Diabetic Retinopathy — Diabetic Retinopathy Study (DRS)
Citation(s)
Diabetic retinopathy study Report Number 6. Design, methods, and baseline results. Report Number 7. A modification of the Airlie House classification of diabetic retinopathy. Prepared by the Diabetic Retinopathy. Invest Ophthalmol Vis Sci. 1981 Jul;21(1 Pt 2):1-226.
Ederer F, Podgor MJ Assessing possible late treatment effects in stopping a clinical trial early: a case study. Diabetic Retinopathy Study report No. 9. Control Clin Trials. 1984 Dec;5(4):373-81.
Ferris FL 3rd, Podgor MJ, Davis MD Macular edema in Diabetic Retinopathy Study patients. Diabetic Retinopathy Study Report Number 12. Ophthalmology. 1987 Jul;94(7):754-60.
Rand LI, Prud'homme GJ, Ederer F, Canner PL Factors influencing the development of visual loss in advanced diabetic retinopathy. Diabetic Retinopathy Study (DRS) Report No. 10. Invest Ophthalmol Vis Sci. 1985 Jul;26(7):983-91.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
