Advancements in biophotonics have driven the development of miniaturized imaging probes for high-resolution in vivo imaging. Probe-based confocal laser endomicroscopy (pCLE) enables cellular-level visualization of tissues but remains challenging for retinal imaging due to the need for non-contact operation, tremor compensation, and precise focal control. This study introduces a novel handheld confocal endomi-croscope system that integrates a custom-built imaging probe, an optical coherence tomography (OCT) distance sensor, and motor-assisted tremor suppression to improve imaging stability and resolution. The system employs a fiber-based common-path swept-source OCT (CPSS-OCT) sensor to maintain a stable focal distance while compensating for involuntary hand tremors using motorized stabilization. A gated recurrent unit (GRU)-based tremor prediction algorithm further enhances image stability. The imaging probe features a PZT tube-driven fiber cantilever resonance for Lissajous scanning, providing a wide field of view with minimal image distortion. In experiments using bovine eye samples, the CR score improved from 0.318 to 0.472, with a 48.43% increase in the in-focus condition when tremor compensation was activated, confirming enhanced image clarity and stability. Experimental results demonstrate that the system effectively stabilizes imaging, reduces motion artifacts, and ensures high-resolution, non-contact retinal imaging. By addressing the limitations of conventional pCLE devices, this system represents a significant advancement in ophthalmic imaging and can potentially improve retinal diagnostics and precision-guided interventions.

This paper proposes a novel form of a three-dimensional coaxial bowtie-shaped mechanical amplifier. The proposed model incorporates a lever mechanism into the Sarrus linkage structure. It allows the target plate to move along one axis with amplified displacement in a parallel manner. The amplifier was assembled after machining the components using a computer numerical control machine. A flexible hinge was incorporated into the amplifier design for simplified fabrication and reduced friction in the actuation mechanism. Castigliano’s theorem is used to build a mathematical model of the proposed mechanical amplifier, and the performance was validated through finite element analysis and prototype fabrication. We achieved the amplification ratio of ×8.44, resulting in the axial displacement up to 86 µm. The demonstrated amplifier is expected to apply to compact microsurgical robots or biomedical imaging apparatus requiring coaxial displacement amplification in confined spaces.

In minimally invasive pain management procedures, precise needle positioning is paramount for effective treatment and patient safety. Traditional techniques like the loss-of-resistance (LOR) method may be insufficient, especially in patients with narrowed epidural spaces. The use of imaging tools such as C-arms carries risks due to radiation exposure for medical professionals. A new system for detecting the epidural space based on optical interferometry is proposed to tackle this issue. Prior research has focused on force measurement systems to identify tissue puncture or rupture. Although mechanical sensors have been utilized, they add bulk and complexity to systems. Optical sensors like Fiber Bragg grating (FBG) and Fabry-Pérot interferometer (FPI) offer stable, high-resolution measurements suitable for complex biological tissues. This study aims to develop a sensor and needle system for epidural injections, incorporating quantitative metrics for validation. An optical interferometer-based force measurement sensor was integrated into a commercial epidural needle, and calibration was performed to establish a correlation between system output and actual force. The system employs a graphical user interface (GUI) to identify puncture points based on abrupt force decreases. A user study involving interventionalists assessed the system’s performance by measuring invasive depth and success rates. The user study demonstrated that the proposed sensorized system could detect the puncture with an average success rate of 72.63 %. This study represents a significant advancement toward safer and more precise epidural procedures, addressing critical clinical considerations for practical applications.

Diseases affecting the retina, such as retinal detachment, diabetic retinopathy, and macular degeneration, are significant contributors to blindness globally, with a substantial risk of vision loss among those afflicted. Surgical treatment of these conditions is complex due to the delicate nature of retinal tissue and the challenges posed by involuntary hand movements. While existing methods aim to compensate for hand tremors using sensor-based systems, they are hindered by limitations in accurately tracking retinal surface movement during surgery, particularly in response to patient movements under anesthesia. To address these issues, this study proposes a novel handheld micro-surgical tool equipped with a 1-degree of freedom (DOF) mechanism and a 3-axis Hall sensor to mitigate physiological hand tremors effectively. By utilizing magnetic flux density measurements, the tool can pinpoint the position of a magnet embedded within the surgical instrument, enabling precise tremor compensation without reliance on a global coordinate system. The design incorporates a piezoelectric (PZT) linear actuator and a Hall sensor for compactness and sensitivity. Optimization of the magnet’s dimensions through simulation ensures optimal sensor performance. Experimental validation using artificial and ex-vivo porcine eye models demonstrates the tool’s effectiveness in reducing hand tremors, suggesting potential enhancements in the safety and accuracy of retinal surgeries. For the desired positions from 4000 µm to 1000 µm, the RMS error of the synthetic eye model and porcine eye decreased from 71.10 µm to 33.27 µm and 71.36 µm to 33.39 µm, respectively.