Isotretinoin is a vitamin A derivative used as a first-line treatment for moderate to severe acne. One of its most frequent side effects is dry eye disease (DED), in which tear film instability and neurosensory abnormalities play an etiologic role. The purpose of this research was to analyze changes in corneal innervation and its association with tear film integrity in patients treated with oral isotretinoin. Twenty-eight patients treated with oral isotretinoin and the same number of age and sex distribution-matched healthy volunteers were included in this observational case‒control study. They were examined by in vivo corneal confocal microscopy (IVCM) to quantify the corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and corneal nerve fractal dimension (CNFrD) in addition to the presence of dendritiform cells, microneuromas, and visibility of axonal beadings. Tear film analysis was also performed, as was the perception of discomfort related to ocular surface disease. The results of the comparative analysis of the isotretinoin group vs. the control group (mean [standard error]) were as follows: CNFD 18.57 [1.67] vs. 24. 57 [1.55] fibers per mm2 (p = 0.01); CNBD 19.05 [2.43] vs. 30.62 [3.53] branches per mm2 (p = 0.02); CNFL 13.90 [1.01] vs. 14.64 [0.66] mm per mm2 (p = 0.54); CNFrD 1.46 [0.005] vs. 1.49 [0.006] (p = 0.01); Schirmer test 5.7 [1.1] vs. 10.3 [0.5] millimeters (p < 0.001). The break-up time (BUT) was 5.70 [0.6] vs. 11.2 [0.2] seconds (p < 0.001). A linear regression equation model was developed for BUT (R2 = 0.48; 1-β = 0.98; p = 0.01) and CNFrD (R2 = 0.58; 1-β = 0.99; p = 0.002). Oral isotretinoin treatment promotes a vicious cycle of ocular surface disease that leads to damage to the subbasal nerve plexus. This damage increases with treatment time and impacts basal tear production.

This study evaluates the regenerative potential of a newly developed transparent plasma rich in growth factors (tmPRGF) membrane for corneal wound healing, comparing with the amniotic membrane (AM). The wound closure process, corneal opacity, and the expression of key inflammation and tissue regeneration markers were analyzed in a photorefractive keratectomy (PRK) mouse model. The tmPRGF membrane demonstrated superior optical transparency, allowing direct visualization of the corneal surface post-surger, an advantage over AM, which hampers the visualization of the ocular structures. tmPRGF-treated eyes showed significantly faster epithelial wound closure at day 1 post-surgery compared to AM and control groups. By day 7, all groups achieved complete re-epithelialization, but tmPRGF-treated corneas exhibited more mature epithelial morphology and β-catenin expression, indicating better tissue regeneration. Additionally, tmPRGF reduced corneal haze and stromal fibrosis, as evidenced by lower α-SMA-positive myofibroblast presence. Both tmPRGF and AM treatments significantly decreased IL-6-positive immune cells, suggesting anti-inflammatory effects. However, tmPRGF showed a more favorable profile in minimizing inflammation and fibrosis. The findings suggest that tmPRGF not only supports effective corneal healing but also offers clinical advantages such as transparency for real-time monitoring and reduced risk of immune response. These results position tmPRGF as a promising alternative to AM in ocular surface repair.

Previous studies have reported that exosomes produced by corneal stromal cells from keratoconus patients exhibit a molecular content distinct from those produced by cells from healthy donors.This study investigates differences in the expression of ESCRT components, regarded as the most critical mechanism in exosome biogenesis. The study included analysis of transcription levels of system-encoding genes using qRT-PCR reactions, as well as semiquantitative protein determination through immunocytochemistry.Of the 34 molecules analyzed, mRNA downregulation was observed in 8 in pathological cells. In keratoconus, genes encoding STAM2 from the ESCRT-0 complex and VPS37A, VPS37C, VPS37D and UBAP1 from the ESCRT-I complex were found to be underexpressed, although VPS37D could not be confirmed at the protein level. Additionally, two other expression alterations affected the ESCRT-III complex, involving the core protein CHMP4C and the regulatory protein CHMP1B. Finally, deregulation of the ubiquitin-specific peptidase UBPY was observed.Most changes identified in this study affected specific isoforms, which could suggest functional diversification and differences in cargo recognition in the context of pathology. Altogether, these findings suggest that the previously reported alteration in the molecular content of exosomes produced by stromal cells in keratoconus may be, at least partially, due to disruptions in the exosome synthesis machinery.

Exosomes are extracellular vesicles ranging from 30 to 150 nm in diameter that contain proteins, nucleic acids and other molecules. Produced by virtually all cell types, they travel throughout the body until they reach their target, where they can trigger a wide variety of effects by transferring the molecular cargo to recipient cells. In the context of ocular physiology, exosomes play a very important role in embryological development, the regulation of homeostasis and the immune system, which is crucial for normal vision. Consequently, in pathological situations, exosomes also undergo modifications in terms of quantity, composition and content, depending on the etiology of the disease. However, the mechanisms by which exosomes contribute to ocular pathology has not yet been studied in depth, and many questions remain unanswered. This review aims to summarize the most recent knowledge on the function of exosomes in the ocular system in healthy individuals and the role they play during pathological processes of a degenerative, infectious, neurodegenerative, vascular and inflammatory nature, such as keratoconus, keratitis, glaucoma, diabetic retinopathy and uveitis. Furthermore, given their unique characteristics, their potential as diagnostic biomarkers or therapeutic agents and their application in clinical ophthalmology are also explored, along with the main limitations that researchers face today in the field.

Background: Corneal esthesiometry plays a key role in assessing the integrity of the ocular surface. Its importance lies in the fact that several eye and systemic conditions can alter the corneal sensitivity. This is evidenced by the emergence of new devices to measure this parameter in recent years. Methods: Publications found in Web of Science and Scopus databases from 2000 to 2024 were analyzed. Microsoft Excel, Rayyan, and VOSviewer software were used. Results: A total of 556 articles were included in the study. Andrew JM Boulton had the greatest impact, with the highest h -index. The Centre for Contact Lens Research, School of Optometry, University of Waterloo (Canada), was the most prolific institution, with 25 articles published. The United States led the ranking of countries, with 81 publications. Six keyword clusters were identified, encompassing neurophysiology, dry eye, ocular pathology, diabetic neuropathy, structural nerve assessment, and refractive surgery. Conclusion: This study reports on who, why, how many, and where corneal esthesiometry has been studied, through a bibliometric analysis. The studies centered on sensory physiology, ocular surface disease, and dry eye disease. These emerging trends highlight new clinical, diagnostic, and research perspectives, which may guide future investigations and contribute to more precise strategies for the treatment of ocular surface conditions.

Uveal melanoma is the most common primary intraocular tumor in adults that appears mainly in the choroid, ciliary body, or iris. Standard non-surgical treatment consists of radiotherapy and chemotherapy by intravitreal injection of drugs, which is hampered by unpleasant side effects and high recurrence rate. As an alternative strategy, gene therapy has the capacity of targeting specific pathways in cancer cells by introducing tumor suppressor sequences that are rendered therapeutically effective by the use of suitable delivery vectors. In this paper, we describe the development of protamine nanocapsules as potential gene delivery carriers to the eye by its topical administration. These nanocapsules, composed of spherical oily nano-droplets surrounded by a protamine shell with small particle size (≤ 250 nm) and positive surface charge (+ 33 mV), can efficiently associate different nucleic acids such as pDNA and miRNA, and release them in biorelevant media. In vitro studies evidenced their low cytotoxicity and efficient internalization with 36

The yeast form of Candida albicans uses glycosaminoglycans (GAGs), primarily heparan sulfate, as adhesion receptors for corneal epithelial cells. However, during the transition to the hyphal form, the fungus shifts to using alternative receptors. This study aims to identify fungal adhesins involved in GAG binding and examine their expression dynamics during tissue adhesion. Using chromatography, three proteins from the C. albicans cell wall with high affinity for heparin were identified: methionine synthase, phosphoglycerate mutase, and cytochrome c. These proteins were overexpressed in Escherichia coli and tested in adhesion assays. Methionine synthase and phosphoglycerate mutase partially inhibited yeast adhesion to corneal epithelial cells in a concentration-dependent manner, while cytochrome c enhanced adhesion. Transcriptional analysis of the genes encoding these proteins (MET6, GMP1, and CYC1), along with other genes related to adhesion and yeast-to-hypha transition (ALS3, HWP1, and INT1), revealed that exposure to exosomes or GAGs increased GMP1, CYC1, and ALS3 expression, while reducing HWP1 and INT1. In contrast, direct contact with epithelial cells decreased MET6 and GMP1 expression, but increased HWP1 expression. These results suggest that methionine synthase and phosphoglycerate mutase act as adhesins for GAGs, with their expression modulated by GAG or exosome interaction to promote adhesion. However, epithelial cell contact alters the expression of adhesins and molecules linked to hyphal formation, highlighting their dynamic role in corneal adhesion.

Congenital aniridia is a rare bilateral ocular malformation characterized by the partial or complete absence of the iris and is frequently associated with various anomalies, including keratopathy, cataract, glaucoma, and foveal and optic nerve hypoplasia. Additionally, nearly 50% of individuals with congenital aniridia experience symptoms of ocular dryness. Traditional treatment encompasses artificial tears and autologous serum. This study aimed to assess the effectiveness and safety of using platelet rich in growth factors (PRGF) plasma in patients with congenital aniridia and ocular dryness symptoms. Methods: The included patients underwent two cycles of a 3-month PRGF treatment. At 6 months, symptomatology was evaluated using the OSDI and SANDE questionnaires, and ocular surface parameters were analyzed. Results: The OSDI and SANDE values for frequency and severity demonstrated statistically significant improvements (p < 0.05). Ocular redness, corneal damage (corneal staining), and tear volume (Schirmer test) also exhibited statistically significant improvements (p < 0.05). No significant changes were observed in visual acuity or in the grade of meibomian gland loss. Conclusion: The use of PRGF in patients with congenital aniridia and ocular dryness symptoms led to significant improvements in symptomatology, ocular redness, and ocular damage. No adverse effects were observed during the use of PRGF.

The aim of this study was to evaluate the efficacy of a paraffin ointment enriched with vitamin A in the protection against severe desiccation using 2D and 3D corneal epithelial in vitro models. We used immortalized human corneal epithelial cell cultures to evaluate the efficacy of four compounds -a paraffin ointment enriched with vitamin A (vA-PFF) and its vehicle; an aqueous gel containing hydroxypropyl guar (HPG); and an aqueous gel containing sodium carboxymethylcellulose (CMC)- to preserve cell viability in an in vitro model of desiccation. WST-1 and Live/Dead assays were used to study cell viability. Protection against cell damage was evaluated using a tridimensional reconstructed human corneal epithelial stem cell model (QobuR-RhCE). Compared to CMC, the paraffin ointment produced a significant prosurvival effect and it was similar to hydroxypropyl guar (HPG). The effect of vA-PFF in the protection against cell damage in QobuR-RhCE was significantly higher than CMC and HPG. Our results suggested that reconstructed 3D human corneal epithelia are sensitive tools to evaluate the efficacy of topical formulations against chemical damage and severe desiccation, indicating that would be an alternative method to animal experimentation, valid to use in ocular drug screening. vA-PFF caused no toxicity to cells in culture and was effective against extreme desiccation and cell damage in vitro 2 D and 3D models.

Corneal diseases are a major cause of vision loss, often associated with aging, trauma and disease. Damage to corneal sensory innervation leads to discomfort and pain. Environmental stressors, such as short-wavelength light, can induce oxidative stress that alters mitochondrial function and affects cell and tissue homeostasis, including corneal innervation. Cellular antioxidant mechanisms may attenuate oxidative stress. This study investigates crocin, a derivative of saffron, as a potential antioxidant therapy. In vitro rat trigeminal sensory ganglion neurons were exposed to both sodium azide and blue light overexposure as a model of oxidative damage. Crocin was used as a neuroprotective agent. Mitochondrial and cytoskeletal markers were studied by immunofluorescence analysis to determine oxidative damage and neuroprotection. In vivo corneal innervation degeneration was evaluated in cornea whole mount preparations using Sholl analyses. Blue light exposure induces oxidative stress that affects trigeminal neuron mitochondria and alters sensory axon dynamics in vitro, and it also affects corneal sensory innervation in an in vivo model. Our results show that crocin was effective in preserving mitochondrial function and protecting corneal sensory neurons from oxidative stress. Crocin appears to be a promising candidate for the neuroprotection of corneal innervation.

Skin corrosion testing is integral to evaluating the potential harm posed by chemicals, impacting regulatory decisions on safety, transportation, and labeling. Traditional animal testing methods are giving way to in vitro alternatives, such as reconstructed human epidermis (RhE) models, aligning with evolving ethical standards. This study evaluates the QileX-RhE test system's performance for chemical subcategorization within the OECD TG 431 framework. Results demonstrate its ability to differentiate subcategories, accurately predicting 83% of UN GHS Category 1A and 73% of UN GHS Category 1B/1C chemicals with 100% sensitivity in corrosive prediction. Additionally, this study provides a comprehensive assessment of the test method's performance by employing nuanced parameters such as positive predictive value (PPV), negative predictive value (NPV), post-test odds and likelihood rations, offering valuable insights into the applicability and effectiveness of the QileX-RhE test method.

P URPOSE . Keratoconus (KC) is a corneal disorder with complex etiology, apparently involving both genetic and environmental factors, characterized by progressive thinning and protrusion of the cornea. We aimed to identify novel genetic regions associated with KC susceptibility, elucidate relevant genes for disease development, and explore the translational implications for therapeutic intervention and risk assessment. M ETHODS . We conducted a genome-wide association study (GWAS) that integrated previously published data with newly generated genotyping data from an independent European cohort. To evaluate the clinical translation of our results, we performed functional annotation, gene prioritization, polygenic risk score (PRS), and drug repositioning analyses. R ESULTS . We identified two novel genetic loci associated with KC, with rs2806689 and rs807037 emerging as lead variants (P = 1.71E-08, odds ratio [OR] = 0.88; P = 1.93E08, OR = 1.16, respectively). Most importantly, we identified 315 candidate genes influenced by confirmed KC-associated variants. Among these, MINK1 was found to play a pivotal role in KC pathogenesis through the WNT signaling pathway. Moreover, we developed a PRS model that successfully differentiated KC patients from controls (P = 7.61E-16; area under the curve = 0.713). This model has the potential to identify individuals at high risk for developing KC, which could be instrumental in early diagnosis and management. Additionally, our drug repositioning analysis identified acetylcysteine as a potential treatment option for KC, opening up new avenues for therapeutic intervention. C ONCLUSIONS . Our study provides valuable insights into the genetic and molecular basis of KC, offering new targets for therapy and highlighting the clinical utility of PRS models in predicting disease risk.

Background and Objectives: Dry eye disease (DED) is a common and very symptomatic pathology that affects normal daily activity. The aim of the study was to evaluate the efficacy of plasma rich in growth factors (PRGF) added to one routine treatment protocol for DED (artificial tears substitutes, lid hygiene, and anti-inflammatory therapy). Materials and Methods: Patients were divided into two groups of treatment: standard treatment group (n = 43 eyes) and PRGF group (n = 59). Patients' symptomatology (inferred from OSDI and SANDE questionnaires), ocular inflammation, tear stability, and ocular surface damage were analyzed at baseline and after 3 months of treatment. Results: OSDI test scores were significantly lower in both groups (p < 0.001). SANDE frequency test scores also improved statistically, with differences between groups (p = 0.0089 SANDE frequency and p < 0.0119 SANDE severity). There was a greater reduction in ocular redness (ocular inflammation) in the PRGF group (p < 0.0001) and fluorescein tear break-up time was significantly improved in the PRGF group (p = 0.0006). No significant changes were found in terms of ocular surface damage. No adverse events were obtained in either group. Conclusions: The addition of PRGF to the standard treatment of DED, according to the results obtained, proved to be safe and produced an improvement in ocular symptomatology and signs of inflammation, particularly in moderate and severe cases, when compared to standard treatment.

Alzheimer’s disease (AD), the most prevalent form of dementia, is a neurodegenerative disorder characterized by different pathological symptomatology, including disrupted circadian rhythm. The regulation of circadian rhythm depends on the light information that is projected from the retina to the suprachiasmatic nucleus in the hypothalamus. Studies of AD patients and AD transgenic mice have revealed AD retinal pathology, including amyloid-β (Aβ) accumulation that can directly interfere with the regulation of the circadian cycle. Although the cause of AD pathology is poorly understood, one of the main risk factors for AD is female gender. Here, we found that female APP/PS1 mice at 6- and 12-months old display severe circadian rhythm disturbances and retinal pathological hallmarks, including Aβ deposits in retinal layers. Since brain Aβ transport is facilitated by aquaporin (AQP)4, the expression of AQPs were also explored in APP/PS1 retina to investigate a potential correlation between retinal Aβ deposits and AQPs expression. Important reductions in AQP1, AQP4, and AQP5 were detected in the retinal tissue of these transgenic mice, mainly at 6-months of age. Taken together, our findings suggest that abnormal transport of Aβ, mediated by impaired AQPs expression, contributes to the retinal degeneration in the early stages of AD.