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Childhood visual impairment in England: a rising trend
  1. Danny Mitry1,
  2. Catey Bunce1,2,
  3. Richard Wormald1,2,
  4. Richard Bowman3,4,5
  1. 1National Institute of Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hopsital NHS Foundation Trust, London, UK
  2. 2Institute of Ophthalmology, University College London, London, UK
  3. 3Clinical and Academic Department of Ophthalmology, Great Ormond Street London, UK
  4. 4Institute of Child Health, University College London, London, UK
  5. 5London School Of Hygiene and Tropical Medicine, London, UK
  1. Correspondence to Danny Mitry, National Institute of Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hopsital NHS Foundation Trust, City Road, London EC1V 2PD, UK:mitryd{at}gmail.com

Abstract

Aim To explore temporal trends in the incidence of childhood blindness and partial-sight registration in England between 1982 and 2011.

Methods We obtained blind and partial-sight registration data for all new individuals registered annually in England. We calculated the age-specific incidence of new registrations for childhood blind and partial sight.

Results The incidence of new registration for blindness of all ages has decreased from 2.6 per 10 000 in 1982 to 1.7 per 10 000 in 2011, however the annual incidence of new paediatric blind registration has increased, with an incidence of 0.17 per 10 000 in 1982, doubling to 0.41 per 10 000 in 2011. The annual incidence of new paediatric partial-sight registration showed a comparable trend.

Conclusions Over 30 years, there has been a greater than twofold increase in blind and partial-sight registration in children in England. Better awareness of this is needed to ensure adequate resources are available to help these children.

  • Epidemiology
  • Ophthalmology

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What is already known on this topic

  • There are very few large longitudinal studies on the incidence of childhood blind and partial sight in the UK.

  • Previous studies have suggested that this number may be rising.

What this study adds

  • Examining national data over 30 years has demonstrated a greater than twofold increase in blind and partial-sight registration in children in England.

  • Better awareness of this important trend is needed to ensure adequate resources can be made available.

Introduction

The WHO estimates that 19 million children are visually impaired and 1.4 million are blind, with 90% of the world's visually impaired living in developing countries.1 In the UK it has been estimated that 4 in 10 000 births are diagnosed with severe visual impairment by their first birthday, with this number thought to be rising.2 In the UK, there are few recent studies that have characterised the changes in paediatric blindness over a long time period.3 The National Health Service (NHS) Information Centre for health and social care is the organisation responsible for the analysis and dissemination of demographic data on all blind and partial-sight registered individuals in England. Using reported data, the aim of this study is to explore the trends in the incidence of new registration of childhood blindness and partial sight in England between 1982 and 2011.

Methods

Registration as blind or partially sighted in England is voluntary, thus the ophthalmologist must ask whether an eligible individual wishes to be registered; if so, a Certificate of Vision Impairment is completed. The examining ophthalmologist certifies whether or not the person meets the statutory definition of blindness or the non-statutory definition of partial sight. Table 1 highlights the current recommendations on the Certificate of Visual Impairment for registration as either blind or partially sighted. These criteria apply to the function of the better eye as individuals with good vision in one eye are not eligible. In order to be registered, the cause of visual loss should be irremediable. Treatable causes of visual loss are unlikely to be registered.

Table 1

The legal definition and current recommendations to ophthalmologists for blind and partial-sight registration in England

Once a Certificate of Visual Impairment is completed by the examining ophthalmologist, the Certificate is sent to the Social Service department who contact the individual to offer a needs assessment and to place the individual on the register for visual impairment. Once every 3 years the 152 Councils with Social Services Responsibilities in England are mandated to complete a return which is sent to the NHS information centre for health and social care. This contains the total number of individuals on their register and the number newly added that year. We have used data derived from the 2011 general publication, which is available online: http://www.ic.nhs.uk/statistics-and-data-collections/social-care/adult-social-care-information/registered-blind-and-partially-sighted-people–year-ending-31-march-2011-in-england (accessed: 28 Oct 2011).

The number of new registrations for blind and partial sight in England is available on a 3-yearly basis between 1982 and 2011. We used annual age specific, mid-year population estimates from censuses since 1982 derived from the Office for National Statistics in England. For registrations from the years 1982, 1988 and 2011, the closest age specific population estimates had to be derived from the years 1981, 1986 and 2010. For all new registrations, paediatric blindness or partial sight was defined as registered persons <17 years old. Assuming a Poisson distribution, we calculated the age-specific annual incidence per 10 000 population of new registrations for blind and partial sight. We used a χ² trend with a test p value of <0.05 to signify a significant temporal trend.

Results

In 1982 the total number of new blind registrations (of all ages) was 12 190 (2.6 per 10 000 population), which rose to a peak in 1994 at 14 050 persons (2.9 per 10 000 population), steadily decreasing annually thereafter to 9110 (1.7 per 10 000 population) in 2011. Similarly, in 1982 the total number of new partial sight registrations (of all ages) was 9040 (1.9 per 10 000 population), increasing to a peak of 17 990 in 1997 (3.7 per 10 000 population) and decreasing annually thereafter to 2.3 per 10 000 population in 2011.

Examining the annual incidence of new blind registrations in children however revealed an unexpected pattern (figure 1). The annual incidence of new paediatric blind registration showed an increasing trend, with an incidence of 0.17 per 10 000 in 1982, doubling to 0.41 per 10 000 in 2011 (χ² trend=182; p<0.001). This contrasts with the pattern seen in adults, where the incidence of new blind registration has steadily fallen over the same time period (χ² trend=39; p<0.001).

Figure 1

Annual incidence and associated 95% CI of new paediatric and adult blind registrations in England between 1982 and 2011.

The annual incidence of new paediatric partial-sight registration demonstrated a similar pattern, with an overall rise in incidence from 0.21 per 10 000 in 1982 to 0.59 per 10 000 in 2011 (χ² trend=358; p<0.001). In adults, the annual incidence of new partial-sight registration mirrored the paediatric trend, but to a lesser degree, demonstrating an overall increase from 0.54 per 10 000 in 1982 to 0.67 per 10 000 in 2011 (χ² trend=73; p<0.001). Both groups displayed a dramatic annual increase in the incidence of new partial-sight registration between 1982 and 1997 (figure 2).

Figure 2

Annual incidence and associated 95% CI of new paediatric and adult partial-sight registrations in England between 1982 and 2011.

Conclusions

Current data from England suggest that the annual incidence of new registrations for blind and partial sight in children has risen over the past three decades. Few reports exist on the temporal trends of paediatric blindness in the UK, however a surveillance study highlighted that at least four of every 10 000 children born in the UK will be diagnosed as severely visually impaired or blind by their first birthday.2

There are undoubtedly inherent biases that have influenced the observed trend in this study. Registration in England is both hospital based and is not a statutory requirement, thus the coverage of this database may be incomplete. Nonetheless, these estimates provide useful indicators or minimum estimates of the annual incidence of blind and partial sight in England. Since we report only new registrations for each study year, we minimise bias from registers that may be poorly updated.

There are many reasons that may influence the observed trend. A larger provision of specialised paediatric eyecare in England is likely to have raised awareness and perhaps increased the number of registrations.4 However, one of the commonest causes of childhood blindness that accounts for up to 48% of severe visual impairment in developed countries is cortical visual impairment (CVI).2 CVI is seen with increased frequency in low birth weight (<2500 g) and in pre-term births,2 ,5 the rate of which is rising in the UK, with a reported 41% increase in elective/induced pre-term birth in Scotland between 1980 and 2004.6 This obstetric trend in the UK may account at least in part for the rise in registration noted. In addition, improved survival of children with multiple disabilities may add to a higher rate of visual impairment, although this proportion is thought to be low (<1%).5 Interestingly, while the overall trend for partial-sight registration in children mirrored that in adults, the trend for blind registration was markedly different, suggesting that perhaps better diagnostic acumen or, worryingly, a distinct increase in the incidence of blinding pathology in children over the last three decades may underlie the observed changes.

This study highlights a more than twofold increase in new blind and partial-sight registration in children in England between 1982 and 2011, with significant rising trends. The underlying causes for this observed trend are uncertain and we are currently exploring certification data to characterise the underlying reasons. Blind registration in children accounts for <1% of all blind registrations in England, and is very much the minority when exploring visual impairment in the UK. We believe that the trend reported here has gone unnoticed because of the overall trend of decreasing registration. While increases in registration may not equate to increases in blindness, they do indicate that more children have been offered and accepted the offer of help from Social Services. This increase deserves comment if only to ensure that there are increasing resources to deal with these additional children.

References

Footnotes

  • Contributors DM analysed and wrote the manuscript. CB and RW assisted in data analysis and designed the study. CB and RB edited the manuscript and provided senior authorship.

  • Funding The authors acknowledge (a proportion of their) financial support from the Department of Health through the award made by the National Institute for Health Research to Moorfields Eye Hospital NHS Foundation Trust, and UCL Institute of Ophthalmology, for a Specialist Biomedical Research Centre for Ophthalmology. The views expressed in this paper are those of the authors and not necessarily those of the Department of Health.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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