Risk Factors of Cystoid Macular Edema After Pars Plana Vitrectomy for Pseudophakic Retinal Detachment

Introduction: This study aimed to investigate the prevalence of cystoid macular edema after pars plana vitrectomy for the treatment of pseudophakic rhegmatogenous retinal detachment and identify possible related risk factors. Methods: A retrospective monocentric study was conducted within a cohort of pseudophakic patients undergoing vitrectomy for rhegmatogenous retinal detachment between January 2019 and December 2022. Demographic data, initial and intraoperative characteristics of rhegmatogenous retinal detachment, and postoperative data were analyzed. Cystoid macular edema was defined on optical coherence tomography exclusively. Results: A total of 164 eyes of 164 patients were included for analysis. The mean age of the patients at surgery was 65.7 ± 12.0 years. The mean best-corrected visual acuity was 2.1 ± 1.0 logMAR preoperatively and 1.0 ± 0.7 logMAR postoperatively. The mean follow-up was 13.4 ± 7.7 months. The prevalence of cystoid macular edema was 17.1% [9.8–26.4]. In multivariate analysis, severe proliferative vitreoretinopathy (relative risk 3.6 [1.3–9.7]) and laser retinopexy (relative risk 8.4 [1.1–64.7]) were independently and significantly associated with cystoid macular edema. Conclusion: The prevalence of cystoid macular edema in pseudophakic rhegmatogenous retinal detachment after pars plana vitrectomy was 17.1%. Severe proliferative vitreoretinopathy stage and the use of endolaser retinopexy were independent risk factors for development of cystoid macular edema

Agilité des données et structure organisationnelle : le cas Total. vol.3, n°1.

International audienc

Biological markers of oxidative stress in mitochondrial myopathies with progressive external ophthalmoplegia.

According to experimental models suggesting that overproduction of oxygen free-radicals may occur when the electron transport in the respiratory chain is impaired, we searched for in vivo biological markers of oxidative stress in 11 patients affected by histologically proven mitochondrial myopathy with progressive external ophthalmoplegia (PEO) and partial cytochrome c oxidase deficiency in muscle fibres. Six of the patients carried large-scale deletions of mitochondrial DNA. Biochemical assays included the determination of plasma and erythrocyte reduced glutathione (GSH) concentration, plasma malondialdehyde, fluorescent adducts of aldehydes with plasma proteins, and serum level of lipid peroxides. In patients with PEO the mean values of lipid peroxides and of the fluorescent adducts of aldehydes with plasma proteins were significantly higher with respect to normal controls, while the mean values of plasma and erythrocyte GSH concentration were significantly lower. The reported data indicate an increase of lipid peroxidation indexes along with the reduction of one of the most important antioxidant systems and suggest the hypothesis that overproduction of reduced oxygen species might be an adjunctive cause of cell damage in mitochondrial myopathies and encephalomyopathies associated with defects of oxidative phosphorylation

Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend

This study seeks to characterise the stability of a two-dimensional channel flow involving a 180-degree sharp bend, to infinitesimal three-dimensional disturbances by way of linear stability analysis. A highly accurate global linear stability analysis of the flow is presented via the Reynolds number Re varies in the range 100 ≤ Re ≤ 700, this Re range produces steady state two-dimensional flow solutions for bend opening ratio (ratio of bend width on inlet height) β = 1. The two-dimensional base flow solutions demonstrate that as β decreases, the transition from steady to unsteady occurs at lower Reynolds number. The stability analysis shows that the flow first becomes unstable to a synchronous three-dimensional instability mode with spanwise wavenumber k = 2 at approximately Re = 400, whereas the two-dimensional solution branch undergoes transition to unsteady flow somewhere near Re ≈ 800. Instability mode structures associated with the leading eigenvalues are localized at the re-attachment point of the first separation bubble and the separation point of the second separation bubble. The stability analysis is used to produce neutral stability curves and visualisations of the global modes of the system for typical Reynolds number are also presented