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Biljana Ivanovska Adjievska,1 Salih Boskurt,1 Nikola Orovcanec,2 Vesna Dimovska-Jordanova3 1Department for Posterior Segment, European Eye Hospital, Skopje, Republic of Macedonia; 2Department for Medical Statistics, Institute for Epidemiology and Medical Statistics, Medical Faculty, Skopje, Republic of Macedonia; 3Department for Retinal Diseases, University Clinic for Eyes Diseases, St Cyril and Methodius University, Skopje, Republic of Macedonia Aim: We aimed to evaluate the 1-year efficacy and safety of low-frequency intravitreal bevacizumab in the treatment of macular edema due to retinal vein occlusions (RVOs).Methods: The study comprised an interventional prospective study of patients with macular edema due to central retinal vein occlusion (CRVO) or branch retinal vein occlusion, followed for 12 months. Treatment-naïve patients with reduced best-corrected visual acuity (BCVA) and central macular thickness (CMT) of at least 250 µm received intravitreal injection of bevacizumab. After 1 month, BCVA and optical coherence tomography (OCT) images of the macula were recorded. In patients with 0.3 log of the minimum angle of resolution [logMAR] units) with average number of injections of 1.98. Improvement of mean BCVA in CRVO was significant (P=0.001) from baseline (1.2±0.95 logMAR units) to 1 year (0.75±0.6 logMAR units). Significant improvement of mean BCVA (P

Using Arase observations of the inner magnetosphere during 26 CIR‐driven geomagnetic storms with minimum Sym‐H between −33 and −86 nT, we investigated ring current pressure development of ions (H+, He+, O+) and electron during prestorm, main, early recovery and late recovery phases as a function of L‐shell and magnetic local time. It is found that during the main and early recovery phase of the storms the ion pressure is asymmetric in the inner magnetosphere, leading to a strong partial ring current. The ion pressure becomes symmetric during the late recovery phase. H+ ions with energies of ∼20–50 keV and ∼50–100 keV contribute more to the ring current pressure during the main phase and early/late recovery phase, respectively. O+ ions with energies of ∼10–20 keV contribute significantly during main and early recovery phase. These are consistent with previous studies. The electron pressure was found to be asymmetric during the main, early recovery and late recovery phase. The electron pressure peaks from midnight to the dawn sector. Electrons with energy of <50 keV contribute to the ring current pressure during the main and early recovery phase of the storms. Overall, the electron contribution to the total ring current is found to be ∼11% during the main and early recovery phases. However, the electron contribution is found to be significant (∼22%) in the 03–09 MLT sector during the main and early recovery phase. The results indicate an important role of electrons in the ring current build up. Key Points: The first statistical study of both ring current ions (H+, He+, O+) and electrons during corotating interaction region driven storms using Arase observationsH+ is the major contributor to the total pressure with E = 20–50 keV while O+ pressure with E = 10–20 keV contributed more during main phaseElectron (E < 50 keV) contributes ∼20% to the total ring current pressure in 03–09 MLT during main and early recovery phase [ABSTRACT FROM AUTHOR]

Biljana Ivanovska-Adjievska,1 Salih Boskurt,1 Faruk Semiz,1 Hakan Yuzer,1 Vesna Dimovska-Jordanova21European Eye Hospital, Skopje, Macedonia, 2Clinic for Eye Diseases, University "St Cyril and Methodius", Skopje, MacedoniaPurpose: We analyzed the anatomical and visual outcomes after surgical treatment of idiopathic macular holes with pars plana vitrectomy, internal limiting membrane (ILM) peeling using Brilliant Blue dye, and silicone oil tamponade without postoperative posturing.Methods: This was a retrospective interventional study of 10 eyes in eight patients who underwent surgical treatment of idiopathic macular holes using pars plana vitrectomy, ILM peeling using Brilliant Blue dye, and silicone oil tamponade without postoperative posturing. The preoperative staging of macular holes and postoperative anatomic outcomes were assessed using spectral-domain optical coherence tomography.Results: All patients were women with a mean age of 66.86 ± 4.8 years. In two patients, bilateral macular holes were present and both eyes were operated on. Stage 2 macular hole was diagnosed in three eyes, three eyes had stage 3, and four eyes had stage 4 macular holes. Anatomical success and closure of the macular hole was achieved in nine eyes (90%) after one operation. In one eye, the macular hole was closed after reoperation. The preoperative mean best-corrected visual acuity (BCVA) was 0.15 decimal units (0.8 logMAR units). Until the end of the follow-up period, BCVA was 0.25 decimal units (0.6 logMAR units). Visual acuity was improved in seven patients (70%). In two patients (20%), visual acuity remained at the same level, and in one eye (10%), visual acuity decreased. Postoperatively, all patients reported a significant reduction of metamorphopsia.Conclusion: Initial results after 20G pars plana vitrectomy with peeling of the ILM, use of dye (Brilliant Blue), and tamponade with silicone oil without postoperative posturing gave good anatomical and functional outcome in terms of visual acuity and reduction of metamorphopsia. Taking into account the age of the patients, this method, which does not require prolonged postoperative face-down posturing, was well tolerated by the patients. Because the anatomical and visual outcome as well as the rate of postoperative complications are comparable to those when gas is used as a tamponading agent, silicone oil tamponade can also be safely used as a first option in surgery of macular holes. However, a longer period of follow-up of the operated eyes, as well as a larger group of operated eyes, will be required to identify long-term outcomes of this surgical treatment.Keywords: macular hole, silicone oil, ILM peeling, pars plana vitrectomy

Understanding the physical processes that control the dynamics of energetic particles in the inner magnetosphere is important for both space-borne and ground-based assets essential to the modern society. The storm time distribution of ring current particles in the inner magnetosphere depends strongly on their transport in the evolving electric and magnetic fields along with particle acceleration and loss. In this study, we investigated the ring current particle variations using observations and simulations. We compared the ion (H+, He+, and O+) and electron flux and plasma pressure variations from Arase observations with the self-consistent inner magnetosphere model: Ring current Atmosphere interactions Model with Self Consistent magnetic field (RAM-SCB) during the 7-8 November 2017 geomagnetic storm. We investigated the contribution of the different species (ions and electrons) to the magnetic field deformation observed at ground magnetic stations (09°-45° MLat) using RAM-SCB simulations. The results show that the ions are the major contributor with ~88% and electrons contribute ~12% to the total ring current pressure. It is also found that the electron contribution is non-negligible (~18%) to the ring current in dawn-side during the main phase of the storm. Thus, the electron contribution to the storm time ring current is important and should not be neglected. [ABSTRACT FROM AUTHOR]

During geomagnetic storms, the ring current ions sometimes exhibit rapid loss as suggested by the fast recovery of the Dst index on a time scale of a few hours. The effects of magnetic field line curvature (FLC) scattering on the loss of ring current ions, which have not been well quantified, are studied here by test particle simulations under the T89c magnetic field model. Our simulation results S/Ll show that the prediction of ion loss based on a single-value cutoff of the k parameter or maximum of l of a single FLC scattering is not accurate. Instead, the e-folding lifetime (t) for the loss of ring current ions due to cumulative FLC scattering has been calculated for different initial ion energies, equatorial pitch angles, and L shells under different geomagnetic conditions. The results show that in general the FLC scattering loss is faster for ions of higher energy, higher mass, smaller pitch angle, higher L, and at high Kp level. Specifically, we find that at Kp = 6 the lifetime can be <10 h at L > 5 for 100 s keV protons and at L > 4 for 100 s keV O+, which demonstrates that FLC scattering can be an important mechanism for the observed fast loss (t < 10 h) of ring current ions during geomagnetic storms. Furthermore, we formulate an empirical formula for t as a function of ion energy, pitch angle, position, species, and Kp. The empirical formula can be directly included in ring current models to account for the FLC scattering effects. [ABSTRACT FROM AUTHOR]

Electrons with energies in the keV range play an important role in the dynamics of the inner magnetosphere. Therefore, accurately modeling electron fluxes in this region is of great interest. However, these calculations constitute a challenging task since the lifetimes of electrons that are available have limitations. In this study, we simulate electron fluxes in the energy range of 20 eV to 100 keV to assess how well different electron loss models can account for the observed electron fluxes during the Geospace Environment Modelling Challenge Event of the 2013 St. Patrick's Day storm. Three models (Case 1, Case 2, and Case 3) of electron lifetimes due to wave‐induced pitch angle scattering are used to compute the fluxes, which are compared with measurements from the Van Allen Probes. The three models consider electron losses due to interactions with whistler mode hiss waves inside the plasmasphere and with whistler mode chorus waves outside the plasmasphere. The Case 1 (historical) model produces excessive loss at low L shells before and after the storm, suggesting that it overestimates losses due to hiss during quiet times. During the storm main phase and early recovery all three models show good agreement with the observations, indicating that losses due to chorus during disturbed times are, in general, well accounted for by the models. Furthermore, the more recent Case 2 and Case 3 models show overall better agreement with the observed fluxes. Plain Language Summary: Energetic electrons play a key role in the dynamics of the inner magnetosphere. Consequently, it is of great interest to estimate the electron fluxes in this region. Since the electron lifetimes available to date have limitations, an accurate estimation has been a challenging task. This study aims to assess how well different electron loss models can account for the observed electron fluxes during a geomagnetic storm. Three models of electron losses due to interactions with magnetospheric waves are used in the flux calculations, and the results are then compared with fluxes observed by the Van Allen Probes mission. Our results show that the historical model overestimates the losses at low altitudes before the storm and in the late recovery phase of the storm, indicating that the losses due to interactions with hiss waves in the model are too strong. Furthermore, we find that the more recent models used, based on empirical wave models, are overall in better agreement with the observations over the entire storm. Key Points: Three models of electron lifetimes due to wave‐induced pitch angle scattering in the magnetosphere are comparedElectron flux computed with the lifetimes based on recent empirical wave models show the best agreement with Van Allen Probes observationsThe historical model produces fluxes that are lower than the observed at low L shells, suggesting that it overestimates hiss losses [ABSTRACT FROM AUTHOR]

We simulate equatorial plasmaspheric electron densities using a physics‐based model (Cold PLasma, CPL; used in the ring current‐atmosphere interactions model) of the source and loss processes of refilling and erosion driven by empirical inputs. The performance of CPL is evaluated against in situ measurements by the Van Allen Probes (Radiation Belt Storm Probes) for two events: the 31 May to 5 June and 15 to 20 January 2013 geomagnetic storms observed in the premidnight and postmidnight magnetic local time (MLT) sectors, respectively. Overall, CPL reproduces the radial extent of the plasmasphere to within a mean absolute difference of |ΔLavg|=0.5±0.1 L. The model electric field responsible for E × B convection and the parameterization of geomagnetic conditions (under the Kp‐index and solar wind properties) implemented by CPL did not account for localized enhancements in the duskward electric field during increased activity. Rather, it was found to be largely dependent on the measure of the quiet time background. This property indicates that the agreement between these simulations and observations does not account for the complete set of physical processes during extreme (strong or weak) geomagnetic conditions impacting the plasmasphere. Nevertheless, at the presented resolution of the model CPL does provide good agreement in reproducing Radiation Belt Storm Probes observations of plasmaspheric density and plasmapause location. Key Points: Simulations of premidnight and postmidnight plasmapause encounters achieve agreement with RBSP observations to within 0.5 L absolute errorSolar wind parameterization of convection produces at least 0.5 L deeper erosion at onset of activity than the Kp‐index parameterizationSolar wind parameterization of convection produces at least 0.5 L larger plasmasphere during recovery than the Kp‐index parameterization [ABSTRACT FROM AUTHOR]

Vector valued hyperstructures, i.e., (n, m)-hyperstructures, where n = m + k, k ≥ 1, as a generalization of vector valued structures and n-ary hyperstructures are introduced and supported by many examples. We have presented some initial properties about (n, m)-hypersemigroups and (n, m)-hypergroups. Moreover, by properly defining regular and strongly regular binary relations, from vector valued hypersemigroups (hypergroups) we obtain "ordinary" vector valued semigroups (groups) on quotients. [ABSTRACT FROM AUTHOR]

Abstract: The ion plasma sheet (~few hundred eV to ~few tens keV) is usually dominated by H+ ions. Here changes in ion composition within the plasma sheet are explored both during individual events and statistically during 54 calm‐to‐storm events and during 21 active‐to‐calm events. Ion composition data from the HOPE (Helium, Oxygen, Proton, Electron) instruments onboard Van Allen Probes satellites provide exceptional spatial resolution and temporal resolution of the H+, O+, and He+ ion fluxes in the plasma sheet. H+ is shown to be the dominant ion in the plasma sheet in the calm‐to‐storm transition. However, the energy‐flux of each ion changes in a quasi‐linear manner during extended calm intervals. Heavy ions (O+ and He+) become increasingly important during such periods as charge‐exchange reactions result in faster loss for H+ than for O+ or He+. Results confirm previous investigations showing that the ion composition of the plasma sheet can be largely understood (and predicted) during calm intervals from knowledge of (a) the composition of previously injected plasma at the onset of calm conditions and (b) use of simple drift‐physics models combined with calculations of charge‐exchange losses. [ABSTRACT FROM AUTHOR]

The Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) investigation on the NASA Radiation Belt Storm Probes (now named the Van Allen Probes) mission provides key wave and very low frequency magnetic field measurements to understand radiation belt acceleration, loss, and transport. The key science objectives and the contribution that EMFISIS makes to providing measurements as well as theory and modeling are described. The key components of the instruments suite, both electronics and sensors, including key functional parameters, calibration, and performance, demonstrate that EMFISIS provides the needed measurements for the science of the RBSP mission. The EMFISIS operational modes and data products, along with online availability and data tools provide the radiation belt science community with one the most complete sets of data ever collected. [ABSTRACT FROM AUTHOR]

The global definition of glaucoma considers it as an optic neuropathy with multifactor etiology, which affects the optic nerve head (ONH), provoking visual field loss and permanent impairment of visual function. Bearing in mind the fact that the exact pathogenic mechanism is still not completely established, glaucoma treatment strategies so far are based upon the identification of glaucoma risk factors. Among them, only elevated intraocular pressure (IOP) could undergo therapeutic treatment. However, in spite of the adequate therapy and IOP lowering, very often the disease is still progressing, leading to definite visual loss and permanent blindness. This especially refers to "normal tension glaucoma". Over the last decade, there has been significant scientific research on new strategies for the delay or prevention of retinal ganglion cell loss (RGC), which is the basic pathophysiological event that initiates the cascade of processes leading to optic atrophy. Therefore, a great deal of expectation has been put on the concept of what is known as "neuroprotection". This includes the development of treatment strategies (pharmacological, immunological, genetic) that would be capable of preventing apoptotic death of retinal ganglion cells. The concept of neuroprotection is based upon increasing evidence that glaucoma degeneration is analogous with other neurodegenerative diseases of the central nervous system suggesting a strong relation between the basic cellular processes in glaucoma and Alzheimer’s disease, for example. It is considered that retinal ganglion cell death goes through two phases – primary injury responsible for initiation of damage that is followed by slower secondary degeneration related to a harmful environment surrounding the degenerated cells. Neuroprotection in glaucoma refers to any intervention that is aimed at prevention of the optic nerve head injury and ganglion cells death. Pharmacological intervention is aimed at neutralizing some of the effects of the nerve-derived toxic factors by increasing the ability of the remaining neurons to cope with stressful conditions. On the other hand, immunological reaction stimulates the body’s repair mechanisms so as to hinder the toxic effects of various chemical agents generated during pathological events. [ABSTRACT FROM AUTHOR]