If you’ve had a premature baby—particularly if he’s needed a little medical help in a neonatal intensive care unit (NICU)—you have a lot to learn, think and, often, worry about. New issues that affect his health might seem to crop up daily, and even without these, such babies are constantly being monitored for any new issues.
Yet the monitors, machines and warmer surround a living, breathing little person—someone just begging to be waved to and talked to. But if you do any of that, is he taking it in? And if not, when can you hope to begin that interaction? In other words, when can he truly see and hear?
Making Sense of the Senses: Normal Development
There’s pretty close agreement on when vision and hearing capabilities develop in term infants. A baby’s eyelids are, in most cases, separated, allowing her to open her eyes, by about 26 weeks’ gestation. During the newborn period and the first few weeks, infants can generally see bright lights and major shapes, but take a longer time to focus. However, from an early age, infants do prefer stimuli such as patterns and human faces over other sights. Color vision generally develops by two to five months of age (sources vary on this one), and most healthy babies can generally see quite well by six months.
Many newborns show signs of hearing almost from birth. By a few weeks of age, almost all healthy babies with normal hearing will let you know that they can hear—by changing their behavior after hearing a human voice, for example. Because hearing and communication milestones are so subjective, however, and because it’s important to address hearing problems early for speech development, all newborns in the United States now receive hearing screens.
But…What About My Preemie?
Preemies are not as fully developed as full-term infants and usually take longer to do the same things, whether it be rolling over, grabbing at objects or babbling. The same is true for their vision and hearing development. A good rule of thumb is to subtract the number of weeks the baby was premature from his actual age to get his “developmental age.” Thus, a baby who was born 20 weeks ago but was born 6 weeks before the due date would have a developmental age of 14 weeks. In most cases, he would do what 14-week-old babies born at term do.
There’s really nothing about simply being born premature that would slow development beyond this. Big BUT here: preemies have medical risks that do impact how they develop, especially if very premature. Any of the following can impact development of vision and/or hearing:
- An extended stay in the NICU.
- A long course on a ventilator (a machine that helps the baby to breathe). Also, a long course of oxygen in a premature baby, even without use of a ventilator, poses a special risk for retinopathy of prematurity (ROP) which can have a big effect on vision. Very premature babies can develop ROP even without added oxygen.
- A course of certain life-saving antibiotics.
- Significant jaundice (a yellow color due to a chemical called bilirubin). Most preemies will have a little elevation of their bilirubin level, but a large amount can affect hearing.
- Certain infections more common in premature babies.
What Doctors Do
Naturally, vision and hearing affect all other aspects of a baby’s development. For this reason, doctors take extra care to make sure these senses are developing normally. While this is true of all infants, in many cases preemies get additional screening.
Most babies born under 30 weeks’ gestation, as well as older preemies with risk factors, will get regular ROP screening with an experienced ophthalmologist. If ROP is present and mild, it’s watched closely; more severe forms may be treated surgically. All infants are also screened by a primary care provider at every physical, and there’s now technology for more accurate vision assessment in the pediatrician’s office beginning at six months of age.
As far as hearing goes, all infants, including full-term infants, are screened prior to discharge. Premature babies usually undergo at least one additional screening later in infancy. Regardless of where your preemie got her care, it’s important that her primary care provider has the results of these evaluations. Since this isn’t always automatically the case, you may need to ask for them.
Knowing that your baby can see and hear not only brings peace of mind. It’s one of the most interesting and pleasing things to watch. Understanding the milestones and following through on any needed evaluations will help ensure that your little one will be able to experience the world to the maximum.