Patients who are diagnosed as one of these classifications will be offered entrance into the study. Study patients will be matched for age, sex, and disease severity into a treatment and control group. All study patients will be evaluated in conjunction with an ophthalmologist. This evaluation will include clinical examination and fundus photography. Treatment group patients will undergo weekly pulsatile insulin delivery sessions as per protocol above. Control group patients will have weekly clinic visits to maximize glycemic and hypertensive control. All patients will repeat their fundus photography at three month intervals, with ophthalmologic evaluation as above every six months, or more often if requested by the ophthalmologist.