One of the many joys of being a pediatrician is smiling into a baby's eyes, making "baby talk," and watching his face light up as he smiles back and squeals with delight. We're getting to know one another, and this helps me gain some important information about the baby's vision and hearing.
Normal vision and hearing are essential for a baby's development. He needs to see well to explore new objects or take those first baby steps. And for normal speech to develop, he must first hear the sounds and words we use to communicate. Indeed, there is strong evidence that early intervention for babies with hearing or vision problems can make all the difference in their development. But identifying problems often requires acute observation from both doctors and parents. And understanding how babies see and hear will help you know when something "just isn't right."
Newborns can't see clearly at birth. In fact, vision is about 20/400, making the first days of sight very blurry, like a camera out of focus. But within a week, a baby can focus on objects about 8 to 12 inches from his face. Conveniently, this is about the distance between a mother and baby's face during feeding, making it a great time for getting to know each other. As for the age-old question of how colorful a newborn's world is, we now know that babies can see color right from the start if the color is very bright.
A great test of vision is just having some up-close and personal time with your baby, who by 4 to 6 weeks of age should be gazing intently into your eyes and mimicking your facial expressions. Open your mouth and stick your tongue out, and watch your baby do the same. By 3 months her vision is closer to 20/40. This means she can see almost everything in her field of vision. As a result, you'll notice your infant watch the world more and more intently with each passing day. Your baby can now see colors in different hues and has improved depth perception, which will be evident as she gazes at the colorful mobile circling over the crib. Just don't expect your child to appreciate a pastel-colored toy before about 4 to 6 months. By 4 months, you'll also notice her staring at her hand, and after 6 months she may be able to see well across any room with 20/20 vision.
It will develop naturally, but you can make sure he has something interesting to see. Infants love looking at faces and respond best to contrasting patterns and bright colors, so place these types of toys and pictures in your baby's line of sight. As your baby grows, keep changing his scenery by taking walks and visiting new places. A trip to an art museum can be a feast for his eyes as well as yours.
With sophisticated research tools, 20/20 vision has been documented in toddlers, once the shape and size of their eyeballs have fully matured. However, measuring sight with an eye chart depends on communication skills and cooperation, so your pediatrician won't be able to test for visual acuity until your child is at least 3 years old.
In the meantime, your pediatrician will closely examine your baby's eyes for problems, starting from birth. She'll check both the physical shape and size of the eyes and eyelids. And although newborns don't want to open their eyes to bright light, she'll use the light from an ophthalmoscope to check for the "red reflex," a reassuring red color that is reflected off the back of a baby's eyes, giving them a red glow. If this is absent, it could indicate the presence of a cataract, glaucoma, or a congenital eye defect. She'll also look for common problems, such as blocked tear ducts. If your child was premature or if there is a family history of congenital eye problems, the pediatrician will recommend that your baby be examined by a pediatric ophthalmologist in the nursery or soon after discharge.
In addition, at each well-child visit you'll see your baby's doctor dangling an object over her face to see how well she "tracks" it 180 degrees. And to make sure her eye muscles aren't weak, the doctor will shine a light at her eyes, checking that the reflection is at corresponding locations on each pupil.
Before 6 months, it's common for a baby's eyes to appear "crossed," but after 6 months his eyes should begin to work together to focus on an object. If you notice one of baby's eyes drifting off to the side, especially when he is tired, call your pediatrician and let her know. Other signs of vision problems are tilting his head to see an object or bringing it very close to his eyes, sensitivity to light, chronic redness, and tearing. Older kids may complain of headaches.
Hearing is fully developed at birth -- in fact, your baby was hearing sounds even before she was born. Newborns may startle when they hear a loud noise, or quiet down when they hear soothing sounds or white noise -- such as the sound of a fan -- that reminds them of what they heard in the womb.
Amazingly, babies will recognize their mother's voice even in the first few days of life. But they can't localize a sound or turn their head in that direction until about 3 to 4 months of age.
Most states have mandated universal hearing screening for all newborns, which will identify most serious hearing defects at birth. But because hearing loss can occur at any age, your pediatrician will still be monitoring your baby's hearing at each visit. For example, when a baby is 3 to 4 months, your pediatrician will use a bell or beeper, or just clap her hands, to see if he turns toward the sound. And that's when baby talk comes in handy, as your doctor observes how your child mimics the sounds she makes. Once your baby is 6 months, your pediatrician will follow language development.
Besides checking hearing at office visits, she'll order objective auditory exams if your baby has middle-ear fluid for three months or longer or chronic ear infections, or after he's had a serious infection that can lead to deafness, such as meningitis. Then baby might be tested using auditory brainstem response (electrodes are placed on the head to measure how sound -- transmitted through soft earphones -- is transferred from the inner ear to the brain). Conventional audiometry (a patient raises his left or right hand when a sound is heard in that respective ear) may be used, particularly if your child is older. At home, you can indirectly monitor your baby's hearing by observing his language development. First he'll coo, squeal, and babble. Then by age 1, he should be able to say one or two simple words. If you suspect he's not reacting normally to sounds, call his doctor.
Aside from newborn hearing screening, the American Academy of Pediatrics recommends periodic objective hearing screenings by pediatricians using conventional audiometry, beginning at age 4. At this age, kids are better able to cooperate because they can understand the directions they're told.
That high-pitched voice we all use instinctively when we speak to babies is just what they react to the most in those first weeks. But don't stop there. Talking to your baby is the single most important thing you can do to help her acquire language skills during the first two years. A baby's ears are tuned in to different sounds, and over time your baby will learn which sounds are more essential than others -- this is how speech develops. Babies also love music, which stimulates them and has a calming effect. Watching how your baby reacts to music is another fun way to tell if she is hearing well.
My number-one rule when it comes to questions about a baby's vision or hearing: trust her parents. Often they're the first to notice sensory problems with their infant. Working together is the best way to keep babies seeing and hearing the world around them. So, for instance, when you see your baby reaching for and grabbing objects -- signs of hand-eye coordination -- be a proud parent and tell your pediatrician at the next well-baby visit. These details provide a wealth of information. In this case, they tell the doctor about your baby's fine motor developments and her vision. Between office visits, smile, laugh, sing, and expose your baby to a world of sights and sounds.
By age 3, both the American Academy of Pediatrics and the American Academy of Pediatric Ophthalmologists recommend formal vision screening using charts to help identify vision impairment. This will take place in your pediatrician's office, but if there are any special concerns or a strong family history of eye or visual problems, it's a good idea to visit an ophthalmologist.
During the preschool years, in addition to checking the visual acuity of each eye using eye charts for young children, your doctor will be looking for weakness of one of the eye muscles. It is very important to identify and treat this condition early with patching of the good eye to force the weaker eye to work harder. If treatment occurs before age 5 or 6, it can prevent a form of blindness in the weak eye called amblyopia (also known as lazy eye).
The best thing you can do to protect your baby's vision is to protect her eyes. Be careful when baby proofing: pad sharp edges on furniture, and keep sharp objects or toys away from your child. Also have your baby wear sunglasses with UV protection when she's in the sun. When your child gets older and plays sports, make sure she wears protective eye gear.
Profound hearing loss is found in 1 to 6 children out of every 1,000 births, and the number of infants with less severe hearing loss is probably higher. Fortunately, most states have mandated universal hearing screening for all newborns. Check with your hospital to make sure that this screening is being done. If it isn't performed routinely in your state, ask your pediatrician what your options are. This is important because we now have clear evidence that early treatment with hearing aids (they can be used as early as when a baby is a few weeks old) and cochlear implants (which can be surgically implanted at 1 year) will improve the outcome of hearing and speech for many babies with hearing impairment and even profound deafness.
If your baby fails the otoacoustic emissions (OAE) screening, which uses a probe to measure acoustic signals generated in the inner ear, he doesn't necessarily have a hearing problem. In this instance, your pediatrician will refer you to an audiologist, who will use an auditory brainstem response (ABR) test to assess how sound is transferred from the inner ear to the brain. When OAE is followed by ABR, there are fewer false-positive results.
Mary Ann LoFrumento, MD, is an attending physician at Goryeb Children's Hospital, in Morristown, New Jersey, and the founder of simplyparenting.com.
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.