Fig. 1.

Screenshots of the app from the first usability test. Participants could self-track ( A ) a meal's carbohydrates and current blood glucose, ( B ) the number and type of alcoholic beverages, and ( C ) the duration and intensity of exercise. Design changes that resulted from the study included: removing the slider bars for data entry, changing check boxes into a pull-down menu, and providing additional features for tracking meals, alcohol, and exercise which required the design of additional icons.