Implantation of a second glaucoma drainage device.

PURPOSE: To evaluate success rates in controlling intraocular pressure (IOP) after implantation of a second glaucoma drainage device (GDD) with a Baerveldt glaucoma implant in patients with refractory glaucoma, with a secondary aim of reducing the need for postoperative glaucoma medications. MATERIAL AND METHODS: This retrospective, noncomparative, interventional study included patients undergoing a second GDD for uncontrolled glaucoma from a tertiary care glaucoma service. Data were obtained from the medical records for the preoperative period and after the 1st, 15th, and 30th day, 3, 6, and 12 months, and then yearly until the last postoperative visit. Visual acuity, IOP, and number of glaucoma medications (NGM) from the follow-up visits were compared to baseline. Success and failure criteria were analyzed based on IOP level or need of glaucoma medications. RESULTS: Forty-nine patients were studied, with a mean follow-up time of 25 ± 21 months. The mean preoperative IOP was 23.7 ± 8.2 mmHg, and decreased to 14.8 ± 4.0 mmHg after 1 year, 14.4 ± 3.9 mmHg after 2 years, and 16.6 ± 8.5 mmHg after 3 years. The mean preoperative NGM was 3.4 ± 1.3, and decreased to 2.0 ± 1.8 after 1 year, 2.5 ± 1.6 after 2 years, and 2.8 ± 2.0 after 3 years. Absolute success was 9% after 1 year for a postoperative IOP between 5 and 18 mmHg, and 76% for a postoperative IOP between 5 and 21 mmHg. The qualified success was 88% at the first and second years and 83% at the third year. CONCLUSION: With up to 3 years of follow-up, a second glaucoma drainage device was successful in reducing IOP to below 21 mmHg, but not as successful below 18 mmHg. The success rate is improved with the use of glaucoma medications with up to 3 years of follow-up.

Drusen measurements comparison by fundus photograph manual delineation versus optical coherence tomography retinal pigment epithelial segmentation automated analysis.

PURPOSE: To compare drusen measurements obtained from color fundus and infrared retromode photographs with those derived from spectral-domain optical coherence tomography. METHODS: Drusen lesions identified on the planar (color and infrared) imaging modalities were manually segmented by two independent graders using previously described reading center software to produce quantitative measurements of drusen area and number. The corresponding volume Cirrus OCT datasets were analyzed using commercial retinal pigment epithelium analysis algorithms to segment the retinal pigment epithelium band and estimated the drusen area. Drusen numbers were extracted from retinal pigment epithelium elevation maps. Intraclass correlation coefficients assessed agreement between graders; graders' average measurements were compared with optical coherence tomography (OCT) using paired T-tests. RESULTS: Excellent agreement between graders was observed (r = 0.951-0.974). No statistical difference was found in the area values obtained by color (0.85 ± 0.26 mm(2), P = 0.43) or retromode (1.15 ± 0.32 mm(2), P = 0.35) compared with those obtained by OCT (0.98 ± 0.28 mm). The number of drusen identified by OCT (13.15 ± 3.19) was significantly lower than that determined by manual segmentation of color (53.7 ± 13.18) and retromode (100.13 ± 16.18) images. CONCLUSION: Although the number of drusen individualized by commercial OCT algorithms is significantly lower than by planar fundus imaging modalities, the OCT-measured drusen area is not affected, suggesting that the algorithm counts confluent drusen as a single drusen.

Performance analysis of ultrahigh-speed vitreous cutter system.

PURPOSE: To evaluate flow rates and duty cycle for different sizes of ultra-high-speed pneumatic vitreous cutters. METHODS: A precision balance measured the mass of water and vitreous removed from a vial. Porcine vitreous was obtained within 12 hours of killed at a local slaughterhouse and kept at 4 °C. Twenty-, 23- and 25-gauge (n = 3 of each gauge) pneumatic cutters were tested at 0 (water), 1,000, 2,000, 3,000, 4,000, and 5,000 cuts per minute with aspiration levels of 100, 200, 300, 400, 500, and 600 mmHg. Frame-by-frame analysis of high-speed video was used to determine the duty cycle. RESULTS: Larger gauge cutters associated with higher aspiration levels produced greater vitreous and water flow rates (P < 0.05). As the cut rate increased, the vitreous flow rate increased (maximum flow at 5,000 cuts per minute) and the water flow rate decreased (P < 0.05). The duty cycle of the new-generation cutters decreased as cut speeds increased, using all 3 gauges (P < 0.001). Vitreous flow rates averaged 10 times less than water flow rates using the same cutter at the same settings. CONCLUSION: Ultra-high-speed vitreous cutters produce consistent vitreous and water flow rates across the tested range of cuts per minute and aspiration levels.

Analysis of a 23-gauge ultra high-speed cutter with duty cycle control.

PURPOSE: The purpose of the study was to determine the performance of dual pneumatic ultra high-speed 23-gauge cutters operated with variable duty cycle (DC) settings. METHODS: Frame-by-frame analysis of high-speed video was used to determine the DC in core, 50-50, and shave modes. Using three cutters at various cycles per minute and aspiration levels, mass of water or vitreous removed from a vial was measured within a specified time period. Average flow rates were calculated for each aspiration level and cut rate with the different DC options. RESULTS: The DC increased with increasing cut rate in the shave mode was relatively stable in the 50-50 mode and decreased for the core mode. The DC converged at 5,000 cycles per minute for the 3 different modes. Water flow curves followed the DC variation. Vitreous flow rates for all the DC modes increased with increasing cut rates and peaked at 5,000 cycles per minute (P < 0.05). The results of the 50-50 mode, which had isolated the DC influence, showed that increasing aspiration and/or cut rate independently increased the vitreous flow rate. CONCLUSION: Progressive values of aspiration and/or cut rate increase the vitreous flow rate, independently of the DC. The DC control also has an important effect on the vitreous flow, but this effect was reduced at high cut rates because of convergence of the DC modes.

Fluidics in a dual pneumatic ultra high-speed vitreous cutter system.

BACKGROUND: Dual pneumatic systems use two separate air line tubes to open and close the cutter and can achieve high cut rates. The purpose of this study is to evaluate the influence of gauge size, cut rate and aspiration on the flow rate performance of ultra high-speed cutters operated with a commercially available dual pneumatic vitrectomy system. METHODS: Analysis of a high-speed video was used to determine duty cycle. Flow rates from 20-, 23- and 25-gauge cutters were calculated in predetermined conditions of aspiration levels and cut rates; water and fresh porcine vitreous samples were studied. RESULTS: For all three gauges of cutters, the duty cycle and water flow showed an inverse correlation with increasing cut rates and a direct correlation with increasing aspiration levels (p < 0.05). Vitreous flow rates from all gauges increased with increasing aspiration and cut rates (p < 0.05). CONCLUSION: Larger gauges of the cutters as well as higher aspiration and cut rate levels resulted in improvement of the vitreous flow rates. A good understanding of the different flow rate settings is essential for the surgeon and optimizes the safety of surgical procedures.

A novel approach for subretinal implantation of ultrathin substrates containing stem cell-derived retinal pigment epithelium monolayer.

OBJECTIVE: To evaluate the feasibility of a new technique for the implantation of ultrathin substrates containing stem cell-derived retinal pigment epithelium (RPE) cells into the subretinal space of retina-degenerate Royal College of Surgeon (RCS) rats. METHODS: A platform device was used for the implantation of 4-µm-thick parylene substrates containing a monolayer of human embryonic stem cell-derived RPE (hESC-RPE). Normal Copenhagen rats (n = 6) and RCS rats (n = 5) were used for the study. Spectral-domain optical coherence tomography (SD-OCT) scanning and histological examinations were performed to confirm placement location of the implant. hESC-RPE cells attached to the substrate before and after implantation were evaluated using standard cell counting techniques. RESULTS: SD-OCT scanning and histological examination revealed that the substrates were precisely placed in the rat's subretinal space. The hESC-RPE cell monolayer that covered the surface of the substrate was found to be intact after implantation. Cell counting data showed that less than 2% of cells were lost from the substrate due to the implantation procedure (preimplantation count 2,792 ± 74.09 cells versus postimplantation count 2,741 ± 62.08 cells). Detailed microscopic examination suggested that the cell loss occurred mostly along the edges of the implant. CONCLUSION: With the help of this platform device, it is possible to implant ultrathin substrates containing an RPE monolayer into the rat's subretinal space. This technique can be a useful approach for stem cell-based tissue bioengineering techniques in retinal transplantation research.

Disintegrin-Integrin Binding for Attachment of Polymer Substrate to the Retina.

OBJECTIVE: We propose a novel attachment method for retinal tissue that utilizes silicone modified with bioactive molecules. DESIGN: This is an experimental study divided into an in vitro section performed in cadaveric pig eyes and an in vivo section performed in rabbits. SUBJECTS: During in vitro experiments 36 cadaveric pig eyes were used. During in vivo experiments 4 rabbits were used. METHODS: Different types of silicone went through a laser irradiation process to determine if binding sites for disintegrins could be created. Laser treated silicones that showed disintegrin binding were evaluated with in vitro testing for retina-silicone attachment. The best silicone binding in vitro was implanted into a rabbit's eye after a full vitrectomy was performed. Post-operative exams were done every two weeks to evaluate placement, attachment and sterilization method. After three months animals were euthanized and eye was enucleated for histology analysis. MAIN OUTCOME MEASURES: Attachment strength between silicone-disintegrin-retina, and signs of endophthalmitis during in vivo studies for biocompatibility purposes. RESULTS: A technique to successfully lase and produce an active area on the silicone surface was described. Scanning electron microscope (SEM) images were evaluated to assess physical ablation/debris field area on the surface, definition of edges, evenness, and symmetry of the lased area allowing us to select MED 4800 silicone family for further testing. Cell culture experiments showed disintegrin binding to the silicone active area. In vitro experiments with cadaveric eyes were performed to test retina-silicone attachment. MED 4860 showed strongest attachment to the retina and it was used during in vivo experiments. A sterilization protocol was tested and proved to be reliable for bioactive materials. Disintegrin coated silicone showed attachment in 2 of 4 rabbits during the 3-month implant period. The adhesion was persistent until reversed with plasmin. All rabbits were implanted for 3 months regardless of attachment, to test the feasibility of the sterilization method. None of the rabbits developed any type of eye infection during the implant period. CONCLUSION: We successfully lased and produced an active area on the silicone surface to allow disintegrin-silicone binding. Different silicones interact differently with the laser energy, and this is reflected in the strength of the silicone-disintegrin-retina attachment.

Standard Electrocardiographic Data from Capuchin Monkeys (Cebus apella, Linnaeus, 1758).

Capuchin monkeys are a species of arboreal primate found in all South American countries. These monkeys have been highlighted for their potential for biomedical research due to their anatomic and physiologic similarities and genetic homology with humans. Here we characterized the electrocardiographic tracings from 12 healthy, young capuchin monkeys that were restrained with ketamine and midazolam. All 12 monkeys had normal sinus rhythms. Neither P-wave duration, PR interval, QT interval, nor P- or R-wave amplitude (in millivolts) differed between males and females. The P waves were small, monophasic, and positive in all animals. The QRS complex showed positive polarity in the D1, D2, aVL, aVF, V2, V4, and V10 derivations and negative polarity in the D3, aVR, and rV2 leads. The T wave exhibited a negative polarity only in the aVR derivation in all animals in the study, and no significant difference was present between sexes. The ST segment was isoelectric in both sexes and lacked reductions and elevations. The anesthetic protocol was well tolerated all of the monkeys and allowed for diagnostic-quality acquisition, measurement, and characterization of the electrocardiogram and establishment of the normal electrocardiographic parameters of chemically restrained capuchin monkeys.

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 3.5 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.

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). The surgery consisted of pars plana vitrectomy, induction of a limited retinal detachment, and peripheral retinotomy for insertion of the monolayer using a novel tissue injector, followed by silicone oil tamponade injection, laser photocoagulation around the retinotomy site, and inferior iridectomy. Oral cyclosporine was administered from day 1 and during the entire follow-up period. Three months later, the animals were euthanized and the eyes and major organs were submitted for histological analysis. Adjacent sections underwent immunohistochemical analysis to detect human cells using anti-TRA-1-85 (human blood group antigen) antibody and DAPI antibodies. RESULTS: The cell monolayer was immunopositive for TRA-1-85 3 months after implantation and migration from the Parylene-C scaffold was not detected. One eye had a mild inflammatory reaction around the implant that was negative for human biomarkers. No intraocular or systemic tumors were detected. CONCLUSION: The hESC-RPE cells survived for 3 months in this animal model. The surgical procedure for subretinal implantation of CPCB-RPE1 is feasible and safe, without cell migration off the scaffold or development of ocular or systemic tumors.

Stem cell therapy for retinal diseases.

In this review, we discuss about current knowledge about stem cell (SC) therapy in the treatment of retinal degeneration. Both human embryonic stem cell and induced pluripotent stem cell has been growth in culture for a long time, and started to be explored in the treatment of blinding conditions. The Food and Drug Administration, recently, has granted clinical trials using SC retinal therapy to treat complex disorders, as Stargardt's dystrophy, and patients with geographic atrophy, providing good outcomes. This study's intent is to overview the critical regeneration of the subretinal anatomy through retinal pigment epithelium transplantation, with the goal of reestablish important pathways from the retina to the occipital cortex of the brain, as well as the differentiation from pluripotent quiescent SC to adult retina, and its relationship with a primary retinal injury, different techniques of transplantation, management of immune rejection and tumorigenicity, its potential application in improving patients' vision, and, finally, approaching future directions and challenges for the treatment of several conditions.

Quantitative OCT subanalysis of eyes with choroidal neovascularization switched from multiple injections of bevacizumab or ranibizumab to intravitreal aflibercept.

BACKGROUND AND OBJECTIVE: To assess the early therapeutic response after switching from multiple injections of bevacizumab or ranibizumab to aflibercept in eyes with neovascular age-related macular degeneration (AMD). PATIENTS AND METHODS: SD-OCT scans of patients with neovascular AMD that was suboptimally responsive to multiple injections of bevacizumab or ranibizumab who were switched to aflibercept were analyzed. After segmenting these scans, the relevant volumes were computed and compared at the various time points by Student's t test. RESULTS: After switching to aflibercept, converse to the outcome of the last injection of bevacizumab or ranibizumab, statistically significant decreases of 0.32 mm(3) in neurosensory retinal volume, 0.08 mm(3) in subretinal fluid, and 0.56 mm(3) in pigment epithelial detachment were observed (P = .01, .04, and .001, respectively). The mean ETDRS visual acuity increased from 62 to 65 letters after switching (P = .04). These favorable outcomes were sustained after three monthly injections of the new drug. CONCLUSION: Switching to aflibercept therapy in eyes with persistent fluid after multiple intravitreal injections of bevacizumab or ranibizumab was associated with an early reduction in all fluid compartments and improvement in visual acuity.

Association of OCT derived drusen measurements with AMD associated-genotypic SNPs in Amish population.

PURPOSE: To investigate the association of OCT derived drusen measures in Amish age-related macular degeneration (AMD) patients with known loci for macular degeneration. METHODS: Members of the Old Order Amish community in Pennsylvania ages 50 and older were assessed for drusen area, volume and regions of retinal pigment epithelium (RPE) atrophy using a Cirrus High- Definition-OCT. Measurements were obtained in the macula region within a central circle (CC) of 3 mm diameter and a surrounding perifoveal ring (PR) of 3 to 5 mm diameter using the Cirrus OCT RPE analysis software. Other demographic information including age, gender and smoking status were collected. Study subjects were further genotyped to determine their risk for the AMD associated SNPs in SYN3, LIPC, ARMS2, C3, CFB, CETP, CFI and CFH genes using TaqMan genotyping assays. The association of genotypes with OCT measures were assessed using linear trend p-values calculated from univariate and multivariate generalized linear models. RESULTS: 432 eyes were included in the analysis. Multivariate analysis (adjusted by age, gender and smoking status) confirmed the known significant association between AMD and macular drusen with the number of CFH risk alleles for drusen area (area increased 0.12 mm2 for a risk allele increase, p<0.01), drusen volume (volume increased 0.01 mm3 for a risk allele increase, p≤0.05) and area of RPE atrophy (area increased 0.43 mm2 for a risk allele increase, p=0.003). SYN3 risk allele G is significantly associated with larger area PR (area increased 0.09 mm2 for a risk allele increase, p=0.03) and larger drusen volume in central circle (volume increased 0.01 mm3 for a risk allele increase, p=0.04). CONCLUSION: Among the genotyped SNPs tested, the CFH risk genotype appears to play a major role in determining the drusen phenotype in the Amish AMD population.

Endoftalmite fúngica bilateral endógena / Bilateral endogenous fungal endophthalmitis

Resumo É apresentado o caso de uma paciente do sexo feminino, 77 anos, internada por pielonefrite e tratada com antibóticos de amplo espectro, tendo desenvolvido endoftalmite endógena bilateral presumida por Candida. Foi submetida à vitrectomia via pars plana e injeção intravítrea de anfotericina B, além de voriconazol oral. São abordados, ainda, os aspectos clínicos da endoftalmite endógena por meio de revisão da literatura.

Abstract A 77 year-old female patient suffering from pyelonephritis developed bilateral endogenous endophthalmitis presumed by Candida after have been treated with global spectrum antibiotics. Early vitrectomy and intravitreal amphotericin B injection were performed, in addition to oral voriconazole. Clinical aspects of endogenous endophthalmitis are also pointed out by a literature review.

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. 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.

Drusen detection by confocal aperture-modulated infrared scanning laser ophthalmoscopy.

AIM: To evaluate the efficiency of drusen detection by scanning laser ophthalmoscopy (SLO) using various infrared confocal apertures and differential contrast (DC) strategies. METHODS: 11 eyes with non-neovascular age-related macular degeneration (AMD) underwent infrared imaging with a Nidek F-10 confocal SLO using multiple confocal apertures: central, ring, aperture on the right side (AR) and left side (AL), with and without use of the DC. A conventional colour fundus photograph was also obtained. Images were exported into a certified grading tool and all visible drusen were manually outlined by two graders. For each image type, the number of drusen and total drusen area were calculated, and the measurements obtained by the two graders were averaged. Intergrader reliability was evaluated, and paired t tests compared measurements between the various aperture/DC modes and the colour image. RESULTS: Agreement between graders was high (r=0.93-0.98). Drusen number values obtained with the AR (121.0, p=0.01) mode were higher than for the colour photographs (69.1). Area measurements were also significantly higher in the AR (1.93 mm(2); p=0.04) and AL modes (1.41 mm(2); p=0.03) when compared with the colour photographs (1.24 mm(2)). The addition of the DC did not seem to improve drusen detection compared with the unmodified infrared images. CONCLUSIONS: In this pilot study, drusen number and area grades were significantly higher using the AR and AL in which the laterally scattered light is captured (retromode). Use of the lateral confocal aperture may highlight subclinical drusen and aid in monitoring disease progression and response to emerging non-neovascular AMD therapies.

Subretinal implantation of retinal pigment epithelial cells derived from human embryonic stem cells: improved survival when implanted as a monolayer.

PURPOSE: To evaluate cell survival and tumorigenicity of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) transplantation in immunocompromised nude rats. Cells were transplanted as a cell suspension (CS) or as a polarized monolayer plated on a parylene membrane (PM). METHODS: Sixty-nine rats (38 male, 31 female) were surgically implanted with CS (n = 33) or PM (n = 36). Cohort subsets were killed at 1, 6, and 12 months after surgery. Both ocular tissues and systemic organs (brain, liver, kidneys, spleen, heart, and lungs) were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned. Every fifth section was stained with hematoxylin and eosin and analyzed histologically. Adjacent sections were processed for immunohistochemical analysis (as needed) using the following antibodies: anti-RPE65 (RPE-specific marker), anti-TRA-1-85 (human cell marker), anti-Ki67 (proliferation marker), anti-CD68 (macrophage), and anti-cytokeratin (epithelial marker). RESULTS: The implanted cells were immunopositive for the RPE65 and TRA-1-85. Cell survival (P = 0.006) and the presence of a monolayer (P < 0.001) of hESC-RPE were significantly higher in eyes that received the PM. Gross morphological and histological analysis of the eye and the systemic organs after the surgery revealed no evidence of tumor or ectopic tissue formation in either group. CONCLUSIONS: hESC-RPE can survive for at least 12 months in an immunocompromised animal model. Polarized monolayers of hESC-RPE show improved survival compared to cell suspensions. The lack of teratoma or any ectopic tissue formation in the implanted rats bodes well for similar results with respect to safety in human subjects.

In vivo detection of hESC-RPE cells via confocal near-infrared fundus reflectance.

BACKGROUND AND OBJECTIVE: To investigate whether the confocal near-infrared reflectance (NIR) imaging modality could detect the in vivo presence of retinal pigment epithelium cells derived from embryonic human stem cells (hESC-RPE) implanted into the subretinal space of the Royal College of Surgeons (RCS) rat. MATERIALS AND METHODS: Monthly NIR images were obtained from RCS rats implanted with either hESC-RPE seeded on a parylene membrane (n = 14) or parylene membrane without cells (n = 14). Two independent, masked investigators graded the images. Histology and immunohistochemistry were performed at different time points (150, 210, and 270 postnatal days of age). RESULTS: NIR images revealed that an average of 20.53% of the parylene membrane area was covered by hESC-RPE. RPE-65 and TRA-1-85 confirmed the presence of human-specific RPE cells in those animals. No areas corresponding to cells were found in the group implanted with membrane only. Intergrader agreement was high (r = 0.89-0.92). CONCLUSION: The NIR mode was suitable to detect the presence of hESC-RPE seeded on a membrane and implanted into the subretinal space of the RCS rat.

Artificial vision through neuronal stimulation.

INTRODUCTION: The term visual prosthesis refers to any device capable of eliciting visual percepts in an individual through electrical stimulation of any part of the visual system. BACKGROUND: Blindness can be due to eye pathology or due to damage of the lateral geniculate or visual cortex. Eye pathology other than diseases that affect the cornea and lens are numerous and some of the leading causes are diabetic retinopathy, age-related macular degeneration, retinal detachment, glaucoma, and retinal vascular occlusions. The visual prosthesis can be divided into non-retinal and retinal approaches. Non-retinal approaches include cortical and optic nerve prosthesis. Retinal approaches are aimed at eye pathologies in which at least part of the optic nerve remains intact whereas when the optic nerve is nearly completely damaged and/or the eye itself is disfigured or degenerated then a non-retinal approach is warranted. The retinal prosthesis can be placed on the surface of the retina, in the subretinal space or in the suprachoroidal space. RESULTS: Several independent groups related variable degrees of success in promoting visual sensations through electrical stimulation of the visual system. Every technique, equipment and anatomical target has its advantages and disadvantages, and the biological/electrical-mechanical interface is still the aspect of the research towards a chronic, long term, reliable biomimetic implant. CONCLUSIONS: The visual prostheses have achieved significant developments in recent years. We see continued improvement in visual acuity with increasing number and density of electrodes. Even though the visual acuity is still poor relative to normal vision, these subjects can read letters using their implants. Perhaps more importantly, blind patients can use these devices for mobility and orientation.

Knowledge, attitudes, practices and biomonitoring of farmers and residents exposed to pesticides in Brazil.

In this study, the knowledge, attitudes and practices regarding pesticide use and the levels of exposure of farmers and residents to organophosphorous and/or carbamates pesticides were evaluated in two rural settings in Brazil. A questionnaire was completed by 112 farm workers aged ≥18 years. Almost all farmers acknowledged that pesticides were potentially harmful to their health (87.5%); however, over half rarely (48.2%) or never (7.2%) used personal protective devices (PPDs). An association was found (p = 0.001) between the work regimen and the use of PPDs, with more frequent equipment use among hired laborers than those involved in family agriculture. A significant correlation (p = 0.027) was found between the reporting of adverse symptoms and the use of backpack sprayers. Mean AChE activities of farmers (n = 64) and residents (n = 18) during the exposure and non-exposure periods were significantly lower than their control groups. Mean BChE activities of farmers and residents were significantly lower than their controls during the exposure period. Among the 60 farmers that had blood samples collected in both the exposure and non-exposure (baseline) periods, 10 (16.7%) had AChE depletion of over 30% during the exposure period compared with the baseline level. Six residents living on the same farms also presented this depletion. AChE was over 30% higher than the baseline level for 19 farmers (31.7%), indicating a reboot effect. Special education programs are needed in these regions to promote the safe use of pesticides in the field to decrease the risks from exposure to pesticides for farmers, and from secondary exposure to these compounds for their families.