The application of metaverse in healthcare

While metaverse is widely discussed, comprehension of its intricacies remains limited to a select few. Conceptually akin to a three-dimensional embodiment of the Internet, the metaverse facilitates simultaneous existence in both physical and virtual domains. Fundamentally, it embodies a visually immersive virtual environment, striving for authenticity, where individuals engage in real-world activities such as commerce, gaming, social interaction, and leisure pursuits. The global pandemic has accelerated digital innovations across diverse sectors. Beyond strides in telehealth, payment systems, remote monitoring, and secure data exchange, substantial advancements have been achieved in artificial intelligence (AI), virtual reality (VR), augmented reality (AR), and blockchain technologies. Nevertheless, the metaverse, in its nascent stage, continues to evolve, harboring significant potential for revolutionizing healthcare. Through integration with the Internet of Medical Devices, quantum computing, and robotics, the metaverse stands poised to redefine healthcare systems, offering enhancements in surgical precision and therapeutic modalities, thus promising profound transformations within the industry.


Introduction
In recent years, the rapid advancements in virtual reality (VR) technology have propelled it into a dynamic and rapidly growing field (1).A significant milestone was reached in June 2020 when surgeons at Johns Hopkins University successfully performed their inaugural augmented reality (AR) surgery on a patient.During the first procedure, surgeons incorporated transparent eye displays integrated into headsets to project computed tomography (CT) scanbased images of the patient's internal anatomy.This innovative approach enabled them to insert six screws and fuse three vertebrae in the spine, effectively alleviating severe back pain (2).Subsequently, a second surgery was conducted to remove a cancerous tumor from the patient's spine.As we approach the imminent era of the metaverse, digital services are anticipated to revolutionize healthcare, according to the World Economic Forum.The COVID-19 pandemic expedited the widespread adoption of telehealth due to the risks associated with face-to-face interactions, resulting in a significant shift toward remote care.
Telepresence, digital twinning, and the convergence of blockchain technology are three major technological advancements that have the potential to revolutionize healthcare.These concepts could introduce entirely new approaches to delivering care, potentially lowering costs and greatly improving patient outcomes (3).Recognizing the vast possibilities in this uncharted domain, major technology companies have actively entered the landscape, exploring numerous potential applications for the industry.The metaverse embodies the integration and convergence of digital and physical worlds, blending digital and real economies, amalgamating digital and social life, incorporating digital assets into the physical realm, and fusing digital and real identities, thus creating a multidimensional space (4).Various technologies, including high-speed communication networks, the Internet of Things (IoT), AR, VR, cloud computing, edge computing, blockchain, and AI, serve as the foundation for this space.These technologies are driving the transition from the current Internet landscape to the metaverse.The transformation is anchored on eight fundamental technologies, namely extended reality, user interaction, AI, blockchain, computer vision, IoT and robotics, edge and cloud computing, and future mobile networks.Achieving the full realization of a Health metaverse remains a significant challenge in the medical and health domain.Existing platforms still require collaborative efforts from all stakeholders (4).Noteworthy players in the AR and VR market include Google, Microsoft, DAQRI, Psious, Mindmaze, Firsthand Technology, Medical Realities, Atheer, Augmedix, and Oculus VR.These innovative concepts are expected to significantly enhance comprehensive healthcare, revolutionize disease prevention and treatment, and usher in a new era in the industry (5).
In the field of healthcare, the application of metaverse is still in its early stages of development, despite its enormous potential, it also faces several challenges and obstacles.The current technological level has not fully supported the widespread application of metaverse in healthcare.Although VR and AR technologies have made some progress, there are still technical limitations in their application in the medical field, as well as regulatory challenges in healthcare.Additionally, the widespread application of metaverse in healthcare also requires overcoming difficulties in public acceptance and trust in new technologies.Since metaverse is a relatively novel concept, more promotion and education are needed to increase public awareness and acceptance.This review provides an exploration of these issues.This review aims to offer a comprehensive analysis of metaverse in healthcare systems (Summarized in Figure 1).

Types of the metaverse
This comprehensive review seeks to delineate and classify the four distinct types of the metaverse while elucidating their potential and limitations in educational settings.Specifically, it aims to describe the defining characteristics of each type of metaverse through illustrative examples.Additionally, the review highlights the advantages and applications of incorporating the metaverse into the field of education.Moreover, it engages in a critical examination of the limitations and disadvantages associated with the utilization of the metaverse.Through these analyses, this review aims to provide foundational insights into the concept of the metaverse and its potential applications in the realm of education.

Augmented reality
Augmented reality represents a groundbreaking technology that enriches our perception of the external world by seamlessly integrating location-aware systems and layered networked information into our daily encounters (6).AR interfaces can be classified into three categories: GPS-based, marker-based, and see-through-based (7).Leveraging the capabilities of mobile devices equipped with GPS and Wi-Fi, AR provides contextual information tailored to the user's location or augments existing information by recognizing markers such as QR codes.Real-time blending of virtual graphics and the physical environment can also be experienced through glasses or lenses.The educational potential of AR has been widely recognized, particularly in areas where direct observation or textual explanations are challenging.It proves invaluable in fields requiring continuous practice, experiential learning, or those associated with high costs and risks (6).As an illustrative example, the Virtuali-Tee developed by Cruscope offers an augmented reality T-shirt that enables students to explore the intricacies of the human body, akin to an anatomy lab experience (8).Another educational application of AR lies in simulation, bridging the gap between abstract visuals and tangible objects by connecting real-world context with virtual elements.In the medical field, numerous examples of AR technology have emerged.Notably, a research team at a Seoul hospital collaborated with university laboratories to develop an augmented reality-based spinal surgery platform.This innovative platform projects real-time images of pedicle screws onto the human body, facilitating spinal fixation procedures (9).Furthermore, this technology serves as the foundation for the development of an effective spinal surgery education program, enabling the implementation of practical training systems.In conclusion, augmented reality blurs the boundaries between the real and virtual worlds, offering transformative opportunities in education and beyond.Its ability to provide enhanced learning experiences and facilitate complex tasks underscores its immense potential for future applications.

Lifelog
A lifelog is a personal record of one's daily life in a varying amount of detail, for a variety of purposes.The record contains a comprehensive dataset of a human's activities.The data could be used to increase knowledge about how people live their lives (10).In recent years, some lifelog data has been automatically captured by wearable technology or mobile devices.The sub-field of computer vision that processes and analyses visual data captured by a wearable camera is called "egocentric vision" or egography (11).For example, Steve Mann was the first person to capture continuous physiological data along with a live first-person video from a wearable camera.His experiments with wearable computing and streaming video in the early 1980s led to the formation of Wearable Wireless Webcam (12).Using a wearable camera and wearable display, he invited others to see what he was looking at, as well as to send him live feeds or messages in real-time (13).In 1998 Mann started a community of lifeloggers which has grown to more than 20,000 members.In 1996, Jennifer Ringley started JenniCam, broadcasting photographs from a webcam in her college bedroom every 15 s; the site was turned off in 2003 (14).The lifelog DotComGuy ran throughout 2000, when Mitch Maddox lived the entire year without leaving his house (15).After Joi Ito's discussion of Moblogging, which involves web publishing from a mobile device (16), came Gordon Bell's MyLifeBits (17) In recent years, with the advent of smartphones and similar devices, lifelogging became much more accessible.For instance, UbiqLog (18) and Experience Explorer (19) employ mobile sensing to perform life logging, while other lifelogging devices, like the Autographer, use a combination of visual sensors and GPS tracking to simultaneously document one's location and what one can see.Lifelogging was popularized by the mobile app Foursquare, which had users "check in" as a way of sharing and saving their location; this later evolved into the popular lifelogging app, Swarm.

Mirror world
The mirror world represents a simulated version of the physical realm, characterized by an informationally enhanced virtual model or a "reflection" of reality.It serves as a metaverse where the real world's appearance, information, and structure are transferred into virtual reality, akin to the reflection seen in a mirror (20).However, it is more appropriate to describe these systems as enabling "efficient expansion" rather than mere reproductions of reality (21).In this virtual domain, all real-world activities can be conducted through internet platforms or mobile applications, offering convenience and efficiency to daily life (22).Notably, mirror world metaverses have found application in education through the creation of "digital laboratories" and "virtual educational spaces" across various mirror world platforms.In essence, the mirror world acts as a bridge between the tangible and intangible, enhancing our interaction with the world around us (23).
By seamlessly integrating the convenience of digital platforms with the richness of our physical surroundings, it opens up new possibilities for education and beyond (24).

Virtual reality
VR represents a metaverse that simulates the inner world, leveraging sophisticated 3D graphics, avatars, and instant communication tools (25).As users immerse themselves in this virtual realm, they experience a profound sense of presence.VR can be viewed as the opposite end of the spectrum from mixed reality and augmented reality.However, this technology relies on our eyes' working principle to present flat images in three dimensions.It also serves as an internet-based 3D space where multiple users can simultaneously access and participate by creating expressive avatars that reflect their true selves.VR offers an unparalleled opportunity to explore the intricacies of the human mind, enabling us to navigate the inner world like never before.By leveraging cutting-edge technologies, it opens up new vistas for communication, education, and entertainment, paving the way for a future where the boundaries between the real and virtual worlds continue to blur.
In this VR metaverse, the spatial configurations, cultural contexts, characters, and institutions are uniquely crafted, diverging from their real-world counterparts (26).Through user-controlled avatars, individuals navigate virtual spaces inhabited by AI characters, fostering interactions with fellow players and pursuing designated objectives.Narrowly construed, VR, also known as the metaverse, encompasses scenarios where physical actions, tactile sensations, and The application of metaverse in healthcare.
Wang et al.

Medical education
Transformation awaits medical education and training through the integration of AR and VR.With the ability to virtually immerse themselves in the human body, students gain comprehensive perspectives, enabling them to replicate real-life treatments (29).AR also offers hands-on learning opportunities by simulating patient and surgical interactions, empowering medical interns to envision and practice novel techniques (30).Furthermore, the development of more realistic experiences based on actual surgeries allows students to engage in surgery as if they were the surgeons themselves.This immersive approach to learning not only rewards success but also employs data analytics to target precision education.Traditional medical schools face resource limitations when it comes to practical surgical training due to the expenses associated with cadaver surgeries and their impact on students' tuition fees.However, incorporating VR in medical education enables trainees to undergo intensive surgical instruction within a simulated environment at a significantly reduced cost, surpassing mere knowledge transmission.Metaverse-based healthcare training necessitates additional technological advancements for advanced hand skills and interactions.For instance, surgical interventions require precise mastery of human anatomy and dexterity in handling equipment, which can be facilitated through appropriate tracking devices or software.Leveraging technology in the metaverse can also aid in complex surgical procedures as doctors strive for higher success rates.By utilizing data collected from a patient's digital twin, doctors can estimate recovery periods, anticipate potential difficulties, and plan necessary therapies as part of a preventive strategy (21).Instructors play a crucial role in providing high-quality data to support virtual programs that simulate on-site nursing competencies.Learners should feel no difference in clinical therapy when transitioning from the metaverse context to a real clinical field experience program.Such advancements hold significant promise for improving patient care in the long run.
Here are examples of AR and VR in the application of medical education (31-34). (

Cloud and edge computing
(1) Cloud Services: Cloud services are essential for supporting large-scale metaverse healthcare applications due to their scalability and flexibility.Providers like AWS, Google Cloud, and Microsoft Azure offer on-demand computing power and storage, enabling healthcare applications to scale resources based on demand.This scalability is crucial for handling peak usage times, such as during virtual training sessions or remote consultations.Cloud services also provide robust data storage solutions, ensuring the secure storage and easy accessibility of medical datasets, patient records, and simulation data.Advanced data management tools offered by cloud providers help organize, retrieve, and analyze data efficiently, facilitating improved decision-making and patient care.Additionally, utilizing cloud services can be more cost-effective than maintaining on-premises infrastructure, allowing healthcare organizations to reduce capital expenditure and only pay for the resources they use, making cloud computing a financially viable option for deploying VR/AR healthcare applications.(2) Edge Computing: Edge computing is pivotal for enhancing the performance of VR/AR applications in healthcare by bringing computing resources closer to the data source.This approach reduces latency, improving the responsiveness of time-sensitive medical applications and ensuring real-time processing for effective experiences like VR-based physical therapy sessions.Additionally, edge computing offloads processing tasks from central cloud servers to local edge devices, thereby enhancing overall performance and reducing the load on the network, particularly beneficial for real-time processing and high-speed data transfer in applications such as surgical simulations and diagnostic tools.Furthermore, processing data at the edge can enhance security and privacy by minimizing sensitive information transmitted over the network, reducing the risk of data breaches and safeguarding patient information.Additionally, implementing voice feedback provides auditory cues and confirmations, aiding users with visual impairments in their interactions and navigation within the applications.(2) Multi-Language Support: Offering multi-language support in metaverse healthcare applications is crucial for promoting inclusivity and global accessibility, enabling non-English speakers to benefit from the services.Users should have the option to select their preferred language from a comprehensive list during initial setup or within the application's settings.Localized content, which adapts to cultural nuances and regional medical terminology, ensures that information is relevant and understandable.In regions with multiple predominant languages, bilingual user interfaces allow seamless switching between languages, enhancing user experience.Additionally, incorporating voice recognition and synthesis capabilities for multiple languages enables users to interact through voice commands and receive auditory feedback in their native language, improving usability for those who may struggle with reading or typing in a non-native language.

Prospects
Over the next 5 years, we can expect significant developments in the application of the metaverse in healthcare.As technology continues to advance, the metaverse holds immense potential to revolutionize various aspects of healthcare delivery and patient care.We anticipate several key developments: (1) Enhanced Virtual Healthcare Experiences: The metaverse will enable the creation of immersive virtual environments where patients can receive healthcare services remotely.This includes virtual clinics, telemedicine consultations, and remote monitoring of vital signs and health data.( 2 Although the application of metaverse in healthcare holds promising prospects, there are several challenges that need to be addressed.These challenges include but are not limited to the following aspects: (1) Technological Maturity and Stability: Despite significant advancements in metaverse technology, there is still a need for more mature and stable technical support, especially in areas such as remote diagnosis, surgical simulation, and virtual therapy.Ensuring the stability and reliability of the metaverse platform is crucial to safeguarding patient safety and healthcare quality.(2) Data Privacy and Security: As the use of metaverse in healthcare increases, there are higher requirements for the privacy and security of patients' health data.Strict data protection measures and access control mechanisms need to be established to prevent unauthorized access and misuse of patient data, as well as encryption and protection of data transmission and storage processes.(3) User Experience and Accessibility: Achieving widespread adoption of metaverse in healthcare requires consideration of user experience and accessibility issues.It is essential to ensure that the metaverse platform has a user-friendly interface, simple operation, and provide training and support services to help healthcare professionals and patients quickly adapt to new workflows and communication methods.(4) Legal Regulations and Regulatory Policies: With the continuous expansion of metaverse applications in healthcare, it is necessary to establish corresponding legal regulations and regulatory policies to regulate the use and operation of metaverse platforms.This includes the formulation and enforcement of laws on data privacy protection, standards for medical virtual reality technology, and regulations on medical device supervision.(5) Cost and Resource Investment: The application of metaverse requires substantial financial and resource investment, involving hardware equipment, software development, talent training, and other aspects.When healthcare institutions and enterprises consider adopting metaverse technology, they need to comprehensively consider cost-effectiveness, long-term benefits, as well as compatibility and integration with existing medical systems.
In conclusion, while the application of metaverse in healthcare offers vast prospects, overcoming numerous challenges and obstacles is essential.Only through continuous innovation and collaboration can we fully leverage the advantages of metaverse technology to achieve transformation and progress in the healthcare field.

FIGURE 1
FIGURE 1 , an experiment in digital 10.3389/fpubh.2024.1420367Frontiers in Public Health 04 frontiersin.orgroutine economic activities unfold within the virtual realm (27).For instance, Zepeto and Roblox exemplify VR platform.Zepeto, a recently introduced 3D avatar-based interactive service, and Roblox, a versatile platform enabling user-generated virtual worlds and games, epitomize this evolving landscape.Zepeto, an augmented reality avatar service under Naver Z, stands as a prominent metaverse platform in Korea, leveraging facial recognition, augmented reality, and 3D technology to facilitate user communication and diverse virtual experiences since its launch in 2018.Notably, Roblox, featuring the use of virtual currency and a fully realized economic ecosystem.Its hallmark lies in users' ability to construct and partake in self-authored VR games using Lego-shaped avatars or to immerse themselves in experiences crafted by others.When capturing or uploading an image on a smartphone, AI technology generates a character resembling the user, allowing for extensive customization of skin tone, facial features, height, expression, gestures, and fashion preferences (28).This interactive experience incorporates social networking service (SNS) functionalities, facilitating user connections to follow others and engage in text or voice-based communication.Within this VR framework, diverse activities, including gaming and educational roleplaying, can be seamlessly conducted across multiple maps.For instance, educators can opt for a classroom map, create a virtual room, invite students, and foster interactive exchanges through voice or messaging within the designated classroom environment.
Gbps to support the seamless streaming and downloading of large medical datasets, high-resolution 3D models, and real-time video feeds.In remote consultations, high-speed internet ensures uninterrupted communication with clear audio and video quality for both healthcare providers and patients, contributing to stable and reliable connectivity critical for maintaining the effectiveness of VR/AR-based medical applications during critical procedures and training sessions.(2) Low Latency Networks: Low latency networks are crucial for smooth and responsive real-time VR/AR applications in healthcare.The emergence of 5G technology has significantly reduced network latency, offering ultra-low latency as low as 1 millisecond.This low latency is especially important in healthcare scenarios like remote surgery, where real-time feedback and precise control are critical.Surgeons using VR equipment to perform procedures remotely can rely on the quick response time provided by 5G networks to make accurate and timely movements, minimizing the risk of errors.Additionally, low latency networks enhance the overall user experience by ensuring that VR/AR interactions are seamless and responsive, particularly in immersive training simulations where delays can disrupt the learning process and reduce the realism of the experience.
and complex surgical simulations.The HTC Vive offers a wide field of view and high precision in motion tracking, making it suitable for applications that require accurate representation of movements, such as physical therapy training and interactive diagnostic procedures.The Valve Index, with its advanced display technology and finger-tracking capabilities, is ideal for (1) High-Speed Internet: Reliable high-speed internet is a fundamental necessity for VR/AR applications in healthcare, enabling quick and efficient data transmission.Fiber optic connections deliver the required bandwidth, offering speeds exceeding 1 ) Training and Education: Healthcare professionals will increasingly use the metaverse for training simulations, medical education, and skill development.VR and AR technologies will provide realistic training scenarios and hands-on experiences for medical students, nurses, and other healthcare professionals.(3)VirtualTherapy and Rehabilitation: The metaverse will play a significant role in mental health treatment and physical rehabilitation.Virtual reality therapy will offer immersive environments for exposure therapy, relaxation exercises, and cognitive-behavioral interventions.Additionally, virtual rehabilitation programs will assist patients in recovering from injuries or surgeries through interactive exercises and simulations.(4)CollaborativeHealthcare Platforms: The metaverse will facilitate collaboration among healthcare providers, researchers, and patients.Virtual meeting spaces and collaborative platforms will enable multidisciplinary teams to discuss cases, share knowledge, and collaborate on research projects regardless of geographic location.(5)Personalized Healthcare Solutions: With advances in AI and data analytics, the metaverse will support personalized healthcare solutions tailored to individual patient needs.AI-powered virtual assistants will provide personalized health recommendations, medication reminders, and lifestyle coaching based on real-time health data and patient preferences.Overall, the metaverse holds immense promise for transforming healthcare delivery, improving patient outcomes, and advancing medical research.However, challenges such as data privacy, security, and accessibility must be addressed to realize the full potential of this technology in healthcare.