Autonomous Positioning of Eye Surgical Robot Using the Tool Shadow and Kalman Filtering

Vitreoretinal surgery is one of the most difficult surgical operations, even for experienced surgeons. Thus, a master-slave eye surgical robot has been developed to assist the surgeon in safely performing vitreoretinal surgeries; however, in the master-slave control, the robotic positioning accuracy depends on the surgeon's coordination skills. This paper proposes a new method of autonomous robotic positioning using the shadow of the surgical instrument. First, the microscope image is segmented into three regions-namely, a micropipette, its shadow, and the eye ground-using a Gaussian mixture model (GMM). The tips of the micropipette and its shadow are then extracted from the contour lines of the segmented regions. The micropipette is then autonomously moved down to the simulated eye ground until the distance between the tips of micropipette and its shadow in the microscopic image reaches a predefined threshold. To handle possible occlusions, the tip of the shadow is estimated using a Kalman filter. Experiments to evaluate the robotic positioning accuracy in the vertical direction were performed. The results show that the autonomous positioning using the Kalman filter enhanced the accuracy of robotic positioning.

Diabetic Macular Edema: Emerging Strategies and Treatment Algorithms

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic patients, and its management is often a long process requiring frequent monitoring and therapeutic interventions. During the past several decades, numerous treatments have been developed for the treatment of DME. Although many of them have been found to be effective and safe, there is relatively little comparative data, and no established guidelines for the optimal treatment approach exist. In this chapter, the evolution of DME therapies is reviewed, and the current common practice patterns are discussed. Available data from clinical trials on the commonly used agents, as well as comparative studies and combination therapies are reviewed. Additionally, recent advances and novel treatment options that are currently being investigated are also discussed.

Impact of robotic assistance on precision of vitreoretinal surgical procedures

PURPOSE

To elucidate the merits of robotic application for vitreoretinal maneuver in comparison to conventional manual performance using an in-vitro eye model constructed for the present study.

METHODS

Capability to accurately approach the target on the fundus, to stabilize the manipulator tip just above the fundus, and to perceive the contact of the manipulator tip with the fundus were tested. The accuracies were compared between the robotic and manual control, as well as between ophthalmologists and engineering students.

RESULTS

In case of manual control, ophthalmologists were superior to engineering students in all the 3 test procedures. Robotic assistance significantly improved accuracy of all the test procedures performed by engineering students. For the ophthalmologists including a specialist of vitreoretinal surgery, robotic assistance enhanced the accuracy in the stabilization of manipulator tip (from 90.9 µm to 14.9 µm, P = 0.0006) and the perception of contact with the fundus (from 20.0 mN to 7.84 mN, P = 0.046), while robotic assistance did not improve pointing accuracy.

CONCLUSIONS

It was confirmed that telerobotic assistance has a potential to significantly improve precision in vitreoretinal procedures in both experienced and inexperienced hands.

[Analysis of factors causing peripheral visual field defects after vitreomacular surgery]

As a result of the study analysis of potential causes of visual field defects (VFD) after vitreomacular surgery is performed. 110 cases are enrolled in the study: 81 patient with macular hole and 29 patients with epiretinal fibrosis. Correspondence of VFD to position of irrigation port including unusual inferior-nasal position was revealed as well as VFD absence in epiretinal fibrosis operated without air pump. VFD did not appear after lowering of air pump pressure by 15-20 mmHg. The cause of VFD after vitreomacular surgery is a mechanical damage of internal retinal surface by directed air/gas jet after total fluid exchange with too high pressure in an air pump. This complication is an easily preventable iatrogenic effect and may serve as one of quality criterion for this treatment procedure.