Doctors can identify infants who are most likely to benefit from early treatment for a potentially blinding eye condition called retinopathy of prematurity (ROP) with eye exams, according to research at Oregon Health & Science University’s Casey Eye Institute. Doctors also can identify the best time to administer the treatment, according to the work conducted at OHSU and other institutions participating in the study. The results will improve the eyesight for thousands of premature infants born in the United States each year.
“We found we could identify the optimal time of treatment,” said Earl Palmer, M.D., Oregon Elks professor of ophthalmology in the OHSU School of Medicine, who helped design the research and manage the study. “We now know how early is beneficial and how early is too early to treat. This is important because if we treat some of these cases too early, the child’s vision may not ultimately be as good.”
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.
The current study followed the same 370 children through age 6, when researchers checked their vision and examined the development of their eyes.
“By looking at eyes that were treated early, it was possible to segregate eyes by the most severe form of ROP – classified as Type 1 eyes – and those eyes that had a less severe form of the disease – classified as Type 2 eyes,” OHSU’s Palmer said. “Type 1 eyes needed immediate treatment and Type 2 eyes, which are likely to improve on their own, need monitoring. Doctors still were able to perform treatment and ultimately give the child significantly better vision in cases where the Type 2 eyes did not improve on their own.”
ROP is caused by abnormal blood vessel development. 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. Earlier research has shown that laser therapy or cryotherapy, using freezing temperatures, are the most effective treatments to slow or stop the growth of abnormal blood vessels.
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About Casey Eye Institute
As part of Oregon Health & Science University, the Casey Eye Institute is an academic regional eye center. It is named after James and George Casey, founders of United Parcel Service. The Casey Eye Institute is also one of only seven regional eye research centers in the nation sponsored by Research to Prevent Blindness, the world's leading voluntary organization in support of eye research. The Casey Eye Institute has operated the Elks Children’s Eye Clinic since 1949, thanks to the generous support of the Oregon State Elks Association.
Oregon Health & Science University is the state’s only health and research university, and Oregon’s only academic health center. OHSU is Portland's largest employer and the fourth largest in Oregon (excluding government). OHSU's size contributes to its ability to provide many services and community support activities not found anywhere else in the state. It serves patients from every corner of the state, and is a conduit for learning for more than 3,400 students and trainees. OHSU is the source of more than 200 community outreach programs that bring health and education services to every county in the state.
About the National Eye Institute
The National Eye Institute, part of the National Institutes of Health, leads the federal government’s research on the visual system and eye diseases. NEI supports basic and clinical science programs that result in the development of sight-saving treatments. For more information, visit 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.