This study is designed as a prospective, controlled, single blinded evaluation of pulsatile insulin in the role of diabetic retinopathy. The patients entered into the study will be from two distinct sources. First, in conjunction with a national eye imaging company, patients with known type 1 or type 2 diabetes will be evaluated for retinal disease. This evaluation will consist of mydriatic fundus photography in diabetic patients not having had recent ophthalmologic evaluation (period greater than 12 months). The fundus photographs will be read by an observer under the auspices of the Wilmer Ophthalmologic Institute at Johns Hopkins Hospital. Classifications of patients will be evaluated in this study include: