Premature babies, especially very tiny ones, will have a much better chance for good eyesight thanks to a successful nationwide clinical study involving a local pediatric ophthalmologist.

Dr. Jane D. Kivlin, assistant professor at the University of Utah's department of ophthalmology, said Tuesday that freezing a portion of the eye's surface can protect many premature infants against blindness from retinopathy of prematurity, commonly known as ROP.ROP, a potentially blinding disorder in very low birth weight infants, affects the developing blood vessels of the retina, the light sensing tissue at the back of the eye. It causes the vessels to grow and branch excessively, leading to bleeding, scaring or retinal detachment.

Cryotherapy, the treatment investigated, freezes the area of the eye without blood vessels, creates a ring of scar tissue, and slows or stops the growth of these vessels halting the progression of ROP, she explained.

The treatment, which takes about 11/2 hours, reduced the risk of severe visual loss by half in 172 babies with advanced ROP. One or two treatments were proven adequate throughout the study.

The U. physician said previous studies have shown that from one-third to one-half of eyes with severe ROP end up with permanent vision problems that are not correctable with glasses. A few are totally blind.

Kivlin cautioned that retinal scarring from cryotherapy may cause some loss of the infant's peripheral, or side vision. However, she said it does not affect the central part of the retina that is responsible for vision used for reading, writing and other everyday tasks.

Among smaller premature babies those weighing less than 2.3 pounds 90 percent will have some ROP, the ophthalmologist said. The disease is very uncommon in babies weighing 3.5 pounds or more.

Kivlin was principal investigator of the study at the U. Hospital, Primary Children's Medical Center and Utah Valley Regional Medical Center. The three facilities comprised one of 23 participating medical centers across the country.

Study investigators examined 3,862 premature infants whose low birth weight put them at high risk for ROP. Of these, 172 developed severe ROP and were entered into the study.

Kivlin said 114 local premature infants were examined and 10 subsequently treated for severe ROP. The outcome in Utah corresponded with the national results, with 50 percent showing favorable results.