Can Preterm Birth Cause Myopia?

Implications of preterm birth on a baby’s eyesight

There are frequent worries regarding the consequences of prematurity when a baby is born prematurely. Medical and ocular complications may arise from preterm babies’ incomplete development. Premature birth weight is linked to a higher risk of myopia of prematurity (MOP) and retinopathy of prematurity (ROP).

What is myopia of prematurity (MOP)?

If a baby is born before 37 weeks of pregnancy, it is deemed preterm. The likelihood of medical issues increases with the time a baby is born before the 37-week mark. Babies born before their due date are immature at birth. Preterm babies may therefore not have the same progression of eye development and growth as a full-term baby. The first year of a baby’s life is when the eye grows at its fastest rate. Premature babies are more likely to acquire myopia during the first year of life.

How is MOP different from common myopia?

Changes to the cornea, lens and anterior chamber in preterm babies result in myopia. It is linked to severe ROP, low birth weight, and adverse reactions to ROP treatments. On the other hand, axial myopia is the most prevalent type of myopia when it comes to children in their first and second decades of life. An increase in the eyeball’s length leads to axial myopia. 

MOP and ROP

There is a substantial correlation between severe ROP and MOP, even though MOP can occur without ROP. In premature infants born before 31 weeks, ROP causes abnormalities to the retina. The retinas of the infants develop leaky, abnormal blood vessels as a result of it. Loss of vision due to retinal detachment may arise from these leaky blood vessels. In premature babies, alterations to the front of the eye cause MOP. A highly steep cornea, a thick natural lens and a smaller anterior chamber are some of these changes. Myopia is the outcome of these alterations combined together.

MOP and ROP treatments

Most premature infants only develop mild to moderate ROP. In fact, in the absence of treatment, the ROP may regress or disappear on its own. However, some infants develop advanced ROP and need medical attention. Advanced ROP can be treated with cryotherapy, which freezes abnormal blood vessels, laser therapy which burns abnormal blood vessels, or an injection into the eye that prevents new abnormal blood vessels fr5om growing in the retina. Treatments with lasers and cryotherapy are applied to the abnormal blood vessels located on the retina’s periphery. While these treatments lessen peripheral vision, they aid to maintain central vision. Treatments for ROP are also associated with the development of MOP as a side effect.

Myopia and vision issues in preterm babies

Infants born prematurely may be susceptible to myopia. Severe ROP and low birth weight are linked to MOP. Anisometropia and astigmatism are two other eye conditions that might affect a child born prematurely. A young child’s vision may deteriorate as a result of any of these conditions. Amblyopia, or irreversible vision loss, can result from poor vision problems in young children if they are not identified and treated early. Monitoring the vision and eye health of children born prematurely is crucial. Comprehensive eye exams can ensure that visual issues are identified early and managed properly as a preterm baby grows.

Hyperopia in Children

Children are usually farsighted at birth and childhood because they have smaller eyes. As children get older, their eyeballs will lengthen and the optical focus is shifted from behind the retina onto the retina. In some cases, children can progress from being hyperopic to myopia.

Mild degrees of hyperopia may not show any symptoms of blurred vision as young children have a strong focusing ability which is known as accommodation, to focus close-up prints or objects. Children with low or moderate hyperopia tend to be able to compensate for farsightedness with good accommodation, therefore not experiencing any blur or difficulty reading. In comparison, high degrees of hyperopia can give rise to symptoms.

Hyperopia diagnosed through a thorough eye examination. However, there are common signs and symptoms to look out for. They include the following:

  • Not achieving their potential at school or reluctant to read and learn
  • attention difficulties
  • Frequent headaches or fatigue after near activities such as reading, writing or computer use.
  • Eye squinting to or turns inwards
  • Eye strain or fatigue
  • Images/vision are blur at near but clear in the distance

Dilated Eye Examination for Children

A cycloplegic refraction is a procedure often performed on children which uses eye drops to relax the eyes’ iris muscles. The cycloplegic eye drop will dilate the pupil to prevent over-focusing during eye examination. This is an important diagnostic step, to obtain accurate results in the child’s refraction. It also can identify early signs of serious eye conditions such as lazy eye or misalignment of the eyes.

Treatment

Most children with mild to moderate degree of hyperopia do not require treatment. In high degrees of hyperopia, children are treated with spectacles. Parents are advised to seek a proper consult from a paediatric ophthalmologist for diagnosis and management of the condition.

Myopia Control Treatment

Children with myopia, also known as short sightedness or near sightedness tend to show regular progression or worsening of their vision over time. The increase in myopia prevalence has led to new development of new standards of care. There are several effective treatment to slow down its progression.

Atropine Eye Drops

Atropine eye drops are given to slow down myopia progression in children. A 0.01% concentration of atropine is usually advised to be used at night. This eye drop works by relaxing the ciliary muscle in the eye which gives an effect to the brain to increase the release of dopamine. Dopamine prevents elongation of the eye and thus reducing the progression of myopia. Low-dose atropine for myopia is used for children between 5 and 18 years old. The drops are put in the eye each night at bedtime. Side effects may include redness or itchiness around the eye.

Ortho-K Lenses

Orthokeratatology are special contact lenses that a child wears overnight to correct blurry vision during the day. It is used to flatten or steepen the curvature while sleeping, reshaping the cornea to get clearer vision during the day. Ortho-K lenses only improves your vision for a short time. Once a child stops wearing the lenses, the cornea goes back to its normal shape and myopia recurs. However, it does provide reduction in myopia progression.

Myopia Control Glasses

Bifocal or multifocal glasses are also prescribed to young children to prevent myopia progression. The top portion of the glasses allows for clear distant vision while the bottom portion contains reading power by reducing or eliminating the accommodative effort associated with myopia. Special spectacle lens design has also been developed which work similarly as Ortho-K lenses by causing peripheral blur and reducing the overgrowth of the eyeball. These spectacle design has shown to be more effective than bifocal or multifocal lens design in controlling childhood myopia progression.