Premature babies are babies who are born at 37 weeks or earlier. Since a normal pregnancy lasts about 40 weeks, premature babies have less time to develop in the womb. This makes them more likely to have health complications and birth defects.

Some of the health issues that may affect premature babies include vision and hearing problems. This is because the final stages of vision and hearing development occur in the last few weeks of pregnancy. Experts note premature birth is responsible for 35 percent of instances of vision impairment and 25 percent of instances of cognitive or hearing impairment.

Read on to learn about the eye and ear problems that can affect premature babies, and get information on appropriate treatments.

The March of Dimes estimates that around 1 out of 10 babies in the United States are born prematurely each year. It’s not always known what causes premature labor and birth. However, certain risk factors can contribute to premature birth. Some of these risk factors are listed below.

Risk factors that can’t be changed:

  • Age. Women under 17 and over 35 are more likely to have premature births.
  • Ethnicity. Babies of African descent are born prematurely more often than babies of other ethnicities.

Risk factors related to pregnancy and reproductive health:

Risk factors related to general health:

Risk factors related to lifestyle:

Other risk factors:

  • Domestic violence increases the risk of complications during pregnancy. If you don’t feel safe in your home or there’s danger of someone hitting or hurting you, seek help to protect yourself and your unborn baby. Call the National Domestic Violence Hotline at 800-799-7233 for help.

The eyes develop the most during the last three months of pregnancy. This means that the earlier a baby is born, the more likely they are to experience eye problems.

Many eye issues stem from an abnormal development of blood vessels, which can lead to vision impairment. While the eyes might look normal, you may notice that your baby doesn’t respond to objects or changes in light. These abnormalities may be signs of a vision problem or an eye defect.

Retinopathy of prematurity (ROP)

The eye disease retinopathy of prematurity (ROP) develops when blood vessels grow abnormally in the eye. According to the National Eye Institute, ROP is most prevalent among babies born before 31 weeks or at a very low birth weight.

Of the millions of premature babies born in the United States each year, the National Eye Institute notes around 28,000 babies weigh 2 3/4 pounds or less. Between 14,000 and 16,000 have ROP, but most infants have a mild case. Annually, only 1,100 to 1,500 infants develop ROP that’s serious enough to warrant treatment.

ROP is more likely to occur in premature babies because early delivery disrupts normal blood vessel growth. This causes abnormal vessels to form in the retina. The blood vessels supply a constant flow of oxygen to the eyes for proper eye development. When a baby is born prematurely, the flow of oxygen is altered.

In particular, most premature babies require extra oxygen in the hospital for their lungs. The altered flow of oxygen disrupts their normal oxygen level. This disruption can lead to the development of ROP.

The retina may become damaged if the abnormal blood vessels begin to swell and leak blood due to improper oxygen levels. When this happens, the retina can detach from the eyeball, triggering vision problems. In some cases, it can lead to blindness.

Other potential complications of ROP include:

Complications from ROP don’t usually occur until later in childhood and adulthood.

How often your baby is screened for ROP depends on the retina’s status. Usually, exams are done every one to two weeks until ROP is cured or stabilized. If ROP is still present, then your child will be examined every four to six weeks to ensure ROP doesn’t worsen or require treatment.

Most infants will require checkups for a while, even if the condition is mild. Those with severe ROP may need to receive examinations into adulthood.

All premature babies will receive regular testing and monitoring for ROP from 1 month old and on. If there’s any concern, the eyes will be monitored weekly. Treatment depends on the baby and severity of ROP. You can discuss options with your baby’s doctor to try and prevent further progression.

Strabismus

Strabismus (crossed eyes) is an eye condition that’s common in children under the age of 5 years old. It causes misalignment of one or both of the eyes. It can lead to permanent vision problems if it isn’t diagnosed and treated early.

There are several risk factors for strabismus, including ROP. A 2014 study found that a low birth weight also dramatically increases the risk of an infant developing strabismus later in life: Infants born weighing less than 2,000 grams, the equivalent of 4.41 pounds, were 61 percent more likely to develop strabismus.

Strabismus may be caused when the cranial nerves that cause eye movement are weak, or there’s a problem with the eye muscles. Different types of strabismus have different symptoms:

  • Horizontal strabismus. In this type, one or both eyes turn inward. It may be referred to as being “cross-eyed.” Horizontal strabismus can also cause an eye or eyes that turn outward. In this case, it may be referred to as being “wall-eyed.”
  • Vertical strabismus. In this type, one eye is higher or lower than a normally positioned eye.

Blindness

Blindness is another possible complication associated with premature birth. Retinal detachment associated with ROP sometimes causes this. If the detachment goes undetected, it can lead to blindness.

Other cases of blindness in premature babies are separate from ROP. Some babies are born without certain parts of the eye, such as the eyeball or iris, resulting in vision loss. These conditions are very rare and not necessarily more common in premature babies.

Ear problems can also occur in premature babies. Some babies might have both hearing and vision impairment. Others may have hearing issues without vision problems. Physical abnormalities of the ears can also affect premature babies.

Hearing loss and hearing difficulties are among the most common concerns.

Congenital hearing loss

Congenital hearing loss refers to hearing problems that are present at birth. These issues may affect one ear or both ears, resulting in either partial or complete deafness.

Hearing loss in babies is most often the result of a genetic defect. However, the risk of hearing impairment is greater in premature babies. This is especially true if the mother had an infection during pregnancy, such as:

A 2017 analysis reports hearing loss affects between 2 and 4 percent of high-risk babies. Premature babies are considered high-risk.

Physical abnormalities

Physical abnormalities of the ears aren’t as common as hearing loss in premature babies, but they can occur. These may arise from an underlying health issue. Rarely, exposure to medication during pregnancy can result in physical abnormalities of the ears in premature babies.

Possible ear abnormalities that may affect babies include:

  • shallow depressions around the ear
  • skin tags, which can appear in the inner and outer parts of the ear
  • malformations of the ear, which are usually caused by chromosomal issues

All newborns delivered in hospitals or birthing centers are screened for both vision and hearing problems at birth. However, premature babies might undergo further testing to detect possible issues.

Vision tests

An ophthalmologist will check your baby’s vision and perform tests to check for signs of ROP. This is an eye doctor who specializes in treating and diagnosing eye problems.

During an ROP test, drops are inserted into the baby’s eyes to dilate them. The doctor will then mount an ophthalmoscope on their head so they can examine the baby’s retinas.

In some cases, the doctor may press on the eye with a small tool or take photos of the eye. This test will be repeated regularly to monitor and check for ROP.

Your baby’s eye doctor may also check the position of the eyes to look for signs of strabismus.

Hearing tests

If your baby doesn’t pass their hearing exam, an audiologist may examine them. Audiologists specialize in diagnosing and treating hearing disorders. They can conduct further tests to detect hearing problems.

Hearing tests that may be performed include:

  • Otoacoustic emissions (OAE) test. This test measures how well the inner ear reacts to sounds.
  • Brainstem auditory evoked response (BAER) test. This test measures the reaction of the auditory nerves using a computer and electrodes. Electrodes are sticky patches. A doctor will attach some to your baby’s body. They’ll then play sounds and record your baby’s reactions. This test is also known as an automated auditory brainstem response (AABR) test.

Most babies with ROP don’t require treatment. If treatment is required, your baby’s doctors will decide on the best individual treatment for your baby. You can also follow up with an eye doctor after your baby comes home.

The following procedures can treat more severe cases of ROP:

Your baby’s doctor can treat a missing eye using surgical implants when your child gets older.

Treatment for strabismus depends on the severity of the condition. Your baby’s doctor may also use a combination of treatments to achieve the best results. Treatments that may be used for strabismus include:

  • glasses, with or without prisms to help refract light
  • an eye patch to be placed over one eye
  • eye exercises to strengthen the eye muscles
  • surgery, which is reserved for severe conditions or conditions that aren’t corrected with other treatments

Placing a cochlear implant in the ear may be done for hearing loss. A cochlear implant is a small electronic device that does the work of the damaged parts of the ear. It helps restore hearing by providing sound signals to the brain.

Cochlear implants aren’t for all types of hearing loss. Talk with your baby’s doctor to see if a cochlear implant is right for them.

Your baby’s doctor may also recommend:

  • hearing aids
  • speech therapy
  • lip reading
  • sign language

Surgery is usually performed to correct problems with the formation of the ear.

All babies go through a series of screening tests soon after birth, regardless of how early or late they’re born. However, these tests are especially important for premature babies, since they’re more likely to experience complications. A doctor might be able to detect problems right away and provide specific recommendations for short- and long-term care.

The risk for eye and ear problems varies significantly among premature babies. The earlier a baby is born, the more likely they are to have these issues. Early detection is critical, especially since some issues can get worse over time. While success rates for treatments may vary, early intervention can resolve most eye and ear problems.

For any premature baby, there’ll be additional visits to their pediatrician to ensure that they’re developing normally. A premature baby requires some extra care during their first few weeks and months of life, with or without any vision or hearing problems.

If your baby has a vision condition, then you’ll have regular visits with an ophthalmologist. Treatment for hearing conditions will include regular visits with an audiologist.

It’s important that you take your baby to all of their scheduled appointments. These checkups will help their pediatrician catch any issues early and ensure your baby receives the best care for a healthy start.

Doctors, nurses, and staff are there to help you. Feel free to ask many questions about the care and health of your premature baby.

There are also several support groups that can help answer questions and remind you that you and your child aren’t alone. You can also get information on support groups in your area, among other things, from your neonatal intensive care unit (NICU) social worker.