Search Results (373)

Background: Optical coherence tomography angiography (OCTA) enables non-invasive, high-resolution visualization of the retinal microvasculature and is increasingly utilized in pediatric ophthalmology. However, its clinical application in children is limited by the absence of age-specific normative data. Methods: In this cross-sectional study, macular vessel density (VD) and foveal avascular zone (FAZ) area were assessed in 118 healthy Caucasian children aged 4 to 17 years. OCTA scans were obtained using the OCT Topcon Triton^® device with 3 × 3 mm and 6 × 6 mm macular cubes. Vascular metrics from the superficial (SCP) and deep capillary plexuses (DCP) were analyzed in relation to demographic, refractive, biometric, and structural OCT parameters. Correlation and multivariate linear regression analyses were performed to evaluate associations. Results: Age-stratified reference percentiles for macular VD and FAZ area in SCP and DCP are presented for 118 children. Key associations included: (1) Increased macular thickness correlated with higher VD in the fovea and inner ring (SCP and DCP, all p < 0.05); (2) Thicker maculas were associated with smaller FAZ areas (SCP: r = −0.72, DCP: r = −0.58, both p < 0.001); (3) Older age was linked to reduced VD in the inner macular ring and smaller FAZ area (SCP and DCP, all p < 0.001); and (4) longer axial length correlated with lower central VD (SCP: r = −0.27, DCP: r = −0.37, both p < 0.05). No significant sex-based differences were observed. Conclusions: This study provides normative OCTA data for macular VD and FAZ area in healthy Caucasian children and identifies key associations with ocular parameters. These findings support improved diagnostic accuracy and clinical decision-making in pediatric retinal evaluation. Full article

Galileo and the telescope revolutionized the concept of the Sun. The discovery of its rotation was possible due to the continuous observation of the sunspots. The faculae and the maculae with umbra and penumbra became accessible daily to new instruments, leaving the perfectly lucid disk to the realm of symbolism. Was this new view possible before the telescope? Technically, pinhole cameras can show the largest sunspots, as well as the naked eye under very particular conditions. However such observations were too scattered to produce any change in the established understanding of the Sun. Synoptic observations of the largest sunspots of the XXV solar cycle made with the naked eye, pinhole camera, and a telescope in camera obscura are presented and compared with the historical ones. Sunspots could have been discovered in Florence as early as 1475 with the pinhole meridian line of S. Maria del Fiore: the Spörer minimum (1460–1550) of the solar activity prevented it. Indications of white light flares and prominence observations appear in a drawing dated back to 1635, well before the first H-alpha inspections in the 19th century. Full article

Shiga toxins (Stx), produced by Shiga toxin-producing Escherichia coli, preferentially attack renal tissue and frequently induce acute kidney injury (AKI) and renal failure. To prevent irreversible damage, the injured renal tissue, particularly renal tubular epithelium, mounts a remodeling and regeneration response to repair itself. However, how such intrinsic renal repair processes are initiated and coordinated in infected renal tubular regions remains elusive. Herein, we reported that macula densa apparatus, in addition to its conventional role as a salt sensor in nephron, can function as an endogenous sensor for exogenous toxins (e.g., Stx). We demonstrated that macula densa cells orchestrate a rapid repair niche by initiating transcriptional activation of repair and regeneration factors in both Stx-injured murine models and human kidney organoids. Mechanistically, we showed that in response to Stx exposure, macula densa cells release a specific repair factor CCN1, which effectively promotes the regeneration of toxin-injured renal tubular epithelium and facilitates renal tubular repair through integrin-mediated signaling pathways. Moreover, we demonstrated that treatment with recombinant CCN1 can greatly ameliorate the structural damage and significantly restore the proximal tubular reabsorption capacity in Stx-infected kidney organoids. Our finding highlights a novel role of macula densa apparatus in toxin-induced renal injury, and paves a new avenue for treatment of AKI-associated renal diseases. Full article

Plant-insect mutualisms often drive the evolution of adaptive morphological and physiological traits, enabling ecological specialization and diversification. Fig trees (Ficus spp., Moraceae) and their pollinating wasps (Agaonidae) are engaged in a brood-site pollination mutualism that exemplifies such adaptive specializations. This study investigates the morphological and ecological roles of maculae, characterized as distinct-pigmented regions on the fig surface, in the mutualistic interaction between Ficus citrifolia and fig wasps. Through morphological analyses using light and electron microscopy, we demonstrated that maculae concentrate numerous stomata and exhibit secretory activity. This activity is evidenced by the exudation of a sugary-like solution and by the presence of epidermal and subepidermal cells with features consistent with sugar- and terpene-secreting cells, such as abundant starch reserves, numerous mitochondria, plastids containing osmiophilic droplets, a Golgi complex with dilated cisternae, oil bodies, and extensive endoplasmic reticulum. Histochemical tests confirmed a terpenic-sugary secretion in the macula cells. We demonstrated that non-pollinating fig wasps avoid ovipositing through macular regions. This behavior may reflect a selective pressure to prevent structural damage to maculae caused by ovipositor insertion, thus preserving their functional integrity. Temperature measurements revealed that figs are up to 10% cooler on average than the ambient air. Therefore, our findings suggest that fig maculae are multifunctional structures, simultaneously performing the roles of extrafloral nectaries, gas exchange, and thermal regulation, which are crucial for maintaining suitable internal conditions for wasp larval development. These results provide novel insights into previously underexplored plant adaptations supporting specialized brood-site pollination mutualisms. Full article

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the elderly, characterized by progressive degeneration of the retinal pigment epithelium (RPE) and photoreceptors in the macula. Current treatment options primarily focus on slowing disease progression in neovascular AMD, while effective therapies for dry AMD remain limited. Optogenetics, a revolutionary technique utilizing light-sensitive proteins (opsins) to control the activity of genetically targeted cells, has emerged as a promising therapeutic strategy for restoring vision in retinal degenerative diseases. In retinal disease models, adeno-associated viruses (AAVs) serve as delivery vectors via intravitreal or subretinal injections. This review explores the principles of optogenetics, its application in preclinical AMD models, and the potential for clinical translation of this approach. We discuss the various optogenetic tools, delivery methods, and the challenges and future directions in harnessing this technology to combat AMD-related vision loss. Full article

Recent advances in artificial intelligence (AI) have transformed ophthalmic diagnostics, particularly for retinal diseases. In this prospective, non-randomized study, we evaluated the performance of an AI-based software system against conventional clinical assessment—both quantitative and qualitative—of optical coherence tomography (OCT) images for diagnosing diabetic macular edema (DME). A total of 700 OCT exams were analyzed across 26 features, including demographic data (age, sex), eye laterality, visual acuity, and 21 quantitative OCT parameters (Macula Map A X-Y). We tested two classification scenarios: binary (DME presence vs. absence) and multiclass (six distinct DME phenotypes). To streamline feature selection, we applied paraconsistent feature engineering (PFE), isolating the most diagnostically relevant variables. We then compared the diagnostic accuracies of logistic regression, support vector machines (SVM), K-nearest neighbors (KNN), and decision tree models. In the binary classification using all features, SVM and KNN achieved 92% accuracy, while logistic regression reached 91%. When restricted to the four PFE-selected features, accuracy modestly declined to 84% for both logistic regression and SVM. These findings underscore the potential of AI—and particularly PFE—as an efficient, accurate aid for DME screening and diagnosis. Full article

With the use of Optical Coherence Tomography Angiography (OCTA), the present study is the first study to examine if retinal vascular densities (vessel densities and perfusion densities) could be associated with empathetic levels in young and non-clinical adults. Methods: Fifty-one university students aged from 18 to 25 years (26 males and 24 females) were recruited from a university in Hong Kong. OCTA was conducted to assess their retinal vessel density (VD) and perfusion density (PD) in different scan patterns over the macula (1 mm center subfield, 3 × 3 mm scan, 6 × 6 mm scan). Empathy (cognitive, affective, and somatic) was measured by using the Cognitive, Affective, and Somatic Empathy Scales (CASES). Results: After controlling for age, the multiple linear regression results showed that both the VD and PD in the 1 mm center subfield were significantly and negatively associated with the empathy total score, the affective empathy subscore, and the somatic empathy subscore, respectively (ps < 0.05). Conclusion: The present findings indicate that a lower level of empathy is associated with increased retinal vascular densities in the 1 mm center subfield, specifically involving variations in vascular density (VD) and perfusion density (PD). This suggests the dilation of retinal venules might lead to lower empathy. These results establish a foundation for future studies investigating the underlying mechanism of retinal imaging and empathy in healthy individuals. Full article

Objectives: To describe the anatomical and functional outcomes of paediatric rhegmatogenous retinal detachment (RRD) managed primarily with scleral buckle and to identify factors predicting single-surgery anatomical success (SSAS) and postoperative best-recorded visual acuity (BRVA). Methods: A retrospective review was conducted of 49 patients (≤18 years) who underwent primary scleral buckle for RRD between 2008 and 2023 at the Manchester Royal Eye Hospital. Data on patient and RRD characteristics, ocular comorbidities, surgical technique, complications, and postoperative outcomes were collected. SSAS, final anatomical success, and BRVA were assessed. Results: The mean age at surgery was 12 ± 3 years, with macula-off detachment in 57% (28/49). SSAS after scleral buckle surgery was achieved in 71% (35/49). At the second surgery, 13 out of 14 patients underwent vitrectomy, and one patient had repeat scleral buckling. The final anatomical success rate was achieved in 96% (47/49). On multivariable analysis, older age independently predicted higher odds of SSAS (odds ratio [OR] 1.41, 95% confidence interval [CI] 1.05–1.91, p = 0.023), whereas macula status, drainage, and trauma were not independent predictors. In a multivariable linear model for postoperative BRVA (logMAR), older age was associated with better BRVA (B = −0.162, 95% CI −0.244 to −0.080, p < 0.001), and macula-off status with worse BRVA (B = 0.520, 95% CI 0.022 to 1.018, p = 0.041); drainage and trauma were not significant. Conclusions: Primary scleral buckle, with secondary vitrectomy if needed, is effective for paediatric RRD, yielding a 71% SSAS and 96% final anatomical success. Older age was independently associated with higher SSAS and better postoperative BRVA, while macula-off presentation was associated with worse postoperative BRVA. Full article

Background/Objectives: Attention deficit hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder. As the retina is an extension of the central nervous system, retinal imaging may provide insights into the ADHD pathophysiology. The objective of this work was to evaluate structural retinal alterations using optical coherence tomography (OCT) in ADHD patients compared to neurotypical controls. Methods: A case–control study involving 200 eyes (100 from 50 patients with ADHD and 100 from 50 controls) was conducted by comparing the thicknesses of the macular region (total retina, inner and outer retinal layers, ganglion cell layer plus inner plexiform layer [GCIPL], and macular retinal nerve fiber layer [mRNFL]), the peripapillary region (pRNFL), and the optic nerve head (ONH) parameters. Areas under the curve (AUCs) were calculated to evaluate diagnostic performance. Right and left eyes were analyzed separately. Results: Patients with ADHD showed a significant reduction in total and outer retinal thickness across several macular sectors in both eyes. No significant differences were observed in mRNFL, GCIPL, inner retina, pRNFL, or ONH parameters between groups. AUC values derived from ROC analysis indicate moderate diagnostic performance for total and outer retinal thickness in the macular region. Conclusions: ADHD is associated with retinal thinning in the macula (total and outer retinal thickness) in both eyes, suggesting the potential of OCT-based biomarkers for this condition. Full article

Objectives: This study aimed to evaluate the 6-month real-world outcomes of switching to faricimab in patients with aflibercept-resistant neovascular age-related macular degeneration (nAMD). Methods: A retrospective review was conducted on the eyes of 60 patients with aflibercept-resistant nAMD that were switched to faricimab. Best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) parameters, including central subfield thickness (CST), subfoveal choroidal thickness (SFCT), and both the maximum height and width of pigment epithelial detachment (PED), at baseline and 1, 3, and 6 months after switching were evaluated. The type of PED and retinal fluid were also analyzed. Results: The results showed that BCVA remained stable at month 6 (p = 0.150), while CST significantly decreased (p = 0.020), and SFCT remained unchanged (p = 0.072). The maximum PED height significantly decreased (p = 0.030), while the maximum PED width did not change (p = 0.07). The mean injection interval significantly increased from 6.8 ± 2.4 weeks before switching to 11.2 ± 1.7 weeks after switching (p = 0.068). Furthermore, the dry macula rate was 43.3% at month 6. Conclusions: Switching to faricimab in aflibercept-resistant nAMD patients showed stable visual outcomes, significant anatomical improvements, and reduced treatment burden over 6 months in real-world clinical settings. Full article

Background/Objectives: Diabetic macular edema (DME) is the primary cause of vision loss in people with diabetes, and if untreated, it can result in irreversible macular damage. Both fluorescein angiography (FA), the gold standard, and optical coherence tomography angiography (OCTA) are used for evaluation of this disease. The objective of this study was to compare the diagnostic value of both. Methods: We conducted a comparative analysis of 98 patients aged 18–80 years with significant DME and best-corrected visual acuity ≥0.1 according to the Snellen chart. Participants underwent glycated hemoglobin blood test (HbA1c) and ophthalmological examinations, including OCTA and FA. OCTA 3 × 3 mm scans of superficial (SCP) and deep capillary plexus (DCP) along with FA scans were exported to the Gimp computer program. Size of the foveal avascular zone (FAZ), the number of visible microaneurysms (MAs), and ETDRS report number 11 classification of the images were assessed. Results: FAZ size differed significantly in superficial plexus (0.41 mm²), deep plexus (0.43 mm²) OCTA, and FA (0.38 mm²) (p < 0.001). FAZ size in DCP OCTA closely correlated with that of FA (τ = 0.79, p < 0.001). The total number of MAs visualized in the OCTA was significantly lower than in FA (p < 0.001). ETDRS classification of scans revealed that the level of consistency between the examinations was moderate to very strong. Conclusions: OCTA may be useful in evaluating macular ischemia. It is less sensitive in detecting MAs in DME eyes. FAZ has sharper boundaries and is larger when measured in OCTA. Poor glycemic control results in higher incidence of MAs in macula. Full article

North Africa has a poorly and unevenly known hoverfly fauna. Xanthogramma Schiner, 1861 (Syrphinae, Syrphini) is represented in this territory by some scattered records of four species, Xanthogramma dives (Rondani, 1857), Xanthogramma evanescens Becker & Stein, 1913 (endemic to North Africa), Xanthogramma marginale (Loew, 1854), and Xanthogramma pedissequum (Harris, 1776). After examination of old Xanthogramma material collected in Tanger, Morocco, from the ‘Museo Nacional de Ciencias Naturales, Madrid, Spain (MNCN)’, specimens with distinctive morphology were spotted and found to be different from a syntype of X. evanescens collected in the same locality. Consequently, we revised all the available material of Xanthogramma from North Africa, characterised a new species, proposed a lectotype for X. evanescens, and provided an identification key to the North African species of this genus. The new species is also found in Tunisia and differs from X. evanescens in facial width, colour of the thoracic pleura, length of mesonotum hairs, wing pollinosity, and shape of the yellow maculae on tergum 2. Full article

Dopaminergic amacrine cells (DACs) are a subclass of amacrine cells that modulate retinal processing and light adaptation by releasing dopamine. Although the role of dopamine is largely conserved, their retinal distribution across mammals remains incompletely characterized. In mice, rats, thirteen-lined ground squirrels (TLGSs), and macaques, we systematically compared the localization, number, and topography of DACs by their expression of tyrosine hydroxylase (TH), a crucial enzyme in the biosynthesis of dopamine. In all species examined, TH+ cells were primarily located in the inner nuclear layer; however, there was a species-dependent influence on their number and distribution. Mice exhibited the highest density of TH+cells but completely lacked displaced TH+cells (dTH+cells) in the ganglion cell layer. Despite interspecies variation in the total number of TH+cells in the retina, the overall density in rats, TLGSs, and macaques was similar. Most species displayed a higher density of DACs toward central retinal regions. However, rats exhibited a distinctive dorsal concentration, particularly among dTH+cells. Although most species examined exhibited a similar ratio of TH+cells to Brn3a+ retinal ganglion cells, TLGSs showed a marked reduction, indicating a potentially diminished dopaminergic modulatory role. Species-specific DAC topographies aligned with specialized visual regions, such as the visual streak in TLGS and the macula in macaques. These results reveal both conserved and divergent features of retinal dopamine circuitry, reflecting evolutionary adaptations to visual processing demands. Full article

Background/Objectives: To identify the predictive biomarkers of treatment response following a switch to brolucizumab in patients with aflibercept-refractory neovascular age-related macular degeneration (nAMD). Methods: This retrospective study included 47 eyes of 44 patients with nAMD who were switched to brolucizumab; a two-year follow-up was completed for 37 eyes of 34 patients after the switch. The patients were classified into two groups based on the presence (fluid group) or absence (dry group) of retinal fluid at one and two years after switching, and their visual acuity, central retinal thickness, subfoveal choroidal thickness, injection interval, and dry macular rate were evaluated. Results: A dry macula was achieved for approximately 80% of patients at two years after the switch (p < 0.001), and the mean injection interval was significantly extended from 6.4 ± 1.8 weeks to 10.5 ± 2.6 weeks during the same period (p < 0.001). Both the mean central retinal thickness and subfoveal choroidal thickness showed a significant decrease at two years after the switch (p < 0.001 for both). A significantly higher proportion of patients in the Dry group exhibited punctate hyperfluorescence in the fellow eye (p < 0.001), and all patients in the dry group achieved a dry macula at two years. Conclusions: Switching to brolucizumab may be an effective treatment option for patients with aflibercept-refractory nAMD. Punctate hyperfluorescence may serve as a favorable prognostic factor following a switch to brolucizumab. Full article

Background: This study aimed to evaluate retinal arteriole parameters using adaptive optics (AO) rtx1™ (Imagine Eyes, Orsay, France) and peripapillary and macular vessel densities with optical coherence tomography angiography (OCTA) in eyes with different stages of primary open-angle glaucoma (POAG) compared to healthy eyes. It also investigated the associations between vascular parameters and glaucoma severity, as defined by structural (OCT) and functional (visual field) changes. Methods: Fifty-seven eyes from 31 POAG patients and fifty from 25 healthy volunteers were examined. Retinal arteriole morphology was assessed using the AO rtx1™-fundus camera, which measured lumen diameter, wall thickness, total diameter, wall-to-lumen ratio (WLR), and wall cross-sectional area. OCTA was used to measure vessel densities in superficial (SCP) and deep (DCP) capillary plexuses of the macula and radial peripapillary capillary plexus (RPCP) and FAZ area. Structural OCT parameters (RNFL, GCC, rim area) and visual field tests (MD, PSD) were also performed. Results: Glaucoma eyes showed significantly thicker arteriole walls (12.8 ± 1.4 vs. 12.2 ± 1.3 µm; p = 0.030), narrower lumens (85.5 ± 10.4 vs. 100.6 ± 11.1 µm; p < 0.001), smaller total diameters (111.0 ± 10.4 vs. 124.1 ± 12.4 µm; p < 0.001), and higher WLRs (0.301 ± 0.04 vs. 0.238 ± 0.002; p < 0.001) than healthy eyes. In glaucoma patients, OCTA revealed significantly reduced vessel densities in SCP (36.39 ± 3.60 vs. 38.46 ± 1.41; p < 0.001), DCP (36.39 ± 3.60 vs. 38.46 ± 1.41; p < 0.001), and RPCP plexuses (35.42 ± 4.97 vs. 39.27 ± 1.48; p < 0.001). The FAZ area was enlarged in eyes with glaucoma (0.546 ± 0.299 vs. 0.295 ± 0.125 mm²); p < 0.001). Positive correlations were found between vessel densities and OCT parameters (RNFL, r = 0.621; GCC, r = 0.536; rim area, r = 0.489), while negative correlations were observed with visual field deficits (r = −0.517). Conclusions: Vascular deterioration, assessed by AO rtx1™ and OCTA, correlates closely with structural and functional damage in glaucoma. Retinal microcirculation changes may precede structural abnormalities in the optic nerve head. Both imaging methods enable the earlier detection, staging, and monitoring of glaucoma compared to conventional tests. Full article