Current Eye Research最新文献

Purpose: The purpose of this study was to compare the visual function, using standard optometric clinical procedures, between children with ADHD and healthy controls, and to examine the mediating role of psychostimulant medication. This work aims to provide clinically relevant evidence that may contribute to a better management of children with ADHD in eye care settings.

Methods: A total of 112 children aged 6 to 14 years old were divided into three different groups: 58 non-medicated ADHD children, 22 medicated ADHD children, and 32 age-matched controls. A series of visual variables commonly assessed in clinical practice (i.e. refractive error, visual performance, accommodation, and binocular system) were measured according to standard procedures.

Results: Statistically significant differences were observed for contrast sensitivity (p-value = 0.014), with the control group showing better results. Regarding accommodative and binocular parameters, only the accommodative facility showed a statistically significant (p = 0.048) tendency toward a worse ability to change accommodative focus in children with ADHD compared to controls. Psychostimulant treatment did not have any effect on visual function (p > 0.05 in all cases).

Conclusions: From all the variables assessed, only accommodation facility and contrast sensitivity appear to differ from the control group, and these appear to be independent of psychostimulant treatment in children with ADHD.

Purpose: To investigate innate and adaptive immune responses in allergic conjunctivitis induced by simultaneous sensitization with Orchard grass and Alternaria antigens.

Materials and methods: An experimental allergic conjunctivitis (EAC) mouse model was developed by instilling mixed antigen solutions of Orchard grass and Alternaria antigens after sensitization via intraperitoneal administration of a mixed antigen solution. BALB/cj mice were divided into four groups based on sensitization and number of antigen eye drop instillations: (1) A1 group (single instillation without intraperitoneal administration), (2) S1 group (single instillation with intraperitoneal administration), (3) M1 group (three instillations with intraperitoneal administration), (4) C group (negative control with receiving neither instillation nor intraperitoneal administration). Clinical observations and histological examinations for eosinophils were performed, and eosinophil density in the conjunctival tissue was quantified. Gene expression levels of thymic stromal lymphopoietin (TSLP), interleukins (IL-4, IL-5, IL-13, IL-16, and IL-33), and CCL11/eotaxin-1 in the conjunctiva were evaluated using real-time reverse transcriptase polymerase chain reaction.

Results: The clinical symptoms of allergic conjunctivitis were observed in the A1, S1, and M1 groups. Eosinophil density at 1 h after the last instillation was significantly higher in the A1, S1, and M1 groups compared to the C group (p < 0.01), with the M1 group showing higher density than the S1 group (p < 0.01). Conjunctival TSLP messenger RNA (mRNA) expression levels were increased in the sensitized (S1 and M1) groups compared to the C group (p < 0.01 and p < 0.05, respectively), with the M1 group exhibiting higher expression than the S1 group (p < 0.01). Additionally, mRNA expression levels of IL-16 and CCL11 in the M1 group were significantly higher than those in the A1 group.

Conclusions: Allergic conjunctivitis induced by Orchard grass and Alternaria antigens is characterized by early eosinophil infiltration, and TSLP upregulation exacerbates the allergic inflammation in the conjunctiva.

Purpose: To analyze proteoglycans and other extracellular matrix macromolecules from normal (NL) and keratoconus (KC) human corneas.

Methods: Corneas from eye banks (NL) and penetrating keratoplasty (KC) were obtained. Halves of the corneas were fixed and prepared for immunofluorescence using confocal microscopy; the other halves were subjected to macromolecule extraction with GuHCl for protein quantification, macromolecule identification by polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS-PAGE) and western blotting, and quantification by enzyme-linked immunosorbent assay (ELISA).

Results: In the study population (N = 8 for NL and N = 12 for KC), there was no difference in sex, laterality, wet weight, or preservation time, but only in age. Western blotting detected keratan sulfate (KS), decorin, and lumican in both groups, with structural differences in decorin in the KC group. The mean protein concentration by corneal wet weight was significantly lower in the KC group. The mean concentrations of decorin, lumican, and KS did not show any difference between the groups when normalized by wet weight but showed a higher concentration in the KC group when normalized by μg of extracted protein. Immunofluorescence analysis revealed a similar macromolecular distribution among the groups.

Conclusions: In corneas with KC, non-collagenous proteins decreased without affecting decorin, lumican, or KS levels, which were relatively increased. In addition, decorin was highly glycosylated.

Purpose: Dry eye disease (DED) is a prevalent ocular surface condition characterized by tear film instability and inflammation, significantly impacting patients' quality of life. While the Schirmer test remains a key diagnostic tool, Schirmer strips are increasingly used for tear fluid collection in metabolomics studies aimed at, e.g. identifying biomarkers for DED. However, both pre-analytical and analytical variables inherent to Schirmer strip use can compromise data integrity and hamper reproducibility.

Methods: For this review, the PubMed database and Google Scholar were searched for published human studies in English relevant to pre-analytical and analytical aspects of tear metabolomics, especially from dry eye patients, when tear samples were collected with Schirmer strips.

Results: This article discusses the critical pre-analytical factors, including variability in Schirmer strip materials, tear sampling techniques, storage conditions, and potential contamination, that influence metabolomic data quality. Analytical considerations are also examined, with particular focus on volume-adjusted extraction protocols that address tear volume variability.

Conclusion: We conclude that standardized guidelines for Schirmer strip use, covering material selection, sampling protocols, storage, and extraction, are urgently needed to advance tear metabolomics as a reliable clinical and research tool. Future research should focus on validating these recommendations in multi-center studies, exploring inter-individual variability, and developing innovative analytical workflows to optimize metabolite recovery and quantification. Such efforts will enhance the translational potential of tear metabolomics, paving the way for biomarker discovery and improved management of DED.

Purpose: This study aims to conduct a mini review of published literature concerning the role of exosomes in the field of ophthalmology, with a specific focus on Age-Related Macular Degeneration (AMD).

Methods: In this study, a comprehensive search was conducted using PubMed and Google Scholar to identify relevant publications. Additionally, trials submitted to clinicaltrials.gov were reviewed to identify further relevant articles. The selected studies specifically focused on the ocular implications of exosomes in Age-Related Macular Degeneration.

Results: Exosomes, small extracellular vesicles measuring less than 200 nm, play a crucial role in cell signaling and are involved in various physiological and pathological processes. Recent research has focused on utilizing exosomes for disease detection and treatment. Studies have investigated the ocular implications of exosomes, particularly in AMD. Exosomes found in aqueous fluid and blood have been examined as potential markers for AMD and as indicators of treatment response. Additionally, research in animal models has indicated the potential of exosomes in preventing AMD, as well as their promise for targeted and efficient drug delivery. This mini review primarily emphasizes the clinical aspects of publications related to AMD, rather than focusing solely on basic science.

Conclusions: Exosomes have a great potential for understanding Age-related Macular Degeneration and effective and targeted treatment for retinal diseases.

Purpose: Dry eye disease (DED), a multifactorial disease of the lacrimal system, manifests itself in patients with various symptoms such as itching, inflammation, discomfort and visual impairment. In its most severe forms, it results in the breakdown of the vital tissues of lacrimal functional unit and carries the risk of vision loss. Despite the frequency of occurrence of the disease, there are no effective curative treatment options available to date. Treatment using stem cells and its secreted factors could be a promising approach in the regeneration of damaged tissues of ocular surface. The treatment using secreted factors as well as extracellular vesicles has been demonstrated beneficial effects in various ocular surface diseases. This review provides insights on the usage of stem cell derived exosomes as a promising therapy against LG dysfunction induced ADDE for ocular surface repair.

Methods: In order to gain an overview of the existing research in this field, literature search was carried out using the PubMed, Medline, Scopus and Web of Science databases. This review is based on 164 publications until June 2024 and the literature search was carried out using the key words "exosomes", "lacrimal gland regeneration", "exosomes in lacrimal dysfunction".

Results: The literature and studies till date suggest that exosomes and other secreted factors from stem cells have demonstrated beneficial effects on damaged ocular tissues in various ocular surface diseases. Exosomal cargo plays a crucial role in regenerating tissues by promoting homeostasis in the lacrimal system, which is often compromised in severe cases of dry eye disease. Exosome therapy shows promise as a regenerative therapy, potentially addressing the lack of effective curative treatments available for patients with dry eye disease.

Conclusion: Stem cell-derived exosomes represent a promising, innovative approach as a new treatment option for ADDE. By targeting lacrimal gland dysfunction and enhancing ocular surface repair, exosome therapy offers potential for significant advances in dry eye disease management. Future research is needed to refine the application of this therapy, optimize delivery methods, and fully understand its long-term efficacy in restoring ocular health.

Purpose: To assess the therapeutic potential of extracellular vesicles (EVs) derived from stem cells and ocular tissues as a cell-free alternative to traditional stem cell therapies for a broad spectrum of ocular diseases.

Methods: A comprehensive literature review was performed, focusing on preclinical studies involving EVs derived from mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), embryonic stem cells (ESCs), neural progenitor cells, immune cells, and ocular-resident cells. Data were extracted on EV cellular origin, isolation methods, routes of administration, preclinical disease models, therapeutic outcomes, and proposed mechanisms of action. Registered clinical trials were also evaluated.

Results: EVs exhibited regenerative and immunomodulatory effects across a range of ocular conditions, including dry eye, uveitis, glaucoma, retinal degenerations, and optic neuropathies. Various cell sources have been explored for EV production, including MSCs, iPSCs, hESCs, retinal organoids, and other ocular tissue-resident cells. In addition, bioengineered EVs have been developed to modify surface properties or enhance therapeutic cargo. Reported mechanisms of action include miRNA-mediated gene regulation, immune modulation, and oxidative stress reduction. Several early-phase clinical trials are currently underway to translate these findings into human therapies.

Conclusion: Stem cell-derived EVs represent a promising next-generation, cell-free regenerative therapy for ocular diseases. While preclinical data are promising, successful clinical translation will require optimal EV source selection, scalable and GMP-compliant production, identification of disease-relevant mechanisms of action, rigorous cargo characterization, and alignment with regulatory standards.

Purpose: A stable ocular surface is crucial for maintaining ocular health by protecting against various infections. This is achieved by coordinated function of ocular structures (cornea, limbus, conjunctiva), innervation, and the tear film which forms a protective barrier over the ocular surface ensuring proper hydration, lubrication, and overall ocular comfort. This complex three-layered tear film secreted by different sources ensures its stability by adhesion to the corneal epithelium. Ocular surface fluid kinetics and tear secretion involve complex processes influenced by neural regulation, environmental factors, and molecular composition. Recent advances in cell biology and secretome has unravelled the mysteries of cellular cargo of almost every cell and system i.e. the extracellular vesicles (EVs) which facilitate intercellular communication. EVs are of different sizes, amongst which small EVs (sEVs) potentially are more informative than other EVs.

Methods: An extensive review of literature on sEVs in tears and ocular surface was conducted.

Results: Emerging literature on sEVs derived from ocular surface structures such as cornea and limbal stem cells contribute to corneal wound healing, regeneration and reduced fibrosis by the activation of specific proteins. A recent study documents that homeostasis between cornea and conjunctiva is maintained by the expression of specific genes triggering trans differentiation in diseased conditions. There is also mounting evidence on role of tear-derived sEVs in normal and diseased states. The approach in which tear layers secreted from three different sources form into a single tri-layered stable biofilm covering the entire ocular surface remains elusive. Hence not surprisingly, the tear sEVs therefore have been referred to as one entity and not attributed to any of the 3 different sources that they originate from.

Conclusion: This review attempts to present the recent concepts of sEVs, ocular surface, tears and highlight the gaps in our understanding of tear-derived exosomes and its potential role in homeostasis and disease conditions.

Purpose: Exosomes, small extracellular vesicles ranging from 30 to 150 nm in diameter, have emerged as crucial mediators of intercellular communication in ocular tissues. This review explores the roles of exosomes in ocular health and disease, focusing on their biogenesis, functions in different eye structures, and potential as diagnostic biomarkers and therapeutic agents.

Methods: This comprehensive review synthesizes current research on ocular exosomes, drawing from global studies to present an integrated view of exosome biology in the eye.

Results: Exosomes play vital roles in maintaining retinal homeostasis, corneal function, and lens transparency. They are implicated in the pathogenesis of major eye diseases, including glaucoma, age-related macular degeneration, and diabetic retinopathy. Recent advances have revealed the potential of exosomes as biomarkers for early disease detection and as vehicles for targeted drug delivery. Emerging technologies, such as microfluidics and nanotechnology, enhance exosome isolation and analysis capabilities.

Conclusions: Exosome research in ophthalmology is rapidly advancing, offering promising avenues for novel diagnostic and therapeutic approaches. However, challenges remain in standardization, scalability, and clinical translation. Addressing these issues and ethical considerations will be crucial for realizing the full potential of exosomes in improving ocular health outcomes globally.

Exosomes are small membrane-bound vesicles which have emerged as crucial mediators in various biological and pathological processes, as well as potential therapeutic delivers. In recent years, the role of exosomes in the lens, a specialized tissue essential for vision, has been stressed. The purpose of this review is to sum up the current understanding of exosome function within the lens and their implications in lens-related diseases.