Search Results (1,750)

Background: Non-syndromic retinitis pigmentosa (RP) is characterized by rod–cone degeneration, resulting in night blindness, visual field constriction, and eventual blindness. Recessively inherited RP is predominantly exacerbated in consanguineous populations, such as Pakistan. This study aimed to perform the genetic analysis of sixteen non-syndromic RP segregating Pakistani families, and to summarize the mutation spectrum of non-syndromic RP in our population by reviewing related literature. Methods: We screened 16 non-syndromic RP families using targeted capture panel sequencing of 344 genes related to inherited retinal dystrophies. Variants were prioritized based on rarity (minor allele frequency (MAF) < 0.001 in the gnomAD South Asian subset), pathogenicity assessments using ACMG/AMP criteria, and REVEL scores (>0.5). Candidate variants were validated for familial segregation through Sanger sequencing. Results: We identified 15 distinct variants across 14 genes associated with non-syndromic retinitis pigmentosa, comprising 6 missense, 7 nonsense, 1 frameshift, and 2 splice-site variants, including 4 novel variants, i.e., p.(Val220Met) and p.(Pro1282SerfsTer2) in RP1, 1 each in PDE6B (c.2021+5G>A), and PRCD p.(Ser38Ter). Homozygosity predominated, underscoring the impact of consanguinity on the burden of autosomal recessive disease in the present cohort, while the CERKL disease-causing mutation, i.e., p.(Arg257Ter), recurred in two families. Conclusions: This study expands Pakistan’s non-syndromic RP mutational spectrum by identifying novel variants in RP1, PDE6B, and PRCD, alongside recurrent CERKL and RHO mutations of the local population. The literature review suggests that RP1, TULP1, and PDE6B are among the most mutated genes in our population, supporting the value of population-specific genetic panels to enhance diagnostics and carrier screening. Full article

Objectives: To assess the association of structural biomarkers derived from optical coherence tomography (OCT) and choriocapillaris (CC) flow information with point-wise retinal sensitivity (PWS) measured by microperimetry (MP) in intermediate age-related macular degeneration (iAMD). Methods: Patients with iAMD received imaging with spectral-domain (SD)-OCT (Spectralis, Heidelberg Engineering) and OCT-angiography (OCT-A) (PLEX Elite 9000, ZEISS). In addition, MP examinations in photopic setting (MP-3, NIDEK) and mesopic background illumination (MAIA2, ICare) were performed. The thickness of the ellipsoid-zone (EZ) and the outer nuclear layer (ONL), as well as the volume of drusen and HRF, were segmented using deep-learning (DL)-based approaches. CC flow deficit percentage (FD%) was extracted from OCT-A slabs using a novel binarization method. Semiautomatic co-registration of MP examinations, OCT-A slabs, and OCT volumes was performed. Three exploratory models were calculated using multivariable mixed-effects models: (1) structure–function (SF) using structural OCT biomarkers, (2) flow–function (FF) utilizing OCT-A derived flow information, and (3) structure–flow–function (SFF) incorporating both OCT and OCT-A data. Model performance was evaluated using AIC and BIC criterion. Results: 19 eyes of 19 patients were evaluated, totalling 3297 MP-stimuli, 1873 B-scans, and 19 OCT-A slabs. Mean (SD) age was 76 (7) years, and sensitivity was 26.0 (3.36) dB in the MP-3 and 22.42 (3.64) dB in the MAIA2. Mesopic MAIA2 examinations showed significantly lower PWS values (−3.56 to −3.63 dB; p < 0.001). Drusen and HRF volume decreased PWS (−0.6 [95% CI: −1.04; −0.16] dB/nL; p = 0.007 and −9.56 [95% CI: −12.86; −6.26] dB/nL; p < 0.001), while ONL was positively associated with PWS (0.06 [0.05; 0.07] at an eccentricity of 5.2°; p < 0.001) in the SF model. CC FD% was not significantly associated with PWS in the FF and the SFF model (p > 0.05 in both cases). In the SFF model drusen volume (−1.69 [95% CI: −2.09; −1.29] dB/nL; p < 0.001), EZ (0.04 [95% CI: 0.02; 0.06] dB/µm; p < 0.001), and ONL thickness (0.03 [95% CI: 0.02; 0.04] dB/µm; p < 0.001) were significant predictors for PWS. The SF model exhibited the lowest AIC and BIC indicating best model performance. Conclusions: Structural parameters derived from SD-OCT such as HRF, drusen volume, and outer retinal layer thickness may be more closely associated with PWS, with CC FD% as an OCT-A-derived metric contributing limited additional explanatory benefit in cross-sectional analyses. Full article

Retinal ganglion cell (RGC) degeneration underlies glaucomatous optic neuropathy and remains a leading cause of irreversible vision loss worldwide. Although elevated intraocular pressure (IOP) is the primary modifiable risk factor, RGC death reflects converging mechanisms including mechanical stress, vascular insufficiency, metabolic dysfunction, and neuroinflammation. We conducted a PRISMA-guided systematic review with PICOS-defined eligibility criteria, searching PubMed, Cochrane Library, ScienceDirect, Scopus, Google Scholar, and ProQuest for studies through January 2026 on RGC degeneration and neuroprotective or regenerative therapies in glaucoma. Included studies supported OCT-based structural assessment and imaging biomarkers as essential tools for early detection, risk stratification, and monitoring of progression and treatment response. Continued RGC loss despite IOP control in many patients highlights the need for mechanism-based interventions; neuroprotective strategies targeting excitotoxicity, oxidative stress, mitochondrial dysfunction, and neurotrophic insufficiency are emerging, while stem cell and gene-based regenerative therapies remain under active investigation. Integrating molecular insights with advanced imaging and biomarker-guided endpoints may enable earlier, more individualized intervention and help explain progression despite adequate pressure control. Full article

Background: Recent studies strongly suggest that low intracranial pressure (ICP) may be involved in the pathogenesis of glaucomatous optic neuropathy. As retinal ganglion cells (RGCs) are highly susceptible to mitochondrial dysfunction, mitochondrial injury may be associated with optic neuropathy related to reduced ICP. In this study, aquaporin-1 (AQP1)-null mice were used to investigate whether reduced ICP is associated with alterations in mitochondrial structure and the release of optic atrophy type 1 (OPA1) and cytochrome c from mitochondria. Methods: Intraocular pressure (IOP) and ICP were measured in AQP1-null mice, and mitochondrial structural changes were examined using transmission electron microscopy (TEM). Total OPA1 and cytochrome c protein levels were evaluated using immunocytochemistry and Western blotting. Cytosolic and mitochondrial fractions were extracted from retinal tissues, and the subcellular distribution of OPA1 and cytochrome c was further analyzed by Western blotting. Bax and Bcl-2 expression levels were also detected. Results: TEM revealed mitochondrial fission, matrix swelling, and abnormal cristae depletion in the retinas of 1-, 3-, and 6-month-old AQP1-null mice. Morphometric quantification further confirmed significantly reduced mitochondrial length across all age groups and increased mitochondrial width at 1 and 6 months in AQP1-null mice compared with wild-type controls. Decreased retinal OPA1 immunoreactivity and protein expression were observed across all age groups of AQP1-null mice compared with age-matched C57BL/6 control mice. Subcellular fractionation showed increased mitochondrial release of OPA1 (at 3 and 6 months) and cytochrome c (at 1, 3, and 6 months) in the retinas of AQP1-null mice. Altered Bax expression was also detected in the retinas of AQP1-null mice with reduced ICP at all examined ages. Conclusions: Mitochondrial ultrastructural abnormalities, including fission and cristae depletion, altered OPA1 distribution, increased mitochondrial release of OPA1 and cytochrome c, and upregulated Bax expression were observed in the retinas of AQP1-null mice with reduced ICP. These concurrent changes indicate a close association between reduced ICP and retinal mitochondrial dysfunction. Maintaining mitochondrial integrity may therefore serve as a potential protective strategy against optic nerve degeneration in patients with chronic low ICP. Full article

Porcine organotypic retinal explant cultures are widely used to study retinal neurodegeneration under controlled conditions, but the biological processes that occur in the retinal explant over time due to preparation-induced injury and culture are not well understood. Here, we generated a time-resolved transcriptomic reference for porcine neural retinal explants, which were maintained ex vivo for 10 days. Global expression profiles are strongly separated by culture time, with Day 0 clearly distinct from cultured samples and Day 7 and Day 10 showing the highest similarity, indicating a transition toward a later stabilized state. Across the time course, 3187 genes were differentially expressed relative to Day 0, with the largest shifts occurring at an early stage of culture (Day 1–Day 3). Pathway-level analyses revealed coordinated remodeling involving inflammatory signaling and metabolic/bioenergetic changes, including reduced mitochondrial and oxidative phosphorylation-related programs at later time points. Here, we provide a time-resolved transcriptomics reference dataset for cultured porcine retinal explants. These data can build a foundation to interpret data generated in this model, differentiate changes inherent to the explant culture from treatment-specific effects and select appropriate experimental windows for mechanistic studies of retinal degeneration. Full article

The retina is a complex sensory neural tissue composed of six major types of neurons and one type of glial cell. The cell fate specification of retinal cells is tightly governed by intrinsic factors and extrinsic microenvironmental cues. Among the key regulators directing retinal cell fate differentiation is a group of bHLH family transcription factors (TFs). Our previous work demonstrated that the bHLH TF Ngn3 exhibits robust potential to induce retinogenesis in both distantly related fibroblasts in vitro and late retinal progenitor cells (RPCs) in vivo. However, the underlying molecular mechanisms remain largely elusive. In this study, we combined immunohistological examination and RNA-seq and ATAC-seq analyses to investigate the cellular and molecular mechanisms governing Ngn3-driven retinogenesis in late RPCs. Our results revealed that Ngn3 overexpression promotes premature cell cycle exit in late RPCs and remodels their transcriptomic and epigenomic landscape towards a state favoring rod photoreceptor and RGC differentiation. Furthermore, cross-comparison with Ngn3-overexpressing fibroblasts in vitro revealed cell-type-specific mechanisms underlying Ngn3-mediated neuronal fate reprogramming. These findings advance our understanding of Ngn family-mediated retinal cell fate regulation and provide a mechanistic framework for optimizing Ngn3-based retinal regeneration strategies for the treatment of retinal degeneration diseases. Full article

Background and Objectives: Age-related macular degeneration (AMD) is a multifactorial retinal disease in which inflammation and blood-retinal barrier dysfunction may contribute to disease pathogenesis. Claudin-5 is a key tight-junction protein involved in endothelial barrier integrity. Hemogram-derived indices such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), and pan-immune-inflammation value (PIV) reflect systemic inflammatory status. This study aimed to evaluate circulating claudin-5 levels and systemic inflammatory indices in patients with wet and dry AMD and to investigate their associations with visual function. Materials and Methods: This prospective case–control study included 90 participants: 30 patients with wet AMD, 30 patients with dry AMD, and 30 healthy controls. All participants underwent detailed ophthalmologic examination, including best-corrected visual acuity (BCVA) assessment and optical coherence tomography. Serum claudin-5 levels were analyzed by enzyme-linked immunosorbent assay, and NLR, PLR, MLR, and PIV were calculated from complete blood count parameters. Group comparisons, correlation analyses, and age-adjusted analyses were performed using appropriate statistical methods. Results: Age differed significantly among the groups (p = 0.032), with the highest median age in the dry AMD group. BCVA (logMAR) also differed significantly (p < 0.001), and both AMD groups had worse visual acuity than controls. Median serum claudin-5 levels were 2.42 in controls, 3.28 in the wet AMD group, and 3.10 in the dry AMD group, with no significant between-group difference (p = 0.280). NLR, MLR, and PIV were also comparable among the groups (p = 0.310, p = 0.410, and p = 0.752, respectively). PLR differed among the groups (p = 0.019), and post hoc analysis showed higher PLR values in the dry AMD group than in the wet AMD group (p = 0.013). However, this difference was no longer statistically significant after adjustment for age (adjusted p = 0.098). Serum claudin-5 was not significantly correlated with age, BCVA, NLR, PLR, MLR, or PIV. Conclusions: Circulating claudin-5 did not differ significantly across AMD phenotypes and was not associated with age, visual function, or systemic inflammatory indices. Although PLR differed between wet and dry AMD before adjustment for age, the overall findings suggest that single-point peripheral serum measurements of claudin-5 may have limited utility in reflecting local retinal barrier-related changes in AMD. Larger longitudinal studies are needed to clarify its potential biomarker role. Full article

Prominin-1 (Prom1/CD133) has long been recognized as a structural determinant of photoreceptor outer segment (OS) morphogenesis, yet rapidly accumulating evidence extends its role to retinal pigment epithelium (RPE) homeostasis, encompassing autophagy–lysosomal flux, outer segment phagocytosis, mitochondrial function, and regulation of inflammatory stress. This review synthesizes mechanistic and transcriptomic insights that position PROM1 as a central regulator of photoreceptor and RPE integrity, reframing Prom1 disease as a multi-compartment retinal disorder relevant to both inherited retinal dystrophies (IRDs) and atrophic age-related macular degeneration (aAMD). We develop a dual-axis conceptual model in which Prom1 dysfunction can initiate pathology in either the photoreceptors (OS morphogenesis failure) or the RPE, including impaired autophagic flux, lysosomal activity, defective phagocytosis, and Epithelial-Mesenchymal Transition (EMT)-like de-differentiation, with secondary cross-compartmental degeneration. Clinically, autosomal-dominant missense variants associate with macular or cone-rod dystrophy, whereas biallelic truncating/splice-site mutations drive early-onset rod–cone disease and panretinal/RPE atrophy, illustrating genotype–phenotype diversity. By integrating recent high-resolution transcriptomic data from Prom1-deficient RPE cells with long-standing insights into photoreceptor biology, we highlight converging pathways of degeneration that challenge a photoreceptor-centric view and unify disparate phenotypes within a single molecular framework. These insights broaden the therapeutic landscape, advancing gene augmentation and pathway-targeted strategies to preserve RPE integrity, sustain photoreceptor function, and modify disease course in PROM1-associated IRDs and atrophic AMD. Full article

Purpose: Neuroinflammation and oxidative stress are increasingly recognized as central, interconnected drivers of neurodegeneration in the visual system. This review examines the pathogenic mechanisms shared across glaucoma, age-related macular degeneration (AMD), diabetic retinopathy (DR), and Alzheimer’s disease (AD), and evaluates the therapeutic rationale for targeting both pathways simultaneously. Methods: A narrative review of peer-reviewed literature was conducted using PubMed. Searches included the following MeSH terms: neuroinflammation, oxidative stress, retinal neurodegeneration, microglia, Müller glia, mitochondrial dysfunction, glaucoma, age-related macular degeneration, diabetic retinopathy, and Alzheimer’s disease. Priority was given to original research, systematic reviews, and high-impact publications from 2000 through 2025. However, seminal foundational works were included regardless of publication date. Studies were selected based on relevance to glial activation, mitochondrial dysfunction, reactive oxygen and nitrogen species, and disease-specific neuronal outcomes. Results: Across all four diseases, persistent microglial and Müller glial activation, mitochondrial electron transport chain dysfunction, and excess reactive oxygen species (ROS) and reactive nitrogen species (RNS) production form a self-amplifying feed-forward loop that accelerates neuronal injury. In glaucoma, these mechanisms drive intraocular pressure-independent retinal ganglion cell loss. In AMD and DR, lipid dysregulation, complement activation, and chronic hyperglycemia sustain oxidative-inflammatory injury to the retinal pigment epithelium, photoreceptors, and neurovasculature. In AD, retinal amyloid deposition and oxidative burden mirror cortical pathology, positioning the retina as a noninvasive biomarker site. Conclusions: Neuroinflammation and oxidative stress constitute unifying upstream mechanisms across major vision-threatening neurodegenerative diseases. Combination therapeutic strategies that simultaneously modulate glial activation and restore redox homeostasis may offer superior neuroprotective efficacy compared to approaches targeting isolated downstream mediators. Full article

Background/Objectives: Macular pigment optical density (MPOD) represents a biomarker of retinal antioxidant status in intermediate age-related macular degeneration (iAMD). Strategies aimed at increasing macular carotenoid availability may contribute to disease stabilization. This study evaluated the effects of oral supplementation and transscleral iontophoresis on MPOD and retinal parameters in iAMD. Methods: This prospective, non-randomized pilot study included 60 eyes of 60 patients with intermediate AMD enrolled at the Eye Clinic of the University of Naples Federico II between July 2024 and May 2025 (ClinicalTrials.gov NCT06465342). Patients received either oral carotenoid supplementation (n = 30) or transscleral iontophoresis (n = 30). Best-corrected visual acuity (BCVA), central macular thickness (CMT), and MPOD measured by one-wavelength reflectometry ( Visucam 200; Carl Zeiss Meditec, Jena, Germany) were assessed at baseline and 6 months. Results: BCVA remained stable in both groups without significant changes (p > 0.05). MPOD significantly increased in the iontophoresis group (0.40 ± 0.11 to 0.49 ± 0.12, p < 0.001) with no statistically significant difference between them (p = 0.09). CMT showed a mild, non-significant increase in both groups (p > 0.05). No adverse events were observed. Conclusions: Both oral supplementation and transscleral iontophoresis were associated with a significant increase in MPOD while preserving visual acuity in intermediate AMD. Within the limitations of this non-randomized pilot study, transscleral iontophoresis produced MPOD changes comparable to those observed with oral supplementation. These findings are exploratory and support further investigation of localized delivery strategies in larger, randomized trials. Full article

Age-related macular degeneration (AMD) is a complex retinal disease influenced by genetic and metabolic factors. Genetic variants impact disease susceptibility, while alterations in amino acid and purine metabolism are involved in AMD development. This study aimed to examine the association between the COL2A1 rs1635529 polymorphism and AMD, as well as its relation to specific metabolites. The study comprised 919 participants: 261 with early AMD, 229 with exudative AMD, and 429 controls. DNA was extracted using the salting-out method, and genotyping was performed using real-time PCR. Metabolite levels were analysed with liquid chromatography–mass spectrometry. Statistical analysis was conducted using IBM SPSS Statistics 27.0. Logistic regression revealed that carriers of the GT + TT genotypes had a 1.63-fold higher risk of early AMD (p = 0.046). The T allele was also linked to a 1.67-fold elevated risk (p = 0.033). No significant associations were observed in exudative AMD. Furthermore, lower leucine levels were noted in exudative AMD patients, and inosine levels were reduced in GT genotype carriers within the early AMD group. The COL2A1 rs1635529 polymorphism showed a nominal association with early AMD, but not exudative AMD. Differences in leucine and inosine levels were observed, suggesting a potential link between genetic variation and metabolic alterations. These findings indicate possible involvement of collagen-related and metabolic pathways in early disease development; however, the results should be interpreted with caution and require validation in larger studies. Full article

The retinal pigment epithelium (RPE) is a long-lived, highly polarised epithelial monolayer that performs essential functions in retinal homeostasis, including outer blood–retina barrier maintenance, visual cycle activity, metabolic exchange, phagocytic clearance of photoreceptor outer segments, and regulation of oxidative and immune balance. Because RPE cells persist for decades under conditions of sustained oxidative, metabolic, and phagocytic stress, this tissue provides a valuable model for examining how long-lived post-mitotic cells preserve function over time and how age-related dysfunction emerges when that balance weakens. Although much of the current literature on RPE ageing has been shaped by age-related macular degeneration (AMD), age-dependent change in the RPE should not be understood solely as a preclinical stage of disease. Rather, the ageing RPE offers a broader framework for studying cellular maintenance under chronic physiological load. In this review, we synthesise current evidence on RPE ageing across four interrelated domains: structural remodelling, mitochondrial and metabolic imbalance, proteostatic and lysosomal burden, and chronic inflammatory dysregulation. Across these processes, ageing in the RPE is expressed less as widespread cell loss than as progressive decline in cellular organisation, buffering capacity, and functional precision. Structural irregularity, altered mitochondrial regulation, incomplete degradative clearance, and persistent low-grade inflammatory signalling together reduce the ability of the RPE to maintain long-term homeostasis and increase vulnerability to age-related retinal dysfunction. We further argue that ageing in the RPE is best understood not as abrupt failure of isolated pathways, but as gradual loss of system coherence among interacting homeostatic systems that remain active while operating under increasing constraint. This view helps integrate diverse cellular and molecular findings and highlights the RPE as an informative model for understanding ageing in long-lived post-mitotic tissues. Full article

Coenzyme Q10 (CoQ10), a natural antioxidant produced by the human body, has strong anti-inflammatory properties, reduces oxidative stress, and improves mitochondrial function. It is also known for its strong neuroprotective effects. With age, endogenously produced CoQ10 levels decline, contributing to the development of chronic diseases, including eye disorders. Irreversible ocular diseases that result in blindness present a significant challenge in contemporary medicine, as no fully effective cure exists; current treatments primarily aim to decelerate disease progression, manage symptoms, and preserve residual vision. Our study reviews research on the use of CoQ10 in eye diseases like age-related macular degeneration (AMD), retinitis pigmentosa (RP), and glaucoma, which can cause permanent vision loss and are linked to oxidative stress and mitochondrial dysfunction. This article explores whether CoQ10 can be a safe and effective addition to treatment for these conditions. We also outline directions for future research and explain how CoQ10 functions in the studies discussed in this review. Full article

Background/Objectives: Cisplatin is a potent chemotherapeutic agent whose clinical utility is limited by severe side effects, including neurotoxicity affecting the ocular system. The pathophysiology involves oxidative stress and mitochondrial dysfunction, to which the retina is particularly vulnerable. Selenium (Se), an essential trace element and component of antioxidant enzymes, has shown potential in mitigating cisplatin toxicity, although its efficacy with respect to retinal structure and the influence of administration routes remain underexplored. This study aimed to evaluate the protective efficacy of selenium against cisplatin-induced retinal toxicity and compare the effects of intraperitoneal and oral selenium administration. Methods: Forty adult male Wistar rats were randomized into four groups (n = 10 each): Group A (Cisplatin Monotherapy, 3.5 mg/kg IP for 5 days; cumulative dose 17.5 mg/kg); Group B (Cisplatin + Intraperitoneal Selenium, 2.73 mg/kg; cumulative dose 60 mg/kg); Group C (Control); and Group D (Cisplatin + Oral Selenium). Selenium prophylaxis, administered as sodium selenite (Na₂SeO₃), began two days prior to cisplatin administration and continued for 15 days post-treatment. Retinal evaluation two weeks after cisplatin cessation included light microscopy, semi-quantitative immunohistochemical (IHC) analysis for inflammatory (IL-6) and fibrotic (TGF-β2) markers, and Transmission Electron Microscopy (TEM) for ultrastructural analysis, which were the primary endpoints. Statistical differences in the IHC scores were analyzed via the Kruskal-Wallis H test with Dunn’s post hoc comparisons. Results: Cisplatin monotherapy (Group A) caused severe disruption of the retinal architecture, including edema, reactive gliosis, and significant upregulation of IL-6 and TGF-β2. Ultrastructural analysis revealed mitochondrial swelling (cristolysis) and photoreceptor disk fragmentation. Intraperitoneal selenium (Group B) was associated with significant structural preservation and intact mitochondria, with TGF-β2 levels comparable to those of the controls, although the IL-6 level remained moderately elevated. Conversely, oral selenium (Group D) suppressed both IL-6 and TGF-β2 expression to near-negative levels but provided less ultrastructural protection, resulting in persistent mitochondrial swelling and focal photoreceptor disruption. Conclusions: Systemic cisplatin induces severe subcellular retinal toxicity characterized by mitochondrial damage and photoreceptor degeneration. Selenium supplementation attenuates these effects; however, outcome patterns differ by administration route. Intraperitoneal selenium was associated with greater morphological and ultrastructural preservation despite persistent IL-6 elevation, whereas oral selenium normalized immunohistochemical marker expression to near-control levels but was associated with more pronounced residual subcellular damage on qualitative TEM assessment. These preliminary morphological and immunohistochemical findings suggest that the route of selenium delivery may influence its neuroprotective profile; however, pharmacokinetic measurements and functional retinal assessments, such as electroretinography, are warranted before its clinical translation. Full article