CHILDHOOD BLINDNESS Twenty years of childhood blindness:

what have we learnt? TOGO

Clare Gilbert for countries where these data were not Professor, International Centre for Eye available, which was based on the associ- Health; Medical Advisor, Sightsavers ation between under-five mortality rates and International, UK. the prevalence of blindness in children. This Mohammed Muhit method is still being used, as data from more Clinical Research Fellow, International recent population-based surveys confirm Centre for Eye Health, UK. that the prevalence of blindness in children and under-five mortality rates correlate Over the last 20 years, much has been reasonably well. Under-five mortality rates www.marko-kokic.com/Canadian Red Cross. Red www.marko-kokic.com/Canadian achieved in controlling blindness in children. are also being used as a proxy indicator of Prior to the launch of VISION 2020, a number in children.2 of international initiatives and programmes In 1990, experts agreed that corneal had raised the profile and increased inter- scarring, mainly from vitamin A deficiency ventions for child health and survival, which and measles, was the major cause of also had a positive impact on eye diseases childhood blindness in most low-income and blindness in children, e.g. the Expanded countries.1 However, as a simple classifi- Programme for Immunisation (EPI )(1974) cation of causes did not exist, the As a result of intense efforts to and the Global School Health Initiative International Centre for Eye Health (ICEH) reduce under-five mortality (1995). Since 2000, the United Nations’ worked with WHO to develop a new system rates over the last 20 years, the Millennium Development Goals have for classifying the causes of blindness in prevalence of corneal blindness in emphasised the need to promote child children, which was published in 1993.3 health and survival. Data collected using this system, which has children has declined Since VISION 2020 was launched in clear definitions, a standard recording form, 1999, controlling blindness in children has and a data analysis package, is being used today, such as those living in urban slums been a high priority. Child Eye Care Centres to compile a global database of causes.4 and poor communities in rural areas. are being established with well-trained, In 1997, it was estimated that 45% of blind Measles immunisation is another large- well-equipped teams, particularly in Asia. children were blind from avoidable causes scale public health intervention to reduce Programmes for detecting babies with retin- and that the pattern of causes varied child morbidity and mortality. Since the opathy of prematurity (ROP) are expanding in widely between and even within countries.4 launch of EPI in 1974, coverage with Latin America, India, China, and other The following conditions were prioritised for measles immunisation has increased to countries in Asia. Many school-going children control: corneal scarring, , target levels in most regions. The numbers are having their measured and of prematurity, (mostly of measles cases and measles-related those with refractive error are being provided ), and low vision.5 Other studies deaths have declined as a consequence. with spectacles. Finally, there is improved have shown that most blind children are Measles epidemics are now relatively rare availability of affordable consumables and either born blind or lose their sight before and measles-related corneal blindness has equipment, such as paediatric low vision their sixth birthday. Novel methods have also declined. As with vitamin A deficiency, devices, small diameter intraocular lenses, also been developed which can provide there are still communities of children at and spectacles for children. important information on the prevalence risk, particularly in sub-saharan Africa, This article presents an overview of what and causes of blindness in children, such where the majority of measles cases and we have learnt over the past twenty years as the use of local volunteers who act as measles-related deaths now occur. and outlines some of the challenges we still key informants.6 There is no reason to be complacent, as have to face in order to control avoidable there is evidence that under-five mortality blindness in children and adequately 2 Vitamin A deficiency and measles rates are no longer declining at the same support those with incurable visual loss. During the 1980s, it was realised that rate as in earlier decades in the poorest parts vitamin A deficiency was an important cause of the world. Our role as eye care profes- 1 Magnitude and causes of child mortality and that high-dose vitamin sionals is to advocate for children – when we In 1988, there was little information on the A supplementation significantly reduced see a child with corneal ulceration from magnitude and causes of blindness and child deaths, even in communities with low vitamin A deficiency or following measles, we in children. At that time, levels of clinical . Intermittent should not only treat the child, but we should most of the information on causes had high-dose vitamin A supplementation is an also inform the relevant authorities so that come from examining children in schools for important public health intervention and they can improve their programmes. the blind and prevalence data were very approximately 500 million doses are given limited. However, we have since made annually throughout the world at a cost of 3 Cataract in children substantial progress, both in collecting data approximately US $1 per dose. As a result, Because corneal blindness is declining in and in finding ways to estimate the magnitude the prevalence of vitamin A deficiency has many countries in Africa and Asia, cataract and causes of childhood blindness. declined in many regions of the world. There is becoming a relatively more important cause In 1990, the World Health Organization is also evidence that blindness in children of avoidable blindness. The management of (WHO) organised the first meeting of experts due to corneal scarring has also declined. cataract in young children has changed on the prevention of blindness in children; For example, in Uganda, 53% of all blind dramatically over the last 20 years. When they estimated that there were 1.5 million children born between 1951 and 1965 intraocular lenses (IOLs) were first used in blind children in the world.1 In 1997 WHO were blind from corneal scarring, compared the late 1970s, they were thought not to be held a second meeting, during which the with 14% for children born between 1980 suitable for children. Over the last decade, estimate was revised to 1.4 million: a new and 1995.7 However, some communities smaller, high-power IOLs, suitable for method was used to estimate the magnitude are still affected by vitamin A deficiency children, have become available; surgical

46 Community Eye Health Journal 20th ANNIVERSARY EDITION | Vol 21 ISSUE 67 | SEPTEMBER 2008 techniques and equipment have also 7 Conclusion evolved. Many paediatric ophthalmologists The control of blindness in children is a now insert IOLs in children as young as VISION 2020 priority because the number Clare Glibert Clare 12 months of age. However, this technique of ‘blind person years’ resulting from requires considerable expertise and a blindness starting in childhood is second only vitrectomy machine, as the posterior capsule to cataract. If VISION 2020 targets for and anterior vitreous have to be removed in children can be met, the global prevalence young children. Long-term follow-up is also of blindness will have fallen from crucial to manage visual axis opacities and 7.5/10,000 children (in 1997) to to ensure the child is given optimal optical 4/10,000 children by the year 2020. The correction and low vision devices, if required. number of children who are blind will decline to approximately 800,000. Premature baby in a neonatal intensive 4 Retinopathy of prematurity (ROP) care unit. VENEZUELA Visual loss from refractive error and In the early 1990s, it became apparent that cataract is treatable, and blindness from an epidemic of blindness due to ROP was findings show that refractive errors are more vitamin A deficiency, measles, or ROP is occurring in middle-income countries.8 prevalent in children in Asian countries than potentially preventable. As eye care workers, There are three main reasons for this in other regions, and that myopia, which we must provide the relevant information, epidemic: neonatal care services have increases with increasing age, is the services, and support to reduce blindness expanded and premature babies are commonest refractive error in older children. and visual impairment in children from these surviving; levels of neonatal care are not Myopia is also more common in children avoidable causes. We also need to ensure always adequate to prevent ROP, particularly from urban areas than in those from rural that children with incurable visual loss are in larger, more mature babies; finally, not all areas. The current thinking is that myopia is not denied their equal right to education and babies at risk are being examined by an caused by the influence of genes as well as to lives that are fulfilled and rewarding. ophthalmologist and treated, if required. environmental factors, and that outdoor activity may protect children from myopia. References Recent evidence suggests that ROP is also 1 World Health Organization. Report of the WHO 9 emerging as a new cause of blindness in We also know from studies in Tanzania and Meeting on the Prevention of Childhood Blindness. urban centres in India, China, and other Mexico, that a high proportion of children WHO/PBL/90.19. WHO, Geneva, 1990. 2 Sommer A et al. Assessment and control of vitamin A countries in Asia. In these low- and middle- with refractive error identified in school eye deficiency: The Annecy Accords. J Nutr 2002;132: income regions, premature babies are also health programmes do not wear the 2845S–2850S. spectacles provided. All these studies provide 3 Gilbert C et al. Childhood blindness: a new form at risk of severe ROP with higher birth weights for recording causes of visual loss in children. Bull World than is currently the case in industrialised important information for those planning Health Organ 1993;71: 485–489. countries. The implications of these findings school screening for refractive error. 4 Gogate P et al. Blindness in children: a wordwide perspective. Comm Eye Health J 2007;20(62); 32–33. are that neonatal care needs to be improved 5 World Health Organization. Preventing blindness in to prevent ROP and that examination of 6 Functional low vision in children children. WHO/PBL/00.77. WHO, Geneva, 1999. 6 Muhit M. Finding children who are blind. Comm Eye babies in neonatal units needs to include Recent data from the studies of refractive Health J 2007;20(62); 30–31. larger premature babies. error mentioned above suggest that the 7 Waddell K. Childhood blindness and low vision in prevalence of functional low vision (corrected Uganda. Eye 1998;12: 184–192 8 Gilbert C. Retinopathy of prematurity: a global 5 Refractive error in children visual acuity in the better eye ranging from perspective of the epidemics, population of babies at Little was known about the magnitude of <6/18 to, and including, light perception risk and implications for control. Early Hum Dev 2008;84: 77–82. vision loss due to refractive error in children from untreatable causes) is approximately 9 Wedner SH et al. Two strategies for correcting refractive until the late 1990s. Since 2000, WHO has twice the prevalence of blindness: there are errors in school students in Tanzania: randomised worked with the National Eye Institute, USA, almost 3 million children worldwide who comparison, with implications for screening programmes. Brit J Ophthalmol 2008;92: 19–24. to undertake standard, population-based have the potential to benefit from low vision 10 Gilbert CE et al. The prevalence and causes of surveys of the prevalence of refractive error care.10 It is, therefore, essential that low functional low vision in school-age children: results from standardized population surveys conducted in in all regions of the world among children vision services be part of eye care services Asia, Africa and Latin America. Invest Oph Vis Sci aged five or seven up to 15 years. The for children at all levels of service delivery. 2008;49: 877–881. Challenges for the future

1 Integrating eye health into broader population of 10 million people, rather on refractive error alone means that child health initiatives than the 1 million used for adult blindness. opportunities for health promotion and • International initiatives for the promotion of education are being missed. School- child health 3 Increasing uptake of services going children have siblings and parents • Primary health care (e.g. kindergartens, • We have to be much more proactive in at home. Maternal Child Health Clinics, or micro- finding children who need treatment, credit schemes for women) for most of particularly girls (e.g. by using local key 4 Recognising the importance of the preventable eye conditions. informants) education and rehabilitation • We must try to make services affordable • Many children attending eye care services 2 Tailoring services specifically for children (free or greatly subsidised) have visual loss from untreatable condi- for children and inform the community of how much tions. It is our responsibility to ensure • Not treating children like small adults is being charged they are seen in low vision clinics and • Adopting a holistic, child-centred • Health education for mothers is crucial: referred for education and rehabilitation approach, which includes parents and they should know how to prevent poten- • As avoidable causes are declining, a carers tially blinding conditions and where they greater emphasis needs to be placed on • Developing and emphasising the should go if their child has a problem preventing disability through education sub-specialty of paediatric ophthalmology, • Health education for children, girls in and rehabilitation. from residency programmes through to particular, is equally important: they are service delivery the parents of the future 5 Ongoing research activities to • Planning services for a catchment • The current focus of school programmes improve programmes

Copyright © 2008 Clare Gilbert and Mohammed Muhit. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.