Joseph N. Martel

Handheld-automated microsurgical instrumentation for intraocular laser surgery.

Laser photocoagulation is a mainstay or adjuvant treatment for a variety of common retinal diseases. Automated laser photocoagulation during intraocular surgery has not yet been established. The authors introduce an automated laser photocoagulation system for intraocular surgery, based on a novel handheld instrument. The goals of the system are to enhance accuracy and efficiency and improve safety.

Comparative Evaluation of Handheld Robot-Aided Intraocular Laser Surgery

This paper presents robot-aided intraocular laser surgery using a handheld robot known as Micron. The micromanipulator enables visual servoing of a laser probe, while maintaining a constant distance of the tool tip from the retinal surface. Automated, semiautomated, and unaided manual performance in patterned laser retinal photocoagulation is compared.

Hybrid position/force control of an active handheld micromanipulator for membrane peeling

Peeling procedures in retinal surgery require micron‐scale manipulation and control of sub‐tactile forces.

Toward monocular camera-guided retinal vein cannulation with an actively stabilized handheld robot

In this paper we describe work towards retinal vessel cannulation using an actively stabilized handheld robot, guided by monocular vision. We employ a previously developed monocular camera based surface reconstruction method using automated laser beam scanning over the retina. We use the reconstructed plane to find a coordinate transform between the 2D image plane coordinate system and the global 3D frame. Within a hemispherical region around the target, we use motion scaling for higher precision. The contribution of this work is the homography matrix estimation using monocular vision and application of the previously developed laser surface reconstruction to Micron guided vein cannulation. Experiments are conducted in a wet eye phantom to show the higher accuracy of the surface reconstruction as compared to standard stereo reconstruction. Further, experiments to show the increased surgical accuracy due to motion scaling are also carried out.

Techniques for robot-aided intraocular surgery using monocular vision

This paper presents techniques for robot-aided intraocular surgery using monocular vision in order to overcome erroneous stereo reconstruction in an intact eye. We propose a new retinal surface estimation method based on a structured-light approach. A handheld robot known as the Micron enables automatic scanning of a laser probe, creating projected beam patterns on the retinal surface. Geometric analysis of the patterns then allows planar reconstruction of the surface. To realize automated surgery in an intact eye, monocular hybrid visual servoing is accomplished through a scheme that incorporates surface reconstruction and partitioned visual servoing. We investigate the sensitivity of the estimation method according to relevant parameters and also evaluate its performance in both dry and wet conditions. The approach is validated through experiments for automated laser photocoagulation in a realistic eye phantom in vitro. Finally, we present the first demonstration of automated intraocular laser surgery in porcine eyes ex vivo.

Scleral Fixation of Posterior Chamber Intraocular Lenses Using Gore-Tex Suture: Clinical Outcomes From a Single Institution

Purpose: The purpose of this article is to examine the clinical outcomes of scleral fixation of intraocular lenses (IOLs) using Gore-Tex suture at our institution. Methods: A retrospective chart review was conducted of patients who underwent scleral fixation of an IOL with Gore-Tex suture with concurrent pars plana vitrectomy. Intraoperative and postoperative complications were assessed. Results: Seventy-four eyes of 74 patients were included with a mean follow-up interval of 210 days (range, 33–720 days). The mean best-corrected visual acuity improved from 20/480 (1.38 logarithm of the minimum angle of resolution [logMAR]) preoperatively to 20/78 (0.59 logMAR) postoperatively (P < .001). Indications included dislocated lens implant (42), aphakia without capsular support (18), and subluxation of crystalline lens (14). Bausch and Lomb Akreos AO60 IOL was implanted in 52 eyes, Alcon CZ70BD in 15, and Bausch and Lomb enVista MX60 in 6. Postoperative complications included temporary ocular hypertension in 9 eyes (12%), temporary hypotony in 7 (9%), cystoid macular edema in 3 eyes (4%), corneal decompensation in 2 eyes (3%), IOL dislocation requiring exchange in 1 case (1.4%), vitreous hemorrhage in 2 cases (3%), and retinal detachment in 2 cases (3%). There were no cases of postoperative suture breakage or erosion, endophthalmitis, or hyphema. Conclusions: The use of Gore-Tex suture in scleral fixation of posterior chamber IOLs was well tolerated at a mean follow-up interval of 210 days. There were no suture-related complications.

Toward Improved Electromagnetic Tracking for Handheld Robotics

We describe early efforts in design and development of an In-Loop Electromagnetic Tracker (ILEMT), designed to meet the demanding latency and resolution requirements for handheld robotic systems that perform active stabilization of hand motion during microsurgery. The objective is to surpass the best commercial electromagnetic trackers in latency while matching them in root-bandwidth/resolution. The concept is to use frequency-domain multiplexing for fast measurement and high accuracy during rapid motion, and bifrequency dual-path eddy-current compensation (reducing distortion from metals without sacrificing speed). The use of two widely spaced carrier frequencies (e.g., 300 Hz and 10 kHz) enables a particularly simple way of reducing the eddy-current interference caused by nonferrous metals. Previously, metal compatibility has come at the price of reduced measurement speed.

Electromagnetic tracker for active handheld robotic systems

This paper describes recent work in the development of the In-Loop Electromagnetic Tracker (ILEMT), designed to meet the demanding latency and resolution requirements for active stabilization of hand motion during precision manipulations such as microsurgery. The prototype surpasses the fastest commercial EM trackers by > 4x in root bandwidth/resolution and 2x in latency. The use of two widely spaced carrier frequencies (e.g., 300 Hz and 10 kHz) enables a particularly simple way of reducing the eddy-current interference caused by nonferrous metals present in the workspace. Previously, metal compatibility has only been achieved at a large cost to measurement speed.

SPONTANEOUS RESOLUTION OF MACULAR EPIRETINAL MEMBRANES AFTER FLUORESCEIN POTENTIATED ARGON LASER TREATMENT OF VON HIPPEL-LINDAU ASSOCIATED RETINAL HEMANGIOMAS: CASE REPORT AND REVIEW OF LITERATURE.

PURPOSE To illustrate spontaneous resolution of macular epiretinal membranes and inactivation of retinal hemangioma exudation after fluorescein potentiated argon laser treatment of bilateral capillary hemangiomas in a patient with a de novo heterozygous deletion in Exon 2 of the von Hippel-Lindau gene. METHODS Interventional case report. RESULTS A 23-year-old man with subjective complaints of blurry vision, photophobia, and glare. On presentation, visual acuity was 20/20 in the right eye and 20/25 in the left eye with metamorphopsia. On the basis of bilateral retinal hemangiomas on clinical examination and characterization with multimodal imaging, a diagnosis of von Hippel-Lindau disease was made. Genetic testing identified a de novo, disease-causing heterozygous deletion in Exon 2 of the von Hippel-Lindau gene. The patient underwent 4 sessions of fluorescein potentiated 532 nm argon green laser treatment directed at retinal hemangiomas. No adverse sequelae of laser treatment were noted. Seven months after the initial presentation, the patients vision was 20/20 in both eyes with interval resolution of metamorphopsia. There was spontaneous resolution of a macular epiretinal membrane with normalization of the macular retinal microstructure. The retinal hemangiomas in both eyes appeared inactive, and no new lesions were noted. CONCLUSION Fluorescein potentiated argon laser successfully treated bilateral retinal hemangiomas in our patient with von Hippel-Lindau disease. Additional studies to characterize the full clinical potential of fluorescein potentiated argon laser therapy may be warranted.