Search Results (527)

Diabetic retinopathy (DR) is a progressive, multifactorial complication of diabetes and one of the major global causes of visual impairment. Its pathogenesis involves chronic hyperglycaemia-induced oxidative stress, inflammation, mitochondrial dysfunction, neurodegeneration, and pathological angiogenesis, as well as emerging systemic contributors such as gut microbiota dysregulation. While current treatments, including anti-vascular endothelial growth factor (anti-VEGF) agents, corticosteroids, and laser photocoagulation, have shown clinical efficacy, they are largely limited to advanced stages of DR, require repeated invasive procedures, and do not adequately address early neurovascular and metabolic abnormalities. Resveratrol (RSV), a naturally occurring polyphenol, has emerged as a promising candidate due to its potent antioxidant, anti-inflammatory, neuroprotective, and anti-angiogenic properties. This review provides a comprehensive analysis of the molecular mechanisms by which RSV exerts protective effects in DR, including modulation of oxidative stress pathways, suppression of inflammatory cytokines, enhancement of mitochondrial function, promotion of autophagy, and inhibition of pathological neovascularisation. Despite its promising pharmacological profile, the clinical application of RSV is limited by poor aqueous solubility, rapid systemic metabolism, and low ocular bioavailability. Various routes of administration, including intravitreal injection, topical instillation, and oral and sublingual delivery, have been investigated to enhance its therapeutic potential. Recent advances in drug delivery systems, including nanoformulations, liposomal carriers, and sustained-release intravitreal implants, offer potential strategies to address these challenges. This review also explores RSV’s role in combination therapies, its potential as a disease-modifying agent in early-stage DR, and the relevance of personalised medicine approaches guided by metabolic and genetic factors. Overall, the review highlights the therapeutic potential and the key translational challenges in positioning RSV as a multi-targeted treatment strategy for DR. Full article

The eye, a complex organ essential for visual perception, is composed of diverse cell populations with specialized functions; however, the complex interplay between these cellular components and their underlying molecular mechanisms remains largely elusive. Traditional biotechnologies, such as bulk RNA sequencing and in vitro models, are limited in capturing cellular heterogeneity or accurately mimicking the complexity of human ophthalmic diseases. The advent of single-cell RNA sequencing (scRNA-seq) has revolutionized ocular research by enabling high-resolution analysis at the single-cell level, uncovering cellular heterogeneity, and identifying disease-specific gene profiles. In this review, we provide a review of scRNA-seq application advancement in ocular physiology and pathology, highlighting its role in elucidating the molecular mechanisms of various ocular diseases, including myopia, ocular surface and corneal diseases, glaucoma, uveitis, retinal diseases, and ocular tumors. By providing novel insights into cellular diversity, gene expression dynamics, and cell–cell interactions, scRNA-seq has facilitated the identification of novel biomarkers and therapeutic targets, and the further integration of scRNA-seq with other omics technologies holds promise for deepening our understanding of ocular health and diseases. Full article

Background/Objectives: Tacrolimus, an immunosuppressant, is increasingly used topically in ophthalmology, particularly for conditions like vernal keratoconjunctivitis and post-keratoplasty rejection prophylaxis. This systematic review aims to evaluate the efficacy and safety of topical tacrolimus in these ocular conditions. Methods: A thorough search was conducted in PubMed and Cochrane Library for relevant studies published up to 16 March 2025. Studies were eligible for inclusion if they were randomized controlled trials investigating topical tacrolimus in human ocular disease, were published in English, and reported clearly defined outcomes. Exclusion criteria included non-randomized studies, animal studies, systemic treatments, non-English publications, and studies lacking clearly reported outcomes. Data regarding study design, patient demographics, intervention details, and outcomes were extracted and analyzed. The Cochrane risk-of-bias tool (RoB 2.0) was used to assess the risk of bias. Results: A total of 10 studies met the inclusion criteria, were retrieved, and were categorized as not highly biased after the risk-of-bias assessment. These studies were included in the systematic review, where a qualitative analysis took place. Our analysis revealed that the topical use of tacrolimus showed promising results, as it improved clinical signs and symptoms in most patients. In half of the studies, tacrolimus demonstrated superior efficacy compared to the control group, while in the remaining studies, it showed equivalent efficacy. Adverse effects, such as a burning sensation, were noted in 7/10 studies but were generally mild. The methodologies were somewhat heterogeneous, and some studies had small sample sizes. Conclusions: Topical tacrolimus shows promising effects in managing various ocular surface diseases. While randomized controlled trials provide evidence, further research with larger sample sizes is necessary to solidify its efficacy and safety profile compared to other immunosuppressants. Full article

This study aimed to comprehensively review surgical interventions for ocular surface diseases (OSDs), including dry eye syndrome (DES), exposure keratopathy, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and ocular graft versus host disease (oGVHD), and to highlight the indications, contraindications, outcomes, and complications of various oculoplastic procedures used in their management. A narrative review was performed based on expert-guided selection of relevant studies retrieved from PubMed, Scopus, and Web of Science. Relevant keywords included “ocular surface disease”, “dry eye syndrome”, “exposure keratopathy”, “thyroid eye disease (TED)”, “neurotrophic keratopathy (NK)”, “Stevens-Johnson syndrome”, “toxic epidermal necrolysis”, “punctal occlusion”, “tarsorrhaphy”, “botulinum toxin”, “eyelid loading”, “retractor weakening”, “corneal neurotization (CN)”, “amniotic membrane transplantation (AMT)”, “conjunctival flap”, “ocular graft versus host disease”, and “salivary gland transplantation (SGT)”. Studies addressing surgical approaches for OSDs were included. In conclusion, surgical options for OSDs offer significant benefits when non-invasive treatments fail. Surgical techniques such as punctal occlusion, eyelid fissure narrowing, AMT, and conjunctival flap procedures help stabilize the ocular surface and alleviate symptoms. Advanced methods like CN and SGT target the underlying pathology in refractory cases such as oGVHD. The outcomes vary depending on the disease severity and surgical approach. Each procedure carries specific risks and requires individualized patient selection. Therefore, a tailored approach based on clinical condition, anatomical involvement, and patient factors is essential to achieve optimal results. Ongoing innovations in reconstructive surgery and regenerative medicine are expected to further improve outcomes for patients with OSDs. Full article

Tear film alterations are commonly associated with ocular pathology. The tear film plays a vital role in maintaining the optical properties of the cornea and contains essential elements required for healing and preserving the integrity of the ocular surface. As a biological fluid, the tear film is easily collected using non-invasive techniques, making it a promising candidate for analysis and often referred to as an ideal biofluid. Several studies have attempted to identify biomarkers in the tear film that could be linked to systemic or ocular disorders, with the goal of developing tools for diagnosis or even early prevention. The quality and quantity of the tear film are influenced by hormonal status, emotional experiences related to social and familial events, and the work environment. Systemic disorders are often reflected at the ocular level through alterations in the tear film. Obesity is a well-recognized public health concern, extensively studied and investigated, much like other common systemic conditions. The presence of low-grade, chronic inflammation associated with excess body weight has been validated in several studies. The strategies for preventing obesity induced dry eye disease are based on regular physical activity, maintaining adequate hydration through sufficient fluid intake, weight loss, and the supplementation of essential fatty acids. This narrative literature review aims to highlight the tear film alterations associated with obesity. The article is intended for ophthalmologists, general practitioners, nutritionists, and researchers. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is known to affect multiple organ systems, including the respiratory tract and nervous and ocular systems. This retrospective study aimed to characterize the spatiotemporal distribution of viral antigen and associated pathological changes in the nose, lungs, brain, and eyes of K18-hACE2 mice intranasally infected with SARS-CoV-2. Using histology and immunohistochemistry, tissues were examined at 3, 6, and 7/8 days post-infection (dpi). In addition, lung and brain tissues were analyzed by means of RT-qPCR to determine viral RNA titers. Viral antigen was most pronounced in the nose, brain, and lung at 3, 6, and 7/8 dpi, respectively, whereas viral antigen was detected at 6 and 7/8 dpi in the retina. Quantitative PCR confirmed increasing viral RNA levels in both lung and brain, peaking at 7/8 dpi. Nasal and lung inflammation mirrored viral antigen distribution and localization. In the brain, the predominantly basal viral spread correlated with lymphohistiocytic meningoencephalitis, neuronal vacuolation, and altered neurofilament immunoreactivity. Retinal ganglion cells showed viral antigen expression without associated lesions. Microglial activation was evident in both the optic chiasm and the brain. These findings highlight the K18-hACE2 model’s utility for studying extrapulmonary SARS-CoV-2 pathogenesis. Understanding the temporal and spatial dynamics of viral spread enhances insights into SARS-CoV-2 neurotropism and its clinical manifestations. Full article

Collagen IV α1/α2 heterotrimers are the major constituents of all basement membranes (BM). Consistently, COL4A1/A2 mutations cause a complex multisystem disorder. While mouse models are invaluable, they alone cannot support the rapid functional validation needed for clinical translation. The FishCOLler project establishes zebrafish as a scalable in vivo platform to model COL4A1/A2 disease, employ rapid assays to monitor key disease traits, and enable mechanistic studies. Our first fish disease faithfully models patient symptoms, i.e., brain hemorrhage and ocular dysgenesis. The work supports FishCOLler as a platform for rapid variant interpretation, therapeutics testing, and highlights potential consequences of gene dosage modulation strategies. Full article

Pupil cycle time (PCT) estimates the dynamics of a biofeedback loop established between pupil size and stimulus luminance, size or colour. The PCT is useful for probing the functional integrity of the retinopupillary circuits, and is therefore potentially applicable for assessing the effects of damage due to retinopathies or neuropathies. In previous studies, PCT was measured by manually counting the number of pupil oscillations during a fixed period to calculate the PCT. This method is scarce, requires a good expertise and cannot be used to estimate several PCT parameters, such as the oscillation amplitude or variability. We have developed a computerised setup based on eye-tracking that expands the possibilities of characterising PCT along several dimensions: oscillation frequency and regularity, amplitude and variability, which can be used with a large palette of stimuli (different colours, sizes, shapes or locations), and further allows measuring blinking frequency and eye movements. We used this method to characterise the PCT in young control participants as well as in patients with several pathologies, including age-related macular degeneration (AMD), diabetic retinopathy (DR), retinitis pigmentosa (RP), Stargardt disease (SD), and Leber hereditary optic neuropathy (LHON). We found that PCT is very regular and stable in young healthy participants, with little inter-individual variability. In contrast, several PCT features are altered in older healthy participants as well as in ocular diseases, including slower dynamics, irregular oscillations, and reduced oscillation amplitude. The distinction between patients and healthy participants based on the calculation of the area under the curve of the receiver operating characteristics (AUC of ROC) were dependent on the pathologies and stimuli (0.7 < AUC < 1). PCT nevertheless provides relevant complementary information to assess the physiopathology of ocular diseases and to probe the functioning of retino-pupillary circuits. Full article

Purpose: To review the current literature on the combined use of cataract surgery (or lensectomy) and vitrectomy in pediatric patients, with a focus on clinical indications, surgical techniques, outcomes, and complications across various pediatric ocular pathologies. Methods: A narrative review of published studies addressing the use of combined lensectomy and vitrectomy (LV) in pediatric patients was conducted. Conditions discussed include congenital cataracts, ectopia lentis, retinopathy of prematurity (ROP), retinal detachment (RD), and persistent fetal vasculature (PFV). Key surgical considerations, visual and anatomical outcomes, and postoperative complications were examined. Results: The literature search yielded a total of 160 articles, of which 43 met the inclusion criteria and were included in this review. Although lens-sparing vitrectomy (LSV) is preferred in many pediatric cases to preserve accommodation and reduce complications, combined LV is often necessary in advanced or complex diseases. Studies have shown that combined LV can achieve favorable anatomical outcomes, but functional visual recovery remains variable and is affected by factors such as patient age, baseline ocular anatomy, and disease severity. Postoperative complications such as glaucoma, visual axis opacification (VAO), and intraocular lens (IOL) dislocation are more frequent with combined procedures and require long-term follow-up and rehabilitation. Conclusions: Combined cataract surgery (or lensectomy) and vitrectomy may represent a valuable strategy in the management of complex pediatric ocular conditions, particularly when individualized to the clinical context. Tailored surgical approaches are essential to optimize anatomic and functional outcomes. Further prospective studies and harmonized multicenter registries are needed to develop evidence-based principles that can guide individualized surgical decision-making in this unique patient population. Full article

Background: The World Health Organization defines myopia as a global epidemic. Its growing prevalence and the increasingly early age onset all raise a major concern for public health due to the elevated risk of loss and deterioration of visual function as a result of myopia-related ocular pathological complications. However, it remains unclear whether the vision-related quality of life of patients with myopia is the same as in healthy individuals. The aim of the present study is to assess the quality of life in children and adolescents with myopia between the ages of 8 and 16 years, who underwent observation at USBOBAL-Varna. Methods: This study prospectively included 190 patients with myopia between −1.00 and −5.50 D, corrected with different optical aids. After a thorough physical ocular examination and inquiry into the best visual acuity with and without distance correction, specially designed questionnaires were completed by the patients and their parents/guardians for the purpose of the study. The data from the questionnaires was statistically processed. The mean age of the patients in the study was 11.65 years, 101 were female and 89 were male. Of these, 83 wore monofocal glasses, 50 were monofocal and 47 were multifocal contact lenses, and 10 wore ortho-K lenses. Results: No significant difference in best corrected visual acuity (BCVA) was found among the three types of optical correction (p-value > 0.05). Cronbach’s alpha of the questionnaire for all 10 factors was higher than 0.6, indicating acceptable internal consistency. Significantly higher scores were reported for overall, near, and distance vision, symptoms, appearance, attitude, activities and hobbies, handling, and perception for soft contact lens wearers than for spectacle wearers (p-value < 0.05). Ortho-K wearers performed better than spectacle wearers in all aspects except for pronounced symptoms (p = 0.74). No significant difference was found between ortho-K wearers and soft contact lens wearers for any factor (p > 0.05). Conclusions: Patients wearing spectacles and with myopia above −5.00 D had the highest anxiety scores and lower quality of life among all myopic participants. The research on the quality of life in children with myopia with different refractive errors and optical correction devices is crucial for improving corrective devices and meeting the needs of patients. Full article

Background/Objectives: Post-keratoplasty astigmatism can limit visual recovery even after successful corneal transplantation. Femtosecond laser-assisted arcuate keratotomy (FSAK) has emerged as a method to reduce high residual astigmatism and enhance visual outcomes. This study aimed to evaluate the outcome of FSAK in treating astigmatism following keratoplasty. Methods: This retrospective study included 32 eyes from 31 patients who underwent FSAK after keratoplasty. Inclusion required complete suture removal, regular corneal topography, and the absence of additional ocular pathology or prior intraocular surgery. Data collected included uncorrected (UCVA) and best-spectacle-corrected visual acuity (BSCVA), manifest refraction, and tomographic parameters. The primary outcomes were changes in visual, refractive, and tomographic measures across the entire cohort, with further subgroup analysis between penetrating keratoplasty (PKP) and lamellar keratoplasty (LKP) eyes. Secondary outcomes were documentation of complications. Results: UCVA improved significantly from 0.92 ± 0.33 to 0.58 ± 0.39 LogMAR (p < 0.001). BSCVA showed a non-significant trend toward improvement from 0.32 ± 0.21 to 0.26 ± 0.22 LogMAR (p = 0.158). The manifest cylinder reduced significantly from −6.15 ± 2.75 D to −4.49 ± 2.92 D (p = 0.037). Corneal topography revealed significant postoperative steepening in keratometric values. While overall outcomes were comparable between the subgroups, LKP eyes demonstrated a greater myopic shift and a higher rate of overcorrection, whereas PKP eyes tended toward undercorrection. Conclusions: FSAK appears to be an effective approach for reducing post-keratoplasty astigmatism and improving uncorrected visual acuity. Given the biomechanical differences between graft types, individualized treatment planning based on graft characteristics may enhance surgical predictability and optimize outcomes. Full article

Cataract remains the leading cause of blindness worldwide, and the number of individuals affected by this condition is expected to rise significantly due to global population ageing. Early diagnosis is crucial, as delayed treatment may result in irreversible vision loss. This study explores and presents a mobile application for Android devices designed for the detection of cataracts using deep learning models. The proposed solution utilizes a multi-stage classification approach to analyze ocular images acquired with a slit lamp, sourced from the Nuclear Cataract Database for Biomedical and Machine Learning Applications. The process involves identifying pathological features and assessing the severity of the detected condition, enabling comprehensive characterization of the NC (nuclear cataract) of cataract progression based on the LOCS III scale classification. The evaluation included a range of convolutional neural network architectures, from larger models like VGG16 and ResNet50, to lighter alternatives such as VGG11, ResNet18, MobileNetV2, and EfficientNet-B0. All models demonstrated comparable performance, with classification accuracies exceeding 91–94.5%. The trained models were optimized for mobile deployment, enabling real-time analysis of eye images captured with the device camera or selected from local storage. The presented mobile application, trained and validated on authentic clinician-labeled pictures, represents a significant advancement over existing mobile tools. The preliminary evaluations demonstrated a high accuracy in cataract detection and severity grading. These results confirm the approach is feasible and will serve as the foundation for ongoing development and extensions. Full article

Background/Objectives: This study explores the ocular anatomy and glandular components of domestic dogs compared to their ancestor, the wolf, with the aim of identifying evolutionary changes due to domestication and their implications for ocular pathologies. Methods: Utilizing histological and histochemical techniques, including hematoxylin–eosin, Periodic Acid–Schiff, Alcian Blue, and lectins, this research conducts a detailed analysis of the canine and wolf ocular systems, focusing on the eyelids, tarsal glands, and conjunctival tissues. Results: There are marked histological differences between the two species, particularly in the thickness and secretion levels of the conjunctival epithelia and the structure of the tarsal glands. Dogs exhibit a thicker epithelium with greater Periodic Acid–Schiff and Alcian Blue positive secretion, suggesting enhanced ocular protection and lubrication adapted to domestic environments. Conversely, wolves display more concentrated glandular secretions and a predominance of acidic mucopolysaccharides, aligning with their adaptation to natural habitats. Conclusions: Although this study is constrained by the limited number of samples, the use of mixed dog breeds, and the focus on the Iberian wolf, it nonetheless suggests histological and evolutionary differences between domestic dogs and wolves, particularly in structures related to ocular surface protection and lubrication. These differences likely reflect adaptive responses to domestication in dogs and environmental demands in wolves. Importantly, the findings emphasize the clinical and translational potential of using dogs as comparative models for human ocular surface disorders, given their anatomical proximity to humans. Full article

The therapeutic potential of exosomes (Exos), a subpopulation of extracellular vesicles (EVs) secreted by various cell types, has been broadly emphasized. Exos are endosome-derived membrane-bound vesicles 50–150 nm in size. Exos can be general or cell type-specific. Their contents enable them to function as multi-signaling and vectorized vehicles. Exos are important for maintaining cellular homeostasis. They are released into extracellular spaces, leading to uptake by neighboring or distant cells and delivering their contents to modulate cell signaling. Exos influence tissue responses to injury, infection, and disease by fusion with the target cells and transferring their cargo, including cytokines, growth and angiogenic factors, signaling molecules, lipids, DNA, mRNAs, and non-coding RNAs. They are implicated in various physiological and pathological conditions, including ocular surface events, such as corneal scarring, wound healing, and inflammation. Their biocompatibility, stability, low immunogenicity, and easy detectability in bodily fluids (blood, tears, saliva, and urine) make them promising tools for diagnosing and treating ocular diseases. The potential to engineer specific Exo cargos makes them outstanding therapeutic delivery vehicles. The objective of this review is to provide novel insights into the functions of Exo cargos and their applications as biomarkers and therapeutics, or targets in the cornea. Full article

Pericytes, specialized mural cells surrounding microvessels, play a crucial role in maintaining vascular homeostasis and function across various organs, including the eye. These versatile cells regulate blood flow, support the integrity of the blood–retinal barrier, and contribute to angiogenesis. Recent advancements in molecular and cellular biology have revealed the heterogeneity of pericytes and their critical involvement in ocular physiology and pathology. This review provides a comprehensive analysis of pericyte functions in ocular health and their implications in diseases such as diabetic retinopathy, age-related macular degeneration, glaucoma, and retinal vein occlusion. Pericyte dysfunction is implicated in vascular instability, neurovascular coupling failure, inflammation, and pathological neovascularization, contributing to vision-threatening disorders. The review further explores recent findings on pericyte-targeted therapies, including pharmacological agents, gene therapy, and cell-based approaches, aiming to restore pericyte function and preserve ocular health. Full article