Ophthalmologists At The Children's Hospital Of Philadelphia See Small Loss Of Peripheral Vision In Premature Infants Treated With Cryotherapy For Devastating Eye Disease

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PHILADELPHIA, April 14, 1996 -- In a companion study to the National Eye Institute's clinical investigation of cryotherapy to prevent blindness in children with severe retinopathy of prematurity (ROP), Ophthalmologists at The Children's Hospital of Philadelphia have determined that children with severe ROP who received the surgical intervention had an approximate 10 percent loss of peripheral or side vision in their treated eye. This pilot study is the first long-term study of its kind and appears in the April issue of Archives of Ophthalmology.

"We followed 8 preterm patients who received cryotherapy at approximately 12 weeks of age," said Graham E. Quinn, M.D., Associate Surgeon, Division of Ophthalmology at The Children's Hospital of Philadelphia. All of the babies enrolled received cryotherapy in one eye, leaving the other eye to serve as a control. Dr. Quinn and his associates at Philadelphia's Children's Hospital and Wills Eye Hospital then followed the patients, testing their vision on an annual basis. "Today, the children are able to see and read letters," said Dr. Quinn. "However, in a test of the child's ability to detect an object off to the side while the child looked straight ahead, we found a deficit in peripheral vision of approximately 10 percent," Dr. Quinn said.

In order to test peripheral vision, a Goldmann projection perimeter test was used when the patient reached at least 6 years of age. This test projects a lighted target onto a screen that surrounds the child's head. When the target became visible, the child was told to push a buzzer, ending the test. The distance from the child's central sight line to where the target was spotted was then measured, providing a calculation of the child's peripheral vision.

"Without question, there is a price to pay for using cryotherapy," said Dr. Quinn. ~However, without the surgical intervention, we would see more children with severe ROP go blind. When you weigh the two outcomes -- sight with a small loss of side vision versus blindness - cryotherapy appears to be the best option in premature infants diagnosed with severe ROP.

Each year, more than 4,000 babies born in the United States develop the progressive eye disease called ROP. Those at greatest risk are premature infants weighing less than 3.3 pounds or born before the eighth month of pregnancy. For those babies whose ROP progresses to a severe level, there is a 50 percent chance the damage will be so great the infant will become legally blind.

The Children's Hospital of Philadelphia's Division of Ophthalmology served as the Philadelphia Center for the multicenter trial of cryotherapy for retinopathy of prematurity sponsored by the National Eye Institute. A total of 268 patients were enrolled at Children's Hospital to determine whether a surgical procedure that freezes the inside lining of the eyeball could stop the disease's devastating course.

During the delicate surgery, a probe is placed on the surface of the eye, freezing through to the retinas. Dr. Quinn and his associates believe the cold temperature of the probe destroys cells within the retina responsible for producing irregular growth of blood vessels along the retina's surface. The abnormal blood vessels contribute to scarring and the scar tissue continually tugs on the retina's surface.

Ultimately, this constant tugging may detach the retina from the wall of the eye, leaving the child blind.

The Philadelphia Center results were then analyzed along with results from 22 other centers across the nation in an effort led by Earl A. Falmer, M.D., of Oregon Health Sciences University. According to Dr. Quinn, The Children's Hospital of Philadelphia's investigation of peripheral vision and the National Eye Institute's follow-up study of cryotherapy for ROP will help Ophthalmologists and parents alike. "This is important information for us to know," said Or. Quinn. ~When you have a child who is at high risk for going blind and there is an option that markedly lowers the risk of blindness, it is important to be able to explain to parents how this option comes with its own risk,~ he said. "We now know that one of the risks associated with cryotherapy is a relatively small loss of peripheral vision."

Working with Dr. Quinn on the visual field study were: Dr. David Schaffer, Chairman of the Department of Ophthalmology at The Children's Hospital of Philadelphia; William Tasman, M.D., and J. Arch McNamara, M.D., of Wills Eye Hospital, and Dennis Miller and Janice Evans of Children's Hospital. In addition, the following collaborated with Dr. Quinn on the National Eye Institute study: Richard Hertle, M.C., Martin Wilson, M.D., Sheryl Menacker, M.D., all with the Department of Ophthalmology at the Children's Hospital of Philadelphia, Jay Kubacki, M.D. of St. Christopher's and Gary Brown, M.D. of Wills Eye Hospital

The Children's Hospital of Philadelphia, the nation's first children's hospital, is a leader in patient care, education and research. This 304-bed multispecialty hospital provides comprehensive pediatric services to children from birth through age 19.

Contact: Sarah Jarvis of The Children's Hospital of Philadelphia, 215-590-4092.