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ABSTRACT Purpose: To evaluate the predictive value of initial intraocular pressure difference of the detached and fellow eyes of patients with complex rhegmatogenous retinal detachment on postoperative persistent ocular hypotony. Methods: This retrospective observational study included 538 eyes of 538 unilateral complex rhegmatogenous retinal detachment patients with a proliferative vitreoretinopathy grade of C-1 or higher, treated with silicone oil endotamponade following pars plana vitrectomy. The patients were divided into Group A (patients having silicone oil removal without ocular hypotony; n=504) and Group B (patients with persistent ocular hypotony following silicone oil removal [n=8, 23.5%] and with retained silicone oil [n=26, 76.5%] due to the risk of persistent ocular hypotony; total n=34). Ocular hypotony was defined as an intraocular pressure of <6 mmHg on two or more occasions. Patients' demographics, including age, sex, and follow-up time, and ocular characteristics, including ocular surgical and trauma history, initial and final best-corrected visual acuity, intraocular pressure and initial intraocular pressure difference of the detached and fellow eyes, and anatomical success rates and postoperative complications, were retrospectively collected from the electronic patient files. Results: The initial intraocular pressure was significantly lower in the detached eyes of Group B than in Group A (8.3 ± 3.5 vs. 12.9 ± 3.3, p<0.001). Also, the initial intraocular pressure difference was significantly higher in Group B than in Group A (8.9 ± 3.2 vs. 2.2 ± 2.7mmHg, p<0.001). The receiver operating characteristic curve analysis showed that the cutoff value of the initial intraocular pressure difference was 7.5mmHg for the risk of persistent ocular hypotony. The most influential factors on postoperative persistent ocular hypotony in the binary logistic regression analysis were the initial intraocular pressure difference and the need for a retinectomy. Conclusion: In eyes with complex rhegmatogenous retinal detachment treated with pars plana vitrectomy and silicone oil tamponade, the initial intraocular pressure difference could be of value in predicting postoperative persistent ocular hypotony and could guide surgeons on the decision of silicone oil removal.

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PURPOSE: To verify the correlation between the full-macular and the ganglion cell complex (GCC) thickness measurements and retinal sensitivity (RS) assessed by microperimetry (MP) 6 months after surgical peeling for idiopathic epiretinal membrane (ERM). METHODS: Forty-three were submitted to pars-plana posterior vitrectomy (PPV) with concomitant peeling of internal limiting membrane (ILM) for idiopathic ERM treatment. Best-corrected visual acuity (BCVA) and 3D volumetric high-definition optical coherence tomography (OCT) imaging were preoperatively acquired. Six months after the surgery, BCVA, OCT imaging, and RS measured by MP were assessed. For the OCT parameters, we analyzed both the full-macular and the ganglion cell layer complex (GCC) thicknesses. The MP parameters tested were 44 points covering 20 central degrees (6 mm), with direct correspondence with the nine sectors of the OCT-ETDRS map. This approach enables the direct topographic correlation between the structure and functional measurements. The OCT and MP exam measurements were also performed in 43 eyes of age-matched healthy controls. Correlations between BCVA, RS, and OCT parameters were examined. RESULTS:  All patients exhibited a substantial improvement in visual acuity following surgery. The RS parameters were significantly lower in patients compared to the controls. The full-macular thickness measurements were thicker than controls preoperatively and significantly reduced postoperatively; however, remaining significantly higher than controls, in the 4 inner sectors, at the fovea and for the average macular thickness. Preoperative GCC measurements were higher than those in controls. There was a significant reduction in GCC thickness in all sectors postoperatively, especially in the outer sectors, as well as in the average macular thickness. A positive correlation was found between full-macular and GCC thickness and RS postoperatively in several sectors. CONCLUSIONS: Our results demonstrate that ERM peeling can improve visual acuity in the postoperative period. However, RS may not fully restore, remaining significantly lower when compared to the controls. Both full-macular and GCC thickness measurements were reduced 6 months after surgery. However, significant thinning of the GCC thickness was observed when compared to the normal control eyes, indicating the occurrence of some degree of ganglion cell layer atrophy. We have demonstrated significant correlations among various OCT thickness parameters, particularly for GCC measurements. We believe that GCC integrity may play an important role in visual function after ERM surgery, and that MP may help better understand the correlations between structural and functional findings following ERM surgery.

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This study aimed to determine the pars plana length in postmortem human eyes using advanced morphometric techniques and correlate demographics to ocular metrics such as age, sex, ethnicity, and axial length. Between February and July 2005, we conducted a cross-sectional observational study on 46 human cadaver eyes deemed unsuitable for transplant by the SBO Eye Bank. The morphometric analysis was performed on projected images using a surgical microscope and a video-microscopy system with a 20.5:1 correction factor. The pars plana length was measured three times per quadrant, with the final value being the mean of these measurements. Of the 46 eyes collected, 9 were unsuitable for the study due to technical constraints in conducting intraocular measurements. Overall, the average axial length was 25.20 mm. The average pars plana length was 3.8 mm in all quadrants, with no measurements below 2.8 mm or above 4.9 mm. There were no statistically significant variations across quadrants or with age, sex, axial length, or laterality. Accurately defining the pars plana dimensions is crucial for safely accessing the posterior segment of the eye and minimizing complications during intraocular procedures, such as intravitreal injections and vitreoretinal surgeries.

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PURPOSE: We aimed to compare the visual outcomes after pars plana vitrectomy (PPV) versus tap and inject (T&I) in fungal endophthalmitis (FE) reported in the literature and to compare the findings from the literature with data from a reference centre. METHODS: We performed a systematic review and meta-analysis of studies reporting the use of PPV versus T&I in FE. We also performed a retrospective review of the clinical records of patients with endophthalmitis from a reference centre in Colombia. RESULTS: We included 13 studies with 334 eyes; 53.59% received PPV and 46.4% received T&I. The overall relative risk of improving ≥ 2 lines in PPV versus T&I was 0.98 (95% confidence interval [CI] 0.80-1.22; p = 0.88) with a mean difference of final visual acuity of 0.26 (95% CI 0.12-0.63; p = 0.18). There were no significant differences in subgroup analysis. Data from the reference centre included 32 endophthalmitis cases, 15.6% of which had a fungal aetiology (80% received PPV and 20% T&I). There were no significant differences in the subgroup analysis. CONCLUSIONS: Based on the findings from the literature and the reference centre, T&I is noninferior to PPV. This is the first meta-analysis in the literature evaluating these effects in FE. It is necessary to execute new prospective randomised controlled studies in patients with endophthalmitis.

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BACKGROUND: To verify the correlation between retinal sensitivity (RS) assessed by the microperimetry (MP) and optical coherence tomography (OCT) parameters measured in eyes submitted to pars-plana vitrectomy (PPV) for idiopathic epiretinal membrane (ERM) treatment. METHODS: 43 patients underwent PPV. Best-corrected visual acuity (BCVA) and OCT imaging were acquired preoperatively and 6 months after surgery. The RS values were recorded 6 months after the surgery. Total macular thickness (TMT) measurements and OCT-evaluated structural findings were also analyzed. The MP examination tested 44 points, with direct topographic correspondence with the OCT-ETDRS map. Correlations between BCVA, RS, and OCT parameters were assessed. RESULTS: TMT measurements in patients were significantly thicker preoperatively and reduced after surgery. All patients demonstrated BCVA improvements after surgery. The RS parameters after surgery were significantly lower in patients. For OCT structural analyses, patients with lower RS at the fovea correlated with the preexisting disorganization of retinal inner layers (DRIL). In addition, lower RS values were associated with DRIL, outer retinal changes (ORC), and intraretinal microcysts after surgery. CONCLUSIONS: The RS values after surgery were significantly lower when compared to controls. The DRIL presence before and after surgery, and microcysts and ORC after surgery were related to worse visual outcomes.

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Purpose: To describe the surgical outcomes of rhegmatogenous retinal detachments (RRDs) associated with giant retinal tears (GRTs) and define factors associated with primary anatomic failure. Methods: This retrospective consecutive study comprised primary GRT-RRD surgeries between 1999 and 2021 at a single institution. Exclusion criteria were a follow-up of less than 3 months and incomplete surgical data. Results: The series included 69 eyes (64 patients). Single-surgery anatomic success (SSAS) was achieved in 75% and final anatomic success (FAS) in 90%. The mean logMAR visual acuity improved from 1.5 ± 1.1 to 0.6 ± 0.9. Preoperative factors significantly associated with redetachment were proliferative vitreoretinopathy (PVR) (odds ratio [OR], 6.2; P < .01), hypotony (OR, 13.6; P < .01), and a 180-degree or larger GRT (OR, 3.3; P = .04). All cases were treated with pars plana vitrectomy (PPV) and perfluoro-N-octane (PFCL). Perfluoropropane (C3F8) was used in 59% and silicone oil in 41%; the redetachment rate was significantly lower in gas cases (15% vs 39%) (P = .02). An encircling band, placed in 84% eyes, had a tendency to reduce redetachment (22% vs 36%) (P = .32). Lensectomy was performed in 61% of phakic eyes, with no effect on redetachment (20% vs 21%) (P = .92). On multivariate analysis, PVR and hypotony were significantly associated with redetachment. Conclusions: PPV with PFCL achieved high SSAS and FAS rates. PVR and hypotony were the main preoperative factors associated with anatomic failure. In cases without PVR, C3F8 tamponade significantly increased SSAS. Encircling scleral buckling showed a nonsignificant tendency toward an increase in SSAS. Lensectomy had no effect on SSAS.

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Dentro de las enfermedades vasculares de la retina, la oclusión venosa retiniana es relativamente frecuente y debido a sus complicaciones afecta de forma moderada o grave la visión. Las opciones terapéuticas aplicadas en el edema macular y los desprendimientos de retina traccionales causados por las oclusiones venosas son varias. Se realizó una revisión en la literatura científica para valorar la eficacia y seguridad del uso combinado de diferentes terapias que incluye los antiangiogénicos y esteroides intravítreos con o sin aplicación de láser, así como la vitrectomía pars plana como alternativas de tratamiento de las complicaciones de la enfermedad oclusiva venosa retiniana. Aun cuando los antiangiogénicos se consideren como primera línea de tratamiento en la oclusión venosa retiniana, en varios casos hay mejor respuesta en sus combinaciones y de los esteroides con láser. Para resolver el desprendimiento de retina traccional y hemorragia vítrea, debidas a las oclusiones venosas, se requiere, mayormente, operación de vitrectomía pars plana. Se realizó una búsqueda en bases de datos electrónicas como PubMed, Cochrane y otras publicaciones relacionadas con las alternativas de tratamiento de la obstrucción venosa retiniana en los últimos años.

Among retinal vascular diseases, retinal venous occlusion is relatively frequent and due to its complications, it moderately or severely affects vision. The therapeutic options applied in macular edema and tractional retinal detachments caused by venous occlusions are several. A review of the scientific literature was performed to assess the efficacy and safety of the combined use of different therapies including intravitreal antiangiogenics and steroids with or without laser application, as well as pars plana vitrectomy as treatment alternatives for the complications of retinal venous occlusive disease. Even when antiangiogenics are considered as first line of treatment in retinal venous occlusion, in several cases there is better response in their combinations and steroids with laser. To resolve tractional retinal detachment and vitreous hemorrhage due to venous occlusions, a pars plana vitrectomy operation is mostly required. A search was made in electronic databases such as PubMed, Cochrane and other publications related to treatment alternatives for retinal venous obstruction in recent years.

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INTRODUCTION AND IMPORTANCE: Complications related to silicone oil tamponade are frequent. There are reports of events related to silicone oil (SO) injection during Pars Plana Vitrectomy (PPV). This case presents the unexpected injection of SO in the suprachoroidal space. The proper management of this complication along with the preventive measures are discussed. CASE PRESENTATION: A 38-year-old male presented with a one-week history of decreased vision in his right eye (OD). His visual acuity was hand motion (HM). A late-onset retinal detachment recurrence with proliferative vitreoretinopathy (PVR) in his OD was diagnosed. Cataract surgery and PPV were scheduled. During PPV, a choroidal detachment (CD) secondary to the suprachoroidal injection of silicone oil (SO) was noted. Suprachoroidal SO was identified timely and was managed with external drainage through a posterior sclerotomy. CLINICAL DISCUSSION: Suprachoroidal silicone oil injection is a potential complication during PPV. For the management of this complication, the drainage of the silicone oil from the suprachoroidal space through a posterior sclerotomy may be considered as an option. This complication may be avoided by periodically checking the correct position of the infusion cannula during the PPV, by injecting the SO into the vitreous cavity under direct visualization and by using automated injection systems. CONCLUSION: Suprachoroidal silicone oil injection is an intraoperative complication that might be avoided by cross-checking the correct position of the infusion cannula and by injecting SO under direct visualization.

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BACKGROUND: We conducted a systematic review to compare  the effects of pneumatic vitreolysis (PV), enzymatic vitreolysis (EVL) with ocriplasmin, and pars plana vitrectomy (PPV) on vitreomacular traction (VMT) syndrome and macular holes (MHs) to assess their efficacy as treatment options. METHODS: Databases, including PubMed, ClinicalTrials.gov ( www. CLINICALTRIALS: gov ), the Cochrane Central Register of Controlled Trials (CENTRAL)-including the Cochrane Eyes and Vision Group Trials Register (The Cochrane Library 2013, Issue 2)-, Ovid MEDLINE, and EMBASE (January 2000-October 2022), were searched to identify studies comparing the outcomes of PV versus PPV, PPV versus ocriplasmin and ocriplasmin versus PV. RevMan 5.1 was used for the meta-analysis of the studies. RESULTS: Among the 89 studies, 79 were considered eligible for qualitative analysis, and 10 quantitative studies were subjected to meta-analysis. PPV resulted in better postoperative visual acuity improvement than ocriplasmin (standardized mean deviation (SMD) = 0.38, 95% CI 0.03-0.73, p = 0.0003). PV resulted in no significant difference in visual improvement compared  with  PPV (SMD = - 0.15, 95% CI - 0.47 to 0.16, p = 0.35). PPV was significantly more effective in terms of the VMT release rate (risk ratio = 0.48, 95% CI 0.38-0.62, p = 0.00001) and MH closure rate (risk ratio = 0.49, 95% CI 0.30-0.81, p = 0.006) than ocriplasmin. PV was more effective than ocriplasmin in terms of the VMT release rate (risk ratio = 0.49, 95% CI 0.35-0.70, p = 0.0001). Qualitative analysis showed MH closure rates of 46%, 47.8%, and 95% and VMT releases rates of 46%, 68% and 100% after ocriplasmin, PV, and PPV treatments, respectively.  Adverse events and postoperative complications occurring after treatment have also been documented in these studies. CONCLUSION: PPV appears to be the most promising option for MH closure and VMT release, with fewer serious complications than EVL  or PV. However, given the limited number of studies comparing these treatments, further research is needed to establish the superiority of PPV over the other options.

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PURPOSE: The aim of this article is to do a comprehensive literature review about the current role of pars plana vitrectomy in uveitis and in its different structural complications such as cystoid macular edema, epiretinal membrane, macular hole, and retinal detachment. METHODS: This comprehensive literature review was performed based on a search on PubMed, BioMed Central, Science Open, and CORE databases, of relevant articles abording pars plana vitrectomy in uveitis. DISCUSSION: Uveitis is a complex disease with multiple etiologies and pathogenic mechanisms. Therapeutic pars plana vitrectomy (PPV) may aid in uveitic structural complications such as cystoid macular edema, epiretinal membranes, macular hole, and retinal detachments even though some cases may present unpredictable visual outcomes. Diagnostic PPV with appropriate ancillary testing is also a valuable tool for the assessment and diagnosis of uveitis in a large proportion of patients. CONCLUSION: Over the years, pars plana vitrectomy has undergone significant transformations since its invention nearly 5 decades ago, however, the quality of evidence in the literature regarding its use for uveitis has not improved in the same way. Even though some structural uveitis complications (as previously mentioned) may respond well to surgery, there is still a certain unpredictability regarding its visual outcomes. On the other hand, diagnostic vitrectomy with appropriate ancillary testing is also a valuable tool for the assessment and diagnosis of uveitis in a large proportion of patients.

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The phenomenon of plasticity in the striatum, and its relation with the striatum-nigra neuronal circuit has clinical and neurophysiological relevance to Parkinson and epilepsy. High frequency stimulation (HFS) can induce neural plasticity. Furthermore, it is possible to induce plasticity in the dorsal striatum and this can be modulated by substantia nigra activity. But it has not been shown yet what would be the effects in the striatum-nigra circuit after plasticity induction in striatum with HSF. Literature also misses a detailed description of the way back loop of the circuit: the striatal firing rate after substantia nigrás inhibition. We here conducted: First Experiment, application of HFS in dorsomedial striatum and measure of spontaneous and longlasting behavior expression in the open field three days later; Second, application of single pulses on dorsomedial striatum and measure of the evoked potentials in substantia nigra before and after HFS; Third Experiment: inhibition of substantia nigra and recording of the firing rate of dorsomedial striatum. HFS in dorsomedial striatum caused increased locomotion behaviors, but not classical stereotypy. However, rats had either an increase or decrease in substantia nigrás evoked potentials. Also, substantia nigrás inhibition caused an increase in dorsomedial striatum firing rate. Present data are suggestive of a potential application of HFS in striatum, as an attempt to modulate behavior rigidity and hypokinesia of diseases involving the basal ganglia, especially Parkinson´s Disease.

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OBJECTIVES: Analyze the prevalence of retractions in different areas of the Tympanic Membrane (TM), the correlations between the involvement of the Pars Tensa (PT) and Pars Flaccida (PF), and the air-bone gaps. METHODS: A cross-sectional study. Patients with moderate and/or severe TM retraction of 2200 consecutive patients with chronic otitis media between August 2000 and January 2019 were included. Ears with previous surgery were excluded. Ears were classified as isolated PF and PT retractions and association of both. The degrees of severity and presence of effusion were evaluated. The data were analyzed using the SPSS Statistics software program. RESULTS: 661 ears were included. The prevalence of isolated atical retractions was 24.9%, of isolated posterior quadrants was 10.6%, and of association of quadrants was 64%. There was no correlation between the retractions in the different areas of the TM (posterior and attic quadrants: r = 0.13; p = 0.041; anterior and posterior quadrants: r = 0.23; p = 0.013, anterior and attic quadrants: r = 0.06; p = 0.043). Effusion was present in 30.7% of the ears. ABG median was lower in ears with PF retraction (6.25 dB HL) than PT retraction, isolated (15 dB HL) or not (13.75 dB HL; p < 0.05); 72% of the ears had an ABG ≤ 20 dB HL. For severity of the retraction of PF, the ABG was similar across groups. For the PT, there was a global difference in the medians of ABG in terms of the degree of severity, with a moderate correlation. CONCLUSION: The prevalence of moderate and severe retractions was 24.5%; 64% of the ears had an association of affected regions. There was no correlation between the retraction in the different areas of the TM. We found a significant correlation between the severity of retraction and the worsening of ABG threshold, only for PT. EVIDENCE LEVEL: 4.

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Abstract Objectives: Analyze the prevalence of retractions in different areas of the Tympanic Membrane (TM), the correlations between the involvement of the Pars Tensa (PT) and Pars Flaccida (PF), and the air-bone gaps. Methods: A cross-sectional study. Patients with moderate and/or severe TM retraction of 2200 consecutive patients with chronic otitis media between August 2000 and January 2019 were included. Ears with previous surgery were excluded. Ears were classified as isolated PF and PT retractions and association of both. The degrees of severity and presence of effusion were evaluated. The data were analyzed using the SPSS Statistics software program. Results: 661 ears were included. The prevalence of isolated atical retractions was 24.9%, of isolated posterior quadrants was 10.6%, and of association of quadrants was 64%. There was no correlation between the retractions in the different areas of the TM (posterior and attic quadrants: r = 0.13; p = 0.041; anterior and posterior quadrants: r = 0.23; p = 0.013, anterior and attic quadrants: r = 0.06; p = 0.043). Effusion was present in 30.7% of the ears. ABG median was lower in ears with PF retraction (6.25 dB HL) than PT retraction, isolated (15 dB HL) or not (13.75 dB HL; p < 0.05); 72% of the ears had an ABG ≤ 20dB HL. For severity of the retraction of PF, the ABG was similar across groups. For the PT, there was a global difference in the medians of ABG in terms of the degree of severity, with a moderate correlation. Conclusion: The prevalence of moderate and severe retractions was 24.5%; 64% of the ears had an association of affected regions. There was no correlation between the retraction in the different areas of the TM. We found a significant correlation between the severity of retraction and the worsening of ABG threshold, only for PT. Evidence level: 4.

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The objectives of this work were to validate two published methods for subadult age estimation based on measurements of the pars lateralis, and to develop a new method based on a wider set of measurements using the Granada Osteological Collection. The pars lateralis of 127 individuals from 6 months prenatal to 4 years of age were measured, taking 6 measurements of the body, the anterior synchondrosis and the condyle. Length and width were used to validate the published methods. Regression functions using age as the independent variable were calculated using each of the six measurements taken, and functions for age estimation were obtained through classical calibration. Functions for calculation of the 95% confidence interval of the estimates were obtained through linear regression using the estimation errors. In the validation of the previous methods, one method showed a linear tendency of the differences, which can be attributed to a circularity in reasoning in the original work. In the other method, a tendency towards overestimation was found, which can be attributed to the limitations of the method itself. The new functions have a consistency rate of 92.2% to 97.1%; the functions derived from all measurements are useful from 6 months prenatal to 2 years of age. Moreover, the functions obtained are applicable to incomplete pars lateralis, allowing for age estimation in a wide set of contexts and providing straightforward age estimates with their respective margin of error.

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RATIONALE: The endocannabinoid modulation of fear and anxiety due to the on-demand synthesis and degradation is supported by a large body of research. Although it has been proposed that anandamide (AEA) in the substantia nigra pars reticulata (SNpr) seems to be important for the organisation of innate fear-related behaviours, a role for endogenous AEA has yet to be clarified. METHODS: Mice were treated with the fatty acid amide hydrolase (FAAH) selective inhibitor URB597 at different concentrations (0.01, 0.1, 1 nmol/0.1 µL) in the SNpr and confronted by rattlesnakes (Crotalus durissus terrificus). The most effective dose of URB597 (1 nmol) was also preceded by microinjections of the CB1 receptor antagonist AM251 (0.1 nmol) into the SNpr, and mice were then confronted by the venomous snake. RESULTS: URB597 (0.1 and 1 nmol) in the SNpr decreased the expression of defensive behaviours such as defensive attention, escape, and time spent inside the burrow of mice confronted by rattlesnakes. Moreover, pretreatment of SNpr with AM251 suppressed these antiaversive effects of URB597 in this midbrain structure. CONCLUSION: Overall, these data clearly indicate that the panicolytic consequences of endogenous AEA enhancement in the SNpr are mediated by CB1 receptor signalling.

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Objective: To describe the development of retinal pigment epithelium (RPE) atrophy after uncomplicated pars plana vitrectomy (PPV) with epiretinal membrane (ERM) and/or internal limiting membrane (ILM) peeling in 2 patients. Cases description: Case 1: A 79-years-old female with diagnosis of a full-thickness macular hole in her right eye (OD) with best corrected visual acuity (BCVA) of: 20/100 and left eye (OS): 20/70. After surgery she developed large RPE hyperplasia and presented hand movement that did not improve with pinhole. Case 2: A 69-years-old female patient who had ERM in her OS with BCVA of 20/30 in both eyes (OU). PPV was assisted with brilliant blue (BB) to better visualize the ILM. During follow-up visits we evidenced RPE atrophy in the zone where peeling was done. In the last control after 2-years, her visual acuity was 20/40 that did not improve with pinhole. Discussion: There are three possible mechanisms to explain this complication: toxic damage, mechanical trauma during the membrane removal with forceps, or a combination of both. In our cases, a combination of them is probably the cause of the presence of RPE atrophy. Conclusion: Vitrectomy with membrane removal is successful in most cases with low rate of complications. Because RPE atrophy is infrequent, our suggestion is to continue performing this technique and if possible, it should be done without dye staining to minimize risks. Abbreviations: ERM = epiretinal membrane, ILM = internal limiting membrane, MH = macular hole, RPE = Retinal pigment epithelium, OD = right eye, BCVA = Best corrected visual acuity, OS = left eye, OU = both eyes, IOL = intraocular lens, OCT = Optical coherence tomography, BB = Brilliant blue, TB = Trypan blue, ICG = indocyanine green.

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Axon-dendrite formation is a crucial milestone in the life history of neurons. During this process, historically referred as "the establishment of polarity," newborn neurons undergo biochemical, morphological and functional transformations to generate the axonal and dendritic domains, which are the basis of neuronal wiring and connectivity. Since the implementation of primary cultures of rat hippocampal neurons by Gary Banker and Max Cowan in 1977, the community of neurobiologists has made significant achievements in decoding signals that trigger axo-dendritic specification. External and internal cues able to switch on/off signaling pathways controlling gene expression, protein stability, the assembly of the polarity complex (i.e., PAR3-PAR6-aPKC), cytoskeleton remodeling and vesicle trafficking contribute to shape the morphology of neurons. Currently, the culture of hippocampal neurons coexists with alternative model systems to study neuronal polarization in several species, from single-cell to whole-organisms. For instance, in vivo approaches using C. elegans and D. melanogaster, as well as in situ imaging in rodents, have refined our knowledge by incorporating new variables in the polarity equation, such as the influence of the tissue, glia-neuron interactions and three-dimensional development. Nowadays, we have the unique opportunity of studying neurons differentiated from human induced pluripotent stem cells (hiPSCs), and test hypotheses previously originated in small animals and propose new ones perhaps specific for humans. Thus, this article will attempt to review critical mechanisms controlling polarization compiled over decades, highlighting points to be considered in new experimental systems, such as hiPSC neurons and human brain organoids.

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PURPOSE: To evaluate a variety of techniques, and their anatomical and functional results, for the treatment of optic disc pit maculopathy (ODP-M). A secondary aim was to report on results of secondary procedures in cases of initial failure or recurrence. METHODS: Multicentre retrospective study of 95 eyes with ODP-M, treated by 25 surgeons from 12 countries. Primary outcomes were anatomical resolution of subretinal fluid (SRF), intraretinal fluid (IRF) and visual acuity (VA) at 12 months. RESULTS: Higher rates of SRF and IRF resorption were achieved in eyes treated with pars plana vitrectomy (PPV) compared to external laser with or without tamponade: 64/72 (88.9%) versus 8/14 (57.1%) for SRF (p = 0.003), and 50/59 (84.7%) versus 3/10 (30%) for IRF (p = 0.002). The addition of juxtapapillary laser or internal limiting membrane (ILM) peel during PPV did not improve SRF or IRF resolution. Pars plana vitrectomy (PPV) with tamponade and PPV with tamponade plus endolaser were associated with significant visual gain. In the former group, VA improved from a mean of logMAR 0.91 (20/162), to a mean of logMAR 0.52 (20/66) at 12 months; in the latter group, VA improved from a mean of logMAR 0.82 (20/132) to a mean of logMAR 0.47 (20/59) at 12 months. Retreatments were performed in 14 eyes (15.7%), only enhancing anatomical outcomes. CONCLUSION: Vitrectomy with tamponade had better final outcomes than external laser treatment with or without gas tamponade. Laser endophotocoagulation and ILM peel provided no additional benefit. A secondary treatment resulted in anatomical but not functional improvement.

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INTRODUCTION: To report a case of a Hispanic girl with late-onset Retinoblastoma (Rb) who was misdiagnosed as a pars planitis prior to referral. Nearly 95% of all Rb cases are detected before age 5, and this patient was 8 years-old. METHODS: Case report of a late-onset Retinoblastoma with anterior chamber (AC) involvement plus the presence of an Ahmed valve. The patient had a history of a couple of months of topical therapy comprising medication for glaucoma, systemic steroids, and a filtration surgery (Ahmed valve), after that a biopsy was performed prior to referral. Upon arrival at our clinic, we performed an examination under anesthesia (EUA) and a B-scan ultrasound (US). RESULTS: Unilateral Retinoblastoma with an Ahmed valve in an AC filled with Rb seeds was diagnosed with the EUA and US in the left eye. An orbital exenteration with map biopsies of the left orbital cavity was performed with confirmation by histopathology of a poorly differentiated endophytic retinoblastoma with Bruch's membrane invasion. Follow-up sessions were then arranged as well as subsequent systemic chemotherapy cycles. CONCLUSION: Given the rare incidence of retinoblastoma in children older than 5 years old, it can be easily mistaken for other differential diagnoses and treated with filtration surgeries that could put the patient's life at risk. In this report, late-onset Rb diagnosis is highlighted as a differential diagnosis in children and adults with atypical uveitis, which required a multidisciplinary approach.

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Carbon nanotubes (CNTs) have been increasingly more prevalent due to their use in product technology owing to their exceptional electrical and thermal conductivity and tensile strength because of their nanostructure and strength of the bonds among carbon atoms. The potential increase of CNTs in the environment is a concern, and studies to assess the toxic effects of these nanomaterials (NMs) are needed. However, so far, most of the studies are focused on aquatic species and much less is understood about the effects of NM in terrestrial organisms. This investigation used a functionalized multi-walled carbon nanotube (f-MWCNT) and the Jamaican cricket Gryllus assimilis to assess the effects of this NM. Cricket nymphs were injected with f-MWCNT suspension-at three different concentrations. The insecticide Fipronil was used as a positive control. Survival was monitored, and histological analysis was made in the brains. Pyknotic cells were quantified in two brain regions, a neurosecretory called Pars intercerebralis (PI), and an associative region called mushroom body (MB). No mortality was observed in any f-MWCNT concentration tested. A significant increase in pyknotic cells was observed as sub-lethal effect for the intermediate concentration of f-MWCNT, at PI, while any significant change was observed at the Kenyon cells of the MB. These results are discussed in the context of agglomeration and dispersion of the f-MWCNT at different concentrations, and availability of the f-MWCNT on the circulatory system, as well as the natural decay of pyknotic cells with time and different patterns of adult cricket neurogenesis. Our results showed that f-MWCNT had negative effects in the neurosecretory region of the brain.

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