It has been estimated that 19 million children globally are visually impaired, of whom 1.4 million are irreversibly blind. Not only does childhood blindness invoke substantial financial burden to the family and country healthcare resources, it impacts neurobehavioral development and survival: up to 60% of these children do not survive within 1 year of becoming blind. While 1 million of these children are considered untreatable by current standards due to retinal dystrophy, microphthalmos, cortical blindness, and optic atrophy or hypoplasia, the remaining 400,000 cases are potentially treatable. The main avoidable causes are corneal scarring from infection or trauma (260,000), cataract (50,000), and retinopathy of prematurity (ROP; 40,000). Other treatable blinding conditions include amblyopia and uncorrected refractive error. Much of the data concerning causes of pediatric blindness in developing countries come from studies of children attending schools for the blind. This information may represent a bias, since data from children not attending these schools would not be included.
The etiologies for global blindness are dynamic, changing with the economic and geographic climate (Fig. 572-1). In developed regions, the rate of childhood blindness is 0.3 per 1000 children. The main causes of pediatric blindness in these areas are ROP, perinatal hypoxic brain injury, optic nerve hypoplasia, inherited retinal dystrophies, congenital anomalies, cataract, and glaucoma. These disorders are largely not preventable, but some are treatable. In poorer countries, rates of blindness can be as high as 1.5 per 1000 children. In these areas, the major causes of childhood blindness are vitamin A deficiency, trachoma, ophthalmia neonatorum, measles infection, harmful traditional medicines, and trauma. All these conditions are largely the result, directly or indirectly, of malnutrition, lack of sanitation, or infection, and most of these factors cause blindness primarily through corneal scarring. All of these conditions are preventable or treatable. While many countries in Africa and Asia now have established programs for measles and vitamin A deficiency, access to resources for cataract management is lacking. Retinopathy of prematurity is emerging as a major cause of blindness in middle-income countries, particularly in Latin America and Eastern Europe, where improvements in medical care leading to enhanced survival of preterm infants is often not matched with similar improved access to ROP screening programs and trained ophthalmologists. A new ROP epidemic is impending in Africa.
Estimates of pediatric blindness by region. Top number = total number of blind children. Bottom number = number blind from avoidable causes. Below each set of numbers is the major cause of regional childhood blindness. ROP, retinopathy of prematurity.
Vision impairment from uncorrected refractive errors affects 12 million children globally. In China, nearly 95% of cases of pediatric vision impairment are due to refractive error, usually high myopia, with up to 60% of these children lacking access to their appropriate corrective spectacles.