The team, led by Farzad Abaszadeh of Kerman University of Medical Sciences and colleagues at Shiraz University of Medical Sciences in Iran, deliberately narrowed their focus in a way previous reviews had not. Earlier syntheses had lumped together desktop simulations, semi-immersive projection systems, augmented reality overlays, and fully immersive head-mounted displays, muddying the picture for educators deciding what to buy and how to deploy it. This review accepted only studies using head-mounted displays such as the Oculus Rift, HTC Vive, or Meta Quest, where the learner’s entire visual field is replaced by a computer-generated environment, and only where students actively practiced psychomotor skills rather than passively watching 360-degree videos. The search window began in January 2014, capturing the modern era of consumer-accessible high-fidelity headsets that started with the Oculus Rift DK2.

The technical distinction matters because immersion changes the learning mechanism. Fully immersive systems use stereoscopic visualization, head tracking, and motion-based hand interactions to generate a sense of presence, the subjective feeling of being physically situated inside the virtual environment, together with embodied interaction that approximates real clinical performance. That heightened realism theoretically supports deliberate practice, immediate feedback, and repeated exposure to rare or high-risk scenarios, all pillars of mastery-based education. Yet the review’s authors argued that evidence from older, non-immersive platforms cannot simply be assumed to transfer to these newer systems, which is precisely why they applied the GRADE framework to grade how much confidence the evidence actually deserves.

After screening 2,847 records from five databases plus grey literature, the reviewers included 19 randomized controlled trials and 12 observational studies published between 2016 and 2024 across Europe, North America, Asia, and Australia. Sample sizes ranged from 12 to 529 participants, with a median of 56. The studies fell into four clinical domains: emergency and urgent care procedures, diagnostic and physical examination skills, surgical and technical skills, and imaging and procedural guidance. So much clinical and methodological heterogeneity existed across hardware, instructional design, comparators, and outcome measures that the team could not pool results statistically and instead performed a narrative synthesis guided by the SWiM reporting guideline.

The strongest and most consistent evidence emerged from an unexpected quarter: imaging and procedural guidance. All four studies in this domain were randomized controlled trials, covering point-of-care ultrasound, ultrasound-guided vascular access, and arterial blood gas collection, and they consistently showed immersive VR was non-inferior or superior to conventional instruction. The greatest benefits appeared in tasks demanding spatial understanding, image interpretation, and coordination of psychomotor actions, where immersive three-dimensional visualization of anatomy seemed to accelerate learning. One high-quality trial even demonstrated that self-directed VR training matched instructor-led ultrasound teaching while substantially reducing start-up costs, a finding with significant implications for scalability in resource-strapped medical schools.

Emergency and urgent care training also fared well, with 12 studies involving 1,560 students. Structured procedural tasks such as basic life support, pediatric respiratory assessment, and nasopharyngeal swab collection showed clear gains or equivalence with conventional training, and a dose-response trial suggested repeated VR sessions maintained emergency skills better than single or infrequent exposures. But a cautionary note came from a crossover study finding that the physical constraints of VR equipment reduced the quality of chest compressions during CPR, with compression depth and recoil suffering. The reviewers concluded that immersive VR should complement rather than replace mannequin-based training for procedures requiring precise physical force.

For diagnostic and physical examination skills, the evidence was largely observational, drawn from 10 studies and 745 students. VR showed promise for history taking, neurological assessment, and examinations in dermatology, ophthalmology, and gynecology, particularly because it can simulate uncommon pathological findings and allow safe, repeatable practice of sensitive or difficult-to-access examinations. However, greater immersion was associated with higher cognitive load and occasional simulator sickness, underscoring that instructional design and learner support are critical. In the surgical domain, five studies found VR equivalent but not superior to conventional instruction for basic suturing, with the volume of deliberate practice, rather than the instructional medium, emerging as the strongest predictor of skill acquisition.

The GRADE assessment laid bare the fragility of the evidence base. For immediate post-training skill performance, based on 23 studies and 2,420 participants, certainty was rated low because of serious risk of bias and imprecision. For skill retention, resting on just six studies and 380 participants, certainty was very low, leaving the long-term durability of VR-acquired skills an open question. Learner satisfaction was consistently high across 21 studies, yet subjective outcomes are notoriously susceptible to bias, so this too earned a very low certainty rating. Among the randomized trials, only four had low overall risk of bias, eleven raised some concerns, and four were judged high risk, with inadequate randomization reporting and unblinded outcome assessment the most common flaws.

Subgroup analyses sharpened the practical message. Highly interactive VR outperformed minimally interactive 360-degree video for objective skill gains, while passive video was better suited to observational learning and clinical communication. The largest benefits appeared when VR replaced passive e-learning or nothing at all; against active hands-on training with mannequins or standardized patients, VR was generally non-inferior rather than superior, suggesting its real advantages lie in accessibility, standardization, scalability, and cost rather than raw educational superiority. The authors recommend integrating immersive VR as a complement to conventional teaching, prioritizing it for skills that rely on spatial understanding and visual interpretation, building in repeated practice over time, and keeping faculty actively involved. Future research, they argue, needs adequately powered randomized trials with blinded assessment, follow-up beyond six months, studies of skill transfer to real patients, and formal economic evaluations before the metaverse can claim a permanent place in the medical curriculum.

Subject of Research: Effectiveness of fully immersive virtual reality for clinical skills training in undergraduate medical education

Article Title: Immersive virtual reality for practical clinical skills training in undergraduate medical education: a systematic review

Article References: Abaszadeh, F., Boldaji, M. R., Jahromi, S. A. F., Hayat, A. A., Zare, S., & Motahedi, M. (2026). Immersive virtual reality for practical clinical skills training in undergraduate medical education: a systematic review. Discover Education, 5(1), Article 801. https://doi.org/10.1007/s44217-026-02080-x

Image Credits: AI Generated

DOI: 10.1007/s44217-026-02080-x

Keywords: virtual reality, medical education, clinical skills, systematic review, head-mounted display, simulation, GRADE, undergraduate medical students, ultrasound training, emergency medicine, skill retention, immersive learning

The project, according to Shogo Fukushima, Associate Professor at Kyushu University’s Faculty of Information Science and Electrical Engineering, began with a very human complaint. One of his students, who spends more of his day inside virtual environments than outside them, found that the headset itself had become the main obstacle to long sessions. He would even try to sleep in VR, Fukushima recalls, but the headset made it impossible to get comfortable. That observation reframed the engineering problem. Rather than asking how to make head-mounted displays lighter or more ergonomic, the team asked a more radical question: what if nothing needed to be mounted on the head at all?

The question matters because the fundamental architecture of modern VR hardware works against comfort. Conventional headsets create a three-dimensional view by presenting slightly different images to each eye through displays and lenses positioned close to the face. To widen the field of view, raise the resolution, or increase processing power, engineers must add more hardware, and every added component translates directly into weight and pressure on the head and neck. Most consumer and professional VR devices are therefore designed with relatively short sessions in mind. That constraint limits how naturally VR can fit into everyday life, whether in workplaces, clinics, classrooms, or living rooms. Fukushima’s lab inverted the design philosophy: instead of shrinking the hardware onto the user, they moved it off the user entirely.

The technical heart of the system is a micromirror array, a device composed of many tiny mirrors that can direct different images toward each of the viewer’s eyes. By steering light precisely, the array reproduces the stereoscopic effect that headsets achieve with lenses and near-eye displays, but from a distance and without any contact with the user. The approach builds on aerial imaging optics, a technique that makes images appear to float in space rather than on a physical screen. Light rays from the display are redirected so that they appear to diverge from a point in mid-air, forming a real image that hovers beyond the apparatus. Viewers perceive depth and volume in empty space, with no screen surface visible anywhere in the optical path.

Aerial imaging optics as a principle has been explored before, but the Kyushu team pushed it further by assembling it into a working VR system that a person can sit in and look around. The optical module is mounted on a chair, and a built-in gyroscope tracks the chair’s rotation in real time. As users turn their bodies, the stereoscopic view rotates with them, allowing them to scan the virtual world naturally. Crucially, this happens without wearing a headset and without any calibration procedure; the sensing is tied to the chair rather than to the person, which removes a whole layer of setup friction that normally separates a curious newcomer from an immersive experience. The compact footprint of the setup also means that a convincing, theater-like virtual scene can be delivered within a relatively small physical space.

The implications for comfort are only the beginning. Fukushima notes that the system also has the potential to reduce VR sickness in the future. Cybersickness, the nausea and disorientation that many users experience in VR, is widely attributed to a mismatch between visual sensations and physical ones, such as when the eyes report motion that the inner ear does not confirm. Because the display no longer has to be constrained to something wearable, larger optical components and moving mechanisms can be incorporated more freely, Fukushima explains. That flexibility could enable new approaches to closing the gap between what the user sees and what the user’s body feels, attacking one of VR’s most persistent adoption barriers at the level of system design rather than software compensation.

Another quiet advantage of the mountless architecture lies in where the computation lives. In a conventional headset, image processing, tracking, and rendering hardware must all be packed into the device strapped to the face, competing for space, power, and thermal headroom with the optics. By moving image processing outside the wearable device, the Kyushu design frees the system from those constraints. Heavier, more power-hungry, and more capable electronics can sit in the chair or nearby, while the user experiences only light and empty air. For applications that demand hours of continuous use, from industrial training to clinical monitoring, that separation between the human and the machinery could prove decisive.

The research team is already looking beyond the laboratory. They are seeking industry partners to bring the technology into everyday life, and the range of envisioned applications is broad: in-car workspaces where a passenger could enter a virtual office during a long ride, interactive museum exhibits where visitors could step into a scene without hygiene concerns or fitting delays, remote-controlled construction machinery operated through immersive views, and disaster-response robots piloted by operators who need sustained, comfortable immersion. In each of these cases, the headset is not merely an inconvenience but a practical liability, whether because of weight, shared use, safety regulations, or the simple fact that a person cannot wear goggles indefinitely while performing real work.

Looking further ahead, Fukushima hopes to create something akin to Doraemon’s famous Anywhere Door, a portal through which two people could share the same immersive virtual scene. The reference is fitting for a system whose charm lies in its apparent magic: a user sits down, and a world opens in front of them with nothing worn and nothing touched. It is also a reminder of the lab’s underlying philosophy. As Fukushima puts it, the lab has always wanted to question what we take for granted in our routines, and technical skills are not the most important thing when it comes to imagining a different future. The team would welcome more people who want to challenge the way things are usually done.

Whether mountless VR becomes the next default or simply a powerful complement to head-mounted systems, the Kyushu prototype demonstrates that the goggled silhouette is not a law of nature. By rethinking the mounted assumption that has defined virtual reality since its inception, and by borrowing optical tricks that let images float freely in air, the researchers have shown that immersion can begin the moment a user takes a seat. For the students and professionals who live much of their lives in virtual spaces, and for the many more who have been deterred by the weight on their heads, that could be the most important development VR has seen in years.

Subject of Research: A headset-free virtual reality system using aerial imaging optics and a rotating chair

Article Title: How to head into VR without wearing a headset

Article References: How to head into VR without wearing a headset. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: virtual reality, aerial imaging optics, micromirror array, head-mounted display, Kyushu University, VR sickness, stereoscopic display, SIGGRAPH, human-computer interaction, remote operation, gyroscope tracking, immersive technology

The stakes could hardly be higher. In neurosurgery, millimetric margins separate eloquent cortex, major blood vessels and white matter tracts from tumour tissue, and prior studies have documented that inadvertent injury to eloquent cortical regions during tumour resection produces permanent neurological deficits in a substantial proportion of patients. Errors exceeding two to three millimetres significantly increase the risk of vascular injury, incomplete resection and neurological deterioration, while deep targets such as the basal ganglia, thalamic nuclei and brainstem demand sub-millimetre precision. In deep brain stimulation surgery, targeting deviations of just one to two millimetres can reduce clinical benefit and provoke stimulation-induced adverse effects. Against these requirements, the errors reported for AR/MR neurosurgical applications—translational errors ranging from 0.62 to 6.93 mm and angular errors from 1.32 to 6.80 degrees depending on hardware and registration method—are sobering.

The problem, the researchers argue, is that the conventional yardsticks of navigation accuracy are fundamentally static. Fiducial Registration Error (FRE), the root mean square distance between corresponding markers after registration, and Target Registration Error (TRE), which measures accuracy at anatomical positions not used in the registration, are both discrete-point measurements computed at a single moment. Neither can capture the dynamic degradation of registration quality during an operation, which can be driven by tracking system drift from thermal effects, electromagnetic interference and line-of-sight occlusions; by patient micro-movements despite rigid cranial fixation; and by brain shift—the displacement of brain tissue caused by cerebrospinal fluid drainage, gravity and tumour resection, which can exceed 10 millimetres. Intraoperative MRI and ultrasound can partially compensate, but these modalities are specialised, interrupt the surgical workflow and are not universally available.

RQI attacks this gap with a deliberately lightweight computer vision pipeline that runs entirely from the headset’s own camera feed. The experimental platform paired a Varjo XR-3 head-mounted display—offering 2880 by 2720 pixels per eye at a 90 Hz refresh rate—with six HTC Vive Lighthouse base stations providing sub-millimetre optical tracking. A ceramic skull phantom, dimensioned to match adult human skull morphometry, served as the anatomical reference, and its virtual counterpart was reconstructed from computed tomography segmentation at 0.5 mm voxel resolution, imported into Unreal Engine 5.0.3 and rendered as a semi-transparent cyan overlay. Spatial registration between the virtual and physical coordinate systems was anchored to a printed 2D ArUco fiducial marker, detected by the headset’s stereo cameras at 30 Hz to compute the six-degree-of-freedom transformation in real time.

The computation itself proceeds in five stages on each passthrough frame. After frame acquisition at 30 Hz and a resolution of 320 by 160 pixels, the skull region is segmented from the background by adaptive thresholding, and Canny edge detection extracts the contours of both the physical phantom and the virtual overlay. Because the virtual model is rendered in cyan—a hue absent from the bone-white phantom—each detected edge pixel can be classified by examining its neighbourhood in the original RGB frame, yielding separate binary maps of physical and virtual boundaries. For every pixel on the physical boundary, the minimum Euclidean distance to the nearest virtual boundary pixel is then computed using OpenCV’s distance transform. Finally, RQI is expressed as the percentage of physical boundary pixels whose displacement exceeds a proximity threshold: a perfectly registered system scores 0 percent, while progressive misregistration drives the value toward 100 percent. Higher RQI, in other words, means worse alignment.

Choosing that proximity threshold was a careful balancing act. A systematic sensitivity analysis across thresholds from 2 to 12 pixels showed that values below 4 pixels produced unstable readings inflated by sub-pixel edge localisation noise, while values above 8 pixels compressed the RQI distribution toward zero and made the metric insensitive to clinically relevant degradation. The selected threshold of 6 pixels—roughly 8 millimetres at the 40 cm working distance, where one pixel corresponds to approximately 1.3 mm—maximised the Pearson correlation with TRE and was independently supported by receiver operating characteristic analysis, discriminating acceptable from degraded registration with a Youden index of 0.87, sensitivity of 0.93 and specificity of 0.94. The authors candidly note that because the threshold was tuned on the same dataset used to characterise the metric, the values carry an optimistic bias and must be confirmed on independent data.

The validation results were striking. Across fifteen experimental trials and seventy-five viewing configurations, RQI correlated strongly with both established metrics: r = 0.89 with FRE (95% CI 0.69–0.96, p < 0.001) and r = 0.93 with TRE (95% CI 0.80–0.98, p < 0.001), the latter meaning that 87 percent of the variance in target accuracy was explained by the surface-wide pixel misalignment. Regression analysis quantified the relationship in practical terms: each 1 percent increase in RQI corresponded to a 0.195 mm increase in FRE and a 0.244 mm increase in TRE. Spearman rank correlations confirmed the relationship was monotonic across the full experimental range—crucial, because for intraoperative monitoring, detecting that registration quality has degraded matters more than knowing the absolute error. Mean FRE was 2.95 ± 0.48 mm and mean TRE 3.78 ± 0.57 mm, while mean RQI was 3.28 ± 1.37 percent.

Speed and usability were also put to the test, with encouraging results. The entire image analysis pipeline averaged about 10 milliseconds per frame on a CPU alongside the GPU-bound rendering, achieving real-time computation at 30 Hz with no dropped frames and no disruption to workflow. A linear mixed effects model across the 75 viewing configurations revealed that viewing angle significantly influenced RQI (p < 0.001, partial η² = 0.49): displacement was lowest at the frontal view and rose at oblique, lateral, posterior and contralateral perspectives, a geometrically predictable effect since errors perpendicular to the viewing axis project maximally. The authors suggest lateral views may serve as a more sensitive early warning of degradation, and that angle-dependent normalisation could improve alert specificity. Three board-certified neurosurgeons rated the system on the System Usability Scale at a mean of 79.0 ± 4.7, well above the acceptability threshold of 68.

The team is equally forthright about limitations. Validation was confined to a rigid phantom under controlled laboratory conditions and cannot account for brain shift, soft tissue deformation, pulsatile brain motion or variable illumination. A particularly important caveat is brain sag—the gravity-driven displacement of the brain after dural opening—which can migrate deep structures by several millimetres while the exposed cortical surface remains comparatively stable; a surface-based metric could then report acceptable alignment even as the true target drifts. The interpretability ranges offered in the study, with band boundaries at 2, 4 and 6 percent RQI, are explicitly exploratory research guidance rather than validated clinical decision boundaries, and the authors stress that RQI is not yet validated for intraoperative clinical decision-making. The most important next step, they write, is a dedicated experiment applying translations and rotations of predetermined magnitude to the registration transform to establish the metric’s sensitivity, linearity, repeatability and failure modes, followed by validation under clinical conditions and integration with intraoperative imaging.

Even so, the implications extend well beyond the cranial theatre. The authors point out that the absence of continuous, marker-free registration monitoring is equally pertinent to spinal navigation, where vertebral mobility between preoperative imaging and the operative position is a recognised source of drift, and where AR/MR guidance and robotic platforms are increasingly used for pedicle screw placement requiring sub-millimetre accuracy. A surface-based stability index computed on exposed bony landmarks could provide intraoperative feedback in those workflows too. If subsequent clinical studies confirm the promise of this proof of concept, the humble act of continuously comparing a cyan wireframe to the anatomy beneath it could become a quiet but essential guardian—watching, frame by frame, that the surgeon’s virtual map never silently stops matching the territory.

Subject of Research: A real-time metric for continuous monitoring of registration stability in mixed reality neurosurgical navigation

Article Title: A real-time metric for quantifying registration stability in mixed reality neurosurgical navigation

Article References: Fontana, C., De Notaris, M., Iaconetta, G., & Cappetti, N. (2026). A real-time metric for quantifying registration stability in mixed reality neurosurgical navigation. International Journal of Computer Assisted Radiology and Surgery. https://doi.org/10.1007/s11548-026-03792-z

Image Credits: AI Generated

DOI: 10.1007/s11548-026-03792-z

Keywords: mixed reality, neurosurgery, neuronavigation, registration accuracy, augmented reality, Registration Quality Index, target registration error, brain shift, head-mounted display, real-time monitoring, surgical navigation, real-time