One embodiment of the present invention sets forth a technique for detecting when a user, notably the driver of a vehicle, is not being attentive based on eye convergence. The technique includes determining a first distance from the user to an obstacle, such as a preceding vehicle. The first distance may be determined using a depth sensor. The technique further includes determining a first vergence angle associated with a left eye of the user and determining a second vergence angle associated with a right eye of the user. The technique further includes determining a first eye convergence distance based on the first vergence angle, the second vergence angle, and an interocular distance between the left eye and the right eye. The technique further includes comparing the first distance to the first eye convergence distance to generate a first result. An inattention alert may be generated based on the first result. Detects if the user is looking in the direction of the object but not paying attention to it, because focussing on something else or simply daydreaming.
