Purpose. In a rat model of branch retinal vein occlusion (BRVO), changes in gene expression of factors implicated in the development of retinal edema and alterations in the properties of Müller cells were determined. methods. In adult Long-Evans rats, BRVO was induced by laser photocoagulation of retinal veins; untreated eyes served as controls. The mRNA levels of after factors were determined with real-time RT-PCR in the neural retina and retinal pigment epithelium after 1 and 3 days of BRVO: VEGF-A, pigment epithelium-derived factor (PEDF), tissue factor, prothrombin, the potassium channel Kir4.1, and aquaporins 1 and 4. Potassium currents were recorded in isolated Müller cells, and cellular swelling was assessed in retinal slices. results. In the neural retina, the expression of VEGF was upregulated within 1 day of BRVO and returned to the control level after 3 days. PEDF was upregulated in the neuroretina and retinal pigment epithelium after 3 days of BRVO. Prothrombin, Kir4.1, and both aquaporins were downregulated in the neuroretina. After BRVO, Müller cells displayed a decrease in their potassium currents and an altered distribution of Kir4.1 protein, an increase in the size of their somata, and cellular swelling under hypoosmotic stress that was not observed in control tissues. conclusions. BRVO results in a rapid transient increase in the expression of VEGF and a delayed increase in the expression of PEDF. The downregulation of Kir4.1 and aquaporins, the mislocation of Kir4.1 protein, and the osmotic swelling of Müller cells may contribute to the development of edema and neuronal degeneration.

Background: To describe cases of retinal vascular events shortly after administration of mRNA or adenoviral-vectored COVID-19 vaccines. Design: Retrospective, multicenter case series. Methods: Six cases of retinal vascular events shortly after receiving COVID-19 vaccines. Results: A 38-year-old, otherwise healthy male patient presented with branch retinal arterial occlusion four days after receiving his second dose of SARS-CoV-2 vaccination with Comirnaty^® (BioNTech^®, Mainz, Germany; Pfizer^®, New York City, NY, USA). An 81-year-old female patient developed visual symptoms twelve days after the second dose of SARS-CoV-2 vaccination with Comirnaty^® and was diagnosed with a combined arterial and venous occlusion in her right eye. A 40-year-old male patient noticed blurry vision five days after his first dose of SARS-CoV-2 vaccination with Comirnaty^® and was diagnosed with venous stasis retinopathy in his left eye. A 67-year-old male was diagnosed with non-arteritic anterior ischemic optic neuropathy in his right eye four days after receiving the first dose of Vaxzevria^® (AstraZeneca^®, Cambridge, UK). A 32-year-old man presented with a sudden onset of a scotoma two days after receiving the second dose of SARS-CoV-2 vaccination with Spikevax^® (Moderna, Cambridge, UK) and was diagnosed with a circumscribed nerve fiber infarction. A 21-year-old female patient developed an acute bilateral acute macular neuroretinopathy three days after receiving the first dose of SARS-CoV2-vaccine Vaxzevria^® (AstraZeneca^®, Cambridge, UK). Conclusion: This case series describes six cases of retinal vascular events shortly after receiving mRNA or adenoviral-vectored COVID-19 vaccines. The short time span between received vaccination and occurrence of the observed retinal vascular events raises the question of a direct correlation. Our case series adds to further reports of possible side effects with potential serious post-immunization complications of COVID-19 vaccinations.

Aims: Fluocinolone acetonide (FAc) is an intravitreal corticosteroid implant approved for the second-line treatment of diabetic macular edema (DME). This study compared outcomes of patients with DME switched directly to an FAc implant, versus indirectly via dexamethasone, after anti-VEGF therapy failure. Methods: This is a retrospective, single-center chart review. Patients were assigned to Group A (switched to FAc after anti-VEGF) or Group B (switched to dexamethasone and then to FAc after > 4 months). Charts were reviewed for best-corrected visual acuity (BCVA), central macular thickness (CMT), intraocular pressure (IOP) and cataract development. Results: Forty-nine eyes were included. BCVA increased and CMT decreased with anti-VEGF (both groups), and dexamethasone (Group B only), but regressed after stopping treatment. With FAc, BCVA increased rapidly and significantly: increases were maintained up to 36 months (P < 0.001), except at 18 and 9 months in Groups A and B, respectively. Significant CMT reductions (P < 0.001) were evident after 3 months and maintained up to 36 months in both groups. IOP increase > 21 mmHg occurred in 14 patients (nine in Group A, five in Group B): all were sufficiently treated with IOP-lowering drops. Nineteen phakic eyes (73.1%) developed cataract: seven underwent phaco-emulsification (two in Group A, five in Group B). Conclusions: Similar functional and anatomical improvements occurred in FAc-treated eyes, regardless of whether they first received dexamethasone or switched directly to FAc after anti-VEGF. Safety signals were consistent with corticosteroid class effects. Early switch to FAc could benefit patients who respond insufficiently to anti-VEGF.

Purpose: To identify the predictors for anatomical and functional outcome after re-vitrectomy with application of autologous platelet concentrate (APC) in eyes with persistent idiopathic macular hole (MH). Methods: Retrospective study of 103 eyes with persistent MHs after vitrectomy with peeling of internal limiting membrane (ILM) and expansive gas. All patients underwent re-vitrectomy with APC and endotamponade. The anatomical MH closure rate and postoperative best-corrected visual acuity (BCVA) were evaluated. Further, predictive factors influencing the success of the surgery were analyzed. Results: Median BCVA (logMAR) before the surgery was 1.00 (interquartile range [IQR] 0.80–1.30) and the median of minimum diameter between hole edges was 508 µm (IQR 387–631). The final closure rate after re-vitrectomy with APC was 60.2% (62 of 103 eyes). The following predictors were identified to significantly influence the closure rate: tractional hole index (THI), axial length, time between first and second surgery, and the experience of the surgeon (p < 0.05). Conclusions: Re-vitrectomy with APC led to the closure of 60.2% of the persistent MHs. The closure rate negatively correlates with increasing axial length, time between the first and second surgery, and the decreased THI. Further, experienced surgeons (with a history of >100 pars plana vitrectomies with ILM peeling) had significantly higher closure rates.