The core activity of Kress Optic et Audition is the manufacture and sale of optical products and services, in particular: Optics: sale of glasses, contact lenses, sunglasses and other optical products; Acoustics: sale of hearing aids and other acoustic products; Services: eye examinations, hearing tests, adjustment of glasses and hearing aids, advice and sale of optical and acoustic products. The company also offers specialized services such as myopia control, prevention of age-related macular degeneration (DMLA) and treatment of dry eyes.