A new study by specialists at the
Children's Center and 25 other institutions nationwide
for the first time gives eye doctors a precise way to
identify premature babies at the highest risk of abnormal
blood vessel growth in the retina and subsequent blindness.
The computerized risk assessment tool they used should lead
to treatment of retinopathy of prematurity, known as ROP,
at its earliest stages, stopping or limiting both loss of
vision and structural damage to the eye.
"Before this study, we did not have a precise clinical
model to follow to help predict which infants will
ultimately develop vision loss from ROP, so we often had to
defer treatment until the disease reached the treatment
'threshold,' at which point there was still a 25 percent
chance of retinal detachment," said Michael Repka, a
the Children's Center, and a member of the study team.
"Unfortunately, delaying therapy to that point leaves some
infants with vision loss."
Using both old and new criteria, researchers were able
to identify which premature infants enrolled in the study
were at highest risk for blindness. Results of their study,
published in the December issue of the Archives of
Ophthalmology, show that early treatment significantly
reduced the likelihood of poor vision from 19.5 percent to
14.5 percent at about 1 year of age. Early treatment also
reduced the likelihood of structural damage to the eye from
15.6 percent to 9.1 percent.
According to Repka, ROP presents ophthalmologists with
difficult treatment decisions because the disease can be
highly unpredictable. In many infants, he said, it can
spontaneously improve and spare the child's vision, while
in others it can suddenly progress and result in
For the study, the researchers identified 499 out of
828 infants diagnosed at birth with ROP as being at higher
than usual risk for vision loss, based on the computerized
guide that assessed birth weight, ethnicity, gestational
age, direct examination of the eye, whether the infant was
a single or multiple birth baby and whether the infant had
been born in a hospital that participated in the study.
Once the high-risk babies were identified, 401 were
randomly assigned to get either early treatment or
treatment at the standard threshold. Visual activity of all
infants was checked at 6 months of age, and structural
outcomes were examined at 6 and 9 months of age.
Current ROP treatments — laser therapy and
cryotherapy — use either heat or freezing
temperatures to destroy the outer portions of the retina,
slowing or reversing the abnormal growth of blood vessels.
A potential side effect of these treatments, known as
retinal ablation, can lead to a partial loss of peripheral
or side vision. However, Repka said the benefits of ROP
treatments far outweighed any potential risks.
"Although there is a slight risk with ROP treatment,
the benefits of these treatments are hard to ignore since
they preserve the most important part of vision — the
sharp, central vision needed to read, see faces or perform
detailed tasks that require hand-eye coordination," Repka
Because visual activity continues to develop during
infancy and early childhood, the study will continue to
follow these infants until the age of 6 years to ensure
that the benefits of early treatment persist into
Each year ROP affects an estimated 14,000 to 16,000
premature, low-birth-weight infants in the United States
and thousands more worldwide, making it a leading cause of
vision loss in children. Of these cases, approximately
1,500 infants will develop severe ROP that requires
treatment. Despite available treatment, about 400 to 600
infants with ROP still become legally blind each year.
Researchers have identified birth weight of 2.75 pounds
(1,250 grams) or less as a major risk factor for developing
The study was funded by the National Eye Institute,
National Institutes of Health and the U.S. Department of
Health and Human Services.