What Babies See

Your newborn, still wet with amniotic fluid, opens his eyes and gazes at your face for the first time. What does he see?

Not a lot, say pediatricians. A newborn's score on an eye chart - if a newborn could read an eye chart - would be something like 20/600. There isn't a letter on the eye chart that large! Your new baby cannot discriminate any fine details.

Researchers cite research finding that babies tend to look at the edges of shapes, so your baby is likely to scan your hairline rather than gaze into your eyes. Still, your little one prefers faces to other patterns. No wonder she finds you so entrancing.

In fact, research has found that babies can imitate facial expressions when they are just three days old. In a 1982 study, people made happy, sad or surprised faces at infants, and observers who could see only the babies were able to identify the expressions.

From this blurry beginning, an infant's eyesight develops rapidly. Pediatricians explain that by the time a child is six months old, sight will have become her dominant sense. Her eye-chart score at that time will be about 20/30 - an amazing improvement, and better than many adults'.

Since babies can't call out the letters as a doctor points to them, some novel techniques have been developed to measure their eyesight. In the past 20 years or so, we've made tremendous leaps forward in our understanding of how babies see their world.

One way to measure visual acuity (or sharpness of vision) is a test called "preferential looking," which recognizes that babies prefer patterned surfaces to blank ones. The baby being tested sits between two screens, one striped and the other blank. When the stripes are broad, the baby looks more at them than the blank screen. But when the stripes become very fine, the baby shows no preference for the striped screen. Researchers conclude that, for the baby, the stripes have become so blurred that he can't really see them at all.

Acuity isn't the only factor in the development of vision. Researchers explain that during the first couple of months, babies aren't able to get their eyes to work together. This ability begins to develop at about three months and continues to improve rapidly until the baby is six months old, when her eyes should work jointly to give her good depth perception. Similarly, a baby's ability to visually follow an object, and to shift focus between things that are close and those that are far away, is weak at birth but gets much better as she nears her half birthday. All these various parts of vision interact as well. For example, a baby's acuity needs to be improving for the ability to focus to develop.

Parents often notice that their newborn seems to have crossed eyes or one eye that turns in. By the time the baby's eyes begin working together at three months, this tendency usually disappears. Some babies, however, will have one eye that continues to turn in. This condition (called amblyopia) is a concern, since that eye isn't used as much, and therefore doesn't develop the same pathway in the brain as the other eye. Usually, the treatment is to cover the good eye with a patch, so that the turned-in eye is forced to start working.

Next to refractive errors like nearsightedness and farsightedness (which are eventually corrected with glasses), a turned-in eye is the most common vision problem seen in babies. More serious concerns are very rare, but your child's doctor should do a routine check of her vision at her six-month visit, just to be sure.

How does vision evolve? There's no question that it's the result of the baby's experiences. If a baby were kept in a dark room most of the time with nothing to look at, there would be problems. On the other hand, there's no point in carrying it too far and trying to continuously stimulate the baby's vision. In any normal environment, your baby should find lots of interesting things to look at.

Most of the physical aspects of vision - the focusing mechanisms and muscles of the eye, for example, are in place at birth. During the first six months, though, the vision pathways are laid down in the baby's brain, and that's what prompts these dramatic improvements.

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