Barriers to childhood cataract services across India. A mixed methods study using the Theoretical Domains Framework (TDF) of behaviour change

Purpose : Early identification and presentation for childhood cataract surgery remains a major challenge in developing countries. The main aim of this study was to identify potential barriers to childhood cataract services from the perspective of parents’ and carers’, as a critical step towards achieving the timely uptake of cataract services. Methods : We used a mixed methods explanatory sequential study and interviewed 572 parents/carers attending tertiary hospitals in 8 states across India for their child's cataract surgery. We collected information on barriers to accessing services using a 12-item questionnaire and for each reported barrier, responses recorded on a 5 point scale ranging from “low to high importance”. Based on the quantitative data, in-depth interview questions were prepared and 35 interviews were conducted with randomly selected parents/ carers. Majority of these interviews were conducted at the hospital and /at home for those who did not undergo the surgery. Quantitative questionnaires were completed by the trained interviewer and responses were recorded in a pre-designed format. In-depth interviews were audio taped and transcribed for analysis. Quantitative data were analysed using SPSS 22 while qualitative data were organised with NVivo 11 and a thematic analysis was conducted utilising TDF, an integrative framework of theories. Results : From the 831 responses the 5 most important barriers were: economic (40%; n=222); child too young for surgery (17%; n=97); the problem was not felt as severe (16%; n=90); distance (14.5%; n=83) and no one to accompany to the hospital (9.5%; n=54). In addition, being advised by a local ophthalmologist to delay the surgery was also reported (n=16). Domains identified by the TDF included “Knowledge”, “Beliefs about consequences”, “Intentions”, “Goals”, “Decision processes”, “Environmental context and resources”, “Social influences and emotion”. This comprehensive TDF approach enabled us to understand the parents perceived barriers to access services for the children. Conclusions : Barriers to accessing childhood cataract services include both practical concerns relating to the family’s socio economic status as well as obstacles from the providers. Mapping out the barriers is necessary to design appropriate intervention for achieving positive behaviour change that can have potential social and economic impact

Delay in presentation to hospital for childhood cataract surgery in India

Purpose Cataract is one of the major causes of avoidable visual disability in children and the aim of this study was to investigate the age at which children with cataract present for surgery at tertiary hospitals across India. Methods: A prospective multicenter study collected data from 9 eye hospitals in 8 states in India. All children admitted for cataract surgery between Nov 2015 and March 2016 were considered eligible. Parents were interviewed at the hospital by trained personnel and socio demographic information, age at diagnosis and at surgery and the relevant clinical data were obtained from the medical records. Mean age, age range at surgery were used and performed logistic regression analyses. Results Parents of 751 consecutive cases were interviewed, of which 469(63%) were boys and 548(73%) were from rural areas. Cataract was bilateral in 493 (66%) and unilateral in 258 (34%); of the unilateral cases, 179 (69%) were due to trauma. The mean age at surgery for ‘congenital’ and ‘developmental’ cataract was 48.2±50.9 and 99.7±46.42 months respectively and the mean age was lower in the southern region compared to other regions. Children with 2 or more siblings at home were five times more likely to undergo surgery within 12 months (OR, 4.69; 95% CI: 2.04 – 10.79; p = <0.001). Conclusions Late surgery for childhood cataract remains a major challenge and the factors determining this issue in India are pertinent also to several other countries and need to be addressed for every child with cataract to achieve full visual potential

Age- and stereovision-dependent eye-hand coordination deficits in children with amblyopia and abnormal binocularity

Purpose: To examine factors contributing to eye-hand coordination deficits in children with amblyopia and impaired stereovision. Methods: Participants were 55 anisometropic or strabismic children aged 5.0-9.25 years with different degrees of amblyopia and abnormal binocularity along with 28 age-matched visually-normal controls. Pilot data were obtained from 4 additional patients studied longitudinally at different treatment stages. Movements of the preferred hand were recorded using a 3D motion-capture system while subjects reached-to-precision grasp objects (2 sizes, 3 locations) under binocular, dominant eye and amblyopic/non-sighting eye conditions. Kinematic and 'error' performance measures were quantified and compared by viewing condition and subject group using ANOVA, stepwise regression and correlation analyses. Results: Movements of the younger (age 5-6) amblyopes (n=30) were much slower, particularly in the final approach to the objects, and contained more spatial errors in reaching (~x1.25-1.75) and grasping (~x1.75-2.25) under all three views (p<0.05) than their age-matched controls (n=13). Amblyopia severity was the main contributor to their slower movements with absent stereovision a secondary factor and the unique determinant of their increased error-rates. Older (age 7-9) amblyopes (n=25) spent longer contacting the objects before lifting them (p=0.015) compared to their matched controls (n=15), with absence of stereovision still solely related to increases in reach and grasp errors, although these occurred less frequently than in younger patients. Pilot prospective data supported these findings by showing positive treatment-related associations between improved stereovision and reach-to-grasp performance

Role of the rumen in copper and thiomolybdate absorption

The rumen is the site of significant interactions between Cu, S and Mo. It also shows reactions between Cu, S and Fe. The interaction between Mo and S results in the formation of thiomolybdates, which in the absence of adequate quantities of rumen Cu are absorbed into the animal and bind to Cu in biological compounds. This is the cause of thiomolybdate toxicity, often misleadingly called Cu deficiency. The effects of thiomolybdates being absorbed into the animal are considered, especially how thiomolybdates bind to Cu-containing compounds such as enzymes, decreasing their activity without removing the active Cu component. The sources of Cu, Mo, Fe and S are examined, including the impacts of water and soil on the animal's intake. Within the present review we have been able to provide evidence that: all classes of thiomolybdates are formed in the rumen; in the absence of available Cu all thiomolybdates can be absorbed into the animal rapidly though the rumen wall or via the small intestine; thiomolybdates bind to Cu in biological compounds and are able to cause problems; effects of thiomolybdate are reversible in vivo and in vitro on cessation of thiomolybdate challenge; the tetra-thiomolybdate form is the most potent Cu binder with decreased potency with decreasing S in the compound. Fe will exacerbate a thiomolybdate problem but will not directly cause it

An Experimental Platform for Pulsed-Power Driven Magnetic Reconnection

We describe a versatile pulsed-power driven platform for magnetic reconnection experiments, based on exploding wire arrays driven in parallel [Suttle, L. G. et al. PRL, 116, 225001]. This platform produces inherently magnetised plasma flows for the duration of the generator current pulse (250 ns), resulting in a long-lasting reconnection layer. The layer exists for long enough to allow evolution of complex processes such as plasmoid formation and movement to be diagnosed by a suite of high spatial and temporal resolution laser-based diagnostics. We can access a wide range of magnetic reconnection regimes by changing the wire material or moving the electrodes inside the wire arrays. We present results with aluminium and carbon wires, in which the parameters of the inflows and the layer which forms are significantly different. By moving the electrodes inside the wire arrays, we change how strongly the inflows are driven. This enables us to study both symmetric reconnection in a range of different regimes, and asymmetric reconnection.Comment: 14 pages, 9 figures. Version revised to include referee's comments. Submitted to Physics of Plasma

Cosmic dust fertilization of glacial prebiotic chemistry on early Earth

Earth’s surface is deficient in available forms of many elements considered limiting for prebiotic chemistry. In contrast, many extraterrestrial rocky objects are rich in these same elements. Limiting prebiotic ingredients may, therefore, have been delivered by exogenous material; however, the mechanisms by which exogeneous material may be reliably and non-destructively supplied to a planetary surface remains unclear. Today, the flux of extraterrestrial matter to Earth is dominated by fine-grained cosmic dust. Although this material is rarely discussed in a prebiotic context due to its delivery over a large surface area, concentrated cosmic dust deposits are known to form on Earth today due to the action of sedimentary processes. Here we combine empirical constraints on dust sedimentation with dynamical simulations of dust formation and planetary accretion to show that localized sedimentary deposits of cosmic dust could have accumulated in arid environments on early Earth, in particular glacial settings that today produce cryoconite sediments. Our results challenge the widely held assumption that cosmic dust is incapable of fertilizing prebiotic chemistry. Cosmic dust deposits may have plausibly formed on early Earth and acted to fertilize prebiotic chemistry

Investigation of current guidelines for prescribing spectacles to children using a modified Delphi approach and the AGREE II tool

Purpose This study aimed to identify clinical guidelines that provide recommendations on prescribing refractive error correction in children, evaluate the overall quality of these guidelines using the Appraisal of Guidelines for REsearch and Evaluation II (AGREE II) tool and subsequently gain consensus on the prescribing recommendations from high‐quality guidelines using the modified Delphi technique. Methods A comprehensive search for prescribing guidelines was conducted using databases and professional websites. The quality appraisal of eligible guidelines was undertaken by scoring the six AGREE II domains. Subsequently, the modified Delphi technique was used by 10 experts (sub‐specialist optometrists, ophthalmologists and orthoptists) to gain consensus on the prescribing recommendation statements extracted from guidelines that had been identified as high quality. Three rounds were conducted in which agreement of these statements were scored using a 9‐point Likert scale with a free‐text option for any additional comments. Results Five eligible guidelines were identified. The AGREE II tool demonstrated that the guidelines varied substantially in quality, with only one guideline identified as being of high quality. A total of 168 prescribing statements were reviewed in the Delphi procedure. Of these, 95 statements reached expert consensus as being appropriate prescribing recommendations. Conclusion There is significant scope for improving current guidelines for prescribing refractive error correction in children. We used the modified Delphi technique to find points of agreement on prescribing recommendations to support professionals prescribing refractive error correction in children. We recommend that further work is needed to address gaps in the guidelines

Isotopic and textural analysis of giant unmelted micrometeorites – identification of new material from intensely altered 16O-poor water-rich asteroids

Bulk oxygen isotope data has the potential to match extraterrestrial samples to parent body sources based on distinctive δ18O and Δ17O ratios. We analysed 10 giant (&gt;500 μm) micrometeorites using combined micro-Computer Tomography (μCT) and O-isotope analysis to pair internal textures to inferred parent body groups. We identify three ordinary chondrite particles (L and LL groups), four from CR chondrites and the first micrometeorite from the enstatite chondrite (EH4) group. In addition, two micrometeorites are from hydrated carbonaceous chondrite parent bodies with 16O-poor isotopic compositions and plot above the terrestrial fractionation line. They experienced intense aqueous alteration, contain pseudomorphic chondrules and are petrographically similar to the CM1/CR1 chondrites. These micrometeorites may be members of the newly established CY chondrites and/or derived from the enigmatic “Group 4” micrometeorite population, previously identified by Yada et al., 2005 [GCA, 69:5789-5804], Suavet et al., 2010 [EPSL, 293:313-320] (and others). One of our 16O-poor micrometeorite plots on the same isotopic trendline as the CO, CM and CY chondrites – “the CM mixing line” (with a slope of ∼0.7 and a δ17O intercept of -4.23‰), this implies a close relationship and potentially a genetic link to these hydrated chondrites. If position along the CM mixing line reflects the amount of 16O-poor (heavy) water-ice accreted onto the parent body at formation, then the CY chondrites and these 16O-poor micrometeorites must have accreted at least as much water-ice as CM chondrites but potentially more. In addition, thermal metamorphism could have played a role in further raising the bulk O-isotope compositions through the preferential loss of isotopically light water during phyllosilicate dehydration. The study of micrometeorites provides insights into asteroid belt diversity through the discovery of material not currently sampled by larger meteorites, perhaps as a result of atmospheric entry biases preventing the survival of large blocks of friable hydrated material