Effectiveness and Safety of Coadministration of Intravitreal Dexamethasone Implant and Silicone Oil Endotamponade for Proliferative Diabetic Retinopathy with Tractional Diabetic Macular Edema

Evidence-based guidelines for drug dosing in intravitreal injections in silicone oil-filled eyes: Pharmacokinetics, safety, and optimal dosage

We evaluate the pharmacokinetics, safety, and optimal dosages of intravitreal agents in silicone oil (SO)-filled eyes, addressing challenges in administering such therapies. We assessed the pharmacological properties and safety profiles of intravitreal drugs in SO-filled eyes, deriving conclusions and guidance from available literature and expert consensus. Preclinical data suggest comparable half-lives of anti-vascular endothelial growth factoragents in SO-filled eyes, but clinical evidence is mainly from case reports and small series. Available research prioritizes standard dosages, particularly for bevacizumab (1.25 mg), supported by stronger evidence than aflibercept (2 mg) or ranibizumab (0.5 mg). Intravitreal steroids, especially dexamethasone at 0.7 mg, show efficacy and safety, while evidence for fluocinolone acetonide at 0.19 mg is limited. Intravitreal methotrexate has been reported at the dosage of 250-400 μg, with keratitis as the primary expected side effect. Case reports indicate tolerability of standard dosages of antivirals (foscarnet 1.2-2.4 mg/0.1 mL, ganciclovir 4 mg/0.1 mL) and the antibiotic combination piperacillin/tazobactam (250 μg/0.1 mL). We offer guidance based on current, but limited, literature. Standard dosage of intravitreal agents should be carefully considered, along with close monitoring for potential side effects, which should be discussed with patients.

Intravitreal Injections for Macular Edema in Silicone Oil Filled Eyes

Purpose

Macular edema is a known complication following complicated retinal detachment repair with silicone oil (SiO) tamponade. Limited previous research has not led to a consensus regarding the safety and efficacy of intra-SiO injections. Consequently, we aim to present our case series study on intra-SiO injections for postoperative macular edema.

Methods

A retrospective, single-center, case series study of eight eyes that developed macular edema postoperatively following complicated retinal detachment repair surgery with SiO tamponade, were treated with different forms of intravitreal injections such as steroids or anti-vascular endothelial growth factor (VEGF). The main outcome measures included visual acuity (VA), central subfield macular thickness (CSMT), and the type and number of injections.

Results

The mean age (±SD) of the patients was 64.75±8.9 years. The mean follow-up period (±SD) was 3.1±2.2 years. The mean (±SD) number of injections was 8.25±7.24. Mean (±SD) VA (in LogMAR) and CSMT before injections were 1.7±0.8 and 488±104 μm, respectively. At the last follow-up visit, the mean (±SD) VA and CSMT were 1.4±0.7 (p-value=0.45) and 396±184 μm (p-value=0.11), respectively. Overall, patients showed a partial response without a significant worsening of the macular edema and VA. No complications were reported following repetitive intravitreal injections.

Conclusion

Macular edema in silicone oil-filled eyes may be safely and effectively treated with intravitreal injections to halt its deterioration and preserve vision, especially when SiO removal is not anticipated in the foreseeable future.

Astaxanthin Ameliorates Diabetic Retinopathy in Swiss Albino Mice via Inhibitory Processes of Neuron-Specific Enolase Activity

Retinopathy is one of the most common complications of diabetes mellitus. Diabetic retinopathy (DR) occurs due to microvascular damage in retinal tissues provoked by high blood sugar levels. The available drugs for DR are limited. Astaxanthin (AST) has anti-hypertensive, anti-obesity, and anti-diabetic properties. However, the therapeutic effect of AST on DR remains elusive. The present study is designed to investigate the effects of AST on DR via inhibition of neuron-specific enolase (NSE) activity. DR was induced by the administration of streptozotocin (STZ, 35 mg/kg: intraperitoneal; and 20 μL of STZ: intravitreal) in mice. AST (10 and 20 mg/kg) was administered orally (p.o.) for 21 days. The DR associated visual changes were assessed at different time intervals via optokinetic motor response (OMR) and penta-maze (PM) tests. Blood glucose level as well as retinal catalase, lactate dehydrogenase (LDH), & neuron-specific enolase (NSE) were estimated. The reference drug i.e., dexamethasone (DEX, 10 mg/kg; p.o.) was administered for 21 days. The administration of AST showed significant ameliorative potential in DR. Hence, AST can be used as a natural medicine for the management of DR due to its potential antioxidant, anti-diabetic, and NSE inhibitory properties.

Clinical Features and Vitreous Biomarkers of Early-Onset Type 2 Diabetes Mellitus Complicated with Proliferative Diabetic Retinopathy

PURPOSE

To compare the clinical features and vitreous biomarkers of proliferative diabetic retinopathy (PDR) between patients with early-onset and late-onset type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This case-control study analyzed the clinical data of 74 patients with PDR who underwent vitrectomy. The patients were divided into the early-onset (T2DM diagnosis age ≤ 40 years, n = 39) and late-onset (T2DM diagnosis age > 40 years, n = 35) groups. Thirty-six specimens were collected, and the liquid chip technology was used to detect the content of 27 types of cytokines in the vitreous. Differences in clinical features and cytokine levels between the two groups were evaluated. Bonferroni correction was applied for multiple comparisons.

RESULTS

Compared with the late-onset group, the levels of hemoglobin A1c (HbA1c) and total cholesterol were significantly higher in the early-onset group (P < 0.001 and P = 0.009, respectively). Patients with early-onset T2DM PDR had worse visual prognoses and a higher rate of postoperative recurrent vitreous hemorrhage. The results of cytokine detection showed that the levels of interleukin-4 (IL-4), IL-6, IL-8, IL-9, granulocyte colony-stimulating factor, interferon-γ, interferon-inducible 10 kDa, monocyte chemotactic protein 1, macrophage inflammatory protein (MIP)-1α, and MIP-1β in the early-onset group were significantly higher than those in the late-onset group (p < 0.0026). Age at diabetes diagnosis and HbA1c, IL-4, and regulated upon activation, normal T cell expressed and secreted levels were independent risk factors for visual acuity after undergoing vitrectomy.

CONCLUSION

Early-onset T2DM PDR patients had poor blood glucose and lipid metabolism, higher levels of inflammatory factors, and worse visual prognosis. Stricter metabolic management and earlier anti-inflammatory interventions may be required for patients with early-onset T2DM.

Comparison of Intraocular Cytokine Levels of Choroidal Neovascularization Secondary to Different Retinopathies

Purpose: To investigate and compare the aqueous concentrations of vascular endothelial growth factor (VEGF) and other inflammatory cytokines in various choroidal neovascularization (CNV) diseases and types.

Methods: This observational study included 127 naive eyes with CNV and 43 control eyes with cataracts. Aqueous humor (AH) samples were obtained prior to intravitreal anti-VEGF injection or cataract surgery. Multiple inflammatory cytokines, including VEGF, interleukin (IL) 6, IL-8, IL-10, interferon-inducible protein 10 (IP-10), and monocyte chemotactic protein 1 (MCP-1) levels, were measured using a multiplex bead assay. The angiogenesis index was defined as the ratio of IP-10 to MCP-1. In addition, the relationship among AH cytokine levels, central macular thickness (CMT), and CNV size on optical coherence tomography angiography (OCTA) was evaluated.

Results: Except in the myopic CNV group (P = 0.452), the AH concentration of VEGF was significantly higher in all other CNV groups than in the control group (P < 0.05 for all comparisons). IL-8, IL-10, IP-10, and MCP-1 levels (P < 0.05 for all groups) were significantly higher in all CNV diseases except those with neovascular central serous chorioretinopathy. The angiogenesis index was significantly higher in all CNV diseases (P < 0.05 for all comparisons). The VEGF level may be associated with the size of the CNV on OCTA (p = 0.043).

Conclusions: The level of intraocular inflammatory cytokines varied among different CNV diseases and CNV types. Therefore, the angiogenesis index may be a more sensitive indicator of angiogenesis.