A computer-implemented method for tokenless authentication of a paying consumer during a payment transaction uses a computing device having a processor and a memory. The method includes receiving a plurality of biometric data sets for a plurality of consumers. Each biometric data set includes at least a biometric image of a consumer and an associated payment account identifier. The method also includes receiving, from a first biometric input device communicatively coupled to the processor, a first biometric image of the paying consumer including an iris image. The method further includes determining a payment account associated with the paying consumer based on at least the first biometric image and the plurality of biometric data sets. The method also includes authenticating use of the payment account by the paying consumer for a payment transaction at the retail location by comparing the first biometric image to the plurality of biometric data sets.