Structural and functional outcome in infants treated with cryotherapy for threshold retinopathy between 1989 and 1999

PURPOSE: To assess visual outcome, funduscopic appearance, and refraction for infants treated with cryotherapy for threshold retinopathy of prematurity (ROP) between 1989 and 1999. METHODS: Retrospective analysis of the medical records of premature infants with threshold ROP who were treated with cryotherapy. RESULTS: A total of 2,146 premature infants were screened for ROP during the study period. Of the 66 infants who were subsequently treated for threshold ROP with cryotherapy, 58 infants had at least 1 year of follow-up and comprised the study population. After correcting for improved survival, the overall incidence of treated infants with cryotherapy increased during the study period. Comparison of infants treated from 1989 through 1995 (group 1; n=26) and 1996 through 1999 (group 2; n=32) showed group 2 infants had improved visual outcome, better funduscopic anatomic appearance, and decreased myopia. CONCLUSION: Although the incidence of treated premature infants increased during the study period, visual outcome improved. The literature attributes improved visual and anatomical outcome to the use of the diode laser in the treatment of threshold ROP. In this study, the improved visual and anatomical results obtained with cryotherapy could be attributed in part to the development over the years of a milder type of retinopathy of prematurity and to earlier treatment of threshold ROP.