Visual demands in primary school classrooms

Purpose To quantify the visual function requirements to perform in a primary school classroom setting. Methods 33 classrooms of Years 5 and 6 (children aged 10-12 years) from 8 schools were included. The classroom activities undertaken for a full day (9am-3pm) were observed and a range of measurements recorded; text size and contrast of learning materials, habitual working distances (distance and near) and time spent performing various classroom tasks. These measures were used to calculate demands for distance and near visual acuity, contrast and sustained use of accommodation and vergence. Results The minimum resolution requirements for distance and near were 0.3±0.1 and 0.7±0.1 logMAR (using maximum viewing distances and smallest target sizes). Mean contrast levels of learning materials at distance and near were >70% (an average contrast reserve of 25:1). Near tasks (47%) dominated the academic tasks performed in the classroom followed by distance (29%), distance to near (15%) and computer-based (9%). On average, children maintained continuous near fixation for 23.2±4.7 minutes at a time and during distance-near tasks performed fixation changes 10±0.9 times per minute. The mean habitual near working distance was 22.9±1.3 cm, which corresponds to a 4.4±0.2 D accommodative demand and the vergence demand was 0.9±0.1Δ at distance and 21.9±1.1 Δ at near assuming an average pupillary distance of 56 mm. Conclusions The visual demands placed on children in modern classrooms were greater than those reported for traditional classrooms, likely due to inclusion of modern technologies. Relatively high levels of visual acuity, contrast processing and sustained accommodative-convergence are required to perform optimally in the classroom environment. These findings are important for determining evidence-based prescribing guidelines and developing paediatric vision screening protocols and referral criterion

Bi-allelic Loss-of-Function CACNA1B Mutations in Progressive Epilepsy-Dyskinesia.

The occurrence of non-epileptic hyperkinetic movements in the context of developmental epileptic encephalopathies is an increasingly recognized phenomenon. Identification of causative mutations provides an important insight into common pathogenic mechanisms that cause both seizures and abnormal motor control. We report bi-allelic loss-of-function CACNA1B variants in six children from three unrelated families whose affected members present with a complex and progressive neurological syndrome. All affected individuals presented with epileptic encephalopathy, severe neurodevelopmental delay (often with regression), and a hyperkinetic movement disorder. Additional neurological features included postnatal microcephaly and hypotonia. Five children died in childhood or adolescence (mean age of death: 9 years), mainly as a result of secondary respiratory complications. CACNA1B encodes the pore-forming subunit of the pre-synaptic neuronal voltage-gated calcium channel Cav2.2/N-type, crucial for SNARE-mediated neurotransmission, particularly in the early postnatal period. Bi-allelic loss-of-function variants in CACNA1B are predicted to cause disruption of Ca2+ influx, leading to impaired synaptic neurotransmission. The resultant effect on neuronal function is likely to be important in the development of involuntary movements and epilepsy. Overall, our findings provide further evidence for the key role of Cav2.2 in normal human neurodevelopment.MAK is funded by an NIHR Research Professorship and receives funding from the Wellcome Trust, Great Ormond Street Children's Hospital Charity, and Rosetrees Trust. E.M. received funding from the Rosetrees Trust (CD-A53) and Great Ormond Street Hospital Children's Charity. K.G. received funding from Temple Street Foundation. A.M. is funded by Great Ormond Street Hospital, the National Institute for Health Research (NIHR), and Biomedical Research Centre. F.L.R. and D.G. are funded by Cambridge Biomedical Research Centre. K.C. and A.S.J. are funded by NIHR Bioresource for Rare Diseases. The DDD Study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003), a parallel funding partnership between the Wellcome Trust and the Department of Health, and the Wellcome Trust Sanger Institute (grant number WT098051). We acknowledge support from the UK Department of Health via the NIHR comprehensive Biomedical Research Centre award to Guy's and St. Thomas' National Health Service (NHS) Foundation Trust in partnership with King's College London. This research was also supported by the NIHR Great Ormond Street Hospital Biomedical Research Centre. J.H.C. is in receipt of an NIHR Senior Investigator Award. The research team acknowledges the support of the NIHR through the Comprehensive Clinical Research Network. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, Department of Health, or Wellcome Trust. E.R.M. acknowledges support from NIHR Cambridge Biomedical Research Centre, an NIHR Senior Investigator Award, and the University of Cambridge has received salary support in respect of E.R.M. from the NHS in the East of England through the Clinical Academic Reserve. I.E.S. is supported by the National Health and Medical Research Council of Australia (Program Grant and Practitioner Fellowship)

Review of guidelines for children\u27s vision screenings

The aim of children\u27s vision screenings is to detect visual problems that are common in this age category through valid and reliable tests. Nevertheless, the cost effectiveness of paediatric vision screenings, the nature of the tests included in the screening batteries and the ideal screening age has been the cause of much debate in Australia and worldwide. Therefore, the purpose of this review is to report on the current practice of children\u27s vision screenings in Australia and other countries, as well as to evaluate the evidence for and against the provision of such screenings. This was undertaken through a detailed investigation of peer-reviewed publications on this topic. The current review demonstrates that there is no agreed vision screening protocol for children in Australia. This appears to be a result of the lack of strong evidence supporting the benefit of such screenings. While amblyopia, strabismus and, to a lesser extent refractive error, are targeted by many screening programs during pre-school and at school entry, there is less agreement regarding the value of screening for other visual conditions, such as binocular vision disorders, ocular health problems and refractive errors that are less likely to reduce distance visual acuity. In addition, in Australia, little agreement exists in the frequency and coverage of screening programs between states and territories and the screening programs that are offered are ad hoc and poorly documented. Australian children stand to benefit from improved cohesion and communication between jurisdictions and health professionals to enable an equitable provision of validated vision screening services that have the best chance of early detection and intervention for a range of paediatric visual problems

Visual demands in modern Australian primary school classrooms

BACKGROUND: The visual demands of modern classrooms are poorly understood yet are relevant in determining the levels of visual function required to perform optimally within this environment. METHODS: Thirty-three Year 5 and 6 classrooms from eight south-east Queensland schools were included. Classroom activities undertaken during a full school day (9 am to 3 pm) were observed and a range of measurements recorded, including classroom environment (physical dimensions, illumination levels), text size and contrast of learning materials, habitual working distances (distance and estimated for near) and time spent performing various classroom tasks. These measures were used to calculate demand-related minimum criteria for distance and near visual acuity, contrast and sustained use of accommodation and vergence. RESULTS: The visual acuity demands for distance and near were 0.33 ± 0.13 and 0.72 ± 0.09 logMAR, respectively (using habitual viewing distances and smallest target sizes) or 0.33 ± 0.09 logMAR assuming a 2.5 times acuity reserve for sustained near tasks. The mean contrast levels of learning materials at distance and near were greater than 70 per cent. Near tasks (47 per cent) dominated the academic tasks performed in the classroom followed by distance (29 per cent), distance to near (15 per cent) and computer-based (nine per cent). On average, children engaged in continuous near fixation for 23 ± 5 minutes at a time and during distance-near tasks performed fixation changes 10 ± 1 times per minute. The mean estimated habitual near working distance was 23 ± 1 cm (4.38 ± 0.24 D accommodative demand) and the vergence demand was 0.86 ± 0.07(Δ) at distance and 21.94 ± 1.09(Δ) at near assuming an average pupillary distance of 56 mm. CONCLUSIONS: Relatively high levels of visual acuity, contrast demand and sustained accommodative-convergence responses are required to meet the requirements of modern classroom environments. These findings provide an evidence base to inform prescribing guidelines and develop paediatric vision screening protocols and referral criteria

Impact of simulated hyperopia on academic-related performance in children

PURPOSE: To investigate the impact of simulated hyperopia and sustained near work on children’s ability to perform a range of academic-related tasks

Apparent inferior rectus palsy with gaze-dependent sensory adaptations

PURPOSE: This report presents a case of apparent congenital inferior rectus palsy notable for sensory adaptations that appeared to vary with direction of gaze. It is shown that readily available clinical tests and an understanding of the physiology of ocular motility can be used to help distinguish from differential diagnoses such as contralateral inferior oblique palsy or the more commonly seen Brown syndrome. CASE REPORT: A 20-year-old male optometry student reported strabismus that had been noted at birth and was diagnosed as Brown syndrome in childhood. The Parks three-step test showed primary gaze hypertropia that increased in left gaze but the "third step" (Bielschowsky head tilt test) was not successful in establishing the apparently correct diagnosis, which was later confirmed by a Hess screen. A proposed "fourth" step by Bajandas proved to be more accurate in this case of inferior rectus palsy. Sensory tests revealed adaptation patterns that varied with gaze direction and showed a cyclotorsional element. The patient reported being relatively unconcerned about his condition as he seemed to be able to voluntarily use a form of shallow suppression to reduce awareness of diplopic images. CONCLUSIONS: Although it is common to consider suppression and retinal correspondence status as hardwired and relatively constant for an individual patient, this case demonstrates that these sensory adaptations are likely to be far more complex and transitory. An understanding of both motor and sensory repercussions of ocular motility dysfunction assists differentiation between benign and sinister causes of nonconcomitant strabismus

Using optical coherence tomography for the differential diagnosis of a pigmented choroidal lesion

Clinicians regularly face the confronting challenge of differentiating a choroidal naevus from a melanoma. Uveal naevi are a relatively common finding during routine eye examinations: a prevalence of 6.5 per cent has been reported.1 In contrast, malignant melanomata are uncommon, being found in six persons per million population, but they can have devastating implications and consequences.2 Differential diagnoses can be difficult to make with certainty; any additional information that can assist in this process is advantageous..

Focal loss volume of ganglion cell complex in diabetic neuropathy

The aim was to investigate the relationship between diabetic peripheral neuropathy (DPN) and abnormalities in ganglion cell complex (GCC); specifically, focal loss volume (FLV) and global loss volume (GLV)

Retinal Tissue Thickness is Reduced in Diabetic Peripheral Neuropathy

AIM: To investigate the relationship between diabetic peripheral neuropathy (DPN) and retinal tissue thickness. METHODS: Full retinal thickness in the central retinal, parafoveal, and perifoveal zones and thickness of the ganglion cell complex and retinal nerve fiber layer (RNFL) were assessed in 193 individuals (84 with type 1 diabetes, 67 with type 2 diabetes, and 42 healthy controls) using spectral domain optical coherence tomography. Among those with diabetes, 44 had neuropathy defined using a modified neuropathy disability score recorded on a 0-10 scale. Multiple regression analysis was performed to investigate the relationship between diabetic neuropathy and retinal tissue thickness, adjusted for the presence of diabetic retinopathy (DR), age, sex, duration of diabetes, and HbA1c levels. RESULTS: In individuals with diabetes, perifoveal thickness was inversely related to the severity of neuropathy (p < 0.05), when adjusted for age, sex, duration of diabetes, and HbA1c levels. DR was associated with reduced thickness in parafovea (p < 0.01). The RNFL was thinner in individuals with greater degrees of neuropathy (p < 0.04). CONCLUSIONS: DPN is associated with structural compromise involving several retinal layers. This compromise may represent a threat to visual integrity and therefore warrants examination of functional correlates

Focal loss in ganglion cell complex in diabetic peripheral neuropathy

Purpose To investigate the relationship between diabetic peripheral neuropathy and abnormalities in ganglion cell complex (GCC) (focal loss volume (GCC FLV) and global loss volume (GCC GLV) Methods One hundred and ninety three individuals (84 with type 1 diabetes, 67 with type 2 diabetes and 42 healthy controls) underwent GCC evaluation using optical coherence tomography. The probability of FLV and GLV being abnormal (borderline or outside normal loss in comparison to population norms) was determined for all participants. Forty four individuals had diabetic neuropathy based on a modified neuropathy disability score (NDS) (expressed as mean ± standard error of the mean). A binary logistic regression analysis was performed in individuals with diabetes, to investigate the relationship of diabetic neuropathy with (i) abnormal FLV and (ii) abnormal GLV, in separate regression models, taking into account, the presence of diabetic retinopathy (DR), type of diabetes, age, sex, duration of diabetes and HbA1c levels Results Twenty five per cent of individuals with diabetic neuropathy had significantly abnormal FLV compared to 11% of those without neuropathy and 5% in the control group (p = 0.011). Fourteen per cent of individuals with diabetic neuropathy, 10% of those without neuropathy and 2% in the control group had abnormal GLV; these differences were not statistically significant (p = 0.185). For every unit increase in NDS, the odds of having an abnormal FLV increased by a multiplicative factor of 1.25 (p = 0.007), when controlled for DR, type of diabetes, age, sex, duration of diabetes and HbA1c levels. For every year increase in age, the odds of having an abnormal GLV increased by a multiplicative factor of 1.07 (p = 0.026), when controlled for NDS, DR, type of diabetes, sex, duration of diabetes and HbA1c levels Conclusions Diabetic peripheral neuropathy is associated with macular focal ganglion cell volume loss, independent of diabetic retinopathy, type of diabetes, age, sex, duration of diabetes and HbA1c levels. The study demonstrated a significant relationship between focal neuronal damage in the retina and in the peripheral nervous system in diabetes. As the macular region subserves the central visual field, a compromise to this region can pose a threat to the visual integrity and therefore necessitates further investigation