Childhood blindness is an important contribution to the national prevalence of the disability of blindness. Blindness in children can be defined as a visual acuity of <3/60 in the eye with better vision of a child under 16 years of age. This generally means that the child cannot see an object 10 feet (about 3 meters) away, that a child with "normal" vision could see if it was 200 feet (about 60 meters) away.

Childhood blindness has many causes. Leading causes include retinopathy of prematurity, vitamin A deficiency, infectious diseases (measles, newborn conjunctivitis), retinoblastoma, and congenital conditions (cataracts and glaucoma). Leber congenital amaurosis primarily affects the retina, and typically severe visual impairment begins in infancy. Mutations in Aryl hydrocarbon receptor interacting protein like-1 have been linked to Leber congenital amaurosis (LCA).

The most frequently affected parts of the eyes are:

Vitamin A deficiency is most common in developing countries where many kids experience malnourishment. This vitamin deficiency blinds hundreds of thousands of kids each year, and is a preventable cause of childhood blindness. Since vitamin A is required for rhodopsin, the photosensitive pigment in the retinol rods, its deficiency can lead to night blindness.

Since 2010, globally 85% of children have been vaccinated for measles significantly reducing the number of measles cases each year. Children who have a vitamin A deficiency and measles infection can develop corneal ulcerations and keratomalacia due to immunosuppression caused by the vitamin deficiency.

Newborn conjunctivitis is present at the time of birth and presents within the first 28 days of life as a severe conjunctival infection with purulent discharge. This increases the risk of corneal ulcerations and perforations that can lead to blindness. The common organisms that lead to this diagnosis include Neisseria gonorrhoea and Chlamydia trachomatis. Infected pregnant women and their partners should be treated to avoid infection of the newborn, and newborns presenting with conjunctivitis should be treated with hourly topical antibiotic drops (gentamicin).

Retinopathy of Prematurity (ROP) is classified by the abnormal growth of blood vessels in the retina, a process called retinal neovascularization. These blood vessels may bleed or grow in the wrong direction. Bleeding can lead to the formation of scar tissue which can cause blurred vision and vision loss. If the vessels grow too far in the wrong direction, they can pull the retina away from the back of the eye – this is called retinal detachment. Retinal detachment is a medical emergency that can cause permanent blindness and thus requires urgent intervention.

Babies who are born prematurely (formally defined as 37 weeks of gestational age or earlier) are at higher risk of developing retinopathy of prematurity. The earlier a preterm baby is born, the greater the baby's risk of developing ROP. Blood vessels in the eye typically finish development by the time of birth. Therefore, a baby who is born early is exposed to various stimuli (oxygen, lights, temperature, etc.) that may influence how the blood vessels of the eye develop. Additional risk factors for ROP include low birth weight (3 pounds or less) and giving the baby excess amounts of oxygen following birth. If preterm infants are experiencing other health problems like anemia, vitamin E deficiency, and/or breathing problems, they are at increased risk of developing ROP.