## 4 Discussion of the Results
Within ARM, we can say that AR has been successfully applied to some products and brands to help clients to have certainty and better decision making in their shopping options [44], generally those products can be placed in AR-fused spaces such as furniture, pictures, decoration objects, stores or even restaurants [42; 43]. There are also products that through AR applications can be tried on clients' bodies such as jewelry, clothes, or makeup [39; 42; 46]. Many brands have started to penetrate the AR fields to save money, increase positioning [40], and obtain information for customer tracking [42]. Some studieseven promoted marketers to look for innovative strategies to gain space in the competitive area of business development [16]. On the other hand, there are certain challenges for AR in marketing. The first one is that there is the perception that AR is still in an immature stage because its adoption in this area does not go as fast as other technologies [40]. Furthermore, there is an important concern in security protection for clients' personal data with no laws regulating or solving this problem [39]. Therefore, there is a critical interest in how this technology can gather information from clients' likes and dislikes, gestures, and even body movements that can be used to manipulate decision making in the clients [39]. Finally, AR needs technical improvements in visualization with more realistic and high-quality graphics [47] so that users do not lose interest in the final product because it has features that AR still cannot emulate [40; 41; 45]. AR has improved medicine in many ways, for example, in three-dimensional (3D) models to analyze the anatomy of patients in surgery [79], medical training, supplying elements that are difficult to visualize within the patient's body [80], computer-assisted surgeries with three-dimensional images, and computed tomography with X-rays and treatments for patients [81]. In this study, we found that AR has also been involved in the successful simulation of scenarios [49; 52; 53; 54; 57], with a great improvement in medical training [17; 53; 51; 54; 55; 56], important benefits for rehabilitation [15], and surgeries and medical treatments. Among the technical problems found, some studies pointed to the complexity of working with AR when light and projection can hinder the accuracy of AR performance, as well as ergonomic devices that can work freely in an operating room [51; 52; 54; 57]. Talking about the challenges in this area, we can say that, different from using AR for doctors' training and decision making [52; 56] before surgeries, the task to be solved is to use AR technology in real-time surgical procedures, which is difficult when there are technical issues such as internet connectivity. Not only with AR but also with VR and now through the metaverse, significant advantages for medicine can be potentially suggested, such as the possibility of creating international databases for disease diagnoses, maintaining connections with doctors from all over the world through virtual rooms, and avatars that will allow training, monitoring, therapies, and remote treatments for patients [82]. Additionally, today there is an increase in metaverse investment that will permit further research and development that will innovate surgical and medical procedures. However, research should be given relevance, especially in spinal column surgeries, so that these new technologies do not remain as \"Vaporware\" (vague future software interactions) [83]. Psychology and psychiatry are also fields where AR and VR are having exponential strength, being auxiliary tools that improve mental and physical health. The recent study in this field guides future researchers to do new health studies across the metaverse [84]. Finally, AR entertainment is implemented in sports [68], in games that help reduce the effects of mental diseases, and in video-gaming interaction mainly through cellphones, Pokemon Go being one of the most popular examples of videogames based on the application of AR [85].