A novel intensified approach for treating produced water from oil extraction using a multi-tube type falling-film distillation column equipped with a biphasic thermosiphon: a promising feasibility study.

This study has the novel aim of experimentally examining the efficiency of a pilot-scale treatment plant, composed of a multi-tube type falling-film distillation column equipped with a biphasic thermosiphon, for treating a real sample of high-salinity produced water (electrical conductivity of 20,700 µS cm-1). It investigates the influence of operational parameters, including feed temperature and steam chamber temperature of the biphasic thermosiphon, on distillate flow rate and reduction of conductivity. All experimental conditions tested achieved a reduction greater than 98% in terms of electrical conductivity. The production of treated water increased with increasing feed temperature; the flow rate increased from 20.8 L h-1 to 28.2 L h-1 as the feed temperature was increased from 80 °C to 90 °C, when the steam chamber temperature was fixed at 119 °C. Within the temperature range of the steam chamber, the specific energy consumption during the treatment process, with respect to the biphasic thermosiphon, remained practically unchanged between 0.58 kWh L-1 and 0.60 kWh L-1, when the feed temperature was 90 °C. The results proved the potential of the falling-film distillation technology assisted by heat pipes to be a promising proposal for removing salinity from produced water from oil extraction operations.

Predictors of Development and Progression of Retinopathy in Patients with Type 2 Diabetes: Importance of Blood Pressure Parameters.

Diabetic retinopathy (DR) is a chronic microvascular complication associated a worse prognosis. We aimed to evaluate the predictors of development/progression of DR in a cohort of 544 high-risk patients with type 2 diabetes who had annual ophthalmologic examinations over a median follow-up of 6 years. Ambulatory blood pressure (BP) monitoring and aortic stiffness by carotid-femoral pulse wave velocity were performed. Multivariate Cox survival analysis examined the independent predictors of development or progression of DR. During follow-up, 156 patients either newly-developed or worsened DR. Patients who developed/progressed DR had longer diabetes duration, higher ambulatory and clinic BP levels, higher aortic stiffness, and poorer glycemic control than patients who did not developed/progressed DR. After adjustments for baseline retinopathy prevalence, age and sex, a longer diabetes duration (p < 0.001), higher baseline ambulatory BPs (p = 0.013, for 24-hour diastolic BP), and higher mean cumulative exposure of HbA1c (p < 0.001), clinic diastolic BP (p < 0.001) and LDL-cholesterol (p = 0.05) during follow-up were the independent predictors of development/progression of DR. BP parameters were only predictors of DR development. In conclusion, a longer diabetes duration, poorer glycemic and lipid control, and higher BPs were the main predictors of development/progression of DR. Mean cumulative clinic diastolic BP was the strongest BP-related predictor.

Neurite óptica isquêmica devida à dose inédita de sildenafila / Ischemic optic neuritis due to unprecedented dose of sildenafil

No presente relato de caso, os autores ressaltam aspectos gerais, neuro-oftalmológicos e psicodinâmicos de um paciente que apresentou neurite óptica isquêmica não arterítica devida ao uso de dose inédita da sildenafila.

In this case report, the authors emphasize general, neuro-ophthalmological and psychodynamic aspects, of a patient who developed non-arteritic ischemic optic neuropathy due to the use of unprecedented dose of sildenafil.

Biochemical analysis and decomposition products of indocyanine green in relation to solvents, dye concentrations and laser exposure.

PURPOSE: To investigate pH, ions, osmolarity and precipitation of indocyanine green (ICG), as well as the profile of ICG decomposition products (DPs) after laser exposure and the interaction with quenchers. METHODS: ICG was diluted in water, 5% glucose (GL) or balanced salt solution (BSS) to achieve concentrations of 2.5, 1, 0.25 and 0.1 mg/ml. Osmolarity, pH and precipitation were analyzed immediately and after 24 h. Precipitation analyses were done with a scanning electron microscope. Anion and iodate analyses of ICG and infracyanine green (IfCG) were performed by capillary zone electrophoresis. With regard to DPs, 0.5 mg/ml of ICG was assessed with high-performance liquid chromatography (HPLC) after 810-nm laser irradiation. DP profiles were evaluated with ICG dilution in quenchers (Trolox, histidine and DABCO) in 3 concentrations (0.1, 1 and 10 M). RESULTS: BSS promoted iso-osmotic ICG solutions of 208 mOsm (147-266) compared to GL with 177 mOsm. BSS solutions had a higher physiological pH of 7.2 compared with the GL one of 6.55. ICG precipitated more when diluted with BSS (5.95 mg); in contrast, GL showed less precipitate (3.6 mg). IfCG has no iodine derivates and other ICGs have an average 4.6% of iodate derivates. From HPLC analysis, 5 DPs were observed. The rate of DPs was higher when BSS was used (p < 0.05). Five DPs have been generated with ICG, and they may be altered with the quenchers DABCO, histidine and Trolox. CONCLUSIONS: BSS dilution induces more precipitation and DPs. ICG dilution in any solvent induces DPs. Quencher use reduces the amount of toxic DPs.

Staining properties of brilliant blue depending on different incubation times and solvents in humans.

PURPOSE: Intravitreous injection of vital dyes, e.g. brilliant blue (BBG), promotes better visualization of the internal limiting membrane (ILM). This paper investigates the staining properties of BBG depending on different incubation times and 2 types of solvents--5% glucose (GL) or saline solution--in a prospective study in patients. METHODS: This paper investigates various aspects of BBG in various methods. An interventional prospective study was conducted in patients to examine the binding properties of the blue dye diluted in either saline or 5% GL to epiretinal membranes (ERMs) and ILMs. Forty-nine consecutive patients older than 18 years scheduled for macular ERM, vitreomacular traction and macular hole surgeries were prospectively recruited. The primary outcomes of this study were the degree of ILM and ERM staining. The secondary outcomes of the study were the need of reinjection of BBG or any other dye, the ability of BBG to stain the vitreous, and frequency of complications. The staining of the ILM and ERM were graded as no staining, little, moderate or strong staining. RESULTS: There was no correlation between age (p = 0.32) or gender (p = 0.33) in the staining affinity of BBG to either the ILM or ERM. BBG may be an appropriate staining agent for the ILM in the majority (82%) of surgeries; however, in approximately half of the cases (45%) surgeons considered BBG not enough for ERM coloring and visualization. There is a tendency of BBG to stain the ILM better when saline solution is used compared to GL 5%; however, this was not statistically significant (p = 0.64). There was no difference in the staining efficacy of BBG to the ERMs by either solution (p = 0.70), despite the low staining affinity. CONCLUSION: BBG became the state-of-the-art dye for ILM identification. Differences in staining properties may imply that BBG should not be considered as first-line stain for ERM surgery. BBG is effective in ILM staining in over 80% of macular hole surgeries.

Retinal pigmented epithelial cells cytotoxicity and apoptosis through activation of the mitochondrial intrinsic pathway: role of indocyanine green, brilliant blue and implications for chromovitrectomy.

PURPOSE: To investigate the in vitro effect of four vital dyes on toxicity and apoptosis in a human retinal pigment epithelial (RPE) cell line. METHODS: ARPE-19 cells were exposed to brilliant blue (BriB), methyl blue (MetB), acid violet (AcV) and indocyanine green (ICG). Balanced salt solution was used as control. Five different concentrations of each dye (1, 0.5, 0.25, 0.05 and 0.005 mg/mL) and two exposure times (3 and 30 min) were tested. Cell viability was determined by cell count and MTS assay and cell toxicity by LDH assay. Real-time PCR and Western blotting were used to access the apoptosis process. RESULTS: ICG significantly reduced cell viability after 3 minutes of exposure at all concentrations (p<0.01). BriB was safe at concentrations up to 0.25 mg/mL and MetB at concentrations up to 0.5 mg/mL, while AcV was safe up to 0.05 mg/ml, after 3 minutes of exposure. Toxicity was higher, when the cells were treated for 30 minutes. Expression of Bax, cytochrome c and caspase-9 was upregulated at the mRNA and protein level after ICG exposure, while Bcl-2 was downregulated. AcV and MetB were similar to control. However, BriB resulted in upregulation of Bcl-2, an antiapoptotic protein. CONCLUSIONS: The safest dye used on RPE cells was MetB followed by BriB and AcV. ICG was toxic at all concentrations and exposure times tested. Moreover, ICG was the only dye that induced apoptosis in ARPE-19 cells. BriB significantly increased Bcl-2 protein levels, which might protect against the apoptosis process.

Effects of light exposure, pH, osmolarity, and solvent on the retinal pigment epithelial toxicity of vital dyes.

PURPOSE: To investigate the in vitro effect of pH, osmolarity, solvent, and light interaction on currently used and novel dyes to minimize dye-related retinal toxicity. DESIGN: Laboratory investigation. METHODS: Retinal pigment epithelium (RPE) human cells (ARPE-19) were exposed for 10 minutes to different pH solutions (4, 5, 6, 7, 7.5, 8, and 9) and glucose solutions (2.5%, 5.0%, 10%, 20%, 40%, and 50%) with osmolarity from 142 to 2530 mOsm, with and without 0.5 mg/mL trypan blue. R28 cells were also incubated with glucose (150, 310, and 1000 mOsm) and mannitol used as an osmotic control agent in both experiments. Dye-light interaction was assessed by incubating ARPE-19 for 10 minutes with trypan blue, brilliant blue, bromophenol blue, fast green, light green, or indigo carmine (0.05 mg/mL diluted in balanced saline solution) in the presence of high-brightness xenon and mercury vapor light sources. RESULTS: Solutions with nonphysiologic pH, below 7 and above 7.5, proved to be remarkably toxic to RPE cells with or without trypan blue. Also, all glucose solutions were deleterious to RPE (P < .001) even in iso-osmolar range. No harmful effect was found with mannitol solutions. Among the dyes tested, only light green and fast green were toxic to ARPE-19 (P < .001). Light exposure did not increase RPE toxicity either with xenon light or mercury vapor lamp. CONCLUSIONS: Solutions containing glucose as a dye solvent or nonphysiologic pH should be used with care in surgical situations where the RPE is exposed. Light exposure under present assay conditions did not increase the RPE toxicity.

In vivo, in vitro toxicity and in vitro angiogenic inhibition of sunitinib malate.

PURPOSE: To evaluate the in vivo and in vitro toxicity of sunitinib malate, a multikinase inhibitor molecule. DESIGN: Experimental, Prospective, Controlled. METHODS: Human retinal pigment epithelial (ARPE-19) and human umbilical vein endothelialcells (HUVECS) were used in a culture toxicity test and exposed to different concentrations of sunitinib malate for 18 hours. The HUVECs also were cultured to evaluate the angiogenesis inhibitory effect of sunitinib malate. Fundus photography and angiographic, electrophysiologic, and histopathologic evaluations with light and electron microscopy were performed in two groups of five rabbits each that received different intravitreal concentrations of the drug. Each rabbit received 0.1 ml of sunitinib malate in the right eye (one group with 12.5 mg/ml, the other group with 25 mg/ml); all animals received 0.1 ml of physiologic saline solution in the left eye. After sacrifice, the eyes were enucleated and fixed with modified Karnovsky solution. RESULTS: No toxicity related to sunitinib malate was observed using an in vitro model with the 12.5 and 25 mg/ml solutions in HUVEC and ARPE cell cultures. No toxicity was observed in the in vivo model with 12.5 mg/ml, but light microscopy showed that the 25 mg/ml solution damaged the photoreceptors layer. No functional changes in the electroretinogram were observed in any group. CONCLUSIONS: Sunitinib malate 12.5 mg/ml caused no toxicity in in vivo and in vitro models, but the 25 mg/ml concentration caused retinal changes suggesting toxicity in the in vivo model. Further research with the drug is needed in models of ocular neovascularization.

Toxicological considerations for intravitreal drugs.

INTRODUCTION: Intravitreal injections are a very common procedure and are the most effective route of drug delivery to the retina. There are currently several drugs available and even more are in development; therefore, safety is a very important concern. AREAS COVERED: The toxicological considerations of the most common drugs used for intravitreal pharmacotherapy such as anti-VEGFs, corticosteroids and antibiotics. Emerging agents such as anti-TNFs, VEGF-trap and kinase inhibitors are also discussed. An assessment of the efficacy and safety issues of the most relevant drugs including bevacizumab, ranibizumab and triamcinolone is presented. EXPERT OPINION: The toxicology and safety profiles are available for several drugs that are either in use or will be available for intravitreal injections. Retinal pharmacotherapy is very effective for different retinal diseases; however safety is a very important issue when intravitreal injections are applied and the possibility of retinal toxicity should always be kept in mind. Bevacizumab and ranibizumab are effective for the therapy of wet-age-related macular degeneration and macular edema, while triamcinolone remains an alternative agent to treat secondary macular edema. It is important, as some of these drugs will be used for extended periods of time, that their long-term toxicological effects are better understood.

Perspective on fluid and solid dynamics in different pars plana vitrectomy systems.

PURPOSE: To summarize current concepts and recent data from the literature about different vitrectomy machines and small-gauge systems based on physical laws. DESIGN: Interpretive essay. METHODS: Review and synthesis of selected recent literature with interpretation and perspective. RESULTS: Pars plana vitrectomy can be performed with a wide variety of treatment strategies, for multiple diseases, and with different materials (solids and fluids). We discuss a variety of machines and system settings (peristaltic pump, duty cycle, aspiration, and infusion controls) targeting safer and the most effective surgery with detailed explanations of the physical properties. CONCLUSIONS: Effective management of new surgical strategies is based on recognizing and addressing various physical characteristics in disease and ocular settings. Although the properties of machine are expanding, the long-term efficacy and safety of most new approaches have yet to be established in controlled clinical trials.

Retinal and ocular toxicity in ocular application of drugs and chemicals--part I: animal models and toxicity assays.

AIMS: Experimental retinal research has gained great importance due to the ophthalmic pharmacotherapy era. An increasing number of drugs are constantly released into the market for the treatment of retinal diseases. In this review, animal species, animal models and toxicity assays in retinal research are discussed. METHODS: An extensive search of the literature was performed to review various aspects of the methods of investigation of drug toxicity. The different types of animal species, as well as single animal models available for the evaluation of safety and efficacy of retinal pharmacotherapy, were identified. In addition, a large variety of reported laboratory techniques were critically examined. RESULTS: In vitro studies are the first-line experiments for the development of a new drug for retinal diseases, using retinal pigment epithelial cells and other cell lines. The next step involves in vivo animal studies where nonhuman primates are considered the gold standard. However, cost and legal issues make their use difficult. Mice and rats provide genetically controlled models for investigations. Pigs, dogs and cats represent good large-size animal models, while rabbits are one of the most used species for retinal toxicity evaluations. Various laboratory methods were identified, including light microscopy, electron microscopy, electroretinography and new emerging methods, such as optical coherence tomography and scanning laser ophthalmoscopy for experimental purposes. CONCLUSIONS: A great number of animal species and models are available that simulate retinal diseases and provide experimental data for further human use. Work with animal models should include properly designed toxicity assays to obtain reliable results for safety and efficacy.

Ability of new vital dyes to stain intraocular membranes and tissues in ocular surgery.

PURPOSE: To evaluate the ability of novel dyes to stain lens capsule (LC), internal limiting membrane (ILM), epiretinal membrane (ERM), and vitreous. DESIGN: Experimental study in animal and human donor eyes. METHODS: Thirteen dyes, methyl violet, crystal violet, eosin Y, sudan black B, methylene blue, toluidine blue, light green, indigo carmine, fast green, congo red, evans blue, brilliant blue, and bromophenol blue, were injected onto the LC and ILM of enucleated porcine eyes. The vitreous was stained with 2 mL of dyes for 1 minute. Six dyes (indigo carmine, evans blue, fast green, light green, bromophenol blue, and brilliant blue) were selected for experiments in human donor eyes and freshly removed ERM. RESULTS: In the porcine eyes, ILM staining with methylene blue, toluidine blue, indigo carmine, evans blue, bromophenol blue, and fast green was moderate, and methyl violet, crystal violet, brilliant blue, or sudan black resulted in strong staining. Methyl violet, crystal violet, sudan black, toluidine blue, and methylene blue caused histologic damage in porcine retinas. Vitreous examination revealed moderate staining with congo red, crystal violet, fast green, eosin Y, methylene blue, toluidine blue, brilliant blue, bromophenol blue, and methyl violet and strong staining with light green and evans blue. ERMs showed strong staining with 0.5% evans blue and moderate staining with 0.5% light green, fast green, brilliant blue, and bromophenol blue. Evaluation of donor eyes disclosed moderate staining with evans blue, light green, and bromophenol blue and strong staining with 0.5% brilliant blue. Moderate or strong staining of the vitreous occurred with most dyes. LC evaluation showed moderate staining with 0.5% evans blue, fast green, and brilliant blue, whereas 0.5% light green produced strong LC staining. CONCLUSIONS: Brilliant blue shows the best ILM staining, whereas bromophenol blue, evans blue, and light green also stain ILM. Most dyes bind well to LC, vitreous, and ERM.

Corantes vitais em cromovitrectomia / Vital dyes in chromovitrectomy

O objetivo do artigo é apresentar os dados atuais da aplicação de corantes vitais durante cirurgia vitreorretiniana, "cromovitrectomia", bem como uma revisão da literatura atual sobre o assunto no tocante às técnicas de aplicação, indicações e complicações em cromovitrectomia. Um grande número de publicações tem abordado o perfil tóxico da indocianina verde na cromovitrectomia. Dados experimentais mostram uma toxicidade dose-dependente da mesma em várias populações de células retinianas. Novas gerações de corantes incluem: azul tripan, azul patente, acetato de triancinolona, infracianina verde, fluoresceína sódica, azul de bromofenol, acetato de fluorometolona e azul brilhante. Novos instrumentos podem permitir um corar seletivo de estruturas durante a vitrectomia. Este artigo mostra que o campo da cromovitrectomia está em plena expansão de pesquisas. Os corantes de primeira linha são a indocianina verde, infracianina verde e o azul brilhante. Azul patente, azul de bromofenol e azul tripan surgem como novos adjuvantes para melhor observação da membrana epirretiniana. Demais corantes que surgiram merecem maior investigação.

The aim of this article is to present the current data with regard to the application of vital dyes during vitreoretinal surgery, "chromovitrectomy", as well as to overview the current literature regarding the properties of dyes, techniques of application, indications and complications in chromovitrectomy. A large body of published research has recently addressed the toxicity profile of indocyanine green for chromovitrectomy. Experimental data demonstrate dose-dependent toxicity of indocyanine green to various retinal cells. Newer generation vital dyes for chromovitrectomy include trypan blue, patent blue, triamcinolone acetonide, infracyanine green, sodium fluorescein, bromophenol blue, fluorometholone acetate and brilliant blue. Novel instruments may enable a selective painting of preretinal tissues during chromovitrectomy. This review suggests that the field of chromovitrectomy represents an expanding area of research. The first line agents for internal limiting membrane staining in chromovitrectomy are indocyanine green, infracyanine green, and brilliant blue. Patent blue, bromophenol blue and trypan blue arose as outstanding biostains for visualization of epiretinal membranes. Novel dyes available for chromovitrectomy deserve further investigation.

The use of vital dyes in ocular surgery.

Vital dyes have advanced diagnosis and surgical technique in various specialties, including oncology, gastroenterology, and ophthalmology. In ocular surgery vital dyes are widely used in cataract and vitreoretinal surgery. Worldwide, intra-operative use of trypan blue during cataract surgery has enhanced visualization of the anterior capsule during capsulorrhexis, and patent blue has been recently licensed in Europe for cataract surgery. For chromovitrectomy, the vital dyes indocyanine green, infracyanine green, and brilliant blue stain the internal limiting membrane, and trypan blue and triamcinolone acetonide help visualize epiretinal membranes and vitreous, respectively. Intra-operative vital dyes are finding uses in corneal, glaucoma, orbit, strabismus, and conjunctival surgery. We provide a summary of current knowledge of the use of vital dyes in ocular surgery. We review the properties of dyes, techniques of application, indications, and complications in ocular surgery. Vital dyes represent an expanding area of research, and novel dyes deserve further investigation.

Preclinical investigation of the retinal biocompatibility of six novel vital dyes for chromovitrectomy.

PURPOSE: To investigate the retinal biocompatibility of six novel vital dyes for chromovitrectomy. METHODS: An amount of 0.05 mL of 0.5% and 0.05% light green (LG), fast green (FG), Evans blue (EB), brilliant blue (BriB), bromophenol blue (BroB), or indigo carmine (IC) was injected intravitreally in the right eye, whereas in the left eye balanced salt solution was applied for control in rabbits' eyes. Clinical examination, fluorescein angiography, histology with light microscopy, and transmission electron microscopy were performed after 1 and 7 days. Retinal cell layers were evaluated for morphologic alterations and number of cells. The electroretinographic changes were assessed at baseline, 24 hours and 7 days. RESULTS: Fluorescein angiography disclosed hypofluorescent spots only in the 0.5% EB group. Light microscopy and transmission electron microscopy disclosed slight focal morphologic changes in eyes exposed to 0.05% IC, FG, BriB, similar to the control at 1 and 7 days. In the lower dose groups, EB, LG, and BroB caused substantial retinal alterations by light microscopy. At the higher dose, BroB and EB produced diffuse cellular edema and vacuolization within the ganglion cells, bipolar cells, and photoreceptors. FG and IC at 0.5% caused slight retinal alterations similar to balanced salt solution injection. LG at 0.5% caused diffuse vacuolization of bipolar cells after 1 and 7 days. Injection of 0.5% EB caused a significant decrease in neuroretinal cell counts in comparison to control eyes in the 7-day examination (P < 0.05). Electroretinography revealed intermittent prolonged latency and decreased amplitude in eyes injected with 0.5% EB, LG, BriB, and BroB, while at the lower dose, only LG and EB induced few functional changes. CONCLUSION: The progressive order of retinal biocompatibility, from safest to most toxic, was IC, FG, BriB, BroB, LG, EB.

Vital dyes and light sources for chromovitrectomy: comparative assessment of osmolarity, pH, and spectrophotometry.

PURPOSE: To investigate the in vitro pH, osmolarity, spectral, and photostability properties of nine vital dyes for vitreoretinal surgery. METHODS: Nine dyes-indocyanine green (ICG), trypan blue (TB), brilliant blue (BriB), bromophenol blue (BroB), Congo red (CR), light green (LG), fast green (FG), indigo carmine (IC) and Evans blue (EB)-diluted in three solvents (saline solution, glucose 5%, and water) were tested for osmolarity and pH. Spectrophotometry was used to determine absorbance properties of 27 solutions. Irradiance emission spectra of seven endoillumination light sources and fiber-optics were compared with dye absorbance curves. RESULTS: Dye osmolarity in saline solution and glucose 5% varied widely (257-385 mOsm) and was lower (0-54 mOsm) when dyes were dissolved in water. Dyes diluted in three solvents showed pH values varying from 2.6 to 9.85. ICG, LG, TB, BroB, CR, and IC demonstrated different absorbances, depending on the solvent. BriB and FG showed similar absorbance curves with different solvents. Spectrophometric analysis showed that all dyes except ICG had remarkable spectral overlap with the light sources. Among endoillumination fiber-optics, overlap was greatest with dual-output illumination with an integrated laser pathway and least with a mercury vapor lamp. CONCLUSIONS: Vital dyes showed variable osmolarity and pH, which also depended on the solvent used. Interaction of light from endoillumination source and vital dye may increase or decrease the risk for toxicity, making appropriate selection of both a desirable way to minimize the risk for phototoxic effects.

[Vital dyes in chromovitrectomy]. / Corantes vitais em cromovitrectomia.

The aim of this article is to present the current data with regard to the application of vital dyes during vitreoretinal surgery, 'chromovitrectomy', as well as to overview the current literature regarding the properties of dyes, techniques of application, indications and complications in chromovitrectomy. A large body of published research has recently addressed the toxicity profile of indocyanine green for chromovitrectomy. Experimental data demonstrate dose-dependent toxicity of indocyanine green to various retinal cells. Newer generation vital dyes for chromovitrectomy include trypan blue, patent blue, triamcinolone acetonide, infracyanine green, sodium fluorescein, bromophenol blue, fluorometholone acetate and brilliant blue. Novel instruments may enable a selective painting of preretinal tissues during chromovitrectomy. This review suggests that the field of chromovitrectomy represents an expanding area of research. The first line agents for internal limiting membrane staining in chromovitrectomy are indocyanine green, infracyanine green, and brilliant blue. Patent blue, bromophenol blue and trypan blue arose as outstanding biostains for visualization of epiretinal membranes. Novel dyes available for chromovitrectomy deserve further investigation.

Técnica para injeção intravítrea de drogas no tratamento de doenças vítreorretinianas / Technique of intravitreal drug injection for therapy of vitreoretinal diseases

A injeção intravítrea é atualmente a técnica mais utilizada no tratamento de várias doenças vítreorretinianas. Neste artigo serão discutidas a técnica e complicações da injeção intravítrea de drogas no tratamento de doenças vítreorretinianas. Em resumo, a técnica envolve várias etapas. Inicialmente dias antes da injeção pode-se realizar aplicação de antibióticos e acetazolamida para prevenção de infecção e redução da pressão intra-ocular. Antes do procedimento deve-se dilatar a pupila e executar anestesia tópica com colírios ou gel anestésico. A antissepsia pré-operatória envolve aplicação de colírios de iodo-povidona 5 por cento no fundo de saco conjuntival ao menos 10 minutos antes do procedimento. A injeção deve ser realizada no centro cirúrgico com uso de luvas estéreis e máscara pelo cirurgião. O olho deve ser exposto com blefarostato estéril, e proteção com "sterile-drape" para evitar contato entre a agulha e pálpebras/cílios. A agulha deve ser posicionada no momento da injeção a 3,5 - 4 mm do limbo, e leve mobilização da conjuntiva com um cotonete estéril ou uma pinça facilitam a penetração da agulha através da conjuntiva e esclera. A agulha deve ser inserida gentilmente para dentro da cavidade vítrea até 6 mm de profundidade. Imediatamente após a injeção o paciente deve ser examinado por técnica de oftalmoscopia binocular indireta. Caso a acuidade visual seja ausência de percepção luminosa ou oclusão vascular arterial retiniana seja observada, terapias para diminuição da pressão como paracentese na camada anterior ou massagem por oculopressão diretamente sobre o globo ocular devem ser imediatamente tomadas. A alta ambulatorial deve ser realizada quando o cirurgião estiver ciente da ausência de complicações intra-operatórias; o paciente deverá sair do centro cirúrgico com curativo oclusivo. O paciente deve ser submetido a exame oftalmológico completo no primeiro dia pós-operatório quando associação de antibióticos com corticosteróides...

Intravitreal injections are the standard technique applied in the treatment of some vitreoretinal diseases. In this paper the technique and complications of intravitreal injections are presented. In summary, the procedure involves various consecutive steps. Initially, days before the treatment topical antibiotics and acetazolamide may be prescribed for reduction of the ocular flora and intraocular pressure. Before the injection, the pupil should be dilated and topical anesthesia should be achieved. Injection shall be performed in the operating room under sterile conditions, the surgeon should wear surgical gloves and mask. The eye is then exposed with sterile blepharostat and sterile-drape thereby providing protection of the needle against the contact with contaminated lashes and lids. Injection is done 3.5 mm from the limbus through the pars plana. The needle should be inserted up to 6 mm into the vitreous cavity. Immediately after injection the patient must be examined by indirect ophthalmoscopy to verify central artery perfusion and complications as vitreous hemorrhage. Visual acuity better than light perception should be detected right after injection. If persistent central retinal artery occlusion is diagnosed, anterior chamber paracentesis should be performed. The patient may be discharged with an occlusive patch. Examination at the first postoperative day should exclude various complications such as endophthalmitis, and topical steroid and antibiotics should be prescribed for 7 days. Some complications encountered after intravitreal injections include retinal detachment, vitreous hemorrhage, cataract, uveitis, ocular hypertension, or endophthalmitis.

Fluid dynamics in three 25-gauge vitrectomy systems: principles for use in vitreoretinal surgery.

PURPOSE: To compare infusion and extrusion fluid volumes with three 25-gauge vitrectomy systems. METHODS: The infusion and aspiration rates of 25-gauge systems from Alcon (Fort Worth, TX, USA), Bausch & Lomb (St Louis, MO, USA), and the Dutch Ophthalmic Research Centre (DORC, Zuidland, the Netherlands) were measured in vitro using balanced saline solution with different heights (40, 60, 80, 100, 120 cm) of infusion bottle, cutter velocities (800, 1100, 1500 cuts/ min) and aspiration powers (100, 200, 300, 400, 500 mmHg). RESULTS: The infusion flow velocities differed among the systems (p < 0.001 for all comparisons [p-values 0.0009-0.0001]). The aspiration rates of the Alcon and Bausch & Lomb systems were lower than that of the DORC system (p < 0.02 for all comparisons [p-values 0.018-0.002]). CONCLUSIONS: Infusion and extrusion fluid rates differ among 25-gauge vitrectomy systems. These results may help to optimize ideal aspiration and infusion parameters among 25-gauge vitrectomy systems used to treat vitreoretinal diseases.

Morphologic and clinical effects of subretinal injection of indocyanine green and infracyanine green in rabbits.

PURPOSE: The aim of this study was to determine the effects of subretinal injection of indocyanine green (ICG), infracyanine (IfCG), and balanced salt solution (BSS) in rabbits. METHODS: Ten (10) animals were subjected to a subretinal injection of 0.05% ICG (279 mOsm), 0.5% IfCG (276 mOsm), and BSS (300 mOsm) used as a control. Animals were examined at 6, 12, and 24 h and 14 days following the surgical procedure by indirect binocular ophthalmoscopy, fluorescein angiography (FA), and light and transmission electron microscopy. RESULTS: The subretinal injection of ICG caused damage to all retinal layers and retinal pigment epithelium (RPE) during the entire follow-up. Subretinal injection of IfCG resulted in abnormalities of the photoreceptor outer segments (POSs) during the entire follow-up; however, abnormalities of the photoreceptor inner segments (PISs) and outer nuclear layer (ONL) were observed only 24 h and 14 days after surgery; no RPE damage was observed. FA showed that window defects were more prominent in the subretinal ICG bleb position than the IfCG-related area. BSS caused only abnormalities of the POS layer and no RPE alterations. CONCLUSIONS: Subretinal injection of 0.05% ICG results in more significant retinal damage than 0.5% IfCG. In this model, iodine-free IfCG demonstrates a safer profile than a tenfold lower concentration of ICG, which contains iodine in its composition.