Photographic grading in the retinopathy of prematurity cryotherapy trial

We report a system for photographic grading of the posterior fundus features of retinopathy of prematurity and correlation of such features with potential future visual function. The severity of temporal vessel traction, retinal fold, macular ectopia, retinal detachment, retrolental mass, blood vessel attenuation, retinal pigment epithelial scarring, and cataract was assessed by review of photographs at the Fundus Photograph Reading Center, Portland, Ore, according to a scheme designed to avoid bias or knowledge of treatment status. Reliability for all features was in the fair to excellent range (kappa greater than .40), except for blood vessel attenuation (kappa = .18), which was not a factor in the final outcome determination. The grading scheme provided the basis for the 3-month conclusions of the multicenter trial of cryotherapy for retinopathy of prematurity. This system will have further application in the 12-month Cryotherapy for Retinopathy of Prematurity Study conclusions and in future long-term correlation with visual acuity as the trial patients mature.