Generally, the risks of this treatment are small and no more than the risks of any kind of surgery on a premature baby. The primary risk comes if a respirator is needed, as it might take time for the baby to breathe without it again, especially if there have been problems getting off a respirator in the past. In a national study of very premature babies, no deaths occurred among 265 babies who had cryotherapy, about a quarter of them under general anesthesia. The tissues around the eyeball may be very swollen for about five days after treatment. The discomfort the baby feels from the treatment does not seem to seriously affect a baby's overall health.
Complications involving the eye itself are possible.
For example, minor bleeding inside the eye occurs 22 percent of the time. Bleeding can occur from retinopathy of prematurity even if a baby doesn't have cryotherapy or laser therapy, but it is sometimes brought on during these procedures. The blood eventually clears up on its own. Pressure on the eyeball during the treatment can stop circulation of blood to the optic nerve. This happens in less than one percent of the treated eyes and seldom damages vision.