Search Results (4,355)

Temporal vision is a vital aspect of human perception, encompassing the ability to detect changes in light and motion over time. Optical scattering, or straylight, influences temporal visual acuity and the critical flicker fusion (CFF) threshold, with potential implications for cognitive visual processing. This study investigates how scattering affects CFF using an Arduino-based psychophysical device and electroencephalogram (EEG) recordings to analyze brain activity during CFF tasks under scattering-induced effects. A cohort of 30 participants was tested under conditions of induced scattering to determine its effect on temporal vision. Findings indicate a significant enhancement in temporal resolution under scattering conditions, suggesting that scattering may modulate the temporal aspects of visual perception, potentially by altering neural activity at the temporal and frontal brain lobes. A compensation mechanism is proposed to explain neural adaptations to scattering based on reduced electrical activity in the visual cortex and increased wave oscillations in the temporal lobe. Finally, the combination of the Arduino-based flicker visual stimulator and EEG revealed the excitatory/inhibitory stimulation capabilities of the high-frequency beta oscillation based on the alternation of an achromatic and a chromatic stimulus displayed in the CFF. Full article

The abnormal growth of irregular new blood vessels into the subretinal or intraretinal space is known as macular neovascularization (MNV). People over 50 are often affected by this disorder, which is typically brought on by age-related macular degeneration. In addition, MNV can be found in people under 50 years of age, who may present primary ophthalmic diseases such as pathological myopia, angioid streaks, traumatic choroidal rupture, or suspected ocular histoplasmosis syndrome. However, it is important to consider a specific set of young individuals who may develop MNV even in the absence of pathological myopia or other identifiable inflammatory, peripapillary, post-traumatic, or degenerative fundus abnormalities. This latter condition is classified as idiopathic MNV. After a literature review focused on young patients affected by one of these two clinical entities, we report the case of a Caucasian young woman suffering for four years from an idiopathic and quiescent MNV that started exuding after childbirth, probably due to the induction with oxytocin, and was treated with intravitreal Aflibercept 2 mg injections. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a multisystemic disease, i.e., influencing various organ systems beyond the liver and, thus, contributing to comorbidities. Characterized by excessive fat accumulation in the hepatocytes, MASLD is frequently linked to metabolic syndrome components, such as obesity, insulin resistance, dyslipidemia, and hypertension. Therefore, exploring the intricate connection between MASLD and other organ systems, including the eyes, seems to be essential. In this context, retinopathy has been investigated for its potential association with MASLD, since both conditions share common pathogenetic pathways. Chronic low-grade inflammation, oxidative stress, insulin resistance, and endothelial dysfunction are only some of those mechanisms contributing to disease progression and, possibly, determining the bidirectional interplay between the liver and retinal pathology. This narrative review aims to summarize data concerning the multisystemicity of MASLD, primarily focusing on its potential association with the eyes and, particularly, retinopathy. Identifying this possible association may emphasize the need for early screening and integrated management approaches that address the liver and eyes as interconnected components within the framework of a systemic disease. Further research is necessary to delineate the precise mechanisms and develop targeted interventions to mitigate the bidirectional impact between the liver and eyes, aiming to reduce the overall burden of disease and improve patient outcomes. Full article

Background/Objectives: Sensitivity to ocular irritation varies among individuals, being influenced by clinical, subjective, and biochemical factors. This study aimed to evaluate individual variability in ocular irritation sensitivity, focusing on clinical parameters, pain perception, and tear neuromediator profiles. Methods: Sixty female participants aged 20–40 were classified into high-sensitivity and low-sensitivity groups based on their response to an irritant (Tween20). Clinical assessments included the ocular surface disease index (OSDI), tear break-up time (TBUT), Schirmer test, and corneal touch threshold measured with the Cochet–Bonnet esthesiometer. Pain sensitivity was assessed using the pain sensitivity questionnaire (PSQ), and tear neuromediators were quantified in tear samples before and after stimulation. The concentrations of calcitonin gene-related peptide (CGRP), nerve growth factor, neuropeptide Y, vasoactive intestinal peptide (VIP), and substance P were measured using an enzyme-linked immune sorbent assay (ELISA). Results: The high-sensitivity group exhibited significantly higher OSDI scores (p = 0.038). No significant differences were observed in TBUT, corneal staining scores, or Schirmer’s test results. The PSQ results revealed that the high-sensitivity group had lower total and moderate pain scores (p = 0.037 and p = 0.040, respectively). An analysis of the tear neuromediator showed elevated baseline CGRP levels (p = 0.017) and a significant post-stimulation increase in substance P (p = 0.021) in the high-sensitivity group. Conclusions: These findings emphasize the value of combining clinical, subjective, and biochemical measures to understand sensitivity to ocular irritation. This comprehensive approach may guide the development of safer cosmetic formulations and improve safety assessment protocols. Full article

Background: Numerous conditions, both physiological and pathological, can influence changes in the retinal vascular architecture. In order to be able to highlight pathological aspects of systemic diseases with ocular activity, it is necessary to understand how physiological fluctuations can influence circulation at the retinal level. The present study attempts to evaluate retinal and choroidal vascular and structural changes in healthy female subjects over the course of a menstrual cycle using OCT-A. Methods: We analyzed 22 eyes from healthy reproductive women with a regular menstrual cycle. We performed five OCT-A scans of the subjects every 7–8 days over the course of a month starting from the first day of the menstrual cycle and ending with the first day of the next cycle, measuring perfusion density in the superficial and deep vascular plexuses, choroidal thickness, and FAZ perimeter. Results: There are physiological variations in retinal hemodynamics that can be identified using OCT-A, choroidal thickness having statistically significant increased values in the parafoveal nasal sector during the ovulatory phase (289.18 µm) compared to the early follicular phase (281.9 µm), and the subfoveal sector during the ovulatory phase (319.04 µm) compared to the early follicular phase (308.27 µm). Conclusions: These findings along with abnormally small FAZ perimeters indicate that the menstrual cycle phase should be considered whenever interpreting OCT-A results. Further studies that include larger cohorts, control groups, and hormone serum levels are necessary to confirm and correlate retinal vascular alterations and the phase of the menstrual cycle using OCT-A. Full article

Particulate matter (PM), particularly fine (PM_2.5) and ultrafine (PM_0.1) particles, originates from both natural and anthropogenic sources, such as biomass burning and vehicle emissions. These particles contain harmful compounds that pose significant health risks. Upon inhalation, ingestion, or dermal contact, PM can penetrate biological systems, inducing oxidative stress, inflammation, and DNA damage, which contribute to a range of health complications. This review comprehensively examines the protective potential of natural products against PM-induced health issues across various physiological systems, including the respiratory, cardiovascular, skin, neurological, gastrointestinal, and ocular systems. It provides valuable insights into the health risks associated with PM exposure and highlights the therapeutic promise of herbal medicines by focusing on the natural products that have demonstrated protective properties in both in vitro and in vivo PM_2.5-induced models. Numerous herbal medicines and phytochemicals have shown efficacy in mitigating PM-induced cellular damage through their ability to counteract oxidative stress, suppress pro-inflammatory responses, and enhance cellular defense mechanisms. These combined actions collectively protect tissues from PM-related damage and dysfunction. This review establishes a foundation for future research and the development of effective interventions to combat PM-related health issues. However, further studies, including in vivo and clinical trials, are essential to evaluate the safety, optimal dosages, and long-term effectiveness of herbal treatments for patients under chronic PM exposure. Full article

Fungal keratitis is a severe ocular infection caused by pathogenic fungi, leading to potential vision loss if untreated. Current antifungal treatments face limitations such as low solubility, poor corneal penetration, and limited therapeutic options. This study aimed to develop a thermosensitive in situ gel incorporating ketoconazole nanoparticles (NPs) to enhance drug solubility, stability, and antifungal activity. Ketoconazole NPs were prepared using the solvent displacement method, achieving a particle size of 198.25 ± 27.51 nm, encapsulation efficiency of 94.08 ± 0.51%, polydispersity index of 0.42 ± 0.08, and a positive zeta potential value of +10.08 ± 0.19 mV. The NPs exhibited sustained zero-order release kinetics. The optimized NPs were incorporated into a poloxamer-based in situ gel, demonstrating a gelation temperature of 34.67 ± 0.58 °C and the shortest gelation time. The formulation provided a 5-fold increase in solubility and a 10-fold improvement in drug release compared to pure ketoconazole. Stability studies confirmed the gel retained its physicochemical and rheological properties for three months under various storage conditions. The in situ gel showed sustained release, effective antifungal activity against Malassezia furfur, and good tolerability, suggesting it as a promising alternative for treating fungal keratitis with improved bioavailability and patient compliance. Full article

Background: This study aims to evaluate subjective visual fatigue and objective optical and morphological changes in ocular structures after intermediate-duration reading on an iPad and an Ebook across different age groups. Methods: The sample included 108 right eyes from healthy subjects aged 18 to 66 years. The participants read for 20 min on an Ebook and another 20 min on an iPad under controlled illumination conditions. Aberrometry and retinal optical coherence tomography (OCT) measurements were taken before and after each reading session. Parameters such as total aberration, high-order aberration (HOA), low-order aberration (LOA), and retinal thickness in the nine Early Treatment Diabetic Retinopathy Study (ETDRS) areas were measured. The sample was analyzed as a whole and divided into five age groups by decade. Results: This study included 66 women (61.11%) and 42 men (38.89%), with an average age of 36.58 years (±14.83). The aberrometry results revealed significant differences in the total root mean square (RMS_TOTAL) after reading on both devices (p = 0.001). Low-order aberrations (RMS_LOA) also changed significantly (p = 0.001 for Ebook, p = 0.002 for the iPad), but high-order aberrations (RMS_HOA) did not. Central retinal thickness increased significantly after reading on the Ebook (p < 0.001) but not on the iPad. The peripheral retinal thickness did not change significantly. Conclusion: Moderate-duration reading increases LOA and central retinal thickness, with variations by age group and more pronounced effects from the Ebook, whereas HOA remains unaffected. Full article

Electroretinography (ERG) is a non-invasive technique for evaluating the retinal function in various ocular diseases. Its results are useful for diagnosing ocular disorders and assessing disease progression or treatment effectiveness. Since numerous studies are based on animal models, validating the ERG results from animals is pivotal. The first part of this paper presents basic information on the types of ERG tests used on rodents, and the second part describes the recorded functional changes in rodents’ retinas when various antioxidant treatments for diabetic retinopathy were used. Our study showed that among the tests for diabetic retinopathy diagnosis in rodents, full-field ERG is accurate and the most commonly used, and pattern ERG and the photopic negative response of the flash ERG tests are rarely chosen. Furthermore, antioxidants generally protect retinas from functional losses. Their beneficial influence is expressed in the preserved amplitudes of the a- and b-waves and the oscillatory potentials. However, prolonging the drug exposure showed that the antioxidants could delay the onset of adverse changes but did not stop them. Future studies should concentrate on how long-term antioxidant supplementation affects the retinal function. Full article

Prime editing (PE) is a CRISPR-based tool for genome engineering that can be applied to generate human induced pluripotent stem cell (hiPSC)-based disease models. PE technology safely introduces point mutations, small insertions, and deletions (indels) into the genome. It uses a Cas9-nickase (nCas9) fused to a reverse transcriptase (RT) as an editor and a PE guide RNA (pegRNA), which introduces the desired edit with great precision without creating double-strand breaks (DSBs). PE leads to minimal off-targets or indels when introducing single-strand breaks (SSB) in the DNA. Low efficiency can be an obstacle to its use in hiPSCs, especially when the genetic context precludes the screening of multiple pegRNAs, and other strategies must be employed to achieve the desired edit. We developed a PE platform to efficiently generate isogenic models of Mendelian disorders. We introduced the c.25G>A (p.V9M) mutation in the NMNAT1 gene with over 25% efficiency by optimizing the PE workflow. Using our optimized system, we generated other isogenic models of inherited retinal diseases (IRDs), including the c.1481C>T (p.T494M) mutation in PRPF3 and the c.6926A>C (p.H2309P) mutation in PRPF8. We modified several determinants of the hiPSC PE procedure, such as plasmid concentrations, PE component ratios, and delivery method settings, showing that our improved workflow increased the hiPSC editing efficiency. Full article

Uncorrected refractive error and unsatisfactory performance on several clinical accommodation and binocular vision tests are more common in children who struggle with reading. The aim of the current study is to explore the prevalence of accommodative and binocular dysfunctions in children with and without reading difficulties. Reading performance was assessed with the Acadience Reading (formerly DIBELS Next) test adjusted and validated for the Latvian language. Children with (N = 39) and without (N = 43) reading difficulties underwent thorough assessment of their subjective refraction, as well as binocular and accommodation functions. The results demonstrate no difference in the prevalence of complaints between children with and without reading difficulties (26% and 23%, respectively). However, children with reading difficulties more frequently present with significant uncorrected refractive errors and/or accommodative and binocular dysfunctions than children without reading difficulties (69% and 47%, respectively). According to the findings, even in cases where a child does not exhibit any ocular or visual complaints, a comprehensive visual function evaluation should be required for any child who struggles with reading. Full article

Glaucoma is a neurodegenerative disease characterized by the loss of retinal ganglion cells (RGCs), with intraocular pressure (IOP) being its primary risk factor. Despite controlling IOP, the neurodegenerative process often continues. Therefore, substances with neuroprotective, antioxidant, and anti-inflammatory properties could protect against RGC death. This study investigated the neuroprotective effects on RGCs and visual pathway neurons of a compound consisting of citicoline and coenzyme Q10 (CoQ10) in a mouse model of unilateral, laser-induced ocular hypertension (OHT). Four groups of mice were used: vehicle group (n = 6), citicoline + CoQ10 group (n = 6), laser–vehicle group (n = 6), and laser–citicoline + CoQ10 group (n = 6). The citicoline + CoQ10 was administered orally once a day starting 15 days before laser treatment, continuing until sacrifice (7 days post-laser). Retinas, the dorsolateral geniculate nucleus (dLGN), the superior colliculus (SC), and the visual cortex (V1) were analyzed. The citicoline + CoQ10 compound used in the laser–citicoline + CoQ10 group demonstrated (1) an ocular hypotensive effect only at 24 h post-laser; (2) prevention of Brn3a+ RGC death in OHT eyes; and (3) no changes in NeuN+ neurons in the dLGN. This study demonstrates that the oral administration of the citicoline + CoQ10 combination may exert a neuroprotective effect against RGC death in an established rodent model of OHT. Full article

Reactive oxygen species (ROS) within the retina play a key role in maintaining function and cell survival. However, excessive ROS can lead to oxidative stress, inducing dysregulation of metabolic and inflammatory pathways. The chm^ru848 zebrafish models choroideremia (CHM), an X-linked chorioretinal dystrophy, which predominantly affects the photoreceptors, retinal pigment epithelium (RPE), and choroid. In this study, we examined the transcriptomic signature of the chm^ru848 zebrafish retina to reveal the upregulation of cytokine pathways and glia migration, upregulation of oxidative, ER stress and apoptosis markers, and the dysregulation of glucose metabolism with the downregulation of glycolysis and the upregulation of the oxidative phase of the pentose phosphate pathway. Glucose uptake was impaired in the chm^ru848 retina using the 2-NBDG glucose uptake assay. Following the overexpression of human PFKM, partial rescue was seen with the preservation of photoreceptors and RPE and increased glucose uptake, but without modifying glycolysis and oxidative stress markers. Therapies targeting glucose metabolism in CHM may represent a potential remedial approach. Full article

Background/Objectives: Endophthalmitis is an intraocular microbial infection that can lead to permanent blindness, even with prompt anti-microbial therapy. Multi-drug-resistant organisms are on the rise, potentially limiting the efficacy of current empiric antibiotic therapies of intravitreal ceftazidime and vancomycin. Cefiderocol is a recent FDA- and EMA-approved antibiotic for multi-drug-resistant Gram-negative bacteria. Methods: To better understand its potential utility in the treatment of ocular infections, the MIC of cefiderocol was compared to ceftazidime and amikacin in endophthalmitis bacterial isolates using Epsilometer testing. Because vancomycin is commonly given concomitantly as part of empiric endophthalmitis treatment, possible synergistic and antagonistic effects of concomitant vancomycin and cefiderocol were also evaluated. Results: Cefiderocol was found to have lower MIC values compared to ceftazidime for Pseudomonadales or Enterobacterales species. When comparing the MICs of cefiderocol and vancomycin, there appeared to be no antagonism between the two antibiotics. Conclusions: This is the first report exploring the use of cefiderocol in endophthalmitis strains. The results of this study show this is a promising antibiotic for multi-drug-resistant Gram-negative organisms but further research is needed to investigate its intraocular safety profile. Full article

Background/Objectives: Ocular proprioception is implicated in balance control and heterophoria is associated with abnormal posture, though previous research focused mainly on the role of vertical phoria and the use of vertical prisms. This study aims to evaluate whether ocular misalignment and prismatic correction of horizontal phoria affect posture. Methods: Sixty-nine (N = 69) young healthy subjects were included and equally divided by horizontal distance phoria: orthophoria (n = 23), esophoria (n = 23) and exophoria (n = 23). A prism of low power (two-diopter) was placed base out on the non-dominant eye, reducing misalignment in esophorics and increasing it in exophorics more than in orthophorics. Dynamic computerized posturography was performed with the sensory organization test protocol (SOT) of the EquiTest^® NeuroCom^® version 8 platform both without and with prism, always maintaining subjects unaware of prism use. A mixed model for repeated measures analysis of variance was run to evaluate the main effect of prism and the interaction effect of prism with baseline phoria. Results: Composite movement strategy score without prism was 88.1 ± 2.8% (ankle-dominant strategy) and slightly increased to 89.0 ± 3.1% with prism insertion (p = 0.004), further shifting toward ankle strategy. Composite equilibrium score without prism was 80.3 ± 6.5% and remained stable with prism insertion (81.3 ± 8.2%, p = 0.117), medio-lateral and antero-posterior projection of center of gravity did not displace significantly under prism insertion (p = 0.652 and p = 0.270, respectively). At baseline, posturographic parameters were statistically independent of individual phoria, and no significant interaction between prism insertion and individual phoria was documented for any parameters (p > 0.05 for all). Secondary analysis and pairwise comparisons confirmed that the effect of prism was strongly selective on condition SOT 5 (eyes-closed, platform sway-referenced) with improvement of equilibrium (70.4 ± 9.7% with prism vs. 65.7 ± 11.6% without) and more use of ankle strategy (81.6 ± 5.3% with prism vs. 78.2 ± 6.0% without), without any interaction of phoria and ocular dominance, while the other conditions were comparable with and without prism. Conclusions: A two-diopter prism base out on the non-dominant eye induces the body to use the ankle joint more independently of individual phoria, suggesting a small improvement in postural control, while maintaining oscillations of the center of gravity unaltered. Prism seems to enhance the function of vestibular system selectively. Phoria adjustments with prismatic correction enable intervention in postural behavior. Extraocular muscles could act as proprioceptors influencing postural stability. Full article