Retinopathy of Prematurity

What is retinopathy of prematurity?
Retinopathy of prematurity (ROP) is a potentially blinding eye disorder that can affect premature infants. The lower a baby’s birth weight, the higher the chance of the baby developing ROP.  ROP usually develops in both eyes and is one of the most common causes of childhood vision loss in premature babies.  

Abnormal blood vessels grow and spread throughout the retina (the light-sensitive tissue that lines the back of the eye). These abnormal blood vessels are fragile and can leak, which can scar the retina and pull it out of position, often causing retinal detachment. Retinal detachment is the main cause of visual impairment and blindness in ROP.

What causes retinopathy of prematurity?
The eye starts to develop at 16 weeks into pregnancy. At this time, the blood vessels of the retina begin to form at the optic nerve in the back of the eye. The blood vessels gradually grow toward the edges of the developing retina, supplying oxygen and nutrients to the eye.

In the last 12 weeks of a pregnancy, the eye develops very quickly. In a baby that is born at full-term, the growth of blood vessels in the retina is almost complete and will finish growing up to a month after birth.

When a baby is born prematurely, the blood vessels in the retina have not fully developed and grown to the edges, and normal vessel growth may stop. Therefore, the edges of the retina (the periphery) might become undersupplied with oxygen and nutrients. As a result, new abnormal blood vessels begin to grow. These new blood vessels are fragile and can leak blood, causing retinal scarring. When there scars shrink, they pull on the retina, causing it to detach from the back of the eye.

How common is retinopathy of prematurity?
With today’s advances in healthcare, more premature infants are being saved. Not all premature babies develop ROP, but the earlier the baby is, the higher the chance of ROP. About 90 percent of cases of ROP in infants are mild and resolves on their own, but infants with more severe cases can suffer further vision complications.

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