Which patient is least likely to develop retinopathy of prematurity?

Which patient is least likely to develop retinopathy of prematurity?

• A. A term infant, 46 weeks postconceptual age, exposed to 100% oxygen for 6 hours
• B. A premature infant 29 weeks postconceptual age exposed to a PaO2 of 150 mm Hg for 1 hour
• C. A premature infant 28 weeks postconceptual age never exposed to supplemental oxygen
• D. A cyanotic infant with tetralogy of Fallot, 34 weeks postconceptual age, receiving supplemental oxygen

Answer: (A)

Retinopathy of prematurity is driven by the immaturity of the retinal vasculature in preterm infants and is strongly influenced by oxygen exposure in the neonatal period. The retina reaches full vascularization late in gestation, so infants who are born at term have mature retinal blood vessels and are much less prone to developing ROP, even if they experience brief high-oxygen exposure after birth. In this scenario, the least likely to develop ROP is the term infant at 46 weeks postconceptual age who had a brief exposure to 100% oxygen for 6 hours. By term-equivalent age, the retina is already fully vascularized, so the hyperoxic insult that disrupts normal retinal vessel development in premature infants is not able to trigger the pathologic neovascularization seen in ROP. The other cases involve prematurity with factors that increase risk: high oxygen tension or supplemental oxygen in a preterm infant can precipitate abnormal vessel growth; prematurity alone, even without oxygen, carries some baseline risk due to immature retinal development; and a cyanotic infant with congenital heart disease on supplemental oxygen combines prematurity, oxygen exposure, and chronic hypoxemia, all of which can heighten the risk of developing ROP.

Retinopathy of prematurity is driven by the immaturity of the retinal vasculature in preterm infants and is strongly influenced by oxygen exposure in the neonatal period. The retina reaches full vascularization late in gestation, so infants who are born at term have mature retinal blood vessels and are much less prone to developing ROP, even if they experience brief high-oxygen exposure after birth.

In this scenario, the least likely to develop ROP is the term infant at 46 weeks postconceptual age who had a brief exposure to 100% oxygen for 6 hours. By term-equivalent age, the retina is already fully vascularized, so the hyperoxic insult that disrupts normal retinal vessel development in premature infants is not able to trigger the pathologic neovascularization seen in ROP.

The other cases involve prematurity with factors that increase risk: high oxygen tension or supplemental oxygen in a preterm infant can precipitate abnormal vessel growth; prematurity alone, even without oxygen, carries some baseline risk due to immature retinal development; and a cyanotic infant with congenital heart disease on supplemental oxygen combines prematurity, oxygen exposure, and chronic hypoxemia, all of which can heighten the risk of developing ROP.