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 addition, anesthesiologists
in these areas are often reluctant to anesthetize small infants. Thus,
many children go untreated for ROP, cataracts, glaucoma, and treatable
blinding disorders. For pediatric ophthalmologists, early infancy
is often the most favorable period to surgically improve glaucoma,
cataract, and structural defects. For example, in the People’s Republic
of China, there are about 200,000 blind children (Fig.
582-2).4 Of them, 22.5% (45,000)
have cataract, glaucoma, ROP, and uveitis and are thus potentially
treatable. At least in China, the situation is improving with more
advanced physician training and alteration of hospital policies
regarding surgery on infants.
A musical band composed of students in a Chinese school
for the blind.
It may appear relatively easy to conceive strategies to combat
blindness, since the causes are often single, identifiable, and
uncomplicated. In regions with a high prevalence of rubella, vaccination
would be beneficial. Yet, the price for a nationwide vaccination
program is often too expensive to consider. Toxoplasmosis prevention
is difficult in areas with a dense population and many pets. Discouraging
consanguinity may be complicated by social and religious mores.
In areas with inadequate numbers of professionals in the field,
the proper training of pediatric ophthalmologists, nurses, and other health
workers will reduce treatable blindness in the future, but there
are financial, geographic, and access issues that make training
new workers a challenge. The widespread distribution of vitamin
A, especially where there is malnourishment, will greatly help to
prevent corneal blindness, both primary blindness due to the deficiency
and secondary blindness due to infection, as would better nutrition.
In developing countries, the most common treatable
cause of pediatric blindness is infection. Antibiotics are often
not an option due to lack of availability and relatively high cost.
For use in developing countries, an antimicrobial agent would need
to meet certain criteria, including effectiveness against bacteria
and other microbes, safety, widespread availability, and ease of
preparation. Importantly, it must not be expensive. Povidone-iodine
meets these criteria. It is effective against all bacteria, viruses,
and fungi in vitro (given enough contact time) and causes few allergic
reactions. It is questionable whether true bacterial resistance
to povidone-iodine even exists.5 It can be prepared
from preexisting powders or solutions, which are available worldwide
and are very cheap. In Kenya, a 5 mL bottle of the solution costs
less than $0.10 to prepare.6 In addition,
the povidone-iodine solution colors the eye brown for about 2 minutes,
confirming proper administration.
Conjunctivitis can lead to keratitis and scarring. The first
randomized controlled trial to investigate the use of povidone-iodine
1.25% ophthalmic solution was as effective as antibiotics
for the treatment of bacterial conjunctivitis and was more effective
against chlamydial conjunctivitis.7 More than 250,000
children are blind due to corneal infections with subsequent scarring.
Corneal scarring in children begins with a compromised corneal surface
produced by a number of possible causes, including trauma, trachoma,
vitamin A deficiency, rubeola, ophthalmia neonatorum, and harmful
traditional medications. Often, bacteria invade a compromised cornea,
causing an ulcerative keratitis that subsequently scars. An appropriate
antimicrobial medication could prevent or treat these maladies.
Povidone-iodine 1.25% ophthalmic solution has been found
to be as effective as topical antibiotics to treat this disorder.8
Prevention of ophthalmia neonatorum has been practiced since
the 19th century by administering prophylactic eyedrops immediately
after birth. Initially, silver nitrate was used followed in more
recent years by antibiotics such as erythromycin. Silver nitrate
is no longer manufactured in the United States and other countries.
Erythromycin and other antibiotics are often too expensive for use
in developing countries. Povidone-iodine 2.5% ophthalmic solution
has proven to be effective and very inexpensive and has few, if
any, side effects. It is now being used in many developing areas
to prevent ophthalmia neonatorum.
The World Health Organization (WHO) has advocated the SAFE strategy
to combat trachoma:
- S: Surgery for those at immediate risk
of blindness, usually adults with trichiasis.
- A: Antibiotic therapy to treat individual
active cases and reduce the community reservoir of infection
(usually children). WHO currently recommends mass drug administration
if the prevalence of active trachoma among children under age 10
exceeds 10%. The most common reatment is either oral azithromycin
or topical tetracycline.
- F: Facial cleanliness and hygiene promotion
to reduce transmission. Children with dirty faces are more likely
to transmit trachoma if infected or to develop trachoma if they
are not infected. Discharge from the eyes and nose attracts flies
that can bring the infection or carry it to other people.
- E: Environmental improvements to change living
conditions in order to reduce the risk for trachoma transmission.
Education can be a powerful preventive tool. Instructing village
healers not to apply “homemade” solutions to the
eye can prevent corneal inflammation and scarring. Teaching families
in trachoma-inflicted areas to have the children frequently wash their
hands and faces will reduce the prevalence of trachoma. Since trauma
is a frequent cause of reduced vision in children, having them wear
ocular protection when engaging in contact sports or potentially
injurious work would be beneficial. The latter is particularly true
in developing countries where children are often engaged in outdoor farming
Uncorrected major refractive errors can be addressed by having
a local government provide visual acuity screening of children and
offer spectacles, as necessary. This initiative can be expensive,
but the increase in productivity of citizens who will see properly
with eyeglasses should offset costs. The screening process also
can uncover cases of cataracts, glaucoma, and other disorders.
The WHO has initiated the VISION 2020 program to address many
of these prevention and treatment strategies.9 Hopefully,
this concerted effort will decrease the tragedy of childhood blindness.