"This study was important because it identified when we should operate and intervene to prevent retinal detachment and total blindness without placing the infant at risk of surgical trauma and its consequences," said Dr. Mary Elizabeth Hartnett, associate professor of ophthalmology in UNC's School of Medicine.
The new findings appeared in the April issue of the journal Retina. Hartnett is the study's lead author.
Retinopathy of prematurity (ROP) is an eye disease causing 550 cases of blindness annually in the United States and many more worldwide. "Prevention of progression to retinal detachment is preferable to surgery to reattach a totally detached retina because even with successful surgery to reattach a totally detached retina, vision can be extremely poor," Hartnett said.
Preterm infants less than 2.7 pounds or less than 28 weeks gestational age are particularly at risk from ROP, since they are born with an immature retina with incomplete blood vessel development, Hartnett said. This leaves a retina area without a blood or oxygen supply, and this ischemic situation then stimulates new blood vessel growth, or angiogenesis.
"But this angiogenesis grows in the wrong part of the eye," Hartnett said. "When the blood vessels grow they grow into the vitreous, the clear gel above the retina. The blood vessels are immature and leak substances that cause scarring and later retinal detachment." The current recommended treatment for severe ROP preceding stage 4 or retinal detachment is laser ablation of the ischemic retina, a process thought to destroy tissue that produces substances causing unwanted angiogenesis into the vitreous.