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Clare Gilbert - One of the best experts on this subject based on the ideXlab platform.
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An update on progress and the changing epidemiology of causes of Childhood Blindness worldwide
Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus, 2012Co-Authors: Lingkun Kong, Clare Gilbert, Melinda Fry, Mohannad Al-samarraie, Paul G. SteinkullerAbstract:Purpose To summarize the available data on pediatric blinding disease worldwide and to present current information on Childhood Blindness in the United States. Methods A systematic search of world literature published since 1999 was conducted. Data also were solicited from each state school for the blind in the United States. Results In developing countries, 7% to 31% of Childhood Blindness and visual impairment is avoidable, 10% to 58% is treatable, and 3% to 28% is preventable. Corneal opacification is the leading cause of Blindness in Africa, but the rate has decreased significantly from 56% in 1999 to 28% in 2012. There is no national registry of the blind in the United States, and most schools for the blind do not maintain data regarding the cause of Blindness in their students. From those schools that do have such information, the top three causes are cortical visual impairment, optic nerve hypoplasia, and retinopathy of prematurity, which have not changed in past 10 years. Conclusions There are marked regional differences in the causes of Blindness in children, apparently based on socioeconomic factors that limit prevention and treatment schemes. In the United States, the 3 leading causes of Childhood Blindness appear to be cortical visual impairment, optic nerve hypoplasia, and retinopathy of prematurity; a national registry of the blind would allow accumulation of more complete and reliable data for accurate determination of the prevalence of each.
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Childhood Blindness and severe visual impairment in Malaysia: a nationwide study
Eye, 2011Co-Authors: Daksha Patel, Clare Gilbert, I Tajunisah, Visvaraja SubrayanAbstract:To determine the causes of Childhood Blindness and severe visual impairment (BL/SVI) in schools for the blind in Malaysia. All children ≤15years attending 24 schools for the blind throughout the country were examined using the WHO Prevention of Blindness Programme (WHO/PBL) eye examination record for children, and visual loss was classified according to the International Classification of Disease (ICD). In all, 469 children were examined, of whom 448 (95.6%) had BL/SVI. The major causes of visual loss were retinal disorders (n=148, 33%; mainly retinopathy of prematurity (n=78, 17.4%)), cataract/pseudophakia/aphakia (n=77, 17.2%), and anomalies affecting the whole globe. (n=86, 19.2%). The major underlying etiology was undetermined (n=193, 43.1%), followed by hereditary factors, 21.7% (mainly retinal dystrophies), and perinatal factors, 20.5%. More than 34 (7.6%) cases were considered potentially preventable and 192 (42.9%) potentially treatable. Diseases of the retina are the major cause of visual impairment, with retinopathy of prematurity being an important avoidable cause. This reflects expansion of neonatal services in Malaysia, and improved survival of very low birth weight and preterm babies. Lens-related causes of visual impairment reflect the need to further improve pediatric ophthalmology services in Malaysia.
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The importance of prenatal factors in Childhood Blindness in India
Developmental medicine and child neurology, 2008Co-Authors: JS Rahi, Clare Gilbert, S Sripathi, Allen FosterAbstract:A cross-sectional study of 1411 children 3-15 years of age attending schools for the blind in 9 states of India in 1993 investigated the causes of visual impairment. 113 of these children (8%) were severely visually impaired and 1205 (85%) were blind. Severe visual impairment or Blindness was hereditary in 23% of cases attributable to intrauterine factors in 2% related to perinatal factors in 1% acquired postnatally in 28% and of undetermined etiology in 46%. The most common mode of inheritance in hereditary cases was autosomal recessive (52%). Retinal dystrophies and albinism together accounted for 84% of hereditary disorders. Vitamin A deficiency was implicated in 19% of cases. If children with congenital anomalies were combined with those in whom definite hereditary or intrauterine factors were identified 47% of all cases of severe visual impairment and Blindness in this study were attributable to prenatal factors. This rate increases to 60% if undetermined cases presumed to involve prenatal factors are included. The 4 major causes of visual impairment and Blindness were vitamin A deficiency congenital ocular anomalies inherited retinal dystrophies and cataract. There were variations in the relative importance of these causes by state. The observed pattern of causes of visual loss is intermediate between those seen in developed countries and the poorest developing countries. Strategies to combat Childhood Blindness in India should address both preventable and treatable causes. Of particular importance in India given the high proportion of autosomal recessive disorders is education about the risks involved in consanguineous marriages.
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Causes of Childhood Blindness in the northeastern states of India
Indian journal of ophthalmology, 2008Co-Authors: Harsha Bhattacharjee, Kalyan Das, Rishi R Borah, Kamalesh Guha, Parikshit Gogate, S Purukayastha, Clare GilbertAbstract:Background: The northeastern region (NER) of India is geographically isolated and ethno-culturally different from the rest of the country. There is lacuna regarding the data on causes of Blindness and severe visual impairment in children from this region. Aim: To determine the causes of severe visual impairment and Blindness amongst children from schools for the blind in the four states of NER of India. Design and Setting: Survey of children attending special education schools for the blind in the NER. Materials and Methods: Blind and severely visually impaired children (best corrected visual acuity Statistical Analysis: Microsoft Excel Windows software with SPSS. Results: A total of 376 students were examined of whom 258 fulfilled the eligibility criteria. The major anatomical causes of visual loss amongst the 258 were congenital anomalies (anophthalmos, microphthalmos) 93 (36.1%); corneal conditions (scarring, vitamin A deficiency) 94 (36.7%); cataract or aphakia 28 (10.9%), retinal disorders 15 (5.8%) and optic atrophy 14 (5.3%). Nearly half of the children were blind from conditions which were either preventable or treatable (48.5%). Conclusion: Nearly half the Childhood Blindness in the NER states of India is avoidable and Vitamin A deficiency forms an important component unlike other Indian states. More research and multisectorial effort is needed to tackle congenital anomalies.
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Childhood Blindness in India.
Journal of the Indian Medical Association, 2001Co-Authors: A. K. Sil, Clare GilbertAbstract:To date there are no published studies on Blindness in children or on its incidence. Recently information on the causes of Blindness in children identified by community based rehabilitation programmes in two states of India has provided very useful population based data. Prevalence and magnitude of Blindness in children in India, avoidable causes and control of Blindness in children at the primary, secondary and tertiary levels of health care are discussed in this article along with probable areas of research.
Allen Foster - One of the best experts on this subject based on the ideXlab platform.
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The importance of prenatal factors in Childhood Blindness in India
Developmental medicine and child neurology, 2008Co-Authors: JS Rahi, Clare Gilbert, S Sripathi, Allen FosterAbstract:A cross-sectional study of 1411 children 3-15 years of age attending schools for the blind in 9 states of India in 1993 investigated the causes of visual impairment. 113 of these children (8%) were severely visually impaired and 1205 (85%) were blind. Severe visual impairment or Blindness was hereditary in 23% of cases attributable to intrauterine factors in 2% related to perinatal factors in 1% acquired postnatally in 28% and of undetermined etiology in 46%. The most common mode of inheritance in hereditary cases was autosomal recessive (52%). Retinal dystrophies and albinism together accounted for 84% of hereditary disorders. Vitamin A deficiency was implicated in 19% of cases. If children with congenital anomalies were combined with those in whom definite hereditary or intrauterine factors were identified 47% of all cases of severe visual impairment and Blindness in this study were attributable to prenatal factors. This rate increases to 60% if undetermined cases presumed to involve prenatal factors are included. The 4 major causes of visual impairment and Blindness were vitamin A deficiency congenital ocular anomalies inherited retinal dystrophies and cataract. There were variations in the relative importance of these causes by state. The observed pattern of causes of visual loss is intermediate between those seen in developed countries and the poorest developing countries. Strategies to combat Childhood Blindness in India should address both preventable and treatable causes. Of particular importance in India given the high proportion of autosomal recessive disorders is education about the risks involved in consanguineous marriages.
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Causes of Childhood Blindness in the People's Republic of China: results from 1131 blind school students in 18 provinces.
The British journal of ophthalmology, 1999Co-Authors: Stella J. Hornby, Clare Gilbert, Allen Foster, Y Xiao, X Wang, X Liang, H Jing, L Wang, W Min, Y ShiAbstract:AIMS To determine the anatomical site and underlying causes of Blindness and severe visual impairment in children under 16 years of age in special education in the People’s Republic of China with a view to determining potentially preventable and treatable causes. METHODS A national study of children attending schools for the blind in China was conducted between April and June 1998 using the WHO Prevention of Blindness Programme (WHO/PBL) eye examination record for children with Blindness and low vision. Eight Chinese ophthalmologists attended a training workshop before conducting the study. 36 blind schools in 18 provinces of China were included. RESULTS 1245 children aged between 5 and 15 years were examined, of whom 1131 (91%) were blind or severely visually impaired (visual acuity less than 6/60 in the better eye). The commonest anatomical sites of visual loss were whole globe (mainly microphthalmos) 25.5% and retina (mainly dystrophies) 24.9%. Lens was the major site in 18.8%, optic nerve in 13.6%, and glaucoma in 9%. Corneal scarring was not a major cause of visual loss. The aetiology was unknown in 52.9%, hereditary factors were responsible in 30.7%, and Childhood causes in 14%. 15% of cases were considered potentially preventable and 22.5% potentially treatable. CONCLUSION The pattern of Childhood Blindness seen in this study is likely to reflect the improved health and socioeconomic status of China but may partly reflect bias in admission to, and location of, blind schools, with higher socioeconomic groups overrepresented. Nutritional and infective causes of Blindness are uncommon, and hereditary and unknown factors are now the predominant causes.
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Measuring the burden of Childhood Blindness.
The British journal of ophthalmology, 1999Co-Authors: Jugnoo S Rahi, Clare Gilbert, Allen Foster, D MinassianAbstract:Globally, the prevalence of Blindness among children is estimated to be approximately one tenth of that in adults, at around 0.7 per 1000.1-3 However, Blindness in Childhood has far reaching implications for the affected child and family, and throughout life profoundly influences educational, employment, personal, and social prospects.4 Thus, the control of Childhood Blindness has been identified as a priority of the World Health Organisation’s (WHO) global initiative for the elimination of avoidable Blindness by the year 2020.5 Measures of disease frequency alone, however, afford a limited understanding of the public health significance of Childhood Blindness. The global financial cost of Blindness with an onset during Childhood, in terms of loss of earning capacity (per capita GNP), is greater than the cost of adult Blindness and has recently been estimated to be between US$6000 million and $27 000 million.6 Most of this is accounted for by children living in high income countries, where the prevalence is less, but life expectancy and earning capacity greater, than in low income countries. These financial costs alone, however, provide only one perspective of the public health burden of Blindness. Improved understanding and quantification require the application of indicators which measure the impact of Blindness in terms of morbidity (years of disability suffered) as well as mortality (years of life lost through premature Blindness associated death). Such indicators are useful in identifying those in the population in greatest need and for setting priorities in provision of health services. They are also important in the assessment of effectiveness of interventions and …
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Childhood Blindness in Uzbekistan.
Eye, 1999Co-Authors: Clare Gilbert, Allen FosterAbstract:Purpose To elucidate the aetiology of Childhood Blindness in the Republic of Uzbekistan and to assess the needs for future provision of ophthalmic services for children. Methods Six hundred and seventy-one children in seven schools for the blind and visually impaired throughout Uzbekistan were examined using the WHO/PBL (World Health Organization Prevention Of Blindness) Childhood Blindness proforma. The locations were chosen to give a representation of the major areas of population within the country. Results Of the 671 children examined, 506 (75.4%) were blind or severely visually impaired (corrected visual acuity of less than 6/60 (20/200) in the better eye). Cataract-related Blindness (35%), retinal dystrophies (24%) and microphthalmos (23%) formed the three largest diagnostic categories. Conclusions The commonest avoidable cause of Blindness was found to be cataract; the cause of poor vision may be due to unoperated cataract, aphakia, amblyopia or post-operative capsular fibrosis. The high proportion of retinal dystrophies may be related to the common practice of consanguineous marriage. The frequent finding of microphthalmos is discussed and compared with findings from other surveys. Glaucoma accounted for approximately 5% of the avoidable Blindness.
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Causes of Childhood Blindness in Sri Lanka: results from children attending six schools for the blind.
The British journal of ophthalmology, 1995Co-Authors: Michael Eckstein, Allen Foster, Clare GilbertAbstract:AIM--The survey aimed to identify the major treatable or preventable causes of visual loss in children attending blind schools in Sri Lanka so that appropriate control measures can be implemented. METHOD--A total of 226 children with Blindness (BL) or severe visual impairment (SVI) attending six schools for the blind were examined and details recorded using the WHO standard reporting form. RESULTS--Cataract was responsible for 17% of BL/SVI and was the commonest 'avoidable' cause of Childhood Blindness. Bilateral microphthalmos accounted for one quarter of BL/SVI. Vitamin A deficiency was not a significant cause of visual morbidity. CONCLUSION--The pattern of Childhood Blindness seen in this study is typical of a growing number of south east Asian countries which are developing rapidly. Childhood cataract is a major avoidable cause that can benefit from future intervention strategies.
Uf Ezepue - One of the best experts on this subject based on the ideXlab platform.
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Causes of Childhood Blindness: results from schools for the blind in south eastern Nigeria
The British journal of ophthalmology, 2003Co-Authors: Ir Ezegwui, R. E. Umeh, Uf EzepueAbstract:Aim: This cross sectional study was undertaken to identify the major causes of Childhood severe visual impairment/Blindness (SVI/BL) among students in schools for the blind in south eastern Nigeria with a view to offering treatment to those with remediable Blindness. Methods: 142 students attending three schools for the blind in the study area were interviewed and examined using the World Health Organization programme for prevention of Blindness (WHO/PBL) Childhood Blindness proforma. Results: By anatomical classification, the major causes of SVI/BL identified in the children (aged 15 years or less) were lesions of the lens (30.4%), corneal lesions (21.7%), whole globe lesions (mainly phthisis bulbi) (17.4%), and glaucoma/buphthalmos (10.9%). For the young adults (more than 15 years) these lesions accounted for 31.9%, 21.3%, 23.4%, and 8.5% of SVI/BL, respectively. For all the students, the commonest single diagnoses were cataract (23.5%) and corneal scarring (21.4%), of which 86.7% were caused by measles. By aetiological classification, Childhood factors (38.6%) constituted the major cause of Blindness: 37.0% in the children and 39.4% in the young adults. In 74.5% of all the students, Blindness was considered avoidable. Conclusions: A high proportion of Childhood Blindness in schools for the blind in south eastern Nigeria is avoidable. Development of paediatric ophthalmology in Nigeria to manage Childhood cataract and glaucoma is advocated.
Ir Ezegwui - One of the best experts on this subject based on the ideXlab platform.
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Using Key Informant Method to Determine the Prevalence and Causes of Childhood Blindness in South-Eastern Nigeria
Ophthalmic epidemiology, 2017Co-Authors: Ae Aghaji, Ir Ezegwui, Jude O Shiweobi, Cyril Chukwukama Mamah, Mary N Okoloagu, E. N. OnwasigweAbstract:ABSTRACTPurpose: To determine the prevalence and causes of Childhood Blindness in an underserved community in south-eastern Nigeria using the key informant method.Methods: This was a descriptive cross-sectional study. Key informants (KI) appointed by their respective communities received 1-day training on identification of blind children in their communities. Two weeks later, the research team visited the agreed sites within the community and examined the identified children. The World Health Organization eye examination record for blind children was used for data collection. Data entry and analysis were done with the Statistical Package for Social Sciences (SPSS) version 17.0.Results: Fifteen blind or severely visually impaired children (age range 3 months to 15 years) were identified in this community; nine of these were brought by the KIs. The prevalence of Childhood Blindness/severe visual impairment (BL/SVI) was 0.12 per 1000 children. By anatomical classification, operable cataract in 6 (40.0%) was ...
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Causes of Childhood Blindness: results from schools for the blind in south eastern Nigeria
The British journal of ophthalmology, 2003Co-Authors: Ir Ezegwui, R. E. Umeh, Uf EzepueAbstract:Aim: This cross sectional study was undertaken to identify the major causes of Childhood severe visual impairment/Blindness (SVI/BL) among students in schools for the blind in south eastern Nigeria with a view to offering treatment to those with remediable Blindness. Methods: 142 students attending three schools for the blind in the study area were interviewed and examined using the World Health Organization programme for prevention of Blindness (WHO/PBL) Childhood Blindness proforma. Results: By anatomical classification, the major causes of SVI/BL identified in the children (aged 15 years or less) were lesions of the lens (30.4%), corneal lesions (21.7%), whole globe lesions (mainly phthisis bulbi) (17.4%), and glaucoma/buphthalmos (10.9%). For the young adults (more than 15 years) these lesions accounted for 31.9%, 21.3%, 23.4%, and 8.5% of SVI/BL, respectively. For all the students, the commonest single diagnoses were cataract (23.5%) and corneal scarring (21.4%), of which 86.7% were caused by measles. By aetiological classification, Childhood factors (38.6%) constituted the major cause of Blindness: 37.0% in the children and 39.4% in the young adults. In 74.5% of all the students, Blindness was considered avoidable. Conclusions: A high proportion of Childhood Blindness in schools for the blind in south eastern Nigeria is avoidable. Development of paediatric ophthalmology in Nigeria to manage Childhood cataract and glaucoma is advocated.
Artur V. Cideciyan - One of the best experts on this subject based on the ideXlab platform.
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effect of an intravitreal antisense oligonucleotide on vision in leber congenital amaurosis due to a photoreceptor cilium defect
Nature Medicine, 2019Co-Authors: Artur V. Cideciyan, Samuel G. Jacobson, Alejandro J. Roman, Alexander Sumaroka, Arlene V Drack, Jason Charng, Alexandra V Garafalo, Ian C Han, Maria D Hochstedler, Wanda PfeiferAbstract:Photoreceptor ciliopathies constitute the most common molecular mechanism of the Childhood Blindness Leber congenital amaurosis. Ten patients with Leber congenital amaurosis carrying the c.2991+1655A>G allele in the ciliopathy gene centrosomal protein 290 (CEP290) were treated (ClinicalTrials.gov no. NCT03140969 ) with intravitreal injections of an antisense oligonucleotide to restore correct splicing. There were no serious adverse events, and vision improved at 3 months. The visual acuity of one exceptional responder improved from light perception to 20/400. RNA antisense oligonucleotide therapy to restore normal splicing of a ciliopathy gene shows promising safety and efficacy results in a clinical trial to treat a form of Childhood Blindness.
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Improvement and decline in vision with gene therapy in Childhood Blindness.
The New England journal of medicine, 2015Co-Authors: Samuel G. Jacobson, Artur V. Cideciyan, Alejandro J. Roman, Alexander Sumaroka, Sharon B. Schwartz, Elise Héon, William W. HauswirthAbstract:Retinal gene therapy for Leber’s congenital amaurosis, an autosomal recessive Childhood Blindness, has been widely considered to be safe and efficacious. Three years after therapy, improvement in vision was maintained, but the rate of loss of photoreceptors in the treated retina was the same as that in the untreated retina. Here we describe long-term follow-up data from three treated patients. Topographic maps of visual sensitivity in treated regions, nearly 6 years after therapy for two of the patients and 4.5 years after therapy for the third patient, indicate progressive diminution of the areas of improved vision. (Funded by the National Eye Institute; ClinicalTrials.gov number, NCT00481546.)
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Lentiviral expression of retinal guanylate cyclase-1 (RetGC1) restores vision in an avian model of Childhood Blindness.
PLoS medicine, 2006Co-Authors: Melissa L Williams, Samuel G. Jacobson, Artur V. Cideciyan, Tomas S. Aleman, Jason E. Coleman, Shannon E. Haire, Izabel Sokal, Krzysztof Palczewski, Susan L. Semple-rowlandAbstract:Background Leber congenital amaurosis (LCA) is a genetically heterogeneous group of retinal diseases that cause congenital Blindness in infants and children. Mutations in the GUCY2D gene that encodes retinal guanylate cyclase–1 (retGC1) were the first to be linked to this disease group (LCA type 1 [LCA1]) and account for 10%–20% of LCA cases. These mutations disrupt synthesis of cGMP in photoreceptor cells, a key second messenger required for function of these cells. The GUCY1*B chicken, which carries a null mutation in the retGC1 gene, is blind at hatching and serves as an animal model for the study of LCA1 pathology and potential treatments in humans. Methods and Findings A lentivirus-based gene transfer vector carrying the GUCY2D gene was developed and injected into early-stage GUCY1*B embryos to determine if photoreceptor function and sight could be restored to these animals. Like human LCA1, the avian disease shows early-onset Blindness, but there is a window of opportunity for intervention. In both diseases there is a period of photoreceptor cell dysfunction that precedes retinal degeneration. Of seven treated animals, six exhibited sight as evidenced by robust optokinetic and volitional visual behaviors. Electroretinographic responses, absent in untreated animals, were partially restored in treated animals. Morphological analyses indicated there was slowing of the retinal degeneration. Conclusions Blindness associated with loss of function of retGC1 in the GUCY1*B avian model of LCA1 can be reversed using viral vector-mediated gene transfer. Furthermore, this reversal can be achieved by restoring function to a relatively low percentage of retinal photoreceptors. These results represent a first step toward development of gene therapies for one of the more common forms of Childhood Blindness.
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Gene therapy restores vision in a canine model of Childhood Blindness.
Nature genetics, 2001Co-Authors: Gregory M. Acland, Artur V. Cideciyan, Gustavo D. Aguirre, Jharna Ray, Qi Zhang, Tomas S. Aleman, Susan E. Pearce-kelling, Vibha Anand, Yong Zeng, Albert M. MaguireAbstract:The relationship between the neurosensory photoreceptors and the adjacent retinal pigment epithelium (RPE) controls not only normal retinal function, but also the pathogenesis of hereditary retinal degenerations. The molecular bases for both primary photoreceptor1 and RPE diseases2,3,4 that cause Blindness have been identified. Gene therapy has been used successfully to slow degeneration in rodent models of primary photoreceptor diseases5,6, but efficacy of gene therapy directed at photoreceptors and RPE in a large-animal model of human disease has not been reported. Here we study one of the most clinically severe retinal degenerations, Leber congenital amaurosis (LCA). LCA causes near total Blindness in infancy and can result from mutations in RPE65 (LCA, type II; MIM 180069 and 204100). A naturally occurring animal model, the RPE65−/− dog, suffers from early and severe visual impairment similar to that seen in human LCA. We used a recombinant adeno-associated virus (AAV) carrying wild-type RPE65 (AAV-RPE65) to test the efficacy of gene therapy in this model. Our results indicate that visual function was restored in this large animal model of Childhood Blindness.