Approximately 500,000 children become blind worldwide
each year. This figure represents one new case of pediatric blindness
every minute. It has been estimated that today there are 1,400,000
blind children in the world,1 and many of these
children will not survive beyond 2 years of age. While 1,000,000
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).2 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.
In developed areas, the main causes of pediatric blindness 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.
Geographically, 90% of all pediatric blindness (1,300,000)
occurs in developing countries with 24% in Africa, 20% in
India, and 29% in the rest of Asia (Fig.
582-1). 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. Blindness in children due to uncorrected
major refractive errors occurs in 0.6% to 2.6% of
children in developing areas. In China, it is thought that nearly
6 millions children are visually impaired simply because they are
in need of glasses that they may never receive.3
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.
In some areas of the world, there are more specific localized
causes of blindness. For example, in Brazil, endemic toxoplasmosis
is very common and often results in bilateral macular scars with
resultant legal blindness. In Uganda, rubella-related congenital
cataract is frequently encountered. In Sri Lanka and many areas
of the Middle East, genetic diseases resulting from consanguinity
can often be found, explaining the relatively high prevalence of infantile
glaucoma, retinal degenerations, and infantile cataract. In other
locations, especially nontropical, semideveloped areas, the major
etiologies of childhood blindness are similar to developed regions.
A contributing factor to worldwide childhood blindness is an
inadequate number of pediatric ophthalmologists. General ophthalmologists
may not want to operate on infants. In ...