There is growing interest in using fluorescence imaging instruments to guide surgery, and the leading options for open-field imaging are reviewed here. There has been a steady growth in commercially marketed FGS systems, each with their own differentiated performance characteristics and specifications. In this review, United States Food and Drug Administration 510(k) cleared commercial systems and some leading premarket FGS research systems were evaluated to illustrate the continual increase in this performance feature base. Generally, the systems designed for ICG-only imaging have sufficient sensitivity to ICG, There is no perfect imaging system, but the feature differences among them are important differentiators in their utility, as outlined in the data and tables.