Background and Objectives: This study explores the relationship between retinal structure, vascular densities (VD), and the progression of myopia, aiming to identify novel biomarkers for assessing myopia severity. Materials and Methods: A total of 260 eyes were divided into four groups: Emmetropia (EM) (n = 74), Low Myopia (LM) (n = 68), Moderate Myopia (MM) (n = 64), and High Myopia (HM) (n = 54). VD and retinal thickness (RT) in the macular and peripheral quadrants were measured using optical coherence tomography-angiography (OCTA). SVD and DVD were analyzed across the paranasal, peritemporal, perisuperior, and peri-inferior quadrants. Results: Significant differences in superficial vessel density (SVD) were found in the paranasal (EM vs. MM, p = 0.017; EM vs. HM, p = 0.001), peritemporal (EM vs. MM, p = 0.006; EM vs. HM, p = 0.001; LM vs. HM, p = 0.004; MM vs. HM, p = 0.032), perisuperior (EM vs. MM, p = 0.005; EM vs. HM, p = 0.001; LM vs. HM, p = 0.027), and perifoveal quadrants (EM vs. MM, p = 0.003; EM vs. HM, p = 0.008; LM vs. HM, p = 0.004; MM vs. HM, p = 0.012). Deep vessel density (DVD) showed significant differences in the paranasal (p = 0.012–0.022), peritemporal (p = 0.002–0.026), perisuperior (p = 0.003–0.034), perifoveal (p = 0.002–0.017), and peri-inferior (p = 0.002–0.022) quadrants. Retinal thickness was significantly reduced in HM eyes, with the most pronounced reduction in the peritemporal quadrant (mean difference: 16.7 ± 3.2 µm; p < 0.001). Conclusions: Structural and vascular changes in the retina become more pronounced as myopia progresses from moderate to high. The strong correlation between DVD, RT, and myopia severity highlights their potential as reliable biomarkers for monitoring myopia progression through OCTA imaging. These findings provide new insights into the vascular and structural changes underlying myopia and their diagnostic significance.

Type 2 diabetes mellitus is a growing global health concern, with diabetic retinopathy (DR) representing a major microvascular complication that contributes significantly to vision impairment. Oxidative stress plays a critical role in the pathogenesis of DR, which is associated with changes in vascularization-associated molecules, such as iNOS, VEGF, and MMP-9. The present study investigates the therapeutic potential of bilberry (Vaccinium myrtillus L.) extract—rich in anthocyanins—applied for 14 days on blood glucose levels, lipid profile, and retinal oxidative stress (lipid peroxidation (TBARS) and advanced oxidized protein products (AOPPs)) in a streptozotocin/nicotinamide (STZ/NA)-induced diabetes rat model. Results showed a significant reduction in non-fasting blood glucose, retinal TBARS, and AOPP levels, and normalization of VEGF and MMP-9 expression in bilberry-treated diabetic rats. Bilberry extract also partially improved lipid profile by lowering LDL levels. However, no significant effects on fasting glucose or serum insulin were observed. These findings suggest that bilberry extract may offer protective effects against oxidative retinal damage and could serve as a complementary approach in managing early diabetic retinopathy.

Background and Objectives: Myopia is a rapidly growing global health burden driven primarily by axial elongation, which exerts mechanical stress on the inner retina, leading to progressive thinning of the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCC). The sector-specific pattern of these changes across the full spectrum of myopia remains incompletely characterized. This study aimed to provide a comprehensive, sector-level analysis of RNFL and GCC changes across four myopia severity grades using optical coherence tomography angiography (OCTA), and to quantify their correlations with axial length (AL) and central foveal thickness (CFD). Materials and Methods: A total of 260 eyes of 130 participants were enrolled in a prospective cross-sectional study. Eyes were classified into four groups: emmetropia (EM, n = 74), low myopia (LM, n = 68), moderate myopia (MM, n = 64), and high myopia (HM, n = 54). All participants underwent cycloplegic refraction, AL measurement, and RTVue XR Avanti OCTA imaging. RNFL thickness was assessed across five peripapillary sectors, and GCC thickness across twelve macular zones. Between-group differences were analyzed using one-way ANOVA with Bonferroni post hoc correction or Kruskal–Wallis/Dunn-Bonferroni tests. Pearson correlations were used to assess associations among structural parameters, AL, and CFD. Results: Both the RNFL and GCC showed progressive, statistically significant thinning with increasing myopia severity. The superior RNFL was the only peripapillary sector that differentiated EM from LM (p = 0.039), with total thinning of 18.8 μm from EM to HM. The paratemporal GCC zone showed the earliest macular structural signal (EM vs. LM, p = 0.049). Temporal and nasal RNFL sectors showed relative preservation, with differences restricted to comparisons involving HM. AL correlated negatively with the RNFL and GCC across all sectors (r = −0.46 to −0.71), with the strongest correlation observed for the superior RNFL in HM (r = −0.71, p < 0.001). CFD demonstrated progressively stronger coupling with GCC thickness as myopia severity increased, peaking in HM (r = 0.72, p < 0.001). Conclusions: The RNFL and GCC thinning in myopia follows a progressive, sector-specific pattern driven by axial elongation. The superior RNFL and paratemporal GCC are the earliest structural indicators of inner retinal change, detectable already at the low-myopia grade. These findings support a neural-first model of myopia-related retinal remodeling and advocate for multiparametric, stage-targeted structural monitoring in clinical practice.

Background and Objectives: Optical coherence tomography angiography (OCTA) devices convert scan angle into retinal distance with a schematic eye, so eyes whose axial length (AL) differs from the assumed value are measured on an incorrect transverse scale. We quantified how this magnification error affects seven OCTA metrics and how well geometric and empirically calibrated corrections perform. Materials and Methods: In this controlled image-based simulation study, segmentation masks of 300 eyes from the public OCTA-500 dataset (6 × 6 mm scans) were re-rendered at ten simulated ALs (21.5 to 30.0 mm). Co-primary outcomes were seven metric-specific scaling exponents from per-eye log–log regression, tested against their geometric values (Holm-adjusted and equivalence tests). Secondary analyses separated field-content from pixel-sampling effects and assessed corrections in individual eyes by cross-fitting. Results: Between simulated ALs of 23.58 and 27.91 mm, uncorrected foveal avascular zone (FAZ) area changed by −30.8% and branch-point density by +37.4%. The FAZ-area exponent was equivalent to its geometric value (−1.985 vs −2), whereas skeleton-derived metrics fell short of theirs (branch-point density +1.72, vessel length density +0.91, caliber −0.74). A decomposition attributed the shortfall of the skeleton-derived exponents mainly to pixel sampling and the vessel density exponent to field content. Empirical exponents reduced the mean bias to 1.0% or less, but individual-eye errors exceeded 5% in 12% to 36% of eyes for vessel density, vessel length density, FAZ circularity and branch-point density. Exploratory analyses showed curved responses for all metrics, negligibly so for FAZ area, and category-dependent responses for vessel density, vessel length density and branch-point density. Conclusions: In this simulation, magnification artifacts were metric-specific: FAZ area followed geometric scaling, whereas skeleton-derived metrics also depended on pixel sampling and field content. Calibrated corrections apply to group means within the tested workflow and require validation in eyes with measured axial length.

Background and Objectives: Diabetes mellitus (DM) is associated with structural and biochemical changes in the cornea that may influence its biomechanical behavior. This study aimed to compare corneal biomechanical properties between healthy individuals and patients with type 2 DM. Materials and Methods: This observational cross-sectional study was conducted at a specialized ophthalmology center from September 2025 to April 2026 and included 115 eyes, which were divided into two groups: 60 healthy control eyes and 55 eyes of patients with DM type 2 (DM2 group). All subjects underwent a complete ophthalmological examination and corneal biomechanical screening using Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany). The study included participants aged 50–70 years, with central corneal thickness from 500 to 600 μm, and normal ocular findings. Exclusion criteria included a history of any previous corneal disease, uveitis, glaucoma, spherical refractive errors exceeding ±3.00 D, cylindrical refractive errors exceeding 3.00 D, prior ocular surgery, contact lens wear and systemic connective tissue diseases. Results: DM2 group was older than the control group (median age 63 years [IQR 57–68] vs. 56 years [IQR 54–59], p < 0.001). In unadjusted comparisons, deformation amplitude at highest concavity (DA HC) was higher in the DM2 group (1.05 [0.98–1.09] vs. 0.98 [0.91–1.06] mm, p = 0.002), as was integrated radius (IR) (8.00 [7.53–8.40] vs. 7.50 [6.60–8.60] mm⁻¹, p = 0.032), whereas radius of curvature at highest concavity (RC HC) (7.41 [6.77–7.86] vs. 7.52 [7.10–8.04] mm, p = 0.038) and stiffness parameter at first applanation (SP-A1) (115.50 [102.18–128.40] vs. 122.50 [107.90–142.90] mmHg/mm, p = 0.023) were lower. After adjustment for age, gender, central corneal thickness and intraocular pressure, only DA HC remained independently associated with DM2 status (β = 0.033 mm, 95% CI 0.007–0.058; p = 0.012). Conclusions: Patients with type 2 DM exhibited a corneal biomechanical profile characterized by greater corneal deformability, reflected by higher DA HC and IR values and lower RC HC and SP-A1 values in unadjusted comparisons. Of these parameters, increased DA HC remained independently associated with DM2 after multivariable adjustment. These findings highlight the complexity of diabetes-related corneal biomechanical alterations and suggest that they may not uniformly manifest as increased corneal stiffness.

Background and Objectives: Diabetes mellitus (DM) may induce structural and biochemical changes in the cornea that can potentially affect corneal transparency. This study aimed to compare corneal optical density (COD) between patients with type 2 diabetes mellitus (T2DM) and healthy controls and to evaluate its association with disease duration. Materials and Methods: This observational cross-sectional study included 90 eyes of 90 participants, with only one eye per participant included in the analysis. The study population comprised 45 eyes from patients with T2DM and 45 age- and gender-matched healthy control eyes. The study was conducted at a specialized ophthalmology center between September 2025 and April 2026. All participants underwent a comprehensive ophthalmic examination followed by corneal densitometry and pachymetry assessment using the Pentacam AXL (Oculus Optikgeräte GmbH, Wetzlar, Germany). COD was analyzed across the total, anterior, central, and posterior corneal layers within the 0–2 mm, 2–6 mm, and 6–10 mm annular zones. COD values and central corneal thickness (CCT) were compared between groups, and correlations between disease duration and COD parameters were evaluated. Results: No statistically significant differences in COD were observed between patients with T2DM and healthy controls across any of the analyzed corneal layers or annular zones (all p > 0.05). CCT also did not differ significantly between groups (p = 0.817). No significant correlations were identified between disease duration and COD parameters (all p > 0.05). Conclusions: In this age- and gender-matched cohort, patients with T2DM did not demonstrate statistically significant differences in corneal densitometry or CCT compared with healthy controls. Disease duration was not significantly associated with COD, suggesting that other factors, including long-term glycaemic control and disease severity, may contribute to diabetes-related corneal alterations.