Contact: Ellen Bank
843.792.2626
Dec. 8, 2003
CHARLESTON, SC -- The MUSC Storm Eye Institute was a participant in an important
clinical trial that has provided doctors with improved prognostic indicators
and treatment options for retinopathy of prematurity (ROP), a blinding disease
that affects premature, low birthweight infants. ROP spurs the growth of abnormal
blood vessels in the back of the eye. These vessels leak fluid and blood and
scar the nerve tissue inside the eye, increasing the risk of retinal detachment
and severe vision loss in infants.
Because it follows an unpredictable course, ROP presents doctors with difficult
treatment decisions. In many infants the disease spontaneously regresses and
spares vision. However, in some infants ROP progresses, resulting in serious
visual impairment. Although current therapy, commonly performed using a diode
laser, usually halts its progression, many infants are still blinded by the
disease. Due to a lack of clinical criteria to predict which patients will ultimately
develop severe vision loss from ROP, ophthalmologists were forced previously
to defer treatment until it was clearly indicated. Unfortunately, as it turns
out, delaying therapy can leave infants who might benefit more from early treatment
with poor visual outcomes.
“I see blindness as the major threat of severe prematurity,” said
Richard Saunders, M.D., an MUSC pediatric ophthalmologist and principal investigator
for the study at the MUSC site. “ROP is a leading cause of vision loss
in children. Some premature infants will grow up with multiple handicaps, and
if you throw blindness into the mix, you have a child facing major obstacles.”
Other MUSC participants in the study were Dilip Purohit, MD, director of neonatology,
Millicent Peterseim, MD, pediatric ophthalmologist, and Lisa Langdale, RN, the
MUSC study center coordinator and a neonatal ICU nurse.
The Early Treatment for Retinopathy of Prematurity (ETROP) study was sponsored
by the National Eye Institute (NEI), a part of the National Institutes of Health
(NIH). Results of the study, published in the December issue of the Archives
of Ophthalmology, demonstrated that premature infants, who are at the highest
risk for developing vision loss from ROP, will retain better vision when therapy
is administered in the earlier stage of the disease. This treatment approach
was found to be better than waiting until ROP has reached the traditional treatment
point, called “threshold.” Just as importantly, the study also established
the value of an improved risk assessment model to identify more accurately those
infants who are at the highest risk for developing severe vision loss from ROP.
“Premature, low birthweight infants face a host of medical complications
with lifelong consequences. The results of this study allow us to improve treatment
for ROP and, hopefully, the quality of life for children who most need sight-saving
therapy,” said Paul A. Sieving, M.D., Ph.D., director of the NEI.
Each year ROP affects an estimated 14,000-16,000 premature, low birthweight
infants in the United States and thousands more worldwide. Of these cases, approximately
1500 infants in the United States will develop severe ROP that requires treatment.
Despite available treatment, about 400-600 infants with ROP still become legally
blind each year. Researchers have identified birthweight of 2.75 pounds (1250
grams) or less as a major risk factor for developing ROP.
The previous standard treatment threshold for ROP hinged on the disease having
progressed enough that the risk of developing retinal detachment approached
50 percent. This determination is made based of specific findings on ophthalmic
examination.
As part of the ETROP study, a new computerized risk model, developed by NEI-supported
researchers, was used to identify high-risk infants early in the disease. The
risk model assessed birthweight, ethnicity, being a single or multiple birth
baby, gestational age, ophthalmic exam findings, and whether the infant had
been born in a hospital that participated in the study.
“This new risk assessment model helps detect infants who have a higher
risk of blindness, justifying moving the treatment window forward a week or
two and giving physicians a defensible reason for early treatment,” said
Saunders, who also serves on a subcommittee for practice guidelines for screening
for retinopathy of prematurity of the American Academy of Pediatrics. “The
study results also indicate that in many cases watchful waiting without immediate
treatment of developing disease is the preferred approach. Laser therapy involves
destruction of the peripheral retina, which is not benign. So it is important
not to treat a large number of infants that are likely to do well anyway. Clinical
judgment and experience of the physician are critical in sorting out the many
factors involved in a decision to treat infants early.”
Once identified, the infants were then assigned randomly either to treatment
at the standard threshold or to early treatment. Researchers found that early
treatment significantly reduced the likelihood of poor vision from 19.5 to 14.5
percent at about one year of age. Early treatment also considerably reduced
the likelihood of structural damage to the eye from 15.6 to 9.1 percent.
Current treatments for ROP involve laser therapy or cryotherapy. Laser therapy
uses heat from light energy while cryotherapy uses freezing temperatures to
retard blood vessel growth. A consequence of these treatments, known clinically
as retinal ablation, is a partial loss of peripheral or side vision. Nonetheless,
treatment is valuable in preserving the most important part of our sight—the
sharp, central vision we need to read, see faces or perform detailed tasks that
require hand-eye coordination.
The study will continue to follow these infants until age six to ensure that
the benefits of early treatment persist through childhood.
The study was conducted at 26 centers in the U.S.
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