Keeping an 'eye' out for preemie ailments

According to the WHO, every year about 15 million babies (one out of 10 babies) born globally are premature. In India, out of 27 million babies born every year, 3.5 babies are premature (2010 data). The country tops the chart when it comes to preterm babies born annually across the world.

Apart from the lungs, one of the organs that bears the brunt of premature birth is eyes. The eyes develop the most during the last three months of pregnancy and since premature birth interrupts this, preterm babies are at the risk of developing eye problems. The earlier a baby is born, the more likely s/he is to develop eye problems. An awareness of the possible problems can help seek appropriate treatments and prevent blindness.

Some of the common eye ailments seen in premature babies are:

Retinopathy of prematurity (ROP): this is a disease where there is an abnormal development of blood vessels in the retina (layer of tissue at the back of the eyeball). The abnormal blood vessels being fragile, leak blood resulting in scarring of the tissue. This scarring can cause the retina to detach from the eyeball, which in turn may lead to blindness.

Babies who are born before 34 weeks and weigh less than 1,750 gm are likely to develop ROP. Other factors include oxygen therapy, ventilator support, anaemia, breathing problems, blood transfusions, and severe infections. ROP can be ascertained only through a thorough examination by a trained retina specialist.

Parents are advised to do a complete eye check-up of the baby within the first month of life and even earlier, especially in babies who are born before 28 weeks. Children who have had ROP are at times susceptible to develop other problems such as myopia (nearsightedness), squint (misalignment of the eyes), amblyopia (lazy eye), glaucoma as well as retinal detachment later on.

The treatment for ROP is retinal laser photocoagulation, antiVeGF injections and, in some cases, vitrectomy.

Strabismus: another eye condition that premature babies may have is childhood squint or strabismus. This happens when the muscles that synchronise the movement of the eyes don't work together. It develops primarily because the baby's  brain  hasn't developed enough to control the eye muscles. Other factors, such as bleeding in the brain, seizure disorders cerebral palsy, retinal damage from ROP, congenital cataract, eye injury etc may also play a role in the development of strabismus.

The treatment involves aligning the eyes and restoring the binocular (two-eyed) vision. In some cases of strabismus, glasses can be prescribed to align the eye of the baby, while others may require surgery on the eye muscles.

Amblyopia: preterm babies also are prone to develop lazy eye or amblyopia. As the eyes focuses on two different directions, the brain receives two different images making it difficult for the baby to process it. Generally, in this condition, the baby's brain ignores the image from the crossed eye and processes only the image from the stronger eye leading to lazy eye or amblyopia.

About one-third of children with strabismus get amblyopia. It can also affect depth perception. Infantile esotropia or crossed eyes is a type that affects premature babies commonly. It can be usually detected at 6-9 months of age. Quite often, it may be first noticed by the paediatrician. Babies need to be evaluated and the treatment should commence before 2 years of age.

In case of treatment for amblyopia, the stronger eye of the baby is blocked so that the brain sees only images from the weaker one forcing it to work. Eyepatch or drops are used to blur the vision which will further strengthen the crossed eye and correct the alignment of the vision.

Amblyopia can become permanent if it isn't treated early. Regular eye examinations, compliance with the treatment and follow-ups is extremely crucial in ensuring that the baby gains vision.

In short, premature babies are at higher risk of developing eye problems. Sadly, many of these problems go undetected till the child learns to speak and complains of vision loss or when s/he joins a school and it is noticed by the teachers.

The onus is on us to ensure adequate awareness among the general public, doctors, paediatricians and eye specialists so that these helpless infants undergo appropriate screening and timely treatment to prevent the burden of lifetime blindness.

(The writer is Consultant Vitreo Retinal Surgeon, Dr Agarwal's Eye Hospital)