At the beginning of the 18th century, Berkeley believed an anomaly pointed outby Isaac Barrow could be regarded as important evidence against the optical theories thathad been established and standardized thanks to the works of Kepler and Newton. In thisarticle, we want to show that Berkeley’s treatment of the Barrovian Case does not falsifythese theories. We will contend that the strategy used by Berkeley to resolve the anomaly byalluding to a change of convention is a strategy that the classical theorist could use as well.In other words, the classical theorist could also appeal to a change of convention to deal withthe problem.