Genetic Diagnosis of Retinoblastoma Using Aqueous Humour-Findings from an Extended Cohort.

The identification of somatic RB1 variation is crucial to confirm the heritability of retinoblastoma. We and others have previously shown that, when tumour DNA is unavailable, cell-free DNA (cfDNA) derived from aqueous humour (AH) can be used to identify somatic RB1 pathogenic variation. Here we report RB1 pathogenic variant detection, as well as cfDNA concentration in an extended cohort of 75 AH samples from 68 patients. We show cfDNA concentration is highly variable and significantly correlated with the collection point of the AH. Cell-free DNA concentrations above 5 pg/µL enabled the detection of 93% of known or expected RB1 pathogenic variants. In AH samples collected during intravitreal chemotherapy treatment (Tx), the yield of cfDNA above 5 pg/µL and subsequent variant detection was low (≤46%). However, AH collected by an anterior chamber tap after one to three cycles of primary chemotherapy (Dx1+) enabled the detection of 75% of expected pathogenic variants. Further limiting our analysis to Dx1+ samples taken after ≤2 cycles (Dx ≤ 2) provided measurable levels of cfDNA in all cases, and a subsequent variant detection rate of 95%. Early AH sampling is therefore likely to be important in maximising cfDNA concentration and the subsequent detection of somatic RB1 pathogenic variants in retinoblastoma patients undergoing conservative treatment.

Papilloedema: a highly specific predictor of raised intracranial pressure in a complex neurosurgical paediatric cohort.

PURPOSE: Papilloedema is recognised as an indicator of raised intracranial pressure, although there is a paucity of literature describing the utility of fundoscopy in screening for raised ICP in children with craniofacial synostosis, particularly young children. We sought to investigate the association of optic disc morphology with ICP in children, and to define the sensitivity and specificity of papilloedema as a clinical indicator of raised ICP and determine if age, or underlying conditions impact the findings. METHOD: Retrospective analysis of all patients undergoing ICP monitoring at a designated paediatric neurosurgical and craniofacial unit in the United Kingdom between October 2009 and October 2018. The fundoscopy findings and ICP monitoring data were analysed for 31 children with craniosynostosis and 29 children without craniosynostosis. RESULTS: All children who had papilloedema had raised ICP confirmed with monitoring. Across the 60-patient cohort, confirmed papilloedema on fundoscopy had Positive Predictive Value (PPV) of 1.00, Negative Predictive Value (NPV) of 0.64 with sensitivity 48% and specificity 100% for the presence of raised ICP (p = < 0.0001). In the craniosynostosis group, PPV was 1.00, NPV was 0.39, sensitivity 48% and specificity 100% (p = < 0.03). There is no correlation between severity of optic disc swelling using Frisen grading and elevation of ICP. Age did not affect the presence of papilloedema in those with raised ICP. CONCLUSION: The presence of papilloedema is a strong indicator of raised ICP in a child, regardless of underlying aetiology. Detailed fundoscopy can prevent the need for further investigations including imaging-related radiation and invasive CSF pressure monitoring.

Electronic Structures and Spectroscopic Signatures of Noble-Gas-Doped Nanodiamonds.

Fluorescent nanodiamonds, that is, those containing optically active defects, have attracted interest for their ability to be used as qubits; for in vivo imaging; and as sensors for spin, stress, and temperature. One of the most commonly studied nanodiamond color centers is the nitrogen vacancy. However, there is strong interest in discovering other impurity centers that provide localized midband gap transitions. Noble gas atoms have garnered attention since they have been discovered within nanodiamonds produced through high-pressure-high-temperature laser-heated diamond anvil cell synthesis methods, where they are commonly used as hydrostatic pressure media. Noble gas atoms that exist in macrosized natural or synthetic diamonds have been shown to be able to form color centers. This research uses ab initio density functional theory and cluster models to systematically study the localized electronic structure for group VIII impurities of nanodiamond, including helium, neon, argon, krypton, and xenon. An in-depth examination of the interaction between the noble gas atom and diamond lattice has been carried out. The changes to the vibrational and UV/vis absorption spectra have been analyzed. It was determined that the energetically preferred geometry is dependent on the atom size. Most noble gas defects are stabilized within the nanodiamond lattice and exist in tetrahedral interstitial positions, except for the largest noble gas studied in this work, Xe, which was determined to prefer a substitutional configuration. Both Kr and Xe are expected to be able to manifest visible/near-IR optical responses when included in the diamond lattice.

Kinetically Corrected Monte Carlo-Molecular Dynamics Simulations of Solid Electrolyte Interphase Growth.

We present a kinetic approach to the Monte Carlo-molecular dynamics (MC-MD) method for simulating reactive liquids using nonreactive force fields. A graphical reaction representation allows definition of reactions of arbitrary complexity, including their local solvation environment. Reaction probabilities and molecular dynamics (MD) simulation times are derived from ab initio calculations. Detailed validation is followed by studying the development of the solid electrolyte interphase (SEI) in lithium-ion batteries. We reproduce the experimentally observed two-layered structure on graphite, with an inorganic layer close to the anode and an outer organic layer. This structure develops via a near-shore aggregation mechanism.

Study of Optimal Perimetric Testing In Children (OPTIC): developing consensus and setting research priorities for perimetry in the management of children with glaucoma.

BACKGROUND: Perimetry is important in the management of children with glaucoma, but there is limited evidence-based guidance on its use. We report an expert consensus-based study to update guidance and identify areas requiring further research. METHODS: Experts were invited to participate in a modified Delphi consensus process. Panel selection was based on clinical experience of managing children with glaucoma and UK-based training to minimise diversity of view due to healthcare setting. Questionnaires were delivered electronically, and analysed to establish 'agreement'. Divergence of opinions was investigated and resolved where possible through further iterations. RESULTS: 7/9 experts invited agreed to participate. Consensus (≥5/7 (71%) in agreement) was achieved for 21/26 (80.8%) items in 2 rounds, generating recommendations to start perimetry from approximately 7 years of age (IQR: 6.75-7.25), and use qualitative methods in conjunction with automated reliability indices to assess test quality. There was a lack of agreement about defining progressive visual field (VF) loss and methods for implementing perimetry longitudinally. Panel members highlighted the importance of informing decisions based upon individual circumstances-from gauging maturity/capability when selecting tests and interpreting outcomes, to accounting for specific clinical features (e.g. poor IOP control and/or suspected progressive VF loss) when making decisions about frequency of testing. CONCLUSIONS: There is commonality of expert views in relation to implementing perimetry and interpreting test quality in the management of children with glaucoma. However, there remains a lack of agreement about defining progressive VF loss, and utilising perimetry over an individuals' lifetime, highlighting the need for further research.

Outcomes following tacrolimus systemic immunosuppression for penetrating keratoplasty in infants and young children.

OBJECTIVE: To report outcomes of tacrolimus immunosuppression after penetrating keratoplasty (PK) in very young children. METHODS: Retrospective, consecutive, cohort study of children undergoing PK at a tertiary children's hospital between 2005 and 2016. Oral tacrolimus immunosuppression was given for 2 years, followed by topical tacrolimus. RESULTS: Fourteen children (20 eyes) had 24 PKs; nineteen eyes had primary PKs, five eyes had repeat PKs. Mean age at primary graft was 95 days (3.1 months) for anterior segment dysgenesis (ASD), 430 days (14.3 months) for non-ASD children. Eleven children (15 eyes) had ASD. Three children (five eyes) had non-ASD: two children (three eyes) had glaucoma-related corneal opacity and one child (two eyes) had congenital hereditary endothelial dystrophy (CHED). One-year rejection-free survival rates following primary PK was 80% for ASD (n = 15) and 100% for non-ASD (n = 4). At final review, 5/15 of primary grafts for ASD were clear. 10/15 failed after a mean of 19 months, specifically attributable to infection (n = 2), rejection (n = 2) and glaucoma (n = 2). 4/4 primary non-ASD grafts are clear at final review (mean follow-up = 77 months). All repeat grafts (n = 5), failed after a mean of 38.25 months. Considering all grafts, 15/24 (62.5%) failed: 5/15 due to infection, 2/15 due to rejection, 8/15 due to glaucoma, phthisis, perforation or vascularised with no rejection. At last review (mean = 58.1 months, range 28-84), overall cohort survival is 37.5%. Final visual acuities range between 0.86 and 2.4 LogMAR. CONCLUSION: We compare our results to published literature: 1-year graft survival was higher than previously reported, with lower failure due to rejection. Overall infection rates did not increase, however, proportionally, severe infections were higher. Overall graft survival is at least comparable to reported literature.

Reducing suspicion of sexual abuse in paediatric chlamydial conjunctivitis using ompA genotyping.

Chlamydia trachomatis is a Gram-negative bacterium that causes urogenital tract infections, and ocular infections including trachoma, neonatal conjunctivitis and adult chlamydial inclusion conjunctivitis. A positive C. trachomatis diagnosis in children often raises suspicions of sexual abuse. While outer membrane protein A (ompA) genotypes A-C are non-invasive and are associated with trachoma; ompA genotypes D-K are often associated with sexually transmitted urogenital infections or sexually acquired chlamydial conjunctivitis. A 10-year-old female presented with a 7-month history of unilateral conjunctivitis with itching, watering and hyperaemia. She had recently moved from an urban centre in Afghanistan to the UK. A conjunctival swab taken from the child tested positive for C. trachomatis Application of ompA genotyping to conjunctival swab chlamydial DNA demonstrated that the C. trachomatis had an ompA genotype C. Chlamydial strains with this ompA genotype cause trachoma and have never previously been associated with urogenital infection. This result supported cessation of child protection investigations.

Reliability and Recommended Settings for Pediatric Circumpapillary Retinal Nerve Fiber Layer Imaging Using Hand-Held Optical Coherence Tomography.

Purpose: To investigate feasibility and reliability of 3-dimensional full circumpapillary retinal nerve fiber layer (cpRNFL) analysis in children, with and without glaucoma, without the use of sedation and to recommend a protocol for hand-held optical coherence tomography use. Methods: A cohort of pediatric glaucoma patients and normal children were imaged with hand-held optical coherence tomography to assess the feasibility of obtaining full cpRNFL. Two consecutive scans were acquired in a smaller sample to investigate test-retest repeatability and interassessor reproducibility. The cpRNFL thickness was assessed in four quadrants, at several visual angles from the optic nerve center. Results: Scanning was attempted in both eyes of 90 children with pediatric glaucoma and 180 controls to investigate feasibility (mean age, 6.98 ± 4.42 years). Scanning was not possible in 68 eyes of glaucoma children mainly owing to nystagmus, unclear optical media, or high refractive errors. Where three-dimensional imaging was possible, success at obtaining full cpRNFL was 67% in children with glaucoma and 89% for controls. Seventeen children with pediatric glaucoma and 34 controls contributed to reliability analysis (mean age, 6.3 ± 3.63 years). For repeatability intraclass correlation coefficients across quadrants ranged from 0.63 to 0.82 at 4° and improved to 0.88 to 0.94 at 6°. Intraclass correlation coefficients for reproducibility were also highest at 6° (>0.97 across all quadrants). Conclusions: We demonstrate that acquisition and measurement of cpRNFL thickness values using 3-dimensional hand-held optical coherence tomography volumes in awake children is both feasible and reliable and is optimal at 6° from optic nerve center. Translational Relevance: Our recommended protocol provides guidance on how pediatric optic nerve pathologies are managed by clinicians.

A Novel G542X CFTR Rat Model of Cystic Fibrosis Is Sensitive to Nonsense Mediated Decay.

Nonsense mutations that lead to the insertion of a premature termination codon (PTC) in the cystic fibrosis transmembrane conductance regulator (CFTR) transcript affect 11% of patients with cystic fibrosis (CF) worldwide and are associated with severe disease phenotype. While CF rat models have contributed significantly to our understanding of CF disease pathogenesis, there are currently no rat models available for studying CF nonsense mutations. Here we created and characterized the first homozygous CF rat model that bears the CFTR G542X nonsense mutation in the endogenous locus using CRISPR/Cas9 gene editing. In addition to displaying severe CF manifestations and developmental defects such as reduced growth, abnormal tooth enamel, and intestinal obstruction, CFTR G542X knockin rats demonstrated an absence of CFTR function in tracheal and intestinal sections as assessed by nasal potential difference and transepithelial short-circuit current measurements. Reduced CFTR mRNA levels in the model further suggested sensitivity to nonsense-mediated decay, a pathway elicited by the presence of PTCs that degrades the PTC-bearing transcripts and thus further diminishes the level of CFTR protein. Although functional restoration of CFTR was observed in G542X rat tracheal epithelial cells in response to single readthrough agent therapy, therapeutic efficacy was not observed in G542X knockin rats in vivo. The G542X rat model provides an invaluable tool for the identification and in vivo validation of potential therapies for CFTR nonsense mutations.

Detection and characterisation of optic nerve and retinal changes in primary congenital glaucoma using hand-held optical coherence tomography.

OBJECTIVE: To investigate (1) the feasibility of scanning the optic nerve (ON) and central retina with hand-held optical coherence tomography (HH-OCT) without sedation or anaesthesia in primary congenital glaucoma (PCG), (2) the characteristics of ON changes in comparison with adult primary open-angle glaucoma (POAG) in comparison with matched controls, (3) the sensitivity and specificity of ON parameters for diagnosis, and (4) changes of foveal morphology. METHODS AND ANALYSIS: HH-OCT (Envisu 2300; Leica Microsystems) was used to investigate ON and foveal morphology of 20 children with PCG (mean age 4.64±2.79) and 10 adult patients with POAG (mean age 66.8±6.94), and compared with age-matched, gender-matched and ethnicity-matched healthy controls without sedation or anaesthesia. RESULTS: HH-OCT yielded useful data in 20 out of 24 young children with PCG. Patients with PCG had significantly deeper cup changes than patients with POAG (vs respective age-matched controls, p=0.014). ON changes in PCG are characterised by significant increase in cup depth (165%), increased cup diameter (159%) and reduction in rim area (36.4%) as compared with controls with high sensitivity (81.5, 74.1% and 88.9%, respectively) and specificity (85.0, 80.0% and 75.0%, respectively). Patients with PCG have a significantly smaller width of the macula pit (p<0.001) with non-detectable external limiting membrane. CONCLUSION: HH-OCT has the potential to be a useful tool in glaucoma management for young children. We have demonstrated the use of HH-OCT in confirming a diagnosis of glaucoma within the studied cohort and found changes in disc morphology which characterise differently in PCG from POAG.

The UK Paediatric Ocular Trauma Study 3 (POTS3): clinical features and initial management of injuries.

PURPOSE: Worldwide, as many as 6 million children annually sustain ocular trauma, with up to a quarter of a million children requiring hospitalization. Management of pediatric ocular trauma differs from that in adults, both in terms of initial assessment and acute intervention, with significant variation in practice between different centers. Patterns of healing and long-term outcomes are also very different for children compared to adults. In order to develop effective protocols for management, it is first necessary to understand current trends in presentation and treatment. METHODS: We conducted a prospective, observational study of pediatric ocular trauma presenting to UK-based ophthalmologists over a one-year period; reporting cards were distributed by the British Ophthalmic Surveillance Unit, and clinicians were asked to report cases of acute orbital and ocular trauma in children aged 16 years or less requiring inpatient or day-case admission. A validated, standardized questionnaire was sent to reporting ophthalmologists to collect data on clinical features and initial management of injury. RESULTS: Eighty-six episodes of pediatric ocular trauma were reported. Trauma involving the globe was reported in 66/86 patients (76.7%), of which 40/66 (60.1%) were open-globe. Trauma to the anterior segment was reported in 57/86 (66.3%), and posterior segment in 23/86 patients (26.7%). Twenty-five of 86 (29.1%) patients sustained severe trauma defined as having best-corrected visual acuity worse than 6/60 Snellen (incidence 0.19 per 100,000 population). CONCLUSIONS: There has been no improvement in the incidence or severity of pediatric ocular injury rates over the past 25 years. Eye-care providers must be able to provide the necessary services for assessment and management of severe pediatric ocular trauma in the emergency setting.

The UK Paediatric Ocular Trauma Study 2 (POTS2): demographics and mechanisms of injuries.

PURPOSE: Pediatric ocular trauma is an important cause of visual morbidity worldwide, accounting for up to one-third of all ocular trauma admissions. It has long-term implications for those affected and significant economic consequences for healthcare providers. It has been estimated that 90% of all ocular trauma is preventable. Targeted strategies are required to reduce the incidence and the severity of pediatric ocular trauma; this requires an understanding of the epidemiology and characteristics of these injuries and the children involved. METHODS: Prospective, observational study of pediatric ocular trauma cases presenting to UK-based ophthalmologists over a 1-year period; reporting cards were distributed by the British Ophthalmological Surveillance Unit, and clinicians were asked to report incidents of acute orbital and ocular trauma in children aged ≤16 years requiring inpatient or day-case admission. A validated, standardized questionnaire was sent to reporting ophthalmologists to collect data on the demographics and circumstances of injury. RESULTS: Median age at presentation was 7.7 years, with boys more than twice as likely to be affected than girls (M:F =2.1:1.0). Almost 50% of injuries occurred at home, with 25% occurring in school or nursery. A total of 67% of injuries occurred during play, and 31% involved a sharp implement. CONCLUSION: Pediatric ocular trauma remains an important public health problem. At least three-quarters of all injuries are preventable through measures, including education of children and responsible adults, restricting access to sharp implements, improving adult supervision, and appropriate use of eye protection.

How to use the direct ophthalmoscope.

Ophthalmoscopy and red reflex examination are core medical skills required to identify sight-threatening and life-threatening disease. We discuss the predictive utility and limitations of findings with an ophthalmoscope and tips as to how to optimise these. We outline important considerations in three clinical scenarios: an abnormal red reflex, an abnormal optic disc and retinal haemorrhages in the context of child protection concerns.

Multiple deprivation, vision loss, and ophthalmic disease in adults: global perspectives.

The association between socioeconomic position and morbidity and mortality has long been recognized. We evaluate the evidence for an association between multiple aspects of deprivation and ocular health in a global context. This is a systematic review of studies that evaluated deprivation in the adult population in the context of the major acquired causes of visual loss such as cataract, diabetic eye disease, glaucoma, age-related macular degeneration, and ocular trauma. The search strategy identified relevant studies reported between 1946 and August 2016, with randomized control trials, case-control, cohort, and cross-sectional study designs being selected for inclusion. The studies identified in this review from across the world demonstrate the extent to which the common themes such as low educational attainment and low income may be associated with increased incidence of various sight-threatening conditions and may adversely affect access to specialist assessment and delivery of treatment. Health inequality may always persist, but an increased recognition of the importance of the various impacts of deprivation may empower policy makers to target limited resources to the most vulnerable groups in order to deliver the greatest benefit.

The UK Paediatric Ocular Trauma Study 1 (POTS1): development of a global standardized protocol for prospective data collection in pediatric ocular trauma.

BACKGROUND: Ocular trauma is an important cause of visual morbidity in children worldwide. Pediatric ocular trauma accounts for up to one third of all ocular trauma admissions, with significant economic implications for health care providers. It is estimated that 90% of all ocular trauma is preventable. Development of strategies to reduce the incidence and severity of pediatric ocular trauma requires an understanding of the epidemiology of these injuries and their characteristics. This will enable appropriate targeting of resources toward prevention and allow effective service planning. At present, there is no standardized methodology for the collection of global cross-sectional data in pediatric ocular trauma, and the ability to undertake detailed epidemiological and health-economic analyses is limited. Furthermore, it is difficult to draw international comparisons in incidence, etiology, and outcomes of pediatric ocular trauma due to the range of published reporting criteria. This study describes two novel questionnaires for standardized data collection in pediatric ocular trauma, which can be adopted across a range of health care settings internationally. METHODS: Two standardized data collection questionnaires have been developed from previously reported templates. The first enables collection of demographic and incident data on serious pediatric ocular trauma requiring hospitalization, and the second enables follow-up outcome data collection. Both the questionnaires are designed to collect primarily categorical data in order to increase ease of completion and facilitate quantitative analysis. These questionnaires enable acquisition of standardized data on the incidence, etiology, and outcomes of pediatric ocular trauma. DISCUSSION: These questionnaires enable collection of standardized data and are designed for global use across all health care settings. Through prospective data collection, epidemiological trends can be determined, allowing health care providers to develop collaborative global preventive strategies. Furthermore, the same questionnaires may be used in future studies to draw comparisons with baseline data, allowing assessment of the efficacy of targeted preventative interventions.

Long-term retinoblastoma follow-up with or without general anaesthesia.

BACKGROUND: Children with treated retinoblastoma undergo frequent examinations to monitor for recurrent or new tumours. Examinations under anaesthesia allow a more complete examination in younger children, however they are stressful for the family, subject the child to medical risk and consume resources. The risk of recurrent or new tumours declines with age and it is common practice to examine older children without general anaesthesia. There are no studies on the safety and cost effectiveness of this practice, or guidelines on when examination without anaesthesia (EWA) can be safely commenced. PROCEDURE: Retrospective case note review of 128 sequential patients treated for retinoblastoma in a national referral centre over 10 years. RESULTS: Following exclusions, 113 eyes of 84 children were analysed. The mean age at diagnosis was 20 months (range birth to 71 months). There were 55 unilateral and 29 bilateral cases. The mean follow-up was 77.7 months (range 12-178 months). EWA was commenced at a mean age of 53 months (range 12-98 months). The age of conversion to EWA was largely dependent on child cooperation and disease activity. Tumour activity was detected on EWA in one child at the age of 86 months, 9 months after the last active treatment and treated successfully. CONCLUSIONS: Examination without general anaesthesia does not appear to expose children to an increased risk of undetected tumour growth. This study highlights the important factors to be considered when deciding a safe time to commence EWA.

The epidemiology and etiology of pediatric ocular trauma.

Eighteen million people worldwide have uniocular blindness from traumatic injury. Injuries occur disproportionally commonly in childhood. Every year a quarter of a million children present with serious ocular trauma. For the vast majority the injury is preventable. We review the international literature that identifies high-risk circumstances.