To determine detailed oculo-visual characteristics of children with intellectual disability studying in special schools and explore the burden of visual impairment.
Detailed ophthalmic examination ...was carried out in all pupils studying at the seven special needs schools of Kathmandu valley, Nepal. Ophthalmic examination included case history, presenting distance visual acuity, cycloplegic refraction, binocular vision examination, contrast sensitivity and anterior and posterior segment evaluation.
Ocular and visual status of children.
Refractive errors (40%) and strabismus (17%) were the commonest visual disorders in our study children. Ninety-five per cent of the children who had clinically significant refractive errors presented without any correction. Visual impairment was present in 25% of the children. Severe visual impairment or worse was present in 3% of the children. Other common ocular findings were conjunctivitis, blepharitis, chalazion and ectropion.
High prevalence of preventable visual impairment in this population requires immediate attention. It is hoped that the formulation of proper vision care guidelines at a national level may help in early detection and management of visual disorders in this special population and enhance their quality of life.
Objective To determine neurodevelopmental outcome at 2 years' corrected age in children randomized to treatment with dextrose gel or placebo for hypoglycemia soon after birth (The Sugar Babies ...Study). Study design This was a follow-up study of 184 children with hypoglycemia (<2.6 mM 47 mg/dL) in the first 48 hours and randomized to either dextrose (90/118, 76%) or placebo gel (94/119, 79%). Assessments were performed at Kahikatea House, Hamilton, New Zealand, and included neurologic function and general health (pediatrician assessed), cognitive, language, behavior, and motor skills (Bayley Scales of Infant and Toddler Development, Third Edition), executive function (clinical assessment and Behaviour Rating Inventory of Executive Function-Preschool Edition), and vision (clinical examination and global motion perception). Coprimary outcomes were neurosensory impairment (cognitive, language or motor score below −1 SD or cerebral palsy or blind or deaf) and processing difficulty (executive function or global motion perception worse than 1.5 SD from the mean). Statistical tests were two sided with 5% significance level. Results Mean (±SD) birth weight was 3093 ± 803 g and mean gestation was 37.7 ± 1.6 weeks. Sixty-six children (36%) had neurosensory impairment (1 severe, 6 moderate, 59 mild) with similar rates in both groups (dextrose 38% vs placebo 34%, relative risk 1.11, 95% CI 0.75-1.63). Processing difficulty also was similar between groups (dextrose 10% vs placebo 18%, relative risk 0.52, 95% CI 0.23-1.15). Conclusions Dextrose gel is safe for the treatment of neonatal hypoglycemia, but neurosensory impairment is common among these children. Trial registration Australian New Zealand Clinical Trials Registry: ACTRN 12608000623392.
Abstract
Background: Visual impairment (VI) has a significant negative impact on quality of life (QoL) amongst older people living in nursing homes. The purpose of this study was to determine the ...prevalence of VI and blindness and to explore the association between severity of VI and vision-specific QoL among older people living in nursing homes of Kathmandu, Nepal.
Methods: This cross-sectional study involved 158 residents aged 60 years or older residing in seven nursing homes of Kathmandu Valley, Nepal. Near acuity, presenting and the best corrected distance visual acuity (VA) were assessed in each eye and considered in the better eye after adequate refraction. A complete anterior and posterior segment examination was carried out. Face-to-face interviews were conducted using a 57-item Nursing Home Vision-Targeted Health-Related Quality of Life (NHVQoL) questionnaire.
Results: The mean age of residents was 75.60 ± 7.12 years and the majority were female (66.46%). The prevalence of VI and blindness was 45.57% and its leading cause was cataract, which was followed by age-related macular degeneration, corneal opacity, glaucoma and macular scar. The mean composite score of NHVQoL questionnaire was 52.22 ± 12.49. There was a consistent overall deterioration in the mean composite score as well as each subscale score of NHVQoL questionnaire with a worsening of VA.
Conclusion: VI and blindness are highly prevalent among older people living in nursing homes. VI has a significant negative impact on vision-specific QoL. Vision-specific QoL is reduced, and the reduction in the QoL bears a positive association with severity of VI among older people living in nursing homes.
Purpose
Mild to moderate vision loss affects many children and can negatively impact a child's early literacy and academic achievement. Nevertheless, there is no consensus on which factors present in ...early childhood indicate the need for long‐term ophthalmic follow up, particularly in children with a history of perinatal adversity. This study identified the relationship between visual, cognitive, motor and demographic factors at 2 years of age and visual acuity (VA) and stereoacuity at 4.5 years of age.
Methods
Five hundred sixteen children identified as being at risk of neonatal hypoglycaemia were recruited soon after birth. At 2 years of age, binocular VA, stereoacuity and non‐cycloplegic refraction were measured and a clinical neuro‐developmental assessment with the Bayley Scales of Infant Development III (BSID‐III) was conducted by a trained examiner. Monocular VA and stereoacuity were measured at 4.5 years of age.
Results
Three hundred twenty‐eight children completed both the 2 and 4.5 year vision and neurodevelopmental assessments. Multiple linear regression showed oblique astigmatism and motor function at 2 years were significantly associated with VA at 4.5 years of age, while spherical equivalent refraction, motor scores and stereoacuity at 2 years were significantly associated with stereoacuity at 4.5 years of age. BSID‐III motor scores had the best sensitivity (81.8%) and specificity (51.5%) for identifying impaired stereoacuity at 4.5 years. However, all measures at 2 years were poorly associated with VA at 4.5 years old.
Conclusion
Vision and neurodevelopmental measures at 2 years were poorly associated with visual function at 4.5 years of age. However, lower scores on tests of motor function at 2 years may be associated with vision abnormalities, particularly reduced stereopsis, at 4.5 years of age and referral for comprehensive vision assessment for these children may be warranted.
We developed and validated a technique for measuring global motion perception in 2-year-old children, and assessed the relationship between global motion perception and other measures of visual ...function.
Random dot kinematogram (RDK) stimuli were used to measure motion coherence thresholds in 366 children at risk of neurodevelopmental problems at 24 ± 1 months of age. RDKs of variable coherence were presented and eye movements were analyzed offline to grade the direction of the optokinetic reflex (OKR) for each trial. Motion coherence thresholds were calculated by fitting psychometric functions to the resulting datasets. Test-retest reliability was assessed in 15 children, and motion coherence thresholds were measured in a group of 10 adults using OKR and behavioral responses. Standard age-appropriate optometric tests also were performed.
Motion coherence thresholds were measured successfully in 336 (91.8%) children using the OKR technique, but only 31 (8.5%) using behavioral responses. The mean threshold was 41.7 ± 13.5% for 2-year-old children and 3.3 ± 1.2% for adults. Within-assessor reliability and test-retest reliability were high in children. Children's motion coherence thresholds were significantly correlated with stereoacuity (LANG I & II test, ρ = 0.29, P < 0.001; Frisby, ρ = 0.17, P = 0.022), but not with binocular visual acuity (ρ = 0.11, P = 0.07). In adults OKR and behavioral motion coherence thresholds were highly correlated (intraclass correlation = 0.81, P = 0.001).
Global motion perception can be measured in 2-year-old children using the OKR. This technique is reliable and data from adults suggest that motion coherence thresholds based on the OKR are related to motion perception. Global motion perception was related to stereoacuity in children.
•Global motion perception is associated gross motor function at 2 years of age.•Stereopsis is associated with fine motor function at 2 years of age.•Acuity is not associated with motor function at 2 ...years of age.•Visual and motor dorsal stream sub-components are associated early in development.
The dorsal visual processing stream that includes V1, motion sensitive area V5 and the posterior parietal lobe, supports visually guided motor function. Two recent studies have reported associations between global motion perception, a behavioural measure of processing in V5, and motor function in pre-school and school aged children. This indicates a relationship between visual and motor development and also supports the use of global motion perception to assess overall dorsal stream function in studies of human neurodevelopment. We investigated whether associations between vision and motor function were present at 2 years of age, a substantially earlier stage of development. The Bayley III test of Infant and Toddler Development and measures of vision including visual acuity (Cardiff Acuity Cards), stereopsis (Lang stereotest) and global motion perception were attempted in 404 2-year-old children (±4 weeks). Global motion perception (quantified as a motion coherence threshold) was assessed by observing optokinetic nystagmus in response to random dot kinematograms of varying coherence. Linear regression revealed that global motion perception was modestly, but statistically significantly associated with Bayley III composite motor (r2=0.06, P<0.001, n=375) and gross motor scores (r2=0.06, p<0.001, n=375). The associations remained significant when language score was included in the regression model. In addition, when language score was included in the model, stereopsis was significantly associated with composite motor and fine motor scores, but unaided visual acuity was not statistically significantly associated with any of the motor scores. These results demonstrate that global motion perception and binocular vision are associated with motor function at an early stage of development. Global motion perception can be used as a partial measure of dorsal stream function from early childhood.
Purpose
Although vanishing optotype preferential‐looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To ...address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters.
Methods
VA was determined uniocularly for adults under conditions of spherical (0.0–3.0 DS; n = 23) and astigmatic (0.0–3.0 DC at 90° and 180°; n = 20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture‐optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart.
Results
The Cardiff Acuity Test over‐estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95% limits of agreement (LOA) 0.10–0.52 logMAR) in focused conditions and 0.64 logMAR (95% LOA 0.25–1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart‐by‐defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P < 0.0001) and cylindrical (P < 0.001) optical defocus than the recognition acuity tasks at all defocus levels.
Conclusion
Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over‐estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.
•Global motion perception is modestly associated with motor development.•Stereoacuity is also associated with both gross and fine motor control.•Visual acuity was not associated with fine or gross ...motor control.
Global motion perception is often used as an index of dorsal visual stream function in neurodevelopmental studies. However, the relationship between global motion perception and visuomotor control, a primary function of the dorsal stream, is unclear. We measured global motion perception (motion coherence threshold; MCT) and performance on standardized measures of motor function in 606 4.5-year-old children born at risk of abnormal neurodevelopment. Visual acuity, stereoacuity and verbal IQ were also assessed. After adjustment for verbal IQ or both visual acuity and stereoacuity, MCT was modestly, but significantly, associated with all components of motor function with the exception of fine motor scores. In a separate analysis, stereoacuity, but not visual acuity, was significantly associated with both gross and fine motor scores. These results indicate that the development of motion perception and stereoacuity are associated with motor function in pre-school children.
•Global motion was unrelated to contrast sensitivity and acuity in preschool children.•Global motion was correlated with stereoacuity.•High contrast stimuli assess motion integration in at-risk ...pediatric populations.
Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioral measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n=117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (ρ=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (ρ=−0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children.
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