A stoma appliance is an external to the body bag for the collection of intestinal output via an aperture in the patient's abdominal wall. The bag is attached to the skin using a wafer, and many stomas have irregular shapes, making a manual wafer fitting very difficult. Better post-operative wafer fitting has been identified as a key area for stoma care improvement. The ostomate (or the ostomate's caregiver) must know the diameter of the stoma to fit the appliance accurately. A cutting error of as little as 2 mm can result in serious complications, including damaged blood vessels or profuse, recurrent bleeding. A novel approach is presented for the design of a visual measurement assistive system called the Individualized Wafer Fitting System (WFS). The system includes a 3D structured light scanner and associated software. The image processing algorithm and smartphone application interact with the sensor and the ostomate. Once the measurement is complete, the outline of the stoma is sent to a printer, which produces the template for cutting the individualized wafer. The system was tested on artificially made stomas as well as on a human subject for a proof of concept. The results show an error of 5% in cutting wafers customized for simple stomas.