used intricate procedures for maintaining test-trial performance without differential reinforcement of the target emergent performance. Also, it used successive simple discrimination procedures, which are rare in such studies. Given the importance of these innovations and the outcomes that they produced, we suggest additional control procedures that would rule out the possibility of adventitious reinforcement of the test-trial performances.

Stimulus control and generalization of point-loss punishment with humans.

Two experiments demonstrated stimulus control and generalization of conditioned punishment with humans. In both studies, responses first were reinforced with points exchangeable for money on a variable-interval schedule in the presence of one line length (S(D)). Next, a second line length was introduced, and point loss followed every response in the presence of that line (S(D)p). In the final training condition, points were deducted at session end. Response rate was lower in the presence of the S(D)p despite equal rates of points for money in the presence of both stimuli. In generalization testing for Experiment 1, the two lines were included in a 10-line continuum; S(D)p fell in the middle and the trained SD was at one end. Lines were presented randomly, and point delivery and loss contingencies were as in training but with points available in the presence of all lines. For all subjects, response rates were lowest around S(D)p and increased towards the SD end of the continuum. Because testing included only one or two lines beyond S(D), this pattern did not rule out S(D) generalization. Thus, in Experiment 2, stimuli beyond S(D) were added to generalization tests. Response rates did not decrease as a function of distance from S(D), clarifying the demonstration of punishment generalization.

The merger and development of equivalence classes by unreinforced conditional selection of comparison stimuli.

Three experiments assessed the likelihood that subjects with histories of equivalence class development would respond conditionally on new discriminations in the absence of differential consequences for responses. In the first two experiments, two groups of subjects with different experimental histories, but whose performances showed four equivalence classes, responded on trials without explicit reinforcement involving samples from two of the classes and comparisons from the other two classes, in a two-choice matching-to-sample format. Subjects consistently selected a particular comparison in the presence of a particular sample. Subsequent tests showed the emergence of equivalence relations between stimuli from classes linked by the unreinforced conditional selections. Subsequently, in Experiment II, the subjects' responses in the conditional selection trials were reinforced if the selection was reversed from that made previously. Although reversed selection was maintained, 2 of the 3 subjects continued to perform on equivalence relation trials according to their original unreinforced selections. In the third experiment, these 2 subjects responded on a series of conditional discriminations involving three new pairs of sample stimuli and one new pair of comparison stimuli. No explicit reinforcement followed responses on any trial in this experiment. Subsequent tests for equivalence between sample stimuli revealed the development of two equivalence classes.

The modified frisby stereotest.

BACKGROUND: The Frisby stereotest commonly is used in clinical practice to estimate stereoacuity. Assessment of the presence or absence of stereopsis is valuable particularly in toddlers because of the difficulties encountered in this age group with assessment of other aspects of visual function, such as monocular visual acuities. METHODS: The present study describes two modifications to the Frisby stereotest: 1) the introduction of a nonstereo practice plate; and 2) the use of an auditory "reward" for correct identification of the target. These modifications aim to increase the success rate of the test and provide a means to discriminate between testable and untestable children. Subjects were 165 children aged between 0.5 and 47 months. RESULTS: The modifications improved the age range over which results could be obtained with the Frisby test, allowing infants as young as 7 months to complete testing. By 12 months of age, more than 60% of children were able to complete testing. The modifications also allowed the examiner to distinguish untestable children from those without stereopsis. CONCLUSIONS: By simple modification of the Frisby stereotest, the authors have increased the ease with which the Frisby stereotest can be used to assess stereoacuity in infants and children and provided a means by which children unable to cooperate with testing can be distinguished from those without stereopsis.