Real-Time Volumetric Imaging of Vitreoretinal Surgery with a Prototype Microscope-Integrated Swept-Source OCT Device

Artificial Intelligence, Digital Imaging, and Robotics Technologies for Surgical Vitreoretinal Diseases

OBJECTIVE

To review recent technological advancement in imaging, surgical visualization, robotics technology, and the use of artificial intelligence in surgical vitreoretinal (VR) diseases.

BACKGROUND

Technological advancements in imaging enhance both preoperative and intraoperative management of surgical VR diseases. Widefield imaging in fundal photography and OCT can improve assessment of peripheral retinal disorders such as retinal detachments, degeneration, and tumors. OCT angiography provides a rapid and noninvasive imaging of the retinal and choroidal vasculature. Surgical visualization has also improved with intraoperative OCT providing a detailed real-time assessment of retinal layers to guide surgical decisions. Heads-up display and head-mounted display utilize 3-dimensional technology to provide surgeons with enhanced visual guidance and improved ergonomics during surgery. Intraocular robotics technology allows for greater surgical precision and is shown to be useful in retinal vein cannulation and subretinal drug delivery. In addition, deep learning techniques leverage on diverse data including widefield retinal photography and OCT for better predictive accuracy in classification, segmentation, and prognostication of many surgical VR diseases.

CONCLUSION

This review article summarized the latest updates in these areas and highlights the importance of continuous innovation and improvement in technology within the field. These advancements have the potential to reshape management of surgical VR diseases in the very near future and to ultimately improve patient care.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparing Three-Dimensional Digitally Enabled Intraoperative OCT With Conventional Microscope-Integrated OCT in Vitreoretinal Surgery: A Post Hoc Analysis of the Discover Study

BACKGROUND AND OBJECTIVE

This study compared the surgeon experience between conventional microscope-integrated intraoperative optical coherence tomography (iOCT) and digitally enabled microscope-integrated iOCT in vitreoretinal surgery.

PATIENTS AND METHODS

This is a post hoc case-control analysis of the DISCOVER study. Conventional microscope-integrated iOCT (Rescan 700, Zeiss) was compared with digitally enabled iOCT (Artevo 800, Zeiss). Compared variables included surgical field-based visualization (ie, ocular heads-up display in the conventional group; three-dimensional screen-based visualization in the digital iOCT group) and non-surgical field-based visualization (ie, review on the external two-dimensional monitor).

RESULTS

A total of 200 patients were included. Surgical field-based visualization of iOCT was significantly higher in the digitally enabled group (P < 0.0001). Required endoillumination level was significantly lower in the digital iOCT group (P < 0.0001). Surgeons reported "significant" back discomfort and headache more frequently when using conventional iOCT (P = 0.003 and P = 0.001, respectively).

CONCLUSIONS

Digitally enabled iOCT resulted in greater surgical visualization efficiency, appeared to require a lower illumination level, and may provide advantages for ergonomic-related discomfort. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Microsurgery Robots: Applications, Design, and Development

Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.

The Role of the Intraoperative Optical Coherence Tomography for Vitreoretinal Surgery in a Real-Life Setting

BACKGROUND

To descriptively report the advantages and the feasibility of microscope-integrated intraoperative optical coherence tomography (i-OCT) in managing different vitreoretinal diseases in a real-life setting.

METHODS

We conducted an observational retrospective study involving 265 eyes that underwent elective retinal surgery and intraoperative OCT between 1 September 2018 and 1 October 2022 at Eyecare Clinic (Brescia, Italy).

RESULTS

52 epiretinal membranes, 30 retinal detachments, 60 high myopic eyes, 30 choroidal transplants, 40 macular holes, and 32 vitreo-proliferative retinopathies underwent vitreoretinal surgery and intraoperative OCT scans. The i-OCT was a useful diagnostic exam for all cases and significantly influenced our surgical management.

CONCLUSIONS

i-OCT is a helpful surgical tool in ophthalmic surgery as it provides real-time feedback of tissue anatomy to surgeons, thereby guiding decision-making. Moreover, it provides additional information on the microarchitectural changes after instrument-tissue interactions, further guiding procedures when necessary and possibly reducing unessential surgical maneuvers.

NOVEL METHOD FOR VISUALIZING PERIPHERAL RETINAL STRUCTURES WITH MICROSCOPE-INTEGRATED OPTICAL COHERENCE TOMOGRAPHY

BACKGROUND/PURPOSE

Visualization of peripheral retinal structures with optical coherence tomography (OCT) can be challenging but can offer valuable clinical information. We describe a method for intraoperative OCT of the peripheral retina.

METHODS

An investigational microscope-integrated OCT system with real-time 4D volumetric imaging was used in conjunction with a Goldmann style mirrored contact lens intraoperatively to capture peripheral images in three patients.

RESULTS

We identified retinoschisis, a retinal break, and areas of focal retinal detachment using our peripheral OCT method.

CONCLUSION

Use of a Goldmann lens in conjunction with intraoperative OCT offers surgeons the ability to resolve peripheral pathology that cannot be easily evaluated with OCT otherwise.

Methods for real-time feature-guided image fusion of intrasurgical volumetric optical coherence tomography with digital microscopy

4D-microscope-integrated optical coherence tomography (4D-MIOCT) is an emergent multimodal imaging technology in which live volumetric OCT (4D-OCT) is implemented in tandem with standard stereo color microscopy. 4D-OCT provides ophthalmic surgeons with many useful visual cues not available in standard microscopy; however it is challenging for the surgeon to effectively integrate cues from simultaneous-but-separate imaging in real-time. In this work, we demonstrate progress towards solving this challenge via the fusion of data from each modality guided by segmented 3D features. In this way, a more readily interpretable visualization that combines and registers important cues from both modalities is presented to the surgeon.

Theoretical error analysis of spotlight-based instrument localization for retinal surgery

Retinal surgery is widely considered to be a complicated and challenging task even for specialists. Image-guided robot-assisted intervention is among the novel and promising solutions that may enhance human capabilities therein. In this paper, we demonstrate the possibility of using spotlights for 5D guidance of a microsurgical instrument. The theoretical basis of the localization for the instrument based on the projection of a single spotlight is analyzed to deduce the position and orientation of the spotlight source. The usage of multiple spotlights is also proposed to check the possibility of further improvements for the performance boundaries. The proposed method is verified within a high-fidelity simulation environment using the 3D creation suite Blender. Experimental results show that the average positioning error is 0.029 mm using a single spotlight and 0.025 mm with three spotlights, respectively, while the rotational errors are 0.124 and 0.101, which shows the application to be promising in instrument localization for retinal surgery.

Robotic Assistance for Intraocular Microsurgery: Challenges and Perspectives

Intraocular surgery, one of the most challenging discipline of microsurgery, requires sensory and motor skills at the limits of human physiological capabilities combined with tremendously difficult requirements for accuracy and steadiness. Nowadays, robotics combined with advanced imaging has opened conspicuous and significant directions in advancing the field of intraocular microsurgery. Having patient treatment with greater safety and efficiency as the final goal, similar to other medical applications, robotics has a real potential to fundamentally change microsurgery by combining human strengths with computer and sensor-based technology in an information-driven environment. Still in its early stages, robotic assistance for intraocular microsurgery has been accepted with precaution in the operating room and successfully tested in a limited number of clinical trials. However, owing to its demonstrated capabilities including hand tremor reduction, haptic feedback, steadiness, enhanced dexterity, micrometer-scale accuracy, and others, microsurgery robotics has evolved as a very promising trend in advancing retinal surgery. This paper will analyze the advances in retinal robotic microsurgery, its current drawbacks and limitations, as well as the possible new directions to expand retinal microsurgery to techniques currently beyond human boundaries or infeasible without robotics.

Clinical applications for intraoperative optical coherence tomography: a systematic review

In this systematic review, we provide an overview of the current state of intraoperative optical coherence tomography (iOCT). As iOCT technology is increasingly utilized, its current clinical applications and potential uses warrant attention. Here, we categorize the findings of various studies by their respective fields, including the use of iOCT in vitreoretinal surgery, corneal surgery, glaucoma surgery, cataract surgery, and pediatric ophthalmology. The trend observed in recent decades towards performing minimally invasive ophthalmic surgery has caused practitioners to recognize the limitations of using a conventional surgical microscope for intraoperative visualization. Thus, the superior visualization provided by iOCT can improve the safety of these surgical techniques and promote the development of new minimally invasive ophthalmic surgeries. Landmark prospective studies found that iOCT can significantly affect surgical decision making and can cause a subsequent change in surgical strategy, and the use of iOCT has potential to improve surgical outcome. Despite these advantages, however, iOCT is still a relatively new technique, and beginning users of iOCT can encounter limitations that can preclude their reaching the full potential of iOCT and in this respect several improvements are needed.

Development, Validation, and Innovation in Ophthalmic Laser-Based Imaging: Report From a US Food and Drug Administration-Cosponsored Forum

In April 2019, the US Food and Drug Administration, in conjunction with 11 professional ophthalmic, vision science, and optometric societies, convened a forum on laser-based imaging. The forum brought together the Food and Drug Administration, clinicians, researchers, industry members, and other stakeholders to stimulate innovation and ensure that patients in the US are the first in the world to have access to high-quality, safe, and effective medical devices. This conference focused on the technology, clinical applications, regulatory issues, and reimbursement issues surrounding innovative ocular imaging modalities. Furthermore, the emerging role of artificial intelligence in ophthalmic imaging was reviewed. This article summarizes the presentations, discussion, and future directions.

Microscope integrated optical coherence tomography system combined with augmented reality

One of the disadvantages in microscope-integrated optical coherence tomography (MI-OCT) systems is that medical images acquired via different modalities are usually displayed independently. Hence, surgeons have to match two-dimensional and three-dimensional images of the same operative region subjectively. In this paper, we propose a simple registration method to overcome this problem by using guided laser points. This method combines augmented reality with an existing MI-OCT system. The basis of our idea is to introduce a guiding laser into the system, which allows us to identify fiducials in microscopic images. At first, the applied voltages of the scanning galvanometer mirror are used to calculate the fiducials' coordinates in an OCT model. After gathering data at the corresponding points' coordinates, the homography matrix and camera parameters are used to superimpose a reconstructed model on microscopic images. After performing experiments with artificial and animal eyes, we successfully obtain two-dimensional microscopic images of scanning regions with depth information. Moreover, the registration error is 0.04 mm, which is within the limits of medical and surgical errors. Our proposed method could have many potential applications in ophthalmic procedures.

[Biomarkers in full-thickness and lamellar defects of the macula]

BACKGROUND

Biomarkers are characteristic biological measurable signs and objective parameters to detect the state of health. Besides functional and temporal factors, imaging biomarkers play an increasingly important role. In full-thickness and lamellar defects of the macula numerous imaging parameters have been described. This knowledge resulted in new classifications for both clinical pictures, which are based on important biomarkers of these clinical pictures and characteristic features of described subtypes.

METHODS

Imaging biomarkers for full-thickness and lamellar macular defects are described with respect to the classification and their functional prognostic importance. The importance of these biomarkers is presented.

RESULTS

The current classification of full-thickness and lamellar macular defects is based on structural biomarkers. Biomarkers are important for prognostic and therapeutic evaluation and they have an impact on the surgical strategy. There are various surgical strategies for treatment of full-thickness macular holes depending on the size of the foramen and other biomarkers. The inverted ILM flap technique improves the closure rate of large macular holes. In lamellar macular holes showing signs of progression an early surgical intervention results in a good anatomical and functional prognosis.

CONCLUSION

Multimodal diagnostics provide important preoperative, intraoperative, and postoperative features for macular holes and lamellar macular holes, which are essential biomarkers for the exact classification, the therapeutic strategy and for assessment of the prognosis.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.