Here's looking at you
Wednesday, September 01, 2004
And that's about the extent of a baby's first vision abilities By Emily Brandon :::::::::::::::::::::::::::::::::Chicago Parent file photo
When your baby is born, it's a whole new world. But don't expect that your baby is seeing it very well.
While babies' vision develops quickly in the first year, newborn vision is about 20 to 30 times worse than adult vision. But it is perfectly suited to what a newborn needs: The average baby is able to discriminate light and dark and is slightly farsighted. What babies see best are objects approximately 18 inches from their eye-or about the distance to their mother's face when they are nursing or being cuddled.
But give them time. In fact, those first few months are critical for vision, and a baby's sight improves quickly during the first year. During that time, babies gain the ability to detect colors, distinguish faces and follow rapid movement. "All sensory capacities improve rapidly during the first 4 months of age, and reach near adult levels by 12 months of age. Visual perception shows dramatic changes during this period," says Dr. Bennett I. Bertenthal, professor of psychology and computational neuroscience at the University of Chicago.
Vision milestones Here are some specifics about vision development in babies.
• Colors. It is difficult for newborns to differentiate some colors at birth, especially blues and purples. However, they are able to perceive red, green and yellow quite well. Infants begin to differentiate blue from other colors at about 4 weeks.
In the months following birth, the parts of the eye that allow color vision, or the cones, migrate toward the center of the eye, grow larger and become more densely packed. In fact, according to Bertenthal, the tight packing of the cones in the center of the eye is responsible for a twentyfold improvement in vision. This allows infants to see more colors, more details, and to be able to see in dimmer light.
"Research suggests that color vision improves quickly and is similar to that of adults by 3 months," says Dr. Velma Dobson, professor of ophthalmology and psychology at the University of Arizona. In fact, she says, infants develop detail, motion and color vision very rapidly in the first 6 months of life.
• Faces. Infants at 1 month are not yet able to distinguish facial features. They instinctively focus their attention on the contours of objects and faces, and often direct their attention to your hairline or the outline of your face.
By 2 months, infants learn to direct their attention toward such features of the face as the eyes and mouth. Three-month-old children prefer their mother's face to the faces of strangers on the basis of vision alone, which indicates that 3-month-olds can see their mother's face well enough to identify it without using any other senses.
However, your child will recognize you before 3 months of age by using their other senses, such as hearing and smell. Any parent knows that, says Peter J. Gallanis of Des Plaines. "Babies use all their senses to identify their loved ones," says the father of two children, now ages 4 and 8. A child often will recognize their parent's voice and smell before 3 months of age. Studies show that newborns move their heads and eyes in the direction of a sound, as if they wish to see what all the noise is about.
• Movement. As every parent already knows, the eyes of newborns as young as 1 week are drawn to look more at moving objects than at stationary objects.
"Both of our kids responded to things that were bright, shiny, or otherwise interesting to them, such as a necklace my wife would wear and her earrings," Gallanis says. "That's why if you look at the baby and toddler sections of stores, all of the kids' toys move, make noise and are brightly colored."
Newborns are able to visually follow a moving object. Infants begin to be able to focus the eye lens on their own at about 3 months, allowing children to see objects at varying distances.
Infants are essentially learning to control their eye muscles in much the same way they will learn to control their legs when they begin to walk. Between 3 and 5 months, infants develop the ability to follow moving objects in a coordinated manner, with both eyes in harmony.
Warning signs During the first year, you should look for signs that your baby's eyesight is developing normally-because it is at that time you can identify problems such as crossed eyes, dropping eyelids and goopy eyes.
Crossed eyes send two different visual pictures to the brain. The brain will eventually stop processing the information from one of the eyes, and only the cells that process information from the other eye will develop properly.
Goopy eyes can indicate there are blocked tear ducts. Infants with normal eyesight also should look more at objects that are moved or light up. All of these can lead to amblyopia or lazy eye, which is really a catch-all term for when one eye has reduced vision that cannot be fixed with corrective lenses.
Amblyopia is treatable, if caught. And the best time to catch it is between 6 months and 2 years. Left untreated, it can affect a child's eyesight and researchers know that can affect brain development.
If you suspect a vision problem, talk to your doctor and think about scheduling a thorough vision exam for your baby.
After 6 months, vision development slows. "[It] progresses much more slowly after that, not reaching adult levels until somewhere between 3 and 5 years, and then there is some evidence that acuity improves even slightly more between 5 and 10 years," Dobson says. Thus, babies can have widely different rates of development during the first year and still end up with normal vision.
Besides, after the first year, you won't be able to stop your child from watching you.
As Gallanis notes: "The kids always seemed to enjoy looking at things they shouldn't be looking at. I guess its Murphy's Law. Every time I tried to steal a kiss or a little love pat from my wife, the darn kids were watching us."
Emily Brandon is a writer and a neurobiology researcher at the University of Rochester Center for Visual Science in New York.