Ocular Surface Structures Research Articles

Randomness-restricted Diffusion Model for Ocular Surface Structure Segmentation.

Ocular surface diseases affect a significant portion of the population worldwide. Accurate segmentation and quantification of different ocular surface structures are crucial for the understanding of these diseases and clinical decision-making. However, the automated segmentation of the ocular surface structure is relatively unexplored and faces several challenges. Ocular surface structure boundaries are often inconspicuous and obscured by glare from reflections. In addition, the segmentation of different ocular structures always requires training of multiple individual models. Thus, developing a one-model-fits-all segmentation approach is desirable. In this paper, we introduce a randomness-restricted diffusion model for multiple ocular surface structure segmentation. First, a time-controlled fusion-attention module (TFM) is proposed to dynamically adjust the information flow within the diffusion model, based on the temporal relationships between the network's input and time. TFM enables the network to effectively utilize image features to constrain the randomness of the generation process. We further propose a low-frequency consistency filter and a new loss to alleviate model uncertainty and error accumulation caused by the multi-step denoising process. Extensive experiments have shown that our approach can segment seven different ocular surface structures. Our method performs better than both dedicated ocular surface segmentation methods and general medical image segmentation methods. We further validated the proposed method over two clinical datasets, and the results demonstrated that it is beneficial to clinical applications, such as the meibomian gland dysfunction grading and aqueous deficient dry eye diagnosis.

Surface Characterization and Tribology Behavior of PMMA Processed by Excimer Laser

Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization and tribological behavior of PMMA processed using an excimer laser were investigated in this study by contrasting different lubrication conditions and friction cycles. The results show that the roughness of the material surface increases with laser processing, which changes its physical structure. Under lubrication, the laser-treated PMMA exhibits better hydrophilicity, especially during the use of eye drops. No obvious relationship exists between the laser-processing time and friction behavior. However, the laser treatment may contribute to the formation of friction and wear mechanisms of PMMA materials. Laser-treated PMMA in saline solution exhibits better abrasive resistance by showing a lower wear rate than that in eye drops, although it has a higher friction coefficient. In this study, the different friction stages in laser-treated PMMA were clarified under two lubrication conditions. The wear rates of the laser-treated PMMA were found to decrease with the number of cycles, and the friction coefficient has a similar variation tendency. The wear behavior of the laser-treated PMMA is dominated by the main abrasive wear and secondary transferred film formation. This study provides a theoretical basis for the development and application of ophthalmic biomaterials in complex environments by examining the material surface interface behavior and wear mechanism after laser processing using PMMA as the research matrix.

Characterization of Porcine Ocular Surface Epithelial Microenvironment.

The porcine ocular surface is used as a model of the human ocular surface; however, a detailed characterization of the porcine ocular surface has not been documented. This is due, in part, to the scarcity of antibodies produced specifically against the porcine ocular surface cell types or structures. We performed a histological and immunohistochemical investigation on frozen and formalin-fixed, paraffin-embedded ocular surface tissue from domestic pigs using a panel of 41 different antibodies related to epithelial progenitor/differentiation phenotypes, extracellular matrix and associated molecules, and various niche cell types. Our observations suggested that the Bowman's layer is not evident in the cornea; the deep invaginations of the limbal epithelium in the limbal zone are analogous to the limbal interpalisade crypts of human limbal tissue; and the presence of goblet cells in the bulbar conjunctiva. Immunohistochemistry analysis revealed that the epithelial progenitor markers cytokeratin (CK)15, CK14, p63α, and P-cadherin were expressed in both the limbal and conjunctival basal epithelium, whereas the basal cells of the limbal and conjunctival epithelium did not stain for CK3, CK12, E-cadherin, and CK13. Antibodies detecting marker proteins related to the extracellular matrix (collagen IV, Tenascin-C), cell-matrix adhesion (β-dystroglycan, integrin α3 and α6), mesenchymal cells (vimentin, CD90, CD44), neurons (neurofilament), immune cells (HLA-ABC; HLA-DR, CD1, CD4, CD14), vasculature (von Willebrand factor), and melanocytes (SRY-homeobox-10, human melanoma black-45, Tyrosinase) on the normal human ocular surface demonstrated similar immunoreactivity on the normal porcine ocular surface. Only a few antibodies (directed against N-cadherin, fibronectin, agrin, laminin α3 and α5, melan-A) appeared unreactive on porcine tissues. Our findings characterize the main immunohistochemical properties of the porcine ocular surface and provide a morphological and immunohistochemical basis useful to research using porcine models. Furthermore, the analyzed porcine ocular structures are similar to those of humans, confirming the potential usefulness of pig eyes to study ocular surface physiology and pathophysiology.

Hormones and dry eye disease

The endocrine system influences all tissues and cells in the human body. The ocular surface is constantly exposed to circulating hormones and expresses their specific receptors. Dry eye disease (DED) is a disorder with multifactorial etiology, and endocrine anomalies are one of the inciting factors. The endocrine anomalies that cause DED include physiological conditions such as menopause, menstrual cycle variations, pathologies such as polycystic ovarian syndrome, androgen resistance, iatrogenic conditions such as contraceptive use, and antiandrogen treatment. This review highlights the status of these hormones in DED along with the mechanism of action of different hormones on the ocular surface structures and the clinical implications of these effects. The influence of androgens, estrogens, and progesterone on the ocular surface tissues, and the implications of androgen-deficient states in DED are also discussed. The physiological and pathological effects of menopause and sex hormone replacement therapy are discussed. The effects of insulin and insulin resistance on the ocular surface and DED, and the growing potential of topical insulin therapeutics for DED are mentioned. Thyroid-associated ophthalmopathy, its impact on the ocular surface, and the tissue effects of thyroid hormone in the context of DED are reviewed. Finally, the potential role of hormonal therapeutics in the management of DED has also been discussed. The compelling evidence suggests that it would be clinically beneficial to consider the possibility of hormonal imbalances and their impact while treating patients with DED.

Tear biomarkers in dry eye disease: Progress in the last decade.

Dry eye disease (DED) is a commonly occurring, multifactorial disease characterized by reduced tear film stability and hyperosmolarity at the ocular surface, leading to discomfort and visual compromise. DED is driven by chronic inflammation and its pathogenesis involves multiple ocular surface structures such as the cornea, conjunctiva, lacrimal glands, and meibomian glands. The tear film secretion and its composition are regulated by the ocular surface in orchestration with the environment and bodily cues. Thus, any dysregulation in ocular surface homeostasis causes an increase in tear break-up time (TBUT), osmolarity changes, and reduction in tear film volume, all of which are indicators of DED. Tear film abnormalities are perpetuated by underlying inflammatory signaling and secretion of inflammatory factors, leading to the recruitment of immune cells and clinical pathology. Tear-soluble factors such as cytokines and chemokines are the best surrogate markers of disease severity and can also drive the altered profile of ocular surface cells contributing to the disease. Soluble factors can thus help in disease classification and planning treatment strategies. Our analysis suggests increased levels of cytokines namely interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-9, IL-12, IL-17A, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α); chemokines (CCL2, CCL3, CCL4, CXCL8); MMP-9, FGF, VEGF-A; soluble receptors (sICAM-1, sTNFR1), neurotrophic factors (NGF, substance P, serotonin) and IL1RA and reduced levels of IL-7, IL-17F, CXCL1, CXCL10, EGF and lactoferrin in DED. Due to the non-invasive sample collection and ease of quantitively measuring soluble factors, tears are one of the best-studied biological samples to molecularly stratify DED patients and monitor their response to therapy. In this review, we evaluate and summarize the soluble factors profiles in DED patients from the studies conducted over the past decade and across various patient groups and etiologies. The use of biomarker testing in clinical settings will aid in the advancement of personalized medicine and represents the next step in managing DED.

Clinico-cytological analysis of conjunctiva and ocular surface symptoms of patients on topical anti-glaucoma medications attending Lagos University Teaching Hospital, Lagos, Nigeria: A case-control study.

The long-term use of topical anti-glaucoma medications is often associated with ocular surface toxicity that can affect the patient's drug compliance and quality of life. This study assessed the effect of these medications, using cytological changes of the conjunctiva and ocular surface symptoms. This was a clinic-based, case-control study that was conducted at the Lagos University Teaching Hospital that compared glaucoma patients on topical medications with age-sex-matched controls. The controls were non-glaucoma patients, who were not on any topical ocular medications at least 6 months prior to the study. The Ocular Surface Disease Index (OSDI) questionnaire was used to assess ocular surface symptoms. Schirmer's I test, tear film break-up time (TBUT) test and corneal fluorescein staining of the ocular surface were used for ocular surface disease (OSD) assessment and conjunctival impression cytology (CIC) for histological assessment and grading. Six hundred and ninety-six eyes of 348 respondents, 174 cases and 174 controls, were assessed for OSD. The mean ages of the case and control groups were 56.3 ± 12.9 years and 55.5 ± 13.2 years, respectively, with no statistical difference (P = 0.589). All ocular parameters assessed were significantly abnormal in the case group compared to the control group. The use of topical anti-glaucoma medications was significantly associated with abnormal TBUT (P < 0.001), Schirmer's test (P < 0.001), ocular surface staining (P < 0.001), CIC (P < 0.001) and OSDI scores (P = 0.001). A significant association was seen between abnormal TBUT and the number of medications (P = 0.044, odds ratio [OR] =0.79, 95% confidence interval [CI]: 0.44-1.14), between abnormal ocular surface staining and duration of anti-glaucoma medications usage (P = 0.0104, OR = 1.2, 95% CI: 1.04-1.43) and between abnormal CIC and the duration of anti-glaucoma medications (P = 0.0007, OR = 0.7, 95% CI: 0.59-0.86). The study demonstrates that prolonged use of topical anti-glaucoma medications may be associated with damage to the ocular surface structures.

Tear cytokines and their relevance as biomarkers in ocular surface inflammatory diseases

Abstract Ocular surface disorders (OSDs) are complex, multifactorial diseases, often coexisting and with overlapping symptoms leading to discomfort and visual compromise. OSD is driven by chronic inflammation and its pathogenesis involves multiple ocular surface structures such as the cornea, conjunctiva, lacrimal glands, and meibomian glands. Diagnosing and monitoring disease progression based on clinical features is crucial for effective treatment implementation. However, achieving a differential diagnosis solely through clinical features can be challenging. The evaluation of biomarkers can facilitate disease diagnosis, aid in classification, and offer insights into disease progression and treatment effectiveness. There remains an unmet clinical need for biological tools to manage ocular surface diseases (OSDs). Tear fluid serves as a readily accessible source of biological material that has undergone extensive analysis in the quest for biomarkers related to OSD. Numerous studies have contributed to the extensive catalog of biomarkers found in tear fluid for OSD. The objective of this review is to provide a comprehensive and up-to-date overview of the most pertinent biomarkers for various OSDs, with a specific focus on quantitative analyses and their correlations with clinical parameters. To achieve this objective, we conducted a review of the PubMed database from January 2013 to June 2023, including original articles that investigated tear cytokines in various OSD pathologies. These studies unveiled a dysregulated interplay of pro- and anti-inflammatory cytokines within these disease pathologies. Pro-inflammatory interleukins (IL-1β, IL-2, IL-8, and IL-17), tumor necrotic factor (TNF-α), interferon-gamma (IFN-γ), as well as IL-4, IL-5, and IL-13 (Th2 pathway), and chemokines such as CCL5, IP-10 (CXCL10), and CX3CL, appear to represent similar inflammatory mechanisms in OSD pathologies. The cytokines identified through tear fluid analysis can aid in categorizing the disease as either pro-inflammatory or pro-fibrotic based on its severity, or they may serve as potential targets for intervention. This, in turn, can facilitate the planning of appropriate management strategies. The integration of biomarker testing into clinical settings holds the potential to advance personalized medicine and represents the next significant step in managing OSD.

Does the conjunctivochalasis accompanied by pseudoexfoliation syndrome affect the ocular surface and anterior segment structures?

The probability of the coexistence of conjunctivochalasis and pseudoexfoliation syndrome (PES) in the same individual may increase with aging. We investigated the effects of conjunctivochalasis accompanied by PES on the ocular surface (OS) and anterior segment (AS) structures. Cases with only conjunctivochalasis were determined as Group 1 (n = 62), cases with conjunctivochalasis accompanied by PES as Group 2 (n = 45), and healthy individuals as Group 3 (n = 56). The OS and AS parameters of the groups were compared. There were a higher grade-3 conjunctivochalasis rate (17.7% vs. 46.7%, p = 0.039), a greater "mean grade of conjunctivochalasis" value (1.72 ± 0.24 vs. 2.29 ± 0.32, p = 0.036), and a higher "total conjunctivochalasis score" (4.27 ± 1.13 vs. 6.12 ± 1.35, p = 0.025) in Group 2 than in Group 1. Additionally, Group 2 had a shorter tear film break-up time (TBUT) (9.17 ± 2.53 vs. 5.41 ± 1.32, p = 0.010) and a greater OS disease index (OSDI) score (16.28 ± 3.15 vs. 27.36 ± 4.12, p = 0.037) than Group 1. Moreover, both Group 1 and Group 2 had shorter TBUTs (Group 1-3: p = 0.004; Group 2-3: p < 0.001) and greater OSDI scores (Group 1-3: p = 0.042; Group 2-3: p = 0.019) compared to Group 3. The groups' ocular surface staining scores, Schirmer 1 tests, central corneal thicknesses, keratometries, axial lengths, anterior chamber depths, lens thicknesses, and intraocular pressures were similar (p > 0.05). To our knowledge, this was the first study comprehensively investigating the effects of conjunctivochalasis accompanied by PES on the OS and AS structures together. We found that conjunctivochalasis might cause the OS disease, while the presence of PES in conjunctivochalasis cases might worsen both the OS disease and conjunctivochalasis findings.

A Review of Emerging Tear Proteomics Research on the Ocular Surface in Ocular Allergy.

Simple SummaryOcular allergy is a localised form of allergy occurring on the surface of the eye and surrounding tissues. Typical signs and symptoms of ocular allergy include itching, redness, swelling of the eyelids and inflammation. Emerging studies on ocular allergy have shown that tears collected from ocular allergy sufferers show significantly different protein contents than in healthy populations. Differences in protein contents in tear samples have been hypothesised to be caused by a number of allergy-mediated factors, including long-term inflammation and eye-rubbing. Excessive eye-rubbing due to allergy-associated itch has also been shown to have significant effects on the physical shape of the eye, thereby potentially causing progressive vision problems in ocular allergy sufferers. This review aims to summarise and explore recent findings in ocular allergy protein research. This is to help determine which ocular surface proteins differ between ocular allergy sufferers and healthy controls, and the role each protein may play in the underlying chemistry of ocular allergy. Additionally, potential benefits of expanding the current pool of research into ocular surface proteins in ocular allergy sufferers in terms of diagnosis and treatment of the condition is discussed.Ocular allergy is an immunoglobulin E-mediated Type I hypersensitivity reaction localised to the ocular surface and surrounding tissues. Primary signs and symptoms of ocular allergy include itching, redness, irritation and inflammation. Eye-rubbing caused by itching has been shown to alter ocular surface protein concentrations in conditions linked to ocular allergy such as keratoconus. In keratoconus, the cornea begins to thin and sag over time, leading to progressive vision loss and blindness in severe conditions. Due to the high incidence of ocular allergy sufferers rubbing their eyes in response to symptoms of itching, the protein landscape of the ocular surface may be significantly altered. Differential protein expression caused by long-term inflammation and eye-rubbing may lead to subsequent changes in ocular surface structure and function over time. This review aims to summarise and explore the findings of current ocular allergy proteome research conducted using techniques such as gel electrophoresis, mass spectrometry and lab-on-a-chip proteomics. Proteins of interest for this review include differentially expressed immunoglobulins, mucins, functional proteins, enzymes and proteins with previously uncharacterised roles in ocular allergy. Additionally, potential applications of this research are addressed in terms of diagnostics, drug development and future research prospects.

Terahertz radiation in ophthalmology (review)

Terahertz (THz) radiation is one of the new, intensively studied interdisciplinary fi elds of scientifi c knowledge, including medicine, in the fi rst decades of the 21st century. At the beginning of this article (review), in a brief form, the basic statements on THz radiation, the main parameters and properties are presented; the modern THz biophtonics technologies used in biology and medicine are considered – THz refl ectometry, THz spectroscopy methods. Then a number of directions and examples of possible use of THz technologies in biology and medicine, including pharmaceuticals, are given. The main part of the review presents the progress of experimental research and the prospects for the clinical application of medical technologies of THz spectroscopy, THz imaging, in ophthalmology in the study of the morphological and functional state of the ocular surface structures, diagnosis, medical testing, and treatment of ophthalmopathology of the ocular surface. The article concludes with a review of experimental studies on the safety of using THz waves for medical diagnostics and treatment of ophthalmopathology. In the fi nal part, the main problems and prospects of introducing medical THz technologies into the clinical practice of an ophthalmologist are considered.

The Effects of Smartphone, Tablet and Computer Overuse on Children’s Eyes During the COVID-19 Pandemic

Aim: Due to restrictions during the Coronavirus disease-2019 (COVID-19) pandemic, smartphone, tablet and computer (STC) overuse might occur. There were some concerns that light sources which emit blue light might affect anterior and posterior segment structures. We investigated the effects of STC overuse on children's eyes during the pandemic. Materials and Methods: Sixty-four children's findings at baseline (the early period of the pandemic) (group 1) were compared with those after 1 year (group 2). Correlations between daily STC use time (DSTCUT) and the ocular parameters in group 2 were evaluated. Results: Compared to group 1, group 2 had longer DSTCUT (1.49 +/- 0.33 vs 5.62 +/- 0.57 hours, p 0.05). In group 2 as DSTCUT increased, TBUT (r=-0.368, p=0.034) decreased, OSDI score (r=0.384, p=0.028) increased and more myopic SER (r=0.340, p=0.045) occurred. Conclusion: To our knowledge, this is the first study in children to comprehensively investigate the effects of STC overuse during a pandemic on ocular surface, anterior and posterior segment structures together. We found that STC overuse during the pandemic might increase the tendency to dry-eye and myopia, and might cause axial elongation. We also determined that at 1-year follow-up, STC overuse had no effect on CCT, keratometry, ACD, LT, and posterior segment parameters.

The effect of cultured autologous oral mucosal epithelial cells on ocular surface reconstruction.

Oral epithelial cells were recently shown to be able to differentiate into corneal epithelium, and the efficacy of cultured autologous oral mucosal epithelial cells (CAOMEC) has been suggested by the presence of epithelium replacement. Therefore, the aim of this study was to evaluate the treatment outcome in limbal stem cell deficiency (LSCD) by adding CAOMEC to regular amniotic membrane (AM) treatment. Eyes with LSCD were randomized to two groups to undergo either autologous oral mucosal epithelial cell sheet (CAOMECS) combined with AM transplantation (A group) or AM transplantation alone (B group). Clinical outcome measures were corneal epithelium healing, best corrected visual acuity, symblepharon, corneal transparency, corneal neovascularization and ocular surface inflammation. The normal corneal epithelialization rate in group A (73.33%) was higher than that in group B (35.48%), and the average healing time was shorter (3.45 ±2.12 weeks vs. 4.64 ±1.63 weeks). The symblepharon in the above two groups was improved in the first 3 months after surgery, but after 6 months, part of the B group had recurrence. In improving corneal transparency, group A has obvious advantages. Corneal neovascularization (CNV) was improved to some extent in the first 3 months after surgery, but group A (1.47 ±0.64) was better than group B (1.94 ±0.85) after 6 months. Both groups can improve the inflammatory state to some extent. The transplantation of CAOMECS offers a viable and safe alternative in the reconstruction of a stable ocular surface. The effect is better than that of traditional AM transplantation, mainly in promoting corneal epithelialization, improving ocular surface structure, and reducing fiber and vascular infiltration.

CannabinEYEds: The Endocannabinoid System as a Regulator of the Ocular Surface Nociception, Inflammatory Response, Neovascularization and Wound Healing.

The endocannabinoid system (ECS) is a complex regulatory system, highly conserved among vertebrates. It has been widely described in nearly all human tissues. In the conjunctiva and cornea, the ECS is believed to play a pivotal role in the modulation of the local inflammatory state as well as in the regulation of tissue repair and fibrosis, neo-angiogenesis and pain perception. This review aims to summarize all the available data on ECS expression and its function in ocular surface structures to provide a specific insight concerning its modulation in dry eye disease, and to propose directions for future research.

Understanding the Dual Dilemma of Dry Eye and Glaucoma: An International Review.

Glaucoma-related ocular surface disease (G-OSD) is a significant, yet often underdiagnosed, ocular co-morbidity affecting 40% to 59% of glaucoma patients worldwide. Although the use of topical glaucoma medications represents a proven strategy to control the untoward effects of high intraocular pressure, this treatment can profoundly disrupt the homeostasis of the tear film. The cumulative effect of medications, preservatives, and excipients alter underlying cellular structures which results in tear film abnormalities and instability of the ocular surface. Furthermore, these chronic inflammatory changes have been shown to impact efficacy of glaucoma treatment, patient compliance with therapy and overall quality of life. The pathogenesis of G-OSD is multifactorial and involves a vicious self-perpetuating cycle of inflammatory cytokines and proteins. The diagnosis of such disease is based on similar tests used in assessing traditional dry eye, taking into consideration findings specific to this patient population. The hallmark of treatment for these patients is to minimize the ocular surface inflammatory response by choosing glaucoma therapies that spare the ocular surface such as preservative free formulations and initiating dry eye treatment early in the course of care. In summary, glaucoma affects millions of patients around the world and chronic use of topical glaucoma medications may negatively impact the patient's ocular surface, symptoms, and vision. Understanding the pathogenesis of G-OSD, recognizing its risk factors and incorporating diagnostic and therapeutic strategies that restore and maintain ocular surface homeostasis will result in improved care for our patients.

Pathophysiological Role and Drug Modulation of Calcium Transport in Ocular Surface Cells.

The ocular surface structure and extraocular accessory organs constitute the ocular surface system, which includes the cornea, conjunctiva, eyelids, lacrimal organs, and lacrimal passages. This system is composed of, and stabilized by, the corneal epithelium, conjunctival cells, conjunctival goblet cells, lacrimal acinar cells and Tenon's fibroblasts, all of which maintain the healthy eyeball surface system. Ocular surface diseases are commonly referred to corneal and conjunctival disease and external ocular disease, resulting from damage to the ocular surface structure. A growing body of evidence has indicated that abnormal activation of the KCa3.1 channel and Ca2+/ calmodulin-dependent kinase initiates ocular injury. Signaling pathways downstream of the irregular Ca2+ influx induce cell progression and migration, and impair tight junctions, epithelial transport and secretory function. In this overview, we summarize the current knowledge regarding ocular surface disease in terms of physical and pathological alteration of the ocular system. We dissect in-depth, the mechanisms underlying disease progression, and we describe the current calcium transport therapeutics and the obstacles that remain to be solved. Finally, we summarize how to integrate the research results into clinical practice in the future.

Разработка и анализ эффективности клинико-математической системы прогнозирования развития ятрогенного синдрома «сухого глаза» после факоэмульсификации возрастной катаракты

Purpose . Development and analysis of effectiveness of predictive clinical-mathematical system of development of dry eye syndrome (DES) after phacoemulsification (PE) of senile cataract (SC). Material and methods . 120 patients (120 eyes) after SC surgery: 52 men and 68 women. Age: from 62 to 83 years (average 69.3±6.4 years). The main selection criteria for study were the absence of objective and subjective signs of DES, the presence of initial or immature SC and optimal conditions for surgery – absence of corneal pathology and mydriasis of 6 mm or more. Standard preoperative examination; 3 months after PE – Schirmer 1 test, tear break-up time, OCT mapping (Avanti RTVue XR, Optovue, USA). The above indicators were selected as potential predictors for development of algorithms for predicting of development of DES after PE of SC. Patients were divided into groups: 1st group consisted of 31 patients (31 eyes) with DES developed after PE, 2nd group consisted of 89 patients (89 eyes) without signs of DES. Results . Based on peculiarities of induced damage to structures of ocular surface in treatment of SC, two algorithms were developed to predict DES after FE of SC, which shown high prognostic characteristics: sensitivity – 80–90% and specificity – 80–87%, allowing to consider them reasonable and informative. Conclusion . The analysis of the developed clinical and mathematical system for predicting the development of DES after PE of SC showed its high efficiency. Application of developed technique in ophthalmic practice is advisable to ensure maximum medical and social rehabilitation of patients with SC.

Изучение субъективного восприятия пациентом состояния структур глазной поверхности в зависимости от исходного уровня слезопродукции после факоэмульсификации возрастной катаракты

«Российская офтальмология онлайн» - электронное информационное издание, создается с 1 марта 2010 года под эгидой Российского общества офтальмологов. Основная задача проекта - научно-информационная поддержка специалистов в области офтальмологии.

Liposomes for effective drug delivery to the ocular posterior chamber

BackgroundAge-related macular degeneration (AMD) is a leading cause of severe visual deficits and blindness. Meanwhile, there is convincing evidence implicating oxidative stress, inflammation, and neovascularization in the onset and progression of AMD. Several studies have identified berberine hydrochloride and chrysophanol as potential treatments for ocular diseases based on their antioxidative, antiangiogenic, and anti-inflammatory effects. Unfortunately, their poor stability and bioavailability have limited their application. In order to overcome these disadvantages, we prepared a compound liposome system that can entrap these drugs simultaneously using the third polyamidoamine dendrimer (PAMAM G3.0) as a carrier.ResultsPAMAM G3.0-coated compound liposomes exhibited appreciable cellular permeability in human corneal epithelial cells and enhanced bio-adhesion on rabbit corneal epithelium. Moreover, coated liposomes greatly improved BBH bioavailability. Further, coated liposomes exhibited obviously protective effects in human retinal pigment epithelial cells and rat retinas after photooxidative retinal injury. Finally, administration of P-CBLs showed no sign of side effects on ocular surface structure in rabbits model.ConclusionsThe PAMAM G3.0-liposome system thus displayed a potential use for treating various ocular diseases.

Reduction of Ocular Surface Damage and Bacterial Survival Using 0.05% Povidone-Iodine Ocular Surface Irrigation before Cataract Surgery

Background: To investigate the effects of 0.05% povidone-iodine (PI) irrigation on the ocular surface structure and bacterial survival rate in patients with cataract. Methods: Ninety eyes of 90 patients with cataract were included. Before surgery, the operative field was irrigated with 0.05% PI and divided into 30-s, 1-, and 2-min groups. Anterior chamber fluid was cultured bacteriologically. Tear film breakup time (BUT), corneal fluorescein staining (CFS), lacrimal river height (LRH), and Schirmer test I (STI) were conducted to assess ocular surface. Results: In all groups, the patients had significantly shorter postoperative BUT at 1 day, 3 days, and 1 week postoperatively than preoperatively. In addition, there was still lower BUT at 1 month postoperatively in the 1- and 2-min groups. STI and LRH were all decreased postoperatively at different time points (1 day, 3 days, 1 week), while CFS was increased. With the extension of time preoperatively (1 and 3 months), the ocular surface indicators returned to the preoperative level. The bacterial cultures after eye irrigating were negative in all groups. Conclusion: 0.05% PI irrigating the conjunctival sac for 30 s can achieve a low bacterial contamination rate. Importantly, it reduced the damage of ocular surface, which is beneficial to the recovery of ocular surface function.

Air pollutant particulate matter 2.5 induces dry eye syndrome in mice

In this study, we explored the effects of particulate matter 2.5 (PM2.5) eye drops on the ocular surface structure and tear function in mice and established a novel animal model for dry eye research. We found that, following treatment with PM2.5, the tear volume and, the tear film break-up time showed statistical differences at each time point (P < 0.05). The FL score of the PM2.5-treated group was higher than that of others (P < 0.05). The average number of corneal epithelial layer cells in groups A and B was significantly lower than that in group C (P < 0.05). Scanning electron microscopy and transmission electron microscopy revealed that the number of corneal epithelial microvilli and corneal desmosomes was drastically reduced in group C. PM2.5 induced apoptosis in the corneal superficial and basal epithelium and led to abnormal differentiation and proliferation of the ocular surface with higher expression levels of Ki67 and a reduced number of goblet cells in the conjunctival fornix in group C. PM2.5 significantly increased the levels of TNF-α, NF-κB p65 (phospho S536), and NF-κB in the cornea. Thus, the topical administration of PM2.5 in mice induces ocular surface changes that are similar to those of dry eye in humans, representing a novel model of dry eye.