The value of randomized clinical trials in ophthalmology.

T HE RANDOMIZED CLINICAL TRIAL IS THE GOLD standard for evaluating a therapy, providing the highest evidence for the practice of evidence-based medicine. However, not all randomized clinical trials are informative and the success of the trial in demonstrating a valid treatment or diagnostic effect will depend on the elements of the study design. The purpose of this report is to highlight the essential elements of the randomized clinical trial and how the failure to appropriately provide such elements can lead to difficulties in interpreting the data and drawing valid conclusions.