Retinopathy of prematurity

Risk factors

Population at risk:

• WHO estimate that there are 15 million preterm births a year (born at <37 weeks)
• Infants born preterm contribute disproportionately to under 5 mortality rates (40% overall)
• Ministries of Health are highly likely to expand neonatal intensive care as a consequence: this will lead to increased survival of preterm babies, so putting them at risk of ROP
• UNICEF is supporting the development of neonatal intensive care units in India
• Those most at risk of ROP are those born at <32 weeks gestational age; babies 32-37 weeks are at less risk.
• India has the largest number of preterm births of any country (ref WHO Born Too Soon, 2012)
• Only preterm babies cared for in neonatal intensive care units develop ROP
• Factors which increase the risk of ROP include preterm birth; too much oxygen; sepsis; chronic lung disease; poor nutrition i.e. less than perfect neonatal care.

Impact

Treatment and successes

Control entails improving neonatal care, the delivery of oxygen, and detecting infants who develop the treatable stages of disease, followed by laser to the peripheral retina. Both these aspects of control are effective at reducing blindness from ROP.

Blindness from ROP can be controlled through 2 broad approaches:

• reducing the incidence through excellent neonatal care
• detecting and treating infants who develop the severe stages of disease

Trends and challenges

ROP was a major cause of blindness in the USA and Western Europe 50-60 years ago. This occurred because all preterm infants were given 100% oxygen whether they needed it or not. Oxygen is highly toxic to blood vessels, including those in the retina. After the role of oxygen was understood, and it was used less freely, blindness from ROP declined dramatically. Until very recently ROP was, therefore, seen as a condition of the west, and an iaterogenic problem that had been solved. ROP was not included in textbooks for nurses or paediatricians.

Over the last 10-15 years it has become clear that ROP is a major cause of blindness in children in middle-income countries in Latin America, Eastern Europe and the emerging economies of south east Asia (e.g. Vietnam). It is being increasingly reported in China and India. This is happening because these countries are expanding neonatal care, but did not know about ROP.