Prevalence and causes of childhood blindness in India: a systematic review

Author: Wadhwani M, Vashist P, Singh SS, Gupta V, Gupta N, Saxena R.

Geographical coverage: India

Sector: Burden of disease

Sub-sector: Epidemiology

Equity focus: Focus on children

Study population: Children in India under 16 years old.

Review type: Other review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis method: Not applicable

Background: Childhood blindness is one of the priority targets of Vision 2020 –Right To Sight, due to its impact on the psychological and social growth of the child.

Objectives: Prevalence and causes of childhood blindness must be reviewed in order to ascertain the success of current interventions in India, and to judiciously allocate future resources, tailored to the needs of the community.

Main findings:

Overall findings of this review showed that the prevalence of childhood blindness in India varied between 0.6 to 1.06 per thousand and the prevalence of visual impairment varied between 2.05 to 13.6 per thousand. Causes of childhood blindness have mainly shifted from corneal causes to whole globe abnormalities.

A total of 30 studies were included in the narrative review. Five community‑based studies on the prevalence of childhood blindness, including two refractive error studies conducted in India with children less than 16 years, were included in the systematic review.

The causes of childhood blindness from the available blind school studies reveal that causes of childhood blindness have mainly shifted from corneal causes to whole globe abnormalities. The community‑based studies indicate that the prevalence of childhood blindness varied between 0.6 per thousand to 1.06 per thousand and prevalence of visual impairment varied between 2.05 per thousand to 13.6 per thousand.

In terms of policy relevant findings, authors note the need for a comprehensive eye care approach in which the provision of a continuum of health promotion, disease prevention, diagnosis, treatment and rehabilitation that addresses the full spectrum of eye diseases is coordinated across and integrated within the community, primary, secondary and tertiary levels within and beyond the health sector, and according to people’s needs throughout their life course. To tackle the current causes of ocular morbidity due to whole globe and retinal abnormalities, a careful, timely genetic counselling of parents before child birth, especially in the cases of consanguineous marriage, and teleophthalmology to diagnose the preventable and potentially blinding diseases like ROP should be emphasised to prevent these children from becoming blind in future years.

Methodology:

The criteria for inclusion encompassed the following aspects: The study setting was in India, specifically within community blind schools and community-based rehabilitation (CBR) programs. The participants’ age and total number were considered. The outcomes measured were the anatomical and etiological causes of childhood blindness, as determined using the WHO/PBL form. Studies that did not follow WHO standard guidelines/ methodologies and not using the anatomical and etiological causes were excluded.

A search was performed to locate research papers on childhood blindness prevalence and its causes in the community-based and blind schools, respectively, conducted from 1990 onwards up to the present. Cross references were manually searched along with expert consultation to enlarge the reference data. The search was conducted from January to June 2018. The search engines used included PubMed, Medline, OVID, Cochrane Library, and Google Scholar. The search was conducted based on medical subject headings (MeSH) and keywords to search in the title and abstract, such as “childhood” and “blindness”, limiting the search to English.

The studies on causes of childhood blindness were divided into two time-frames: those from 1990 to 2007 were compared with the studies that were conducted from 2007 to 2018. For estimating the prevalence, data from blind schools was excluded and only community‑based studies were used.

Applicability/external validity: Authors outline various drawbacks to using community-based studies for establishing prevalence estimates, which may make their findings less applicable.

Geographic focus: The reviews focuses on studies conducted in India. No attempt was made to compare prevalence rates and causes to other low- and middle- income countries. In addition, authors do not consider the marked variation between prevalence rates in different parts of India.

Summary of quality assessment:

There were several limitations in the approaches used to identify, include and appraise studies. The search was restricted to material published in English and there is no evidence of data extraction by two independent reviewers. No attempts appear to have been made to assess the quality of the included studies. While a narrative review was undertaken, the authors did not discuss any differences in quality and findings between the included studies, and what this might mean for the reported results. For these reasons, we have attributed low confidence in the findings of this review.