Researchers at the Cheltenham General Hospital in the United Kingdom were able to use the results of two consecutive years of photographic screening to determine which patients where most likely to develop sight-threatening diabetic retinopathy. The study was detailed online in Diabetes Care. Researchers looked at longitudinal data from retinal photographs in the population-based National Health Service Diabetic Eye Screening Program to determine the risk for sight-threatening diabetic retinopathy (STDR). Over 14,000 patients with no diabetic retinopathy (DR) or only mild diabetic retinopathy were evaluated at two consecutive annual screenings and categorized at each screening based up on whether they had DR in neither, one or both eyes and then the patients were follow for a median of 2.8 years. Patients who had no DR at either of the two screenings progressed to STDR at an annual rate of .7%. Those who had no DR at the first screening and DR in one eye at the second screening progressed to STDR at an annual rate of 1.9%. Those with DR in both eyes at both screenings progressed to STDR at an annual rate of 11%. Researchers determined that by combining the results from two consecutive years of photographic screening the risk of future development of STDR is able to be estimated.