Causes for Retinopathy of Prematurity
The human eye develops rapidly between 28 and 40 weeks gestation. The blood supply to the retina begins to form at about 16 weeks gestation, starting at the optic nerve. Blood vessels grow from the optic nerve toward the edges of the retinaa process that continues until the fetus reaches term.
When a baby is born prematurely, normal blood vessel development may cease and abnormal growth may begin. Supplemental oxygen use is likely associated with development of ROP.
Retinopathy of Prematurity Signs and Symptoms
There are no symptoms of ROP and infants must be screened by an ophthalmologist.
Screening is recommended for
- all premature infants (born at less than 35 weeks gestation or who weighed less that 1800 grams) who received supplemental oxygen, and
- infants born at less than 30 weeks gestation or who weighed less than 1300 grams, whether or not they received supplemental oxygen.
Retinopathy of Prematurity Diagnosis
Diagnosis is made by ophthalmologic examination. The eye exam is usually performed before the baby is discharged, or at 5 to 7 weeks after birth if the infant remains hospitalized. After putting drops in the eyes to dilate the pupils and allow for better visualization, the doctor views the retina through the lens of an indirect ophthalmoscope.
ROP is graded according to its severity.
- Stage I indicates that the outer edges of the retina are not receiving a normal blood supply. A demarcation line is visible where normal and abnormal blood vessels meet.
- Stage II indicates that the demarcation line has progressed to a ridge that develops as the abnormal vessel growth continues.
- Stage III indicates that the ridge has grown and the vessels have spread into the vitreous. There may be scarring and fluid leakage.
- Stage IV indicates progression to partial detachment of the retina.
- Stage V is complete detachment of the retina.