This paper presents a computer vision aided method for non invasive interupupillary (IPD) distance measurement. IPD is a morphological feature requirement in any oftalmological frame prescription. A good frame prescription is highly dependent nowadays on accurate IPD estimation in order for the lenses to be eye strain free. The idea is to replace the ruler or the pupilometer with a more accurate method while keeping the patient eye free from any moving or gaze restrictions. The method proposed in this paper uses a video camera and a punctual light source in order to determine the IPD with under millimeter error. The results are compared against standard eye and object detection routines from literature.