Effect of Low Birth Weight on the Eye’s Development

Introduction

Birth weight is one of the key indicators of a newborn's health. While normal birth weight is the key indicator of a healthy baby, low birth weight is associated with poor health. Low birth weight is one of the prevalent public health issues in the world. Around 30 million babies born worldwide are affected by low birth weight. Several factors like mother malnutrition and premature birth can cause low birth weight. Low birth weight is strongly associated with several systemic and developmental disorders. Ocular disorders are also important clinical factors associated with low birth weight.

What Is a Low Birthweight?

Low birthweight of the infant is associated with babies born with a weight less than 2500 grams. The low birth weight is independent of gestational age. This condition depends upon factors like socioeconomic and mothers' systemic conditions. It is most prevalent in south Asian and African countries. Developed countries have less incidence of low birth weight. The associated risk factors related to low birth weight are:

1. Malnutrition of the mother.

2. Intrauterine Growth Restriction - Less blood and nutrients reach the baby in this condition. The causative factors are:

• Anemic mother.

• Infection during pregnancy: Infections responsible for this condition are rubella (the virus causes a red rash), syphilis (sexually transmitted bacteria), and cytomegalovirus (a common virus responsible for the common cough and cold).

• Effect of medicine: Anti-seizure medicines are associated with low birth weight.

• Low weight gain of the mother during pregnancy.

• Alcohol consumption or smoking.

• Systemic disorders: Different systemic disorders of the mother, like diabetes and autoimmune disorders, are also associated with low birth weight.

• Genetic factors.

What Are the Complications of Low birth weight?

• Low oxygen level after birth.

• Repeated history of infection.

• Low body temperature.

• Breathing problem.

Systemic complications are:

• Cerebral palsy.

• Eyesight problem.

• Hearing problem.

• Growth and developmental delays.

• Severe inflation of the digestive system, such as necrotizing enterocolitis.

• The infant's sudden death may occur in severe cases, known as sudden infant death syndrome.

What Are the Causes of Eye Problems?

Several factors are associated with eye problems related to low birth weight. These are:

• Low birth weight causes retardation of the growth of the tissues and cerebral palsy (brain damage before birth). This condition leads to cerebral ischemia (low oxygen concentration in the brain), which causes periventricular leukomalacia (injury of the brain's white matter). As a result of which, motor and visual pathways are severely damaged.

• Premature birth is one of the main causes of ocular problems. Ocular structures are developed in a protective environment in the placenta under specific temperatures. When a premature baby is born, this protective environment is hampered.

• Different ocular structures develop at different periods of intrauterine life (baby's growth inside the mother's womb), and their growth occurs throughout the whole gestational period (period of pregnancy). In premature babies, these developments are impaired due to early delivery.

What Are the Eye Problems?

Different eye problems are seen in babies born with low birth weights. These are:

Retinopathy of Prematurity

This is the most common condition affecting premature babies. This was first described by Terry in 1942 and named retrolental fibroplasia. The hypoxic condition inside the placenta is helpful for the growth of the retina, but after premature birth, excessive exposure to oxygen damages the capillaries. Based on severity, this condition is classified into several categories, and these are:

1. Stage 1: Line of demarcation present between vascular and avascular retina.

2. Stage 2: A ridge is present between two retina types.

3. Stage 3: Fibrovascular growth is seen outside the retina also.

4. Stage 4: Concave-type partial retinal detachment is seen.

5. Stage 5: Total retinal detachment is seen.

The complications associated with these conditions are:

1. Pathological myopia (a condition where distant objects are not visible).

2. Amblyopia (lazy eye).

3. Total blindness.

Strabismus

It is a condition in which both eyes are placed in different directions. This is a serious problem as the patient needs to focus simultaneously on the same objects. This condition may appear a few months after birth or develop in adulthood. The factor associated with this condition is poor neuromuscular control. Cerebral palsy (abnormal brain development with poor neuromuscular control), poor neural growth, and poor development of the ocular muscles.

Refractive Disorders

Children born with low birth weight often develop refractive disorders. In this condition, the distant object is not properly focused and is known as ametropia. These further develop myopia (distant objects are not visible clearly). This condition can be of three types:

1. Premature babies often have a flat anterior chamber, increased corneal curvature, and spherical lens. These result in the development of myopia.

2. The second type of myopia develops due to prematurity. In this type, the development of the anterior segment of the eye is restricted. As a result, thick lenses and a shallow anterior chamber are observed.

3. The third type of myopia is caused secondary to severe retinopathy of prematurity.

Visual Function Problems

Patients may develop functional visual problems like:

1. Patients may develop color vision defects, specific problems with blue-yellow color.

2. Patients may complain of symptoms of contrast sensitivity. This is characterized by difficulty differentiating the images' sharpness or the object's outline.

3. Children with low birth weight often develop jaundice after birth. Ultraviolet ray application during treatment of jaundice or endotoxins released by the pathogens during pregnancy daisies destroys photoreceptor cells. It also causes injury to the retina. Due to this, patients suffer from low visual acuity and visual fields.

4. In some cases, children with low birth weight develop eye problems later in life. A steeper corneal shape increases corneal power, and a smaller axial length causes this. Corneal abrasion in adult life is higher among persons born with low birth weight.

How to Treat It?

Low birth weight is a multifactorial entity, so it isn't easy to treat. But this can be prevented by following steps:

• Maintenance of proper nutrition and hygiene of the mother.

• Cessation of smoking and alcohol consumption during pregnancy.

• Proper postnatal care and supply of nutrients for premature babies.

Surgical interventions can treat conditions like retinopathy of prematurity or strabismus.

• Scleral Buckle Surgery: A flexible band is placed around the sclera, preventing sclera detachment.

• Vitrectomy: In this procedure, the vitreous is taken out, and the space is filled with saline. Following this, scar tissue of the retina is removed.

• Strabismus: Strabismus can be treated with eyeglasses, prism lenses, and eye muscle surgery.

Conclusion:

Low birth weight is a major health issue all over the world. Infants from poorer economic backgrounds suffer from this mostly. This may cause moderate-to-severe eye problems and even cause blindness. Proper nutrition for the mother and a healthy lifestyle can prevent low birth weight problems. Early diagnosis of ocular problems and timely surgical intervention can cure these conditions.