Assessing intravitreal anti-VEGF drug safety using real-world data: methodological challenges in observational research.

Such challenges include the selection of the most suitable data source, taking into account how well drug utilization is captured and whether the outcomes and covariates of interest can be captured. The strengths and limitations of some analytic methods that can be used to quantify risk, such as the intention-to-treat approach and the as-treated approach, complement each other, and using these together provides a more balanced analysis.