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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. Juvenile porcine vitreous was vacuum held in a vitreous bath while traction was measured using precision force gauge during vitrectomy. The parameters included were aspiration rate, cut-rate, cutter size, and machine types. An empirical probabilistic model was developed. The traction was proportional to the aspiration rate but insignificantly dependent on the cut-rate. The traction probability was inversely proportional to the exponential function of the traction (p

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.Juvenile porcine vitreous was vacuum held in a vitreous bath while traction was measured using precision force gauge during vitrectomy. The parameters included were aspiration rate, cut-rate, cutter size, and machine types.An empirical probabilistic model was developed. The traction was proportional to the aspiration rate but insignificantly dependent on the cut-rate. The traction probability was inversely proportional to the exponential function of the traction (p 0.05). The traction was 0.003 N for 99% of the time using either 23- or 25-gauge cutters.The tractions measured were considered similar to the causative forces of an iatrogenic retinal tear during a pars plana vitrectomy. The results provide a safety reference matrix of instrumental parameters during vitrectomy.

Artificial vision is restoring sight by electrical stimulation of the visual system at the level of retina, optic nerve, lateral geniculate body, or occipital cortex. The development of artificial vision began with occipital cortex prosthesis; however, retinal prosthesis has advanced faster in recent years. Currently, multiple efforts are focused on finding the optimal approach for restoring vision through an implantable retinal microelectrode array system. Retinal prostheses function by stimulating the inner retinal neurons that survive retinal degeneration. In these devices, the visual information, gathered by a light detector, is transformed into controlled patterns of electrical pulses, which are in turn delivered to the surviving retinal neurons by an electrode array. Retinal prostheses are classified based on where the stimulating array is implanted (ie, epiretinal, subretinal, suprachoroidal, or episcleral). Recent regulatory approval of 2 retinal prostheses has greatly escalated interest in the potential of these devices to treat blindness secondary to outer retinal degeneration. This review will focus on the technical and operational features and functional outcomes of clinically tested retinal prostheses. We will discuss the major barriers and some of the more promising solutions to improve the outcomes of restoring vision with electrical retinal stimulation.

Purpose To characterize histologic changes in the optic nerve and the retina of an end-stage retinitis pigmentosa (RP) patient after long-term implantation with the Argus II retinal prosthesis system. Methods Serial cross sections from the patient's both eyes were collected postmortem 6 years after implantation. Optic nerve from both eyes were morphometrically analyzed and compared. Retina underneath and outside the array was analyzed and compared with corresponding regions in the fellow eye. Results Although the optic nerve of the implant eye demonstrated significantly more overall atrophy than the fellow eye (P < 0.01), the temporal quadrant that retinotopically corresponded to the location of the array did not show additional damage. The total neuron count of the macular area was not significantly different between the two eyes, but the tack locations and their adjacent areas showed significantly fewer neurons than other perimacular areas. There was an increased expression of glial fibrillary acidic protein (GFAP) throughout the retina in the implant eye versus the fellow eye, but there was no significant difference in the cellular retinaldehyde-binding protein (CRALBP) expression. Except for the revision tack site, no significant increase of inflammatory reaction was detected in the implant eye. Conclusion Long-term implantation and electrical stimulation with an Argus II retinal prosthesis system did not result in significant tissue damage that could be detected by a morphometric analysis. Translational Relevance This study supports the long-term safety of the Argus II device and encourages further development of bioelectronics devices at the retina-machine interface.

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). The 23-gauge system consistently presented a reduced drop from baseline compared with the 25-gauge system. The overall average drop for the 23- and 25-gauge systems was 12.79 mmHg and 21.17 mmHg, respectively. Both gauge sizes reestablished baseline pressure approximately 1.6 seconds after the initial pressure drop generated at the beginning of aspiration. A peak of IOP (overshooting) was observed when the pressure was returning to baseline using both 23- and 25-gauge systems. CONCLUSION Using IOPc feature turned ON, 23- and 25-gauge probes were effective in reestablishing and sustaining baseline infusion pressures, although 23-gauge probes showed less IOP fluctuation than did 25-gauge probes.

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 3.5 mm × 6.0 mm seeded with hESC-RPE (implant referred to as CPCB-RPE1) were implanted into the subretinal space of 12 Yucatan minipigs. Animals were euthanized immediately after the procedure and underwent spectral domain optical coherence tomography (SD-OCT) and histological analysis to assess the subretinal placement of the implant. Evaluation of the hESC-RPE cells seeded on the substrate was carried out before and after implantation using standard cell counting techniques. Results The tissue injector delivered the CPCB-RPE1 implant through a 1.5 mm sclerotomy and a 1.0–1.5 mm retinectomy. SD-OCT scans and histological examination revealed that substrates were precisely placed in the subretinal space, and that the hESC-RPE cell monolayer continued to cover the surface of the substrate after the surgical procedure. Conclusion This innovative tissue injector was able to efficiently deliver the implant in the subretinal space of Yucatan minipigs, preventing significant hESC-RPE cell loss, minimizing tissue trauma, surgical complications and postoperative inflammation.

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. The smart hydrogel sealant consists of physically cross-linked N-isopropylacrylamide copolymerized with butylacrylate. At low temperatures, it can be injected as a liquid, and when raised to body temperature, a heat-induced gelation converts the hydrogel into a solidified occlusion. The sealant can be repositioned or removed without causing additional trauma via exposure to cold water. In vitro and ex vivo assessments of mechanical adhesion to eye tissue revealed maintenance of intraocular pressure that is five times greater than the physiological range with reversible seal strength comparable to cyanoacrylate (super glue). In vivo assessment in a rabbit model of ocular trauma demonstrated ease of use for TRS deployment, statistically significant improvement in wound sealing, and no evidence of neurotoxicity, retinal tissue degradation, or significant chronic inflammatory response after 30 days of exposure. Given the advantages of body heat-induced gelation, rapid reversible occlusion, and in vivo safety and efficacy, shape-adaptable TRSs have translational potential as smart wound sealants for temporary occlusion of surgical incisions or traumatic injuries.

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). The risk of accidental trauma could be reduced if the surgeon reacted quicker and therefore improve the surgical outcome.Method. We included 47 medical professionals at USC. Demographics and handedness were recorded. Under a microscope, a simple reaction time test was performed, testing all extremities multiple times in a random order. Additionally, a subjective questionnaire was administered.Results. The mean RTs for hands are 318.24 ms±51.13 and feet328.69±48.70. The comparison of hand versus foot showed significant shorter RTs for the hand (P=0.025). Partially significant differences between and within the experience level groups could be demonstrated by level of education (LE) and microscopic surgeries/week (MSW) (P=0.57–0.02). In the subjective questionnaire, 91.5% (n=43/47) of test subjects prefer to use hand controls.Conclusion. Our data show that the RT for hands is faster than feet. Similarly the subjective questionnaire showed a greater preference for hand actuation. This data suggest a hand-controlled ophthalmic instrument might have distinct advantages; however, clinical correlation is required.

O objetivo deste relato de caso é descrever uma nova técnica de refixação escleral, unilateral, de uma háptica cuja sutura escleral prévia rompeu-se, levando ao deslocamento da lente intraocular para o vítreo. Trata-se de um olho submetido anteriormente a dois transplantes de córnea, em que se buscou minimizar a manipulação intraocular e o trauma cirúrgico. Esta técnica consiste em realizar o procedimento em olho fechado, utilizando a mesma lente de fixação, sem a necessidade de externalizar as hápticas ou do uso de instrumentos cirúrgicos especiais. A perda de células endoteliais após o procedimento foi similar à observada após a facoemulsificação em pacientes com ceratoplastia penetrante. A técnica mostrou-se simples, segura, e, portanto, reprodutível, além de ser menos invasiva do que os métodos já descritos, permitindo a reabilitação visual precoce do paciente.

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.

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 Yucatan minipigs, whose eyes are similar to human eyes in size and gross retinal anatomy. This was a prospective, partially blinded, randomized study in 14 normal-sighted female Yucatan minipigs (aged 2 months, weighing 24–35 kg). Surgeons were blinded to the randomization codes and postoperative and post-mortem assessments were performed in a blinded manner. Eleven minipigs received CPCB-RPE1 while three control minipigs underwent sham surgery that generated subretinal blebs. All animals except two sham controls received combined local (Ozurdex™ dexamethasone intravitreal implant) and systemic (tacrolimus) immunosuppression or local immunosuppression alone. Correct placement of the CPCB-RPE1 implant was assessed by in vivo optical coherence tomography and post-mortem histology. hESC-RPE cells were identified using immunohistochemistry staining for TRA-1-85 (a human marker) and RPE65 (an RPE marker). As the study results of primary interest were nonnumerical no statistical analysis or tests were conducted. CPCB-RPE1 implants were reliably placed, without implant breakage, in the subretinal space of the minipig eye using surgical techniques similar to those that would be used in humans. Histologically, hESC-RPE cells were found to survive as an intact monolayer for 1 month based on immunohistochemistry staining for TRA-1-85 and RPE65. Although inconclusive regarding the necessity or benefit of systemic or local immunosuppression, our study demonstrates the feasibility and safety of CPCB-RPE1 subretinal implantation in a comparable animal model and provides an encouraging starting point for human studies.

Graefes Arch Clin Exp Ophthalmol (2016) 254:1553–1565 DOI 10.1007/s00417-016-3386-y BASIC SCIENCE Subretinal implantation of a monolayer of human embryonic stem cell-derived retinal pigment epithelium: a feasibility and safety study in Yucatan minipigs Michael J. Koss 1,2 & Paulo Falabella 2 & Francisco R. Stefanini 3 & Marcel Pfister 2 & Biju B. Thomas 2 & Amir H. Kashani 2 & Rodrigo Brant 3 & Danhong Zhu 2,4 & Dennis O. Clegg 5 & David R. Hinton 2,4 & Mark S. Humayun 2,6 Received: 16 December 2015 / Revised: 23 March 2016 / Accepted: 11 May 2016 / Published online: 22 June 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract 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 differenti- ated, 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 Yucatan minipigs, whose eyes are similar to human eyes in size and gross retinal anatomy. Methods This was a prospective, partially blinded, randomized study in 14 normal-sighted female Yucatan minipigs (aged 2 months, weighing 24–35 kg). Surgeons were blinded to the randomization codes and postoperative and post-mortem * Michael J. Koss michael.koss@me.com Department of Ophthalmology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany USC Eye Institute, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033-4682, USA Department of Ophthalmology, Federal University of Sao Paulo UNIFESP, Rua Botucatu 821, 04023-062 Sao Paulo, Brazil assessments were performed in a blinded manner. Eleven minipigs received CPCB-RPE1 while three control minipigs underwent sham surgery that generated subretinal blebs. All an- imals except two sham controls received combined local (Ozurdex™ dexamethasone intravitreal implant) and systemic (tacrolimus) immunosuppression or local immunosuppression alone. Correct placement of the CPCB-RPE1 implant was assessed by in vivo optical coherence tomography and post- mortem histology. hESC-RPE cells were identified using immu- nohistochemistry staining for TRA-1-85 (a human marker) and RPE65 (an RPE marker). As the study results of primary interest were nonnumerical no statistical analysis or tests were conducted. Results CPCB-RPE1 implants were reliably placed, without implant breakage, in the subretinal space of the minipig eye using surgical techniques similar to those that would be used in humans. Histologically, hESC-RPE cells were found to survive as an intact monolayer for 1 month based on immu- nohistochemistry staining for TRA-1-85 and RPE65. Conclusions Although inconclusive regarding the necessity or benefit of systemic or local immunosuppression, our study demonstrates the feasibility and safety of CPCB-RPE1 subretinal implantation in a comparable animal model and provides an encouraging starting point for human studies. Keywords Human embryonic stem cells . Retinal pigment epithelium . Macular degeneration . Preclinical trial . Animal model Department of Pathology, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033-4682, USA Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA Introduction Institute of Biomedical Therapeutics, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033-4682, USA Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly worldwide and is characterized

© 2015 Elsevier Ltd. 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. This causes degeneration of the overlying photoreceptors and consequential vision loss in advanced NNV-AMD (Geographic Atrophy). In NV-AMD, abnormal growth of capillaries under the retina and RPE, which leads to hemorrhage and fluid leakage, is the main cause of photoreceptor damage. Although a number of drugs (e.g., anti-VEGF) are in use for NV-AMD, there is currently no treatment for advanced NNV-AMD. However, replacing dead or dysfunctional RPE with healthy RPE has been shown to rescue dying photoreceptors and improve vision in animal models of retinal degeneration and possibly in AMD patients. Differentiation of RPE from human embryonic stem cells (hESC-RPE) and from induced pluripotent stem cells (iPSC-RPE) has created a potentially unlimited source for replacing dead or dying RPE. Such cells have been shown to incorporate into the degenerating retina and result in anatomic and functional improvement. However, major ethical, regulatory, safety, and technical challenges have yet to be overcome before stem cell-based therapies can be used in standard treatments. This review outlines the current knowledge surrounding the application of hESC-RPE and iPSC-RPE in AMD. Following an introduction on the pathogenesis and available treatments of AMD, methods to generate stem cell-derived RPE, immune reaction against such cells, and approaches to deliver desired cells into the eye will be explored along with broader issues of efficacy and safety. Lastly, strategies to improve these stem cell-based treatments will be discussed.

We describe a case of bilateral irreversible visual loss of a 64 year-old patient after prolonged use of paclitaxel. Patient presented best corrected visual acuity of 20/400 in both eyes at first visit and optical coherence tomography showed increased macular in both eyes.After six months of the interruption of -paclitaxel therapy, the patient showed slight improvement of visual acuity reaching 20/200 in both eyes, while OCT demonstrated resolution of macular edema.

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. Three cutters of each gauge (20, 23, and 25 G) were tested with an SR and a DP system using the standard DC setting (biased open) at 0 (water only), 1,000, 2,000, 3,000, 4,000, and 5,000 cuts per minute (CPM) with aspiration levels of 100, 200, 300, 400, 500, and 600 mm Hg. RESULTS: The DC was slightly higher with the SR system using most parameters and gauges although without statistical significance. The water flow rate was somewhat higher with the SR system, except for 25 G with 4,000 and 5,000 CPM. The vitreous flow rate was similar using most parameters, with the SR system showing higher flows at lower cut rates (1,000–3,000 CPM). CONCLUSIONS: SR and DP systems produced similar water and vitreous flow rates. Additional studies in human eyes are necessary to confirm these findings. [ Ophthalmic Surg Lasers Imaging Retina . 2015;46:68–72.]

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. We revisit the outcome of the Phase II studies that indicated ocriplasmin was a safe and effective treatment for selected cases of symptomatic VMA and MH. Release of VMA at day 28 was achieved by 26.5% of patients in the ocriplasmin group versus 10.1% in the placebo group (P

Retina Survival and Functionality of hESC-Derived Retinal Pigment Epithelium Cells Cultured as a Monolayer on Polymer Substrates Transplanted in RCS Rats Biju B. Thomas, 1,2 Danhong Zhu, 1,3 Li Zhang, 4 Padmaja B. Thomas, 5 Yuntao Hu, 6 Hossein Nazari, 1 Francisco Stefanini, 1 Paulo Falabella, 1 Dennis O. Clegg, 7 David R. Hinton, 1,3 and Mark S. Humayun 1,2 1 Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, California, United States USC Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, California, United States Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States Eye Center, Second Affiliated Hospital, Medical School of Zhejiang University, Hangzhou, China 5 Cellular Therapies Production Center, City of Hope, Duarte, California, United States Department of Ophthalmology, Beijing Tsinghua Changgung Hospital, Tsinghua University Medical Center, Beijing, China Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, California, United States Correspondence: Biju B. Thomas, Department of Ophthalmology, Uni- versity of Southern California, Los Angeles, CA 90033, USA; biju.thomas@med.usc.edu. Submitted: January 28, 2016 Accepted: April 13, 2016 Citation: Thomas BB, Zhu D, Zhang L, et al. Survival and functionality of hESC-derived retinal pigment epitheli- um cells cultured as a monolayer on polymer substrates transplanted in RCS rats. Invest Ophthalmol Vis Sci. 2016;57:2877–2887. DOI:10.1167/ iovs.16-19238 P URPOSE . 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. M ETHODS . Monolayers of hESC-RPE cells cultured on parylene membrane were transplanted into the SR space of 4-week-old RCS rats. Group 1 (n ¼ 46) received vitronectin-coated parylene membrane without cells (rMSPMþVN), group 2 (n ¼ 59) received rCPCB-RPE1 implants, and group 3 (n ¼ 13) served as the control group. Animals that are selected based on optical coherence tomography screening were subjected to visual function assays using optokinetic (OKN) testing and superior colliculus (SC) electrophysiology. At approximately 25 weeks of age (21 weeks after surgery), the eyes were examined histologically for cell survival, phagocytosis, and local toxicity. R ESULTS . Eighty-seven percent of the rCPCB-RPE1–implanted animals showed hESC-RPE survivability. Significant numbers of outer nuclear layer cells were rescued in both group 1 (rMSPMþVN) and group 2 (rCPCB-RPE1) animals. A significantly higher ratio of rod photoreceptor cells to cone photoreceptor cells was found in the rCPCB-RPE1–implanted group. Animals with rCPCB-RPE1 implant showed hESC-RPE cells containing rhodopsin- positive particles in immunohistochemistry, suggesting phagocytic function. Superior colliculus mapping data demonstrated that a significantly higher number of SC sites responded to light stimulus at a lower luminance threshold level in the rCPCB-RPE1– implanted group. Optokinetic data suggested both implantation groups showed improved visual acuity. C ONCLUSIONS . These results demonstrate the safety, survival, and functionality of the hESC-RPE monolayer transplantation in an RPE dysfunction rat model. Keywords: transplantation, stem cells, parylene, retinal pigment epithelium, optokinetic testing, superior colliculus D ysfunction and death of RPE cells have been observed in human degenerative diseases leading to blindness, such as AMD. Age-related macular degeneration is one of the leading causes of blindness in the Western world. 1–3 Although antiangiogenic therapies were developed to treat exudative AMD, 4 there is no effective method for the treatment of dry AMD, particularly its end-stage, geographic atrophy. 5,6 A number of research groups are in pursuit of strategies to replace degenerated RPE cells with healthy RPE cells in the submacular space. 7–16 Various cell types have been examined for RPE cell replacement. These cells include immortalized cell lines, such as the human RPE cell line ARPE19, 17 sheets of adult RPE, 18 fetal RPE, 19 RPE derived from human embryonic stem cells (hESC-RPE), 20–24 human induced pluripotent stem cell–derived RPE, 9,25,26 and many non-RPE cell lines. 27–37 Stem cells, with their capacity to differentiate and replace diseased cells, can be an excellent source for RPE transplanta- tion. 10,11,16,28,29,38 Almost all previous studies used the method of cell suspension injection to evaluate the feasibility of stem cell–based RPE replacement therapies. This strategy is depen- dent on the integration of injected cells into the host RPE monolayer, which has been shown to occur in some studies 39 but not in others. 20 However, when injected as a cell suspension, most cells fail to form a polarized monolayer and survival rates are poor. 40,41 Furthermore, Bruch’s membrane, iovs.arvojournals.org j ISSN: 1552-5783 This work is licensed under a Creative Commons Attribution 4.0 International License. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/935270/ on 06/05/2017

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 = .003) and longer phacoemulsification duration ( P = .001), suggesting that infection was not associated with patient characteristics but rather with the surgical environment and phacoemulsification duration.

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.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. Measurements in the subjects with the Argus II implant were compared to measurements obtained previously from RP patients and sighted individuals.The presence of the Argus II implant resulted in artifacts that were localized around the patient's implanted eye and did not extend into cortical regions or white matter tracts associated with the visual system. Structural data on V1 cortical thickness and the retinofugal tract obtained from the two Argus II subjects fell within the ranges of sighted and RP groups. When compared to the RP and sighted subjects, Argus II patients' tactile-evoked cross-modal functional MRI (fMRI) blood oxygen level-dependent (BOLD) responses in V1 also fell within the range of either sighted or RP groups, apparently depending on time since implantation.This study demonstrates that successful acquisition and quantification of structural and functional MR images are feasible in the presence of the inactive implant and provides preliminary information on functional changes in the brain that may follow sight restoration treatments.Successful MRI and fMRI acquisition in Argus II recipients demonstrates feasibility of using MRI to study the effect of retinal prosthesis use on brain structure and function.

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. Participant One man, 55 years of age when enrolled in the study, underwent surgical implantation of the Argus I in June 2004, followed by periodic tests from July 2004 through June 2014, spanning a total of 10 years. Methods The decade-long follow-up consisted of implant system performance tests, subject visual function evaluation, and implant–retina interface analysis. Main Outcome Measures Changes in electrode impedance and perceptual threshold over the time course; subject's performance on visual function task, orientation, and mobility tests; and optical coherence tomography data, fundus imaging, and fluorescein angiography results for the assessment of subject's implant–retina physical interface. Results Electrically elicited phosphenes were present 10 years after implantation of an epiretinal stimulator. The test subject not only was able to perceive phosphenes, but also could perform visual tasks at rates well above chance. Conclusions This decade-long follow-up report provides further support for the use of retinal prostheses as a long-lasting treatment for some types of blindness.