Force-based Control for Safe Robot-assisted Retinal Interventions: Evaluation in Animal Studies.

In recent years, robotic assistance in vitreoretinal surgery has moved from a benchtop environment to the operating rooms. Emerging robotic systems improve tool manoeuvrability and provide precise tool motions in a constrained intraocular environment and reduce/remove hand tremor. However, often due to their stiff and bulky mechanical structure, they diminish the perception of tool-to-sclera (scleral) forces, on which the surgeon relies, for eyeball manipulation.

Post-discharge follow-up of patients with COVID-19: A Brazilian experience.

Objective: The objective of this study is to evaluate post-acute symptoms in patients with confirmed severe and critical coronavirus disease 2019 infections.

Methods: We evaluated patients with confirmed severe and critical coronavirus disease 2019 infections. Post-acute symptoms were defined as symptoms persisting 4 weeks after the onset of the symptoms and classified as pulmonary, muscular, hematologic, neuropsychiatric, renal, and dermatological.

Force-based Safe Vein Cannulation in Robot-assisted Retinal Surgery: A Preliminary Study.

Retinal vein cannulation (RVC) is a potential treatment for retinal vein occlusion (RVO). Manual surgery has limitations in RVC due to extremely small vessels and instruments involved, as well as the presence of physiological hand tremor. Robot-assisted retinal surgery may be a better approach to smooth and accurate instrument manipulation during this procedure.

Force and Velocity Based Puncture Detection in Robot Assisted Retinal Vein Cannulation: In-Vivo Study.

Objective: Retinal vein cannulation is a technically demanding surgical procedure and its feasibility may rely on using advanced surgical robots equipped with force-sensing microneedles. Reliable detection of the moment of venous puncture is important, to either alert or prevent the clinician from double puncturing the vessel and damaging the retinal surface beneath. This paper reports the first in-vivo retinal vein cannulation trial on rabbit eyes, using sensorized metal needles, and investigates puncture detection.

FBG-based Kalman Filtering and Control of Tool Insertion Depth For Safe Robot-assisted Vitrectomy.

Vitrectomy is that portion of retinal surgery in which the vitreous gel is removed either as a definitive treatment or to provide direct tool access to the retina. This procedure should be conducted prior to several eye surgeries in order to provide better access to the eyeball posterior. It is a relatively repeatable and straight forward procedure that lends itself to robotic assistance or potentially autonomous performance if tool contact with critical structures can be avoided.

An Optimized Tilt Mechanism for a New Steady-Hand Eye Robot.

Robot-assisted vitreoretinal surgery can filter surgeons' hand tremors and provide safe, accurate tool manipulation. In this paper, we report the design, optimization, and evaluation of a novel tilt mechanism for a new Steady-Hand Eye Robot (SHER). The new tilt mechanism features a four-bar linkage design and has a compact structure.

Adaptive Control Improves Sclera Force Safety in Robot-Assisted Eye Surgery: A Clinical Study.

The integration of robotics into retinal microsurgery leads to a reduction in surgeon perception of tool-to-tissue interaction forces. This blunting of human tactile sensory input, which is due to the inflexible mass and large inertia of the robotic arm as compared to the milli-Newton scale of the interaction forces and fragile tissues during ophthalmic surgery, identifies a potential iatrogenic risk during robotic eye surgery. In this paper, we aim to evaluate two variants of an adaptive force control scheme implemented on the Steady-Hand Eye Robot (SHER) that are intended to mitigate the risk of unsafe scleral forces.

Towards Bimanual Vein Cannulation: Preliminary Study of a Bimanual Robotic System With a Dual Force Constraint Controller.

Retinal vein cannulation is a promising approach for treating retinal vein occlusion that involves injecting medicine into the occluded vessel to dissolve the clot. The approach remains largely unexploited clinically due to surgeon limitations in detecting interaction forces between surgical tools and retinal tissue. In this paper, a dual force constraint controller for robot-assisted retinal surgery was presented to keep the tool-to-vessel forces and tool-to-sclera forces below prescribed thresholds.

Scleral Force Evaluation During Vitreoretinal Surgery: in an In Vivo Rabbit Eye Model.

During vitreoretinal surgery, the surgeon is required to precisely manipulate multiple tools in a confined intraocular environment, while the tool tip to retina contact forces are at the limit of human sensation limits. During typical vitrectomy procedures, the surgeon inserts various tools through small incisions performed on the sclera of the eye (sclerotomies), and manipulates them to perform surgical tasks. During intraocular procedures, tool-tissue interactions occur at the sclerotomy ports and at the tool-tip when it contacts retina.

A Comparison of Manual and Robot Assisted Retinal Vein Cannulation in Chicken Chorioallantoic Membrane.

Retinal vein occlusion (RVO) is a vision threatening condition occurring in the central or the branch retinal veins. Risk factors include but are not limited to hypercoagulability, thrombus or other cause of low blood flow. Current clinically proven treatment options limit complications of vein occlusion without treating the causative occlusion.

Robotic Retinal Surgery Impacts on Scleral Forces: In Vivo Study.

Purpose: This study aims to map force interaction between instrument and sclera of in vivo rabbits during retinal procedures, and verify if a robotic active force control could prevent unwanted increase of forces on the sclera.

Methods: Experiments consisted in the performance of intraocular movements of a force sensing instrument, adjacent to the retinal surface, in radial directions, from the center to the periphery and back, and compared manual manipulations with robotic assistance and also robotic assistance with an active force control. This protocol was approved by the Animal Use and Ethical Committee and experiments were according to ARVO Statement of Animal Use.

Towards securing the sclera against patient involuntary head movement in robotic retinal surgery.

Retinal surgery involves manipulating very delicate tissues within the confined area of eyeball. In such demanding practices, patient involuntary head movement might abruptly raise tool-to-eyeball interaction forces which would be detrimental to eye. This study is aimed at implementing different force control strategies and evaluating how they contribute to attaining sclera force safety while patient head drift is present.

Sclera Force Evaluation During Vitreoretinal Surgeries in Ex Vivo Porcine Eye Model.

Vitreoretinal surgery is among the most challenging microsurgical procedures as it requires precise tool manipulation in a constrained environment, while the tool-tissue interaction forces are at the human perception limits. While tool tip forces are certainly important, the scleral forces at the tool insertion ports are also important. Clinicians often rely on these forces to manipulate the eyeball position during surgery.

Autonomously Navigating a Surgical Tool Inside the Eye by Learning from Demonstration.

A fundamental challenge in retinal surgery is safely navigating a surgical tool to a desired goal position on the retinal surface while avoiding damage to surrounding tissues, a procedure that typically requires tens-of-microns accuracy. In practice, the surgeon relies on depth-estimation skills to localize the tool-tip with respect to the retina in order to perform the tool-navigation task, which can be prone to human error. To alleviate such uncertainty, prior work has introduced ways to assist the surgeon by estimating the tool-tip distance to the retina and providing haptic or auditory feedback.

Artificial intelligence, robotics and eye surgery: are we overfitted?

Eye surgery, specifically retinal micro-surgery involves sensory and motor skill that approaches human boundaries and physiological limits for steadiness, accuracy, and the ability to detect the small forces involved. Despite assumptions as to the benefit of robots in surgery and also despite great development effort, numerous challenges to the full development and adoption of robotic assistance in surgical ophthalmology, remain. Historically, the first in-human-robot-assisted retinal surgery occurred nearly 30 years after the first experimental papers on the subject.

Pilot Study Comparing Topical Anesthetic Agents in Pterygium Surgery: Subconjunctival Injection Versus 2% Lidocaine Gel Versus 5% Lidocaine Gel.

Purpose: To compare the efficacy of different concentrations of topical lidocaine gel with standard subconjunctival anesthesia.

Methods: This was a prospective randomized controlled pilot study with 3 different groups. Group SC received subconjunctival lidocaine and proparacaine drops as needed during surgery.

Diabetes induces changes in neuroretina before retinal vessels: a spectral-domain optical coherence tomography study.

Purpose: To investigate retinal changes prior to vascular signs in patients with type 2 diabetes without diabetic retinopathy or with mild non proliferative diabetic retinopathy.

Methods: A cross-sectional study was performed in three groups: patients without diabetes, patients with type 2 diabetes without diabetic retinopathy, and patients with diabetes with mild diabetic retinopathy. Analysis of retinal layers was performed objectively with the Cirrus Review Software 6.

Development of an experimental model of proliferative retinopathy by intravitreal injection of VEGF165.

Purpose: To develop an experimental model of proliferative retinopathy by intravitreal injection of vascular endothelial growth factor 165 (VEGF165) in pigmented rabbits.

Methods: A prospective, controlled, comparative intervention study. Six pigmented rabbits (Chinchilla breed) were subjected to intravitreal injection of VEGF165 in their right eye.