Clinical trials - more than an assessment of treatment effect: LXV Edward Jackson Memorial Lecture.

PURPOSE: To review the development of clinical trials and demonstrate their value beyond the assessment of the treatment effect.
DESIGN: Retrospective literature review.
METHODS: Retrospective literature review.
RESULTS: There has been a rapid increase in the number of clinical trials in ophthalmology as assessed by the number of ophthalmic publications and the number of ongoing National Eye Institute-(NEI) sponsored clinical trials over the last four decades. The public health significance of the results of these NEI clinical trials goes beyond the demonstration of treatment effects and side effects. From these trials, we learn about the clinical course and risk factors of disease, allowing us to better determine who and when to treat. Furthermore, the collaboration of investigators, as they develop and carry out protocols, facilitates incorporation of new ideas into the practice of medicine.
CONCLUSIONS: The practice of medicine is increasingly dependent on the results of carefully designed clinical trials. The determination as to whether a new treatment is safe and effective is important, but the additional information we can obtain regarding natural history, risk factors, and patient satisfaction adds immeasurably to our ability to care for our patients.