From the National Eye Institute:
Scientists have shown that through an eye exam, doctors can identify
infants who are most likely to benefit from early treatment for a
potentially blinding eye condition called retinopathy of prematurity
(ROP), resulting in better vision for many children.
These long-term results of the Early Treatment for Retinopathy of
Prematurity (ETROP) study confirm that the visual benefit of early
treatment for selected infants continues through 6 years of age. The
research, published April 12 online in Archives of Ophthalmology, was
supported by the National Eye Institute (NEI), part of the National
Institutes of Health.
"This study has set the standard of care for infants with ROP by
showing that early treatment of selected high-risk premature babies has
positive longer-term results on vision," said NEI Director Paul A.
Sieving, M.D., Ph.D.
An estimated 15,000 premature infants born each year in the United
States are affected by some degree of ROP. At-risk infants generally are
born before 31 weeks of the mother's pregnancy and weigh 2.75 pounds or
less.
This disease, which usually develops in both eyes, is one of the most
common causes of vision loss in children. About 90 percent of infants
with ROP have a mild form that does not require treatment, but those who
have a more severe form can develop lifelong visual impairment, and
possibly blindness.
During pregnancy, the blood vessels of the eye gradually grow to
supply oxygen and essential nutrients to the light-sensitive retina. If a
baby is born prematurely, growth of the blood vessels may stop before
they reach the edge of the retina. In these newborns, abnormal, fragile
blood vessels and retinal tissue may develop at the edges of the normal
tissue. The abnormal vessels can bleed, resulting in scars that pull on
the retina. The main cause of visual impairment and blindness in ROP is
retinal detachment. Laser therapy or cryotherapy, using freezing
temperatures, are the most effective treatments to slow or stop the
growth of abnormal blood vessels.
"The long-term study has given clinicians evidence that infants with
ROP should be treated with different strategies based on an infant's
risk for a severe form of the disease, which can be determined through
an exam at the bedside," said study chair William V. Good, M.D., of
Smith-Kettlewell Eye Research Institute in San Francisco.
Previously, doctors treated infants with ROP when they estimated
their risk for retinal detachment to be 50 percent, a strategy developed
through the NEI-supported Cryotherapy for Retinopathy of Prematurity
study. Although this was a major finding, many infants still went on to
develop severe eye disease. Therefore, the first phase of the ETROP
study aimed to discover if doctors could identify infants at a higher
risk for progression of the disease and intervene early to improve their
vision.
In 2003, the ETROP study found that early treatment-upon diagnosis as
higher risk for severe ROP-improved the vision and retinal health of
certain infants after nine months. These infants had dilated or twisted
blood vessels in the retina and substantial growth of new blood vessels,
classified as Type 1 disease. Eyes with Type 2 ROP, or a more moderate
amount of new blood vessel growth, did not benefit from early treatment.
Doctors could predict which infants were more likely to benefit from
early treatment by identifying certain eye characteristics, such as the
appearance and location of the blood vessels.
The current study followed the same 370 children through 6 years of
age, when researchers checked their vision and examined the development
of their eyes. The nine-month study recommendations were confirmed
through 6 years. Type 1 eyes benefitted from early treatment, and Type 2
eyes had similar results with either early treatment or treatment at
the standard time. Seventy-five percent of the early-treated Type 1 eyes
were spared legal blindness, compared with 67 percent of Type 1 eyes
that received treatment at the standard time. Of the Type 2 eyes that
were carefully monitored for disease progression through the standard
protocol, more than half improved without treatment.
"Unfortunately, not all eyes selected for early treatment do well,"
said Robert J. Hardy, Ph.D., director of the ETROP study coordinating
center and professor of biostatistics at the University of Texas School
of Public Health in Houston. "Additional research is needed to identify
still better methods for the prevention and treatment of severe ROP."
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The National Eye Institute (NEI), a component of the National
Institutes of Health, is the federal government's lead agency for vision
research that leads to sight-saving treatments and plays a key role in
reducing visual impairment and blindness. For more information, visit
the NEI Web site at www.nei.nih.gov.
The National Institutes of Health (NIH) — The Nation's Medical
Research Agency — includes 27 Institutes and Centers and is a component
of the U.S. Department of Health and Human Services. It is the primary
federal agency for conducting and supporting basic, clinical, and
translational medical research, and it investigates the causes,
treatments, and cures for both common and rare diseases. For more
information about NIH and its programs, visit www.nih.gov.
http://www.nei.nih.gov/news/pressreleases/041210b.asp