These findings may also lead to better screening protocols of premature infants' eyes while they are under observation in hospital's newborn intensive care units. The results of the multicenter Early Treatment for Retinopathy of Prematurity (ETROP) study are published in the December issue of the Archives of Ophthalmology.
A leading cause of vision loss in infants, retinopathy of prematurity (ROP) is a potentially blinding disease that affects premature, low birth weight infants. ROP is the growth of abnormal blood vessels in the back of the eye. These vessels can leak fluid and blood and lead to scar tissue inside the eye, increasing the risk of retinal detachment and severe vision loss.
Each year ROP affects an estimated 14,000 to 16,000 premature, low birth weight infants in the United States and thousands more worldwide. 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.
"This study represents another important step in our ongoing efforts to decrease preventable blindness in premature babies, said Graham Quinn, M.D., MSCE, principal investigator at the Philadelphia Center (The Children's Hospital of Philadelphia, Hospital of the University of Pennsylvania and Pennsylvania Hospital). "We have identified a group of children whose eyes would not have been treated before using the conventional threshold definition, but many of these eyes clearly benefited from earlier treatment. However, not all treatment is successful and we have more to do."
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. Existing therapy involves using a laser, or less frequently, freezing the retina with very low temperature liquids (a procedure called cryotherapy), to decrease the number of abnormal blood vessels, but the best timing for the treatment was uncertain in some eyes.
The study looked at 317 infants with high-risk factors for ROP. Infants with high-risk disease in both eyes had one eye randomized to early treatment and the other eye managed with observation and conventional treatment if needed. In infants with only one eye at high-risk for ROP, the eye with high-risk pre-threshold ROP was randomized to receive either early treatment or conventional management.
The ETROP study results demonstrated that premature infants who are at the highest risk for developing vision loss from ROP, but whose disease is not severe enough to qualify for conventional treatment, will retain better vision when therapy is administered in the early stage of the disease. This treatment approach was found to be better than waiting until ROP reached the traditional treatment threshold. Just as importantly, the study also established the value of an improved risk assessment model to more accurately identify those infants who are at the highest risk for developing severe vision loss from ROP.
Researchers at Children's Hospital and Pennsylvania Hospital have been involved in retinopathy of prematurity research since the early 1970s and helped define the standard threshold for ROP treatment used in the cryotherapy study that started in 1986.
The previous standard treatment threshold for ROP hinged on the disease having progressed enough that the risk of retinal detachment approached 50 percent. As part of the ETROP study, a new computerized risk model 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 examination findings, and whether the infant had been born in a hospital that participated in the study.
The ETROP trial was sponsored by the National Eye Institute, a part of the National Institutes of Health. The study was conducted at 26 participating centers in the U.S. The Philadelphia Center was composed of The Children's Hospital of Philadelphia, Hospital of the University of Pennsylvania, and Pennsylvania Hospital. Graham Quinn, M.D., MCSE, served as principal investigator for Philadelphia.
The primary investigator of the study was William Good, M.D., of the Smith-Kettlewell Eye Research Institute in San Francisco.
Dr. Quinn's co-investigators from The Children's Hospital of Philadelphia include: Jamie G. Koh, R.N., M.S.N., CCRC; Marianne E. Letterio, R.N., B.S.N.; Molly McDaniel, BA; Soraya Abbasi, M.D.; Jane C. Edmond, M.D.; Brian J. Forbes, M.D. Ph.D.; Albert M. Maguire, M.D.; Monte D. Mills, M.D.; Eric A. Pierce, M.D. Ph.D.; and Terri Young, M.D.
Founded in 1855 as the nation's first pediatric hospital, The Children's Hospital of Philadelphia is ranked in 2003 as the best pediatric hospital in the nation by U.S.News & World Report and Child magazines. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking second in National Institutes of Health funding among children's hospitals. In addition, its unique family-centered care and public service programs have brought the 430-bed hospital recognition as a leading advocate for children and adolescents from before birth through age 19. Children's Hospital operates the largest pediatric healthcare system in the U.S. with more than 40 locations in Pennsylvania, New Jersey and Delaware.
Journal
Archives of Ophthalmology