Search Results (1,568)

Corneal fibrosis, clinically referred to as corneal scarring, disrupts the normal architecture and transparency of the cornea and remains a major cause of visual impairment worldwide. Although corneal transplantation can restore vision, its effectiveness is constrained by limited accessibility, donor tissue shortages, and the risk of allograft rejection. Treatments with human corneal stromal stem cells (hCSSCs) have demonstrated scarless healing in preclinical models of acute corneal injury. Here, we report that hCSSCs also modulated pre-existing corneal opacities. We established a reproducible in vivo model of chronic corneal opacity. Given that scar severity varies among corneas even after identical injuries, we developed a non-invasive, image-based method to quantify opacity volume longitudinally in individual corneas. Using this approach, we evaluated the scar-reducing potential of three hCSSC batches previously shown to inhibit acute scarring. Following cell treatment, the pre-existing opacity volumes gradually decreased. In vitro, hCSSCs exposed to pro-inflammatory stimulus exhibited increased metalloproteinase (MMP) activity relative to tissue inhibitor of metalloproteinase (TIMP), as indicated by an elevated MMP2/TIMP2 ratio. This shift may promote matrix remodeling and scar resolution. Overall, our findings provide proof-of-concept for hCSSC-based therapy as a strategy to reduce established corneal scarring and restore corneal transparency. Full article

Purpose: The aim of this study was to develop a concept for adjustment planning of intraocular lens orientation axes after cataract surgery with implantation of toric intraocular lenses (tIOLs) and to predict the spectacle refraction after tIOL re-alignment. Methods: This calculation concept based on paraxial spherocylindrical vergence transformations uses the actual spherocylindrical refraction at the spectacle plane, corneal power, and the labelled power and measured axis of the implanted tIOL to minimise the refractive cylinder by simulating the rotation of the tIOL in the eye. The axial lens position is derived from simple prediction models using anterior chamber depth and lens thickness or axial length from preoperative biometry or the equivalent tIOL power. The new target axis is predicted together with the spherocylindrical refraction after re-alignment of the tIOL. Results: To show the applicability of this calculation model, we provide four clinical working examples: example 1 deals with keratometric power values; example 2 deals with keratometric curvature values, including surgically induced astigmatism and a statistical posterior astigmatism correction for the cornea (both examples with a thin cornea model); example 3 deals with corneal curvature data for the front and back surface; and example 4 deals with keratometric power data and corneal back surface power data, including surgically induced astigmatism (both examples with a thick cornea model). Conclusions: The effect of tIOL axis adjustment after cataract surgery can be predicted based on actual refraction, corneal power, tIOL power and the measured axis, and a simulation of the tIOL axis rotation enables the best orientation with the lowest refractive cylinder at the spectacle plane to be found. Full article

Objectives: To assess diurnal changes, topographical differences, and day-to-day repeatability of ocular surface epithelial immune cell (EIC) density and morphology in dry eye disease (DED). Methods: Sixteen participants with moderate-to-severe DED (mean (SE) age 49.4 (4.2) years) underwent in vivo confocal microscopy at three timepoints (day-1 morning and evening and day-2 morning) at six locations: central cornea, inferior whorl, inferior cornea, and temporal cornea, limbus and conjunctiva. Diurnal and topographical variation in EIC density and morphology were analyzed using linear mixed-effects models with adjusted pairwise comparisons. Day-to-day repeatability was assessed using the coefficient of repeatability (CoR) for density and Cohen’s kappa for morphology. Results: EIC density and morphology varied by location (p < 0.001) but not by timepoint at any location (p = 0.59–0.90). Density was highest at the inferior cornea (model-estimated mean: 101.2 (SE: 21.7) cells/mm²) and temporal limbus (104.3 (22.7) cells/mm²), and lowest at the central cornea (26.8 [5.1] cells/mm² and inferior whorl (38.3 [8.2] cells/mm²; all pairwise, p < 0.001). EICs with large bodies were more frequent in conjunctiva (100%), inferior cornea (94%), and temporal cornea (87%), than in central cornea (34%) and whorl (19%) (all p ≤ 0.007). EICs with dendrites, and with long dendrites were similarly distributed (p < 0.001). Bland–Altman analysis showed low mean bias and EIC density was more repeatable at the central (CoR ± 23.8 cells/mm²) and temporal cornea (±27.5 cells/mm²) than the inferior cornea (±47.9 cells/mm²) or temporal conjunctiva (±42.3 cells/mm²). Morphology agreement was substantial to near-perfect (κ = 0.71–0.97). Conclusions: In DED, EIC density and morphology are diurnally stable and maintain topographic distribution patterns similar to healthy eyes. Day-to-day repeatability show location dependent patterns. The study provides feasibility data for using IVCM for EIC metrics in disease monitoring. Full article

Background/Objectives: Corneal endothelial cells (CEnCs) exist on the inner surface of the cornea and regulate its hydration. The immune system cannot penetrate CEnCs easily because the cornea is avascular and anterior chamber-associated immune deviation suppresses the immune reaction. Nevertheless, inflammatory cells can infiltrate through the corneal stroma and anterior chambers, and corneal endothelial inflammation can occur. In this cross-sectional study, we investigated the association between the neutrophil-to-lymphocyte ratio (NLR) and human corneal endothelial cells (CEnCs). Methods: A total of 307 eyes from 307 subjects who underwent specular microscopy were included. Corneal endothelial cell density (CECD), hexagonality (HEX), central corneal thickness (CCT), coefficient of variation (CV), and cell area were measured preoperatively using specular microscopy. Whole blood samples were obtained to measure the complete blood cell count. The NLR was calculated, and its relationship with CEnCs was evaluated. Results: In all subjects, CV was positively correlated with the percentage (%) of neutrophils (r = 0.120, p = 0.037) and absolute neutrophil count (r = 0.131, p = 0.022) and negatively correlated with the % of lymphocytes (r = −0.131, p = 0.022). HEX was correlated with the % of neutrophils (r = −0.156, p = 0.006), % of lymphocytes (r = 0.141, p = 0.014), % of basophils (r = 0.142, p = 0.013), the NLR (r = −0.129, p = 0.024), and the mean corpuscular volume (r = 0.121, p = 0.035). Conclusions: CV and HEX, which indicate the stability of CEnCs, are associated with NLR in the peripheral blood, suggesting that systemic inflammation and immunity may implicate in the pathology of CEnCs. Full article

Background/Objectives: The neonatal Fc receptor (FcRn) plays a crucial role in extending the systemic half-life of monoclonal antibodies (mAbs), but its influence on ocular distribution remains incompletely understood. This study investigated the impact of FcRn on the ocular disposition of mAbs following systemic administration in rabbits. Methods: New Zealand White rabbits received a single intravenous dose (1 mg/kg) of either wild-type trastuzumab (TS-WT) or its FcRn non-binding variant (IHH). Plasma and ocular tissues (retina, iris–ciliary body, vitreous humor, aqueous humor, cornea, conjunctiva, and tears) were collected at terminal time points up to 336 h for TS-WT and 168 h for IHH. Antibody concentrations were quantified using a validated sandwich ELISA. Pharmacokinetic parameters and antibody biodistribution coefficients (ABC) were calculated to assess the FcRn-mediated effects on ocular distribution. Results: TS-WT demonstrated 2-fold higher systemic exposure compared to IHH. The iris–ciliary body exhibited the highest absolute exposure for both antibodies, with TS-WT showing significantly higher accumulation (ABC_0–168h: 14.95% vs. 8.89%). Retinal distribution remained comparable between antibodies (5.96% vs. 5.51%). Both antibodies were detectable in tears, with ABC value of ~4% reported for TS-WT. TS-WT also demonstrated markedly increased distribution in vitreous humor and tear fluid (3.5- and 5.5-fold higher ABC values, respectively) compared to IHH. The cornea (5.76% vs. 5.57%) and conjunctiva (7.71% vs. 7.21%) showed comparable relative distribution between TS-WT and IHH, while aqueous humor showed minimal differences (0.44% vs. 0.52%). Conclusions: This investigation reveals distinct tissue-specific patterns of FcRn-mediated mAb distribution within the eye. FcRn binding significantly enhanced antibody distribution in ocular tissues, such as the iris–ciliary body, and tears, with less pronounced effects on the retina, cornea, conjunctiva and aqueous humor. These findings provide mechanistic insights for optimizing mAb-based therapeutics for ocular disease and understanding the ocular toxicity of mAb-based therapeutics, such as antibody–drug conjugates. Full article

Background/Objectives: To characterize sectoral corneal thickness (CT) profiles in eyes with primary open-angle glaucoma (POAG) compared with healthy eyes and to evaluate potential associations between CT, retinal nerve fiber layer (RNFL) thickness, and optic disc rim area (RA). Methods: In this cross-sectional study, 192 participants (91 with POAG and 101 controls) contributed 297 eyes (145 glaucoma eyes and 152 control eyes). All participants underwent comprehensive ophthalmological examination and spectral-domain optical coherence tomography (OCT; Optovue Solix, Fremont, CA, USA) to obtain peripapillary RNFL measurements, optic disc rim area, and corneal pachymetry maps across five sectors (central, superior, inferior, temporal, and nasal). Repeated-measures correlation analyses were used to assess within-subject associations between CT and RA, and generalized estimating equation (GEE) models were applied to evaluate independent associations between CT, glaucoma status, disease severity, and RNFL thickness while adjusting for relevant covariates. Results: Eyes with POAG exhibited significantly thinner corneas across all sectors compared with controls (all p < 0.05), with the greatest differences observed in the superior (median 607.0 μm vs. 640.0 μm, p < 0.001) and temporal (562.0 μm vs. 579.5 μm, p < 0.001) regions. Average RNFL thickness and rim area were also significantly reduced in glaucoma eyes (all p < 0.001). However, no independent associations between sectoral CT and RNFL thickness or RA were observed after adjustment for multiple comparisons. Although nominal associations between thinner inferotemporal CT and reduced RNFL thickness were observed in unadjusted analyses, these did not remain statistically significant after false discovery rate correction. In multivariable GEE models, glaucoma diagnosis and greater disease severity were consistently associated with reduced RNFL thickness (β range: −11.0 to −42.2 μm; all p < 0.001), whereas CT was not independently associated with RNFL thickness (all adjusted p > 0.07). Conclusions: Sectoral corneal thickness is significantly reduced in eyes with POAG but does not independently correlate with RNFL thickness or optic disc rim area after adjustment for confounding factors. These findings support the concept that corneal thinning reflects structural and biomechanical susceptibility to glaucoma rather than serving as a marker of established neuroretinal damage severity. Further longitudinal studies incorporating comprehensive biomechanical assessments are warranted to clarify the role of corneal structure in glaucoma pathophysiology. Full article

Background/Objectives: Anterior segment optical coherence tomography (AS-OCT) and optical coherence tomography angiography (AS-OCTA) have enhanced the evaluation of the cornea, ocular surface, and ocular surface diseases (OSD), offering high-resolution structural and anterior segment vascular imaging. This review summarizes recent advances in these modalities and their clinical applications. Methods: A comprehensive literature search was conducted using PubMed, Web of Science, and Google Scholar with the terms OCT, OCTA, anterior segment, and ocular surface disease. Studies published in the past five years were included, emphasizing more recent developments such as ultra-high-resolution AS-OCT (UHR-AS-OCT) and swept-source AS-OCTA technologies. Results: UHR-AS-OCT provides non-invasive, sub-micron imaging of the cornea and the ocular surface, including tear film morphology and epithelial thickness to correlate with clinical tests such as tear break-up time, and fluorescein staining. Advances in AS-OCTA allow dye-free, depth-resolved imaging of corneal and conjunctival vasculature. These vascular biomarkers have shown promising utility in conditions such as limbal stem cell deficiency, chemical ocular injury, and ocular surface squamous neoplasia. Improvements in image acquisition, motion correction, and segmentation algorithms have enhanced accuracy and repeatability, supporting broader clinical translation. Conclusions: AS-OCT and AS-OCTA have become useful adjunctive imaging tools for the cornea and ocular surface evaluation. Their non-invasive, quantitative, and reproducible metrics may enable earlier diagnosis, objective staging, and longitudinal monitoring of OSD. Integration of OCT-based imaging with artificial intelligence and multimodal data, including tear proteomics and meibography, may optimize personalized treatment for ocular surface disorders. Full article

The relationship between lifestyle, ocular biomechanical behavior, and myopia is not well established in the literature. The present study aims to describe changes in ocular biomechanics during adolescence and to explore their relationship with lifestyle factors and myopic progression. Prospective cohort study including 63 adolescents (126 eyes) with a mean age of 14.1 ± 2.6 years old examined twice over a 30 ± 0.9-month period. The data from biomechanics, biometry, corneal tomography, and lifestyle was addressed. The relationships between biomechanical changes, biometric and refractive variation, and lifestyle variables were analyzed using parametric and non-parametric statistics with a significance level of p < 0.05. A biomechanical stiffening trend was found. Axial elongation was 0.12 ± 0.17 mm, and refractive shift was −0.32 ± 0.87 D. The history of allergies was associated with greater axial growth (p = 0.032) and smaller increase in stress–strain-index (SSI) (p = 0.01). Myopization was higher in eyes with ocular surface symptoms (p = 0.049) and those with reported eye-rubbing habits (p = 0.04), with a lower gain in stiffness (p < 0.05). Outdoor activities were associated with higher gain in corneo-scleral stiffness (p < 0.05). Reduced myopization correlated directly with the increase in the SSI (p < 0.05) and inversely with the Integrated Radius (p < 0.05). Greater increases in axial length (AL), vitreous cavity length (VCL), and the ratio between VCL and AL (R_VCL/AL) correlated negatively with the increase in the SSI (p < 0.05). The increase in the R_VCL/AL correlated positively with the time spent on digital devices and negatively with the amount of outdoor activity (p < 0.05). Biomechanics may represent the physiological bridge between the environmental exposure and myopization, as lower gain in corneo-scleral stiffness was consistently associated with greater axial elongation and refractive myopization, with outdoor activity appearing to be protective. Full article

Neoplasia of the cornea is overall rare, with corneal squamous-cell carcinoma (c-SCC) being most commonly reported in all species. C-SCC pathogenesis has been related to UV exposure in humans and horses, and to papillomavirus infection in humans. In dogs, brachycephalic conformation and chronic keratitis were associated with c-SCC. Corneal vascular tumors have also been exceptionally reported in humans, and rarely in animals. In dogs, they have been suggested to be UV-related. Except for equine c-SCCs, most studies on corneal neoplasms are case reports. The present study aimed to review the literature on epithelial and vascular corneal tumors in dogs, cats, and horses, adding new cases from our archives. Pubmed and Web of Science were searched (1980–2025) using the following keywords: cornea, neoplasia, carcinoma, hemangioma, hemangiosarcoma, dog, cat, and horse. Additionally, 94 new cases of corneal neoplasia were retrieved: 47 dogs (40 epithelial and seven vascular); 29 cats (14 epithelial and 15 vascular) and 18 horses. Signalment, clinical history, and histopathological characteristics were analyzed and compared with the literature. The combined results supported a strong association between brachycephalic dogs and c-SCC occurrence and highlighted the frequent coexistence in the feline species of symblepharon and corneal perforation, with corneal tumors. Full article

An 87-year-old woman was referred to our ophthalmology ward due to decreased visual acuity and intense right orbital pain, which had been present for four weeks. The anamnesis was not contributory, except that she had been vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) four weeks prior to symptom onset. Her best-corrected visual acuity was hand movements in the right eye and 20/20 in the left eye. Intra-ocular pressure was 34 mmHg and 16 mmHg, respectively. Right eye slit lamp examination revealed palpebral oedema, chemosis, and temporal scleral thickening with conjunctival injection. The cornea was edematous with endothelial precipitates. The anterior chamber was shallow with a closed angle, associated with grade 1+ cells and 1+ flare, according to the SUN grading system. Mild vitreous inflammation was present (grade 0.5+ vitreous cells), and a total choroidal detachment was visible. In the absence of any other plausible cause, unilateral choroidal effusion with secondary angle-closure due to severe panuveitis was considered a possible adverse event following vaccination against SARS-CoV2. Full article

Background/Objectives: Eye infection with herpes simplex virus type 1 (HSV-1) can result in keratitis, a leading cause of corneal blindness. We evaluated whether an experimental vaccine containing HSV-2 immunogens to prevent genital herpes also protects against HSV-1 eye infection and neuroinvasion. Methods: Mice were immunized twice, one month apart, with PBS or a nucleoside-modified lipid nanoparticle vaccine containing mRNA encoding for gC2, gD2, and gE2. One month later, 10⁶ plaque forming units (PFU) (10 lethal dose 50, LD₅₀) of the HSV-1 McKrae strain were added to the intact cornea of each eye. Results: The vaccine prevented death and markedly reduced eyelid and attached conjunctival inflammation (blepharoconjunctivitis) and weight loss compared with the PBS group. Tissues from the ocular conjunctiva and eye bulb, olfactory bulb/peduncle, trigeminal ganglia, and brain (brainstem, cerebrum, and cerebellum) were harvested 5 days post-infection from 5 mice each in the PBS and vaccine groups, and from another 10 mice in the vaccine group 7 weeks post-infection. At 5 days, HSV-1 was not detected in any tissue in the vaccine group, while viral titers were positive in 16 of 25 (64%), and HSV-1 DNA was detected in 22 of 25 (88%) individual tissues in the PBS group. Histopathological and immunohistochemical analysis at 5 days post-infection confirmed that the vaccine protected against inflammation; however, some animals experienced breakthrough blepharoconjunctivitis. At 7 weeks, 3 of 10 (30%) mice in the vaccine group had HSV-1 DNA detected in the eyes or trigeminal ganglia tissues, but no animal had HSV-1 DNA detected in brain tissues. The vaccine produced cross-reactive HSV-1 neutralizing antibodies and gD1 IgG binding antibodies, but low or undetectable cross-reactive binding antibodies to gC1 and gE1. Conclusions: Despite occasional mild, localized breakthrough infections, the vaccine provided disease-modifying immunity and was neuroprotective. The results suggest that a single herpes vaccine effective against genital HSV-2 may be neuroprotective against HSV-1 following eye infection. Full article

Background and Clinical Significance: Currently, the only effective treatment for cataracts is surgery. The most commonly employed method is phacoemulsification, a well-established procedure that uses ultrasound energy to fragment the lens, allowing for easier removal. Potential postoperative complications range from mild to severe corneal edema (pseudophakic bullous keratopathy), which may be caused by intraoperative endothelial cell damage, to the rare formation of iris cysts. Case Presentation: In this paper, we report the case of a patient who underwent cataract surgery in both eyes, where iris incarceration occurred during the surgical procedure, resulting in corneal edema and an iris cyst, both in the left eye. Secondary iris cysts are uncommon following phacoemulsification, with only a few cases reported in the recent literature. The cyst’s impact on corneal edema was unexpected, making this case particularly noteworthy and emphasizing the complexity of cataract surgery and its postoperative complications. Conclusions: This case illustrates the unique interaction between two infrequent complications of cataract surgery. Full article

Oxygen permeability (Dk) is a key parameter for evaluating the ability of contact lenses to supply oxygen to the cornea. Although the polarographic method has been standardized as a reference technique for Dk measurement, conventional polarographic electrode cells are limited to a narrow central measurement area of approximately 4 mm in diameter, which may not adequately represent oxygen transport under actual wearing conditions. In this study, a modified polarographic electrode cell enabling wide-field oxygen permeability measurement over an expanded central area with a diameter of 11 mm was developed and evaluated under ISO 18369 measurement conditions. The performance of the proposed system was evaluated by comparing its accuracy, repeatability, and relative error with those of a conventional polarographic electrode cell using plano hydrogel contact lens samples with different uniform thicknesses. The Dk values obtained using the modified measurement cell did not show a statistically significant difference compared to those measured with the conventional measurement cell (t = 2.682, p = 0.055), and the relative error between the two systems was 1.93%, meeting the ISO acceptance criteria for the development of a new testing method. These results demonstrate that wide-field Dk measurement can be achieved without compromising reliability, providing a more representative and ISO-compliant approach for contact lens oxygen permeability evaluation. Full article

The introduction of modern anticancer therapies, including targeted therapies (TTs), immune checkpoint inhibitors (ICIs), and antibody–drug conjugates (ADCs), has significantly improved survival across a wide range of malignancies. At the same time, these agents have expanded the spectrum of treatment-related adverse events, with ocular toxicities emerging as a clinically relevant and increasingly recognized complication. Ocular adverse events may affect multiple anatomical structures, including the ocular surface, cornea, anterior and posterior segments, and optic nerve, often reflecting drug class-specific biological mechanisms. The pathogenesis of ocular toxicity is multifactorial and includes on-target inhibition of signaling pathways expressed in ocular tissues, off-target effects on rapidly renewing epithelia, non-specific uptake of cytotoxic payloads in ADCs, immune-mediated inflammation associated with ICIs, and microvascular dysregulation observed with selected targeted agents, such as mitogen-activated protein kinase (MEK) inhibitors. Because ocular adverse events are inconsistently reported in clinical trials and frequently described through case reports or pharmacovigilance data, their true incidence is likely underestimated and management strategies remain heterogeneous. This narrative review provides an overview of the epidemiology, biological mechanisms, and clinical manifestations of ocular toxicities associated with contemporary anticancer therapies. In addition, it offers practical, mechanism-based recommendations for prevention, monitoring, and stepwise management, emphasizing the importance of multidisciplinary collaboration to preserve visual function while maintaining effective oncologic treatment. Full article

Background/Objectives: Assessing trace-element status is fundamental for maintaining health across species. However, serum primarily reflects acute physiological variability rather than chronic exposure. Thus, we investigate the cornea as a possible stable, practical alternative for assessing chronic copper and iron accumulation in rabbit’s cornea. Methods: A group of laboratory rabbits was housed under standardized husbandry conditions with comparable environmental and dietary backgrounds for trace-element intake. After completion of the experimental phase, corneal tissues were collected and subjected to quantitative elemental analysis using validated spectrometric procedures. In parallel, the structural integrity of the cornea was evaluated with standard histological techniques to determine whether elevated trace-element levels were associated with detectable morphological alterations. Results: Copper and iron concentrations showed approximately normal distributions, with mean values of 0.93 ± 0.46 μg/g and 0.78 ± 0.32 μg/g. All elemental concentrations were calculated relative to the original (native) wet tissue weight. Several samples exhibited elevated levels of both elements. Importantly, even in the samples with the highest copper and iron concentrations, no histological abnormalities were observed. Epithelial layers were intact, stromal collagen was well organized, and no inflammation or edema was observed. Conclusions: Overall, the cornea contained measurable copper and iron levels, and higher concentrations were not associated with morphological disruption under the trace-element conditions studied. Because ocular tissues are not used in food processing and can be collected in a standardized way during slaughter, the cornea offers a practical matrix for post-mortem monitoring of trace-element load in commercial animal production. Full article