Novel probabilistic model of core vitreous traction using microsurgical vitrectomy tools.

Purpose: Traction exerted on the vitreous base during vitrectomy poses a risk for retinal tears. We aimed to quantify core vitreous traction during vitrectomy using spring return and pneumatic cutters.

Methods: Juvenile porcine vitreous was vacuum held in a vitreous bath while traction was measured using precision force gauge during vitrectomy.

A reversible thermoresponsive sealant for temporary closure of ocular trauma.

Open globe injuries are full-thickness injuries sustained to the eye wall (cornea or sclera), which cause immediate drops in intraocular pressure that may lead to retinal detachment and permanent vision loss if not treated rapidly after injury. The current standard of care for open globe injuries consists of suturing the margins closed, but the technique can be time-consuming, requires specialized training and equipment, and can lead to patient discomfort, abrasion, and infection from eye rubbing. We engineered an injectable, thermoresponsive sealant (TRS) and a custom tool to occlude open globe injuries.

Development of a new tissue injector for subretinal transplantation of human embryonic stem cell derived retinal pigmented epithelium.

Background: Subretinal cell transplantation is a challenging surgical maneuver. This paper describes the preliminary findings of a new tissue injector for subretinal implantation of an ultrathin non-absorbable substrate seeded with human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE).

Methods: Ultrathin Parylene-C substrates measuring 3.

Assessment of Safety and Functional Efficacy of Stem Cell-Based Therapeutic Approaches Using Retinal Degenerative Animal Models.

Dysfunction and death of retinal pigment epithelium (RPE) and or photoreceptors can lead to irreversible vision loss. The eye represents an ideal microenvironment for stem cell-based therapy. It is considered an "immune privileged" site, and the number of cells needed for therapy is relatively low for the area of focused vision (macula).

Subretinal implantation of a monolayer of human embryonic stem cell-derived retinal pigment epithelium: a feasibility and safety study in Yucatán minipigs.

Purpose: A subretinal implant termed CPCB-RPE1 is currently being developed to surgically replace dystrophic RPE in patients with dry age-related macular degeneration (AMD) and severe vision loss. CPCB-RPE1 is composed of a terminally differentiated, polarized human embryonic stem cell-derived RPE (hESC-RPE) monolayer pre-grown on a biocompatible, mesh-supported submicron parylene C membrane. The objective of the present delivery study was to assess the feasibility and 1-month safety of CPCB-RPE1 implantation in Yucatán minipigs, whose eyes are similar to human eyes in size and gross retinal anatomy.

Survival and Functionality of hESC-Derived Retinal Pigment Epithelium Cells Cultured as a Monolayer on Polymer Substrates Transplanted in RCS Rats.

Purpose: To determine the safety, survival, and functionality of human embryonic stem cell-derived RPE (hESC-RPE) cells seeded on a polymeric substrate (rCPCB-RPE1 implant) and implanted into the subretinal (SR) space of Royal College of Surgeons (RCS) rats.

Methods: Monolayers of hESC-RPE cells cultured on parylene membrane were transplanted into the SR space of 4-week-old RCS rats. Group 1 (n = 46) received vitronectin-coated parylene membrane without cells (rMSPM+VN), group 2 (n = 59) received rCPCB-RPE1 implants, and group 3 (n = 13) served as the control group.

An Innovative Surgical Technique for Subretinal Transplantation of Human Embryonic Stem Cell-Derived Retinal Pigmented Epithelium in Yucatan Mini Pigs: Preliminary Results.

Background And Objective: To develop a safe and efficient surgical procedure for subretinal implantation into porcine eyes of a human embryonic stem cell-derived retinal pigmented epithelium (hESC-RPE) monolayer seeded onto a Parylene-C scaffold. This implant is referred to as CPCB-RPE1.

Materials And Methods: Ultrathin Parylene-C scaffolds were seeded with hESC-RPE and surgically implanted into the subretinal space of Yucatan mini pigs (n = 8).

INTRAOCULAR PRESSURE CHANGES DURING VITRECTOMY USING CONSTELLATION VISION SYSTEM'S INTRAOCULAR PRESSURE CONTROL FEATURE.

Purpose: To evaluate intraocular pressure (IOP) changes during experimental vitrectomy and the efficacy of Constellation Vision System's IOP control (IOPc) feature in reestablishing baseline pressure.

Methods: Using a pressure transducer in freshly enucleated porcine eyes, a broad range of parameters (baseline pressures, aspiration levels, and cut rates) were tested with 23- and 25-gauge probes and IOPc turned ON versus OFF.

Results: IOPc turned ON was significantly more effective than IOPc turned OFF in controlling IOP drop and stabilizing pressure during vitrectomy using a wide range of baseline pressures (20-70 mmHg).

Feasibility of Structural and Functional MRI Acquisition with Unpowered Implants in Argus II Retinal Prosthesis Patients: A Case Study.

Purpose: Magnetic resonance imaging (MRI) can measure the effects of vision loss and recovery on brain function and structure. In this case study, we sought to determine the feasibility of acquiring anatomical and functional MRI data in recipients of the Argus II epiretinal prosthesis system.

Methods: Following successful implantation with the Argus II device, two retinitis pigmentosa (RP) patients completed MRI scans with their implant unpowered to measure primary visual cortex (V1) functional responses to a tactile task, whole-brain morphometry, V1 cortical thickness, and diffusion properties of the optic tract and optic radiation.

Ten-Year Follow-up of a Blind Patient Chronically Implanted with Epiretinal Prosthesis Argus I.

Purpose: The Argus I implant is the first-generation epiretinal prosthesis approved for an investigational clinical trial by the United States Food and Drug Administration. Herein we report testing results obtained from a 10-year follow-up to study the physiologic effects of the bioelectronic visual implant after prolonged chronic electrical stimulation.

Design: Case report.

Stem cell based therapies for age-related macular degeneration: The promises and the challenges.

Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly in developed countries. AMD is classified as either neovascular (NV-AMD) or non-neovascular (NNV-AMD). Cumulative damage to the retinal pigment epithelium, Bruch's membrane, and choriocapillaris leads to dysfunction and loss of RPE cells.

Fluidics comparison between dual pneumatic and spring return high-speed vitrectomy systems.

Background And Objective: To compare the water and vitreous flow rates and duty cycle (DC) between two ultrahigh-speed vitrectomy systems: pneumatic with spring return (SR) and dual pneumatic (DP) probes.

Materials And Methods: The flow rate was calculated using a high-sampling precision balance that measured the mass of water and vitreous removed from a vial by a vitreous cutter. Frame-by-frame analysis of a high-speed video of the cutter was used to determine the DC.

Comparison of reaction response time between hand and foot controlled devices in simulated microsurgical testing.

Purpose: We hypothesized that reaction times (RTs) for a switch release are faster for hand-controlled than for foot-controlled switches for physiological and anatomical reasons (e.g., nerve conduction speed).

Profile of ocriplasmin and its potential in the treatment of vitreomacular adhesion.

The recent approval by the US Food and Drug Administration of ocriplasmin for the treatment of symptomatic vitreomacular adhesion (VMA), often associated with vitreomacular traction (VMT) and macular hole (MH), has brought new attention to the field of pharmacologic vitreolysis. The need for an enzyme to split the vitreomacular interface, which is formed by a strong adhesive interaction between the posterior vitreous cortex and the internal limiting membrane, historically stems from pediatric eye surgery. This review summarizes the different anatomic classifications of posterior vitreous detachment or anomalous posterior vitreous detachment and puts these in the context of clinical pathologies commonly observed in clinical practice of the vitreoretinal specialist, such as MH, VMT, age-related macular degeneration, and diabetic macular edema.

Anti-VEGF for the management of diabetic macular edema.

Diabetic retinopathy (DR) is an important cause of vision loss around the world, being the leading cause in the population between 20 and 60 years old. Among patients with DR, diabetic macular edema (DME) is the most frequent cause of vision impairment and represents a significant public health issue. Macular photocoagulation has been the standard treatment for this condition reducing the risk of moderate visual loss by approximately 50%.

Retrochop technique for rock-hard cataracts.

Unlabelled: We describe a recently developed chopper, the retrochopper, and a technique for managing black and brunescent cataracts. The technique enables the surgeon to effectively disassemble the nucleus and perform a safe procedure with a short learning curve.

Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Risk factors for postoperative endophthalmitis caused by Pseudomonas aeruginosa: possible role of environment.

This article describes an investigation to identify risk factors for postoperative endophthalmitis caused by Pseudomonas aeruginosa. A retrospective case-control study, including 8 cases and 24 controls operated from 2005 to 2009, was undertaken. The risk factors associated with P aeruginosa infection were a particular operating room (P = .