Nabin Paudel

Neonatal Glycemia and Neurodevelopmental Outcomes at 2 Years

BACKGROUND Neonatal hypoglycemia is common and can cause neurologic impairment, but evidence supporting thresholds for intervention is limited. METHODS We performed a prospective cohort study involving 528 neonates with a gestational age of at least 35 weeks who were considered to be at risk for hypoglycemia; all were treated to maintain a blood glucose concentration of at least 47 mg per deciliter (2.6 mmol per liter). We intermittently measured blood glucose for up to 7 days. We continuously monitored interstitial glucose concentrations, which were masked to clinical staff. Assessment at 2 years included Bayley Scales of Infant Development III and tests of executive and visual function. RESULTS Of 614 children, 528 were eligible, and 404 (77% of eligible children) were assessed; 216 children (53%) had neonatal hypoglycemia (blood glucose concentration, <47 mg per deciliter). Hypoglycemia, when treated to maintain a blood glucose concentration of at least 47 mg per deciliter, was not associated with an increased risk of the primary outcomes of neurosensory impairment (risk ratio, 0.95; 95% confidence interval [CI], 0.75 to 1.20; P=0.67) and processing difficulty, defined as an executive-function score or motion coherence threshold that was more than 1.5 SD from the mean (risk ratio, 0.92; 95% CI, 0.56 to 1.51; P=0.74). Risks were not increased among children with unrecognized hypoglycemia (a low interstitial glucose concentration only). The lowest blood glucose concentration, number of hypoglycemic episodes and events, and negative interstitial increment (area above the interstitial glucose concentration curve and below 47 mg per deciliter) also did not predict the outcome. CONCLUSIONS In this cohort, neonatal hypoglycemia was not associated with an adverse neurologic outcome when treatment was provided to maintain a blood glucose concentration of at least 47 mg per deciliter. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others.).

Association of Neonatal Glycemia With Neurodevelopmental Outcomes at 4.5 Years

Importance Hypoglycemia is common during neonatal transition and may cause permanent neurological impairment, but optimal intervention thresholds are unknown. Objective To test the hypothesis that neurodevelopment at 4.5 years is related to the severity and frequency of neonatal hypoglycemia. Design, Setting, and Participants The Children With Hypoglycemia and Their Later Development (CHYLD) Study is a prospective cohort investigation of moderate to late preterm and term infants born at risk of hypoglycemia. Clinicians were masked to neonatal interstitial glucose concentrations; outcome assessors were masked to neonatal glycemic status. The setting was a regional perinatal center in Hamilton, New Zealand. The study was conducted from December 2006 to November 2010. The dates of the follow-up were September 2011 to June 2015. Participants were 614 neonates born from 32 weeks’ gestation with at least 1 risk factor for hypoglycemia, including diabetic mother, preterm, small, large, or acute illness. Blood and masked interstitial glucose concentrations were measured for up to 7 days after birth. Infants with hypoglycemia (whole-blood glucose concentration <47 mg/dL) were treated to maintain blood glucose concentration of at least 47 mg/dL. Exposures Neonatal hypoglycemic episode, defined as at least 1 consecutive blood glucose concentration less than 47 mg/dL, a severe episode (<36 mg/dL), or recurrent (≥3 episodes). An interstitial episode was defined as an interstitial glucose concentration less than 47 mg/dL for at least 10 minutes. Main Outcomes and Measures Cognitive function, executive function, visual function, and motor function were assessed at 4.5 years. The primary outcome was neurosensory impairment, defined as poor performance in one or more domains. Results In total, 477 of 604 eligible children (79.0%) were assessed. Their mean (SD) age at the time of assessment was 4.5 (0.1) years, and 228 (47.8%) were female. Those exposed to neonatal hypoglycemia (280 [58.7%]) did not have increased risk of neurosensory impairment (risk difference [RD], 0.01; 95% CI, −0.07 to 0.10 and risk ratio [RR], 0.96; 95% CI, 0.77 to 1.21). However, hypoglycemia was associated with increased risk of low executive function (RD, 0.05; 95% CI, 0.01 to 0.10 and RR, 2.32; 95% CI, 1.17 to 4.59) and visual motor function (RD, 0.03; 95% CI, 0.01 to 0.06 and RR, 3.67; 95% CI, 1.15 to 11.69), with highest risk in children exposed to severe, recurrent, or clinically undetected (interstitial episodes only) hypoglycemia. Conclusions and Relevance Neonatal hypoglycemia was not associated with increased risk of combined neurosensory impairment at 4.5 years but was associated with a dose-dependent increased risk of poor executive function and visual motor function, even if not detected clinically, and may thus influence later learning. Randomized trials are needed to determine optimal screening and intervention thresholds based on assessment of neurodevelopment at least to school age.

Global Motion Perception in 2-Year-Old Children: A Method for Psychophysical Assessment and Relationships With Clinical Measures of Visual Function

PURPOSE 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. METHODS 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. RESULTS 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. Childrens 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). CONCLUSIONS 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.

Comparison of axial lengths in occludable angle and angle-closure glaucoma-The Bhaktapur Glaucoma Study

Purpose. To compare the anterior chamber depth (ACD) and axial length of eyes in a population-based sample among normal, occludable angle, and primary angle-closure glaucoma (PACG) groups. Methods. Totally, 3979 subjects from a population-based glaucoma prevalence study underwent complete ocular examination including four mirror gonioscopy. An angle in which >270 degrees of the posterior trabecular meshwork could not be seen was considered occludable. PACG was considered when there were features of primary angle closure (eye with an occludable angle, peripheral anterior synechiae, increased intraocular pressure, iris whorling, lens opacities, or excessive pigment deposition on the trabecular surface) and optic disc with glaucomatous damage. A handheld ultrasonic biometer was used to measure the ACD and the axial length of subjects. The ACD and axial length were measured on all subjects with occludable angles (n = 86), PACG (n = 17) and a random subgroup of normal subjects (n = 685). The measurements were compared among the groups and statistically analyzed using independent t-test, one-way analysis of variance, &khgr;2 test, and logistic regression. Results. The mean age among occludable angle and angle-closure glaucoma groups was 59.64 ± 9.70 and 71.23 ± 8.5 years, respectively, which was significantly higher (p < 0.001) than the mean of 54.03 ± 10.90 years among normal subjects. In the occludable angle group, the ACD (2.55 ± 0.69) was significantly different (p < 0.001) than the normal group (2.85 ± 0.39). The axial length (22.08 ± 0.83) in the occludable angle group was also considerably different (p < 0.001) when compared with the normal group (22.62 ± 0.90). In PACG group, the ACD and axial length were 2.48 ± 0.22 and 22.02 ± 0.59, respectively. The risk of having an occludable angle decreased with per unit millimeter increase in ACD (odds ratio, 0.24; 95% confidence intervals, 0.12–0.50) and axial length (odds ratio, 0.49; 95% confidence intervals, 0.36–0.67) after adjusting the effect of age and sex. Conclusions. The eyes in Nepalese population with occludable angle and angle-closure glaucoma appear to have significantly shallower anterior chambers and shorter axial lengths when compared with the normal group.

Central Corneal Thickness and Intraocular Pressure in a Nepalese Population: The Bhaktapur Glaucoma Study

PurposeThe purpose of the study was to evaluate the characteristics of central corneal thickness and its association with age, sex, and intraocular pressure in a Nepalese population. Patients and MethodsThe study design was a cross-sectional, population-based survey. Two thousand three hundred thirty patients aged 40 years and older were examined at Tilganga Institute of Ophthalmology, a tertiary referral eye centre in Kathmandu, Nepal. All patients underwent a complete ophthalmic examination that included measurements of central corneal thickness with an ultrasonic pachymeter and intraocular pressure with a Goldman type applanation tonometer. ResultsThe main outcome measures were central corneal thickness and intraocular pressure. Mean age of the 2330 patients examined was 51.3 years (SD±9.56). The mean central corneal thickness and mean intraocular pressure was 539.10 &mgr;m (SD±33.73) and 13.33 mm Hg (SD±2.26), respectively. Central corneal thickness showed an average decrease of 2.67 &mgr;m (95% confidence interval, 2.21-4.1) per decade increase in age. A 100 &mgr;m increase in central corneal thickness was associated with a 1.03 mm Hg (95% confidence interval, 0.79-1.26) increase in intraocular pressure after adjusting for age and sex. ConclusionsThe changes in central corneal thickness values cause a significant variation in intraocular pressure in this population, suggesting that measurement of central corneal thickness will have implications in the diagnosis and management of glaucoma.

Impact of Visual Impairment on Vision-Specific Quality of Life among Older Adults Living in Nursing Home

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.

Visual defects in Nepalese children with Down syndrome

Background:  Down syndrome (DS) is a common chromosomal anomaly. People with this syndrome have recognisable physical characteristics and limited intellectual abilities. The aim of this study was to determine visual defects, especially refractive error and binocular anomalies, in a sample of Nepalese children with DS.

Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children.

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.

Glial Heterotopia of the orbit: A rare presentation

BackgroundGlial heterotopias are rare, benign, congenital, midline, non-teratomatous extracranial glial tissue. They may masquerade as encephalocoele or dermoid cyst and mostly present in nose. Herein, we present an unusual case of glial heterotopia of the orbit with unilateral blindness.Case presentationA 6 year-old-boy presented with a progressive painless mass over the nose and medial aspect of the left eye noticed since birth. On examination, the globe was displaced laterally by a firm, regular, mobile, non-pulsatile and non-tender medial mass. The affected eye had profound loss of vision. Computed tomography scan showed a large hypodense mass in the extraconal space with no intracranial connectivity and bony erosion. The child underwent total surgical excision of the mass and histopathological examination confirmed glial heterotopia of the orbit.ConclusionThough the incidence of this condition is rare, the need of appropriate diagnosis and management of such mass to prevent the visual and cosmetic deterioration is warranted. To our knowledge this is the first reported case of Glial heterotopia of orbit causing unilateral blindness.

Effect of simulated refractive error on adult visual acuity for paediatric tests

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.