## 2 Related Work  
### Augmented Reality  
Research on the integration of AR into TED is still limited, with only a few studies addressing its effectiveness. One such study by [PERSON] et al. [11] created a mobile AR application designed to estimate the carbohydrate content of real foods. The AR application overlays a virtual mesh onto food items, allowing users to resize it to match the real food volume. The application calculates the food's volume and provides an estimation of its weight. For accurate results, a marker needs to be positioned in front of the food. In their study, eight patients participated, and, in 44% of the evaluations, the error margin decreased by no less than 6 g. In a prior work [12], we presented the first version of an AR application for carbohydrate counting, designed for children in Spain. The study included two post-knowledge questionnaires: one with different foods and another that included the same foods as the pre-knowledge questionnaire. No statistically significant differences were found between the results of the two questionnaires. As a continuation of this AR application, a version tailored for Ecuadorian patients was developed [10]. Using this updated version, a study was conducted to evaluate its effectiveness in learning about carbohydrate content to Type 1 diabetes patients in Ecuador, with results compared to a similar study conducted in Spain. In the study [10], patients did not learn using traditional methods. The AR application improved short-term knowledge transfer and demonstrated a significant impact on mid-term retention. The results of learning were not influenced by age or gender, and patient satisfaction was high. The AR application used in the study presented here is the same as the one described in [10]. Other studies, though not directly related, are worth mentioning. The first is an AR application designed to help people with Type 2 diabetes learn about antihypertensive medications [13]. This application scans predefined patterns (e.g., a medication package) using a mobile device and displays augmented digital content. The second is a teddy bear toy ([PERSON](Providence, RI, USA)) with image targets integrated into its body [14], designed to support therapeutic education for children managing Type 1 diabetes. The mobile AR application recognizes the image targets on the bear's body and allows users to simulate measuring blood glucose or administering insulin via a pump or pen. However, the carbohydrate counting component is not integrated into AR. The third study [15] introduced a mobile AR application aimed at delivering information about diabetes medications, using QR codes to show 3D models. The findings from their study, which involved pharmacy students, revealed that AR technology played a significant role in student learning, accounting for 76.2% of their progress, highlighting its effectiveness in improving educational results. The fourth study [16] explored how AR-based therapeutic education influenced the Health Locus of Control in Type 2 diabetes people. Their application employed barcode markers to activate interactive content, covering five essential aspects of management of diabetes: medication, education, nutrition, exercise, and monitoring of blood glucose. The application included quizzes to evaluate individual knowledge and offered guidance on managingdiabetes. The intervention was conducted three times per week for a duration of three months. The patients were divided into two separate groups: one group received the intervention, while the other served as the control group. The results demonstrated that AR-based education significantly enhanced Health Locus of Control scores in Type 2 diabetes patients. Nevertheless, no statistically significant difference was observed in the overall improvement of Health Locus of Control between the control and intervention groups.