When your baby opens his eyes and looks at you for the first time, the last concern you might have is whether or not his vision is normal. Unless vision problems run in the family, most people assume their babies will see their new world well. But many factors, including birth defects, hereditary disorders and acquired eye damage from prematurity can all affect an infant's vision.
Inherited genetic disorders cause poor vision in 60 percent of infants with vision problems, according to the Cleveland Clinic. As many as 40 percent of babies with strabismus -- meaning that one eye (or both) deviates either inward, toward the nose, or outward -- inherit their disorder. Congenital cataracts, a clouding of the lens in the eye or congenital glaucoma, higher than normal pressure within the eye, can be inherited traits, although they can also have non-genetic causes. Vision deviations such as astigmatism myopia, or nearsightedness and hyperopia, or far-sightedness, commonly pass from parent to child in the genes. In addition, as many as 33 percent of children with an inherited medical condition also have eye problems, the Cleveland Clinic reports.
Congenital vision problems and genetic problems aren't necessarily the same thing. While inherited disorders are carried on certain genes, congenital defects can occur during pregnancy from errors in development or toxin exposure. Optic nerve defects, malformations of parts of the eye such as the lens, iris or cornea, or maternal infections during pregnancy such as German measles can cause eye damage that's present from birth. Retinoblastoma, a type of tumor that forms in the eye, can be present as a congenital condition.
Infection and traumatic injury can cause infant vision loss. A common cause of vision loss in premature babies, retinopathy of prematurity, or ROP, affects as many as 40 percent of babies born weighing less than 2 pounds, according to the University of Michigan Kellogg Eye Center and around 5 percent of those weighing around 3 pounds. Supplemental oxygen, once thought to be the primary cause of ROP, is now considered to be a factor but not the entire cause. Poor oxygenation to the retina after birth causes the proliferation of abnormal blood vessel growth; the blood vessels bleed and scar, causing vision loss. Birth trauma, infection acquired from sexually transmitted diseases when passing through the birth canal, poor oxygenation during pregnancy or at delivery as well as physical trauma during infancy can also cause vision loss.
Sometimes the problem that causes vision loss isn't in the eye itself but in the nerve pathways and areas of the brain that "tell" the eye to see. Infections such as meningitis, traumatic head injuries, strokes or brain tumors can all affect the parts of the brain needed for vision. Because the problem isn't within the eye, glasses often won't help these types of vision losses, the Better Health Channel reports.