Experimental Eye Research

PurposeElevated intraocular pressure (IOP) due to increased outflow resistance through the trabecular meshwork (TM) is a major risk factor for primary open-angle glaucoma. Outflow through the TM is segmental, consisting of high flow (HF) and low flow (LF) regions. Here, we investigate how ocular hypertension impacts segmental outflow using a dexamethasone (DEX) mouse model and compare TM stiffness between HF and LF regions. MethodsNanoparticles containing DEX or vehicle were injected twice weekly in 2-4-month-old C57BL/6J mice (n=14), and IOP was measured weekly. At week 4, mouse eyes were perfused in vivo with fluorescent nanospheres to assess flow patterns and the circumferential percentage of high, intermediate, and low flow regions in each eye. Sagittal sections were collected from HF and LF regions, and atomic force microscopy (AFM) was used to measure tissue stiffness. Immunofluorescent labeling was used to compare fibronectin and -SMA protein levels. ResultsDEX treatment significantly elevated IOP by an average of 33.3% and altered tracer distribution but not the percentage of HF and LF regions around the circumference. No significant differences in TM stiffness were detected between DEX-treated and control mice, or between HF and LF regions. Increased fibronectin in LF regions of DEX-treated eyes suggested subtle TM structural changes that were not detected by AFM. ConclusionsDexamethasone alters segmental flow distribution and may impact cell contractility rather than ECM stiffness to cause IOP elevation in young mice. These findings better characterize the nature of segmental outflow and TM mechanics in this model of steroid-induced glaucoma.

PurposeMuller cell (MC) morphology and markers were investigated using histology and immunohistochemistry in an eye with clinically documented multifocal geographic atrophy (GA) and correlated with clinical images. MethodsThe donor was followed clinically for five years and last examined six years before death. The superior posterior pole retina was dissected and immunolabeled with antibodies against glial fibrillary acidic protein (GFAP; activated MCs and astrocytes) and glutamine synthetase (GS, MC) and Ulex Europaeus Agglutinin-1 lectin (blood vessels) before embedding for JB-4 cross section analysis. The inferior macula was cryopreserved. Cryosections were immunolabeled with MC homeostatic and activation markers. Transmission electron microscopy (TEM) of the fellow eye was used to study ultrastructure changes. ResultsGross examination demonstrated mottled retinal pigment epithelium (RPE) over presumably calcified drusen. In the submacular retina, MC processes surrounding both drusen and outer retinal pigmented lesions created a large subretinal membrane. Cryosection analysis demonstrated persistence of aquaporin 4 and GS in MCs with both proteins prominently expressed in the subretinal membrane. Increased MC S100B and GFAP expression were also observed in the atrophic area as well as the OJZ. Cryosection labeling and TEM confirmed the MC encasing calcified drusen and RPE debris as well as invading basal laminar deposits. ConclusionsThis multifocal GA case demonstrates how MC activation and structural changes surrounding individual drusen could coalesce, contributing to photoreceptor loss. MCs penetrating basal laminar deposits and encasing calcified drusen suggests that they are attempting to clear these and/or protect the retina from harmful contents.

PurposeAnti-vascular endothelial growth factor (anti-VEGF) therapy is the standard of care for neovascular age-related macular degeneration (AMD), yet many patients exhibit persistent retinal degeneration, fibrosis, and incomplete therapeutic response. The molecular pathways underlying this incomplete response remain poorly understood. We sought to identify VEGF-independent signaling pathways active in the vitreous of anti-VEGF-treated AMD patients. MethodsWe performed multiplex antibody-based proteomic profiling of 1,000 human proteins in vitreous samples from patients with neovascular AMD receiving anti-VEGF therapy (n=8) and comparative controls (n=6). Differential protein expression was assessed using one-way ANOVA, followed by gene ontology and pathway enrichment analyses. Drug-target relationships were evaluated to identify potential opportunities for therapeutic repositioning. ResultsWe identified 107 differentially expressed proteins (p<0.05), including key regulators of immune signaling, angiogenesis, and metabolism. Notably, multiple components of cytotoxic lymphocyte pathways were dysregulated, including IL-21R, SIGLEC-7, CTLA4, and IL-2-associated signaling. Enrichment analyses revealed significant activation of pathways related to T-cell activation, interleukin signaling, and leukocyte-mediated cytotoxicity. These immune signatures persisted despite suppression of VEGF signaling. Several clinically available immunomodulatory agents--including abatacept, sirolimus, and dupilumab--targeted pathways identified in this dataset. ConclusionsAnti-VEGF-treated neovascular AMD exhibits persistent cytotoxic immune signaling in the vitreous, suggesting that VEGF-independent immune mechanisms may contribute to ongoing retinal damage and incomplete therapeutic response. These findings provide a rationale for combination therapeutic strategies targeting both angiogenic and immune pathways in AMD.

PurposeSubretinal drusenoid deposits (SDDs) are a distinct entity in age-related macular degeneration (AMD) and associated with photoreceptor impairment during progression. Their early impact on photoreceptors remains incompletely understood. This study examined photoreceptor reflectivity during the phase when SDDs were not clinically detectable on optical coherence tomography (OCT) using adaptive optics scanning laser ophthalmoscopy (AOSLO). DesignLongitudinal observational study. ParticipantsPatients with intermediate AMD. MethodsSix eyes of four patients with intermediate AMD and predominantly SDDs underwent multimodal imaging 3-4 times over 3.5 years. Individual SDDs were graded using an OCT-based 3-stage system at each time point. Cross-sectional retinal structure and photoreceptor reflectivity at the location where the new SDDs developed during follow-up were evaluated using OCT and AOSLO. Main Outcome MeasuresPhotoreceptor reflectivity change prior to and during SDD development. ResultsForty-eight retinal locations where new dot-type SDDs developed during follow-up were identified. AOSLO revealed reduced photoreceptor reflectivity in these regions before OCT demonstrated clinically evident deposits (stage [&ge;] 1) between the ellipsoid zone and the retinal pigment epithelium at the corresponding sites. The mean time to development of stage 1, stage 2, and stage 3 SDDs was 11.78 {+/-} 5.01, 17.40 {+/-} 6.08, and 18.72 {+/-} 4.08 months, respectively. ConclusionsHigh-resolution adaptive optics confocal imaging enables detection of photoreceptor optical property alterations at a stage when SDDs are not yet evident on OCT. This finding underscores the exceptional sensitivity of photoreceptors to minimal structural or functional perturbations during SDD formation and defines an early window for potential intervention.

Aim: To evaluate the potential of a three-dimensional microscope combining Laser scanning confocal imaging and white-light interferometry for quantitative topographic characterisation of Descemet's membrane (DM) in Fuchs endothelial corneal dystrophy (FECD). Methods: Descemet's membranes were collected from 38 FECD patients undergoing endothelial keratoplasty and 4 healthy donors. After flat-mounting on glass slide and drying, specimens were analysed using the VK-X3000 system (KEYENCE). Entire samples were reconstructed by image stitching at low magnification (x10) in white-light interferometry mode (0.01nm axial resolution). Higher magnifications (x20-x150) in confocal mode (12nm axial resolution) enabled detailed structural analysis. Three-dimensional height maps were generated to calculate standardised surface roughness parameters. Guttae and other DM features were classified according to spatial organisation and elevation profiles. Results: White-light interferometry enabled full-field mapping of whole 8mm diameter DMs with nanometric vertical resolution (~2 hours/sample). Surface roughness (Sa) was higher in FECD than in controls (median{+/-}IQR: 0.571{+/-}0.259 m vs 0.239{+/-}0.161 m ; p = 0.0018). In FECD, three zones were identified: central (guttae buried in the posterior fibrillar layer; Sa 0.442 {+/-} 0.112 m), paracentral (large uncovered guttae; Sa 0.562{+/-}0.170 m ; p = 0.0423), and outer zone (no confluent guttae; Sa 0.261{+/-}0.143 m ; p < 0.0001). Confocal 3D imaging revealed radial striae, embossments and furrows in the DM, confluent central guttae, and fused or buried structures. Conclusions: Combining white-light interferometry and confocal microscopy enables label-free, high-resolution surface characterisation of DM in FECD, providing quantitative metrics to compare histological subtypes and supporting the predominance of radial structural organisation.

Purpose: Exfoliation glaucoma (XFG) is the most common secondary glaucoma. Prior studies suggest a higher incidence in women and links to reproductive history, implying estrogen-related pathways. Metabolomic data also indicated inverse associations with steroid-related plasma metabolites, suggesting steroid involvement in XFG pathogenesis. Methods: We conducted a nested case-control study within the Nurses' Health Study (NHS) (1980-2018), NHSII (1989-2019), and Health Professionals Follow-up Study (1986-2018), with 217 XFG suspect (XFGS)/XFG cases and 217 matched controls (62 men and 372 women). We evaluated 18 endogenous steroids and five steroid classes using conditional logistic regression. Secondary analyses examined effect modifications by age and residential latitude, and heterogeneity by disease severity (XFGS vs. XFG). Metabolite set enrichment analysis (MSEA) was used for class-level associations. Multiple comparisons were addressed using the number of effective tests (NEF) for individual steroids and false discovery rate (FDR) for steroid classes. Results: No individual steroid or steroid class met NEF- or FDR-adjusted significance thresholds, overall or by sex. Nonetheless, across both sexes, MSEA demonstrated a non-significant inverse trend between androgen levels and XFG/XFGS risk (FDR=0.22), with 11-ketotestosterone showing a nominal inverse association (OR=0.54; 95%CI=0.31-0.93; P=0.03). Progestogens showed enrichment scores in the positive trend (FDR=0.31), with a borderline positive association between progesterone and XFG/XFGS (OR=2.21; 95%CI=1.00-4.87; P=0.05). Conclusions: Although we observed no statistically significant associations with steroids after correction for multiple testing, the suggestive patterns for androgens and progestogens support the possibility of steroid-related pathways in XFG etiology and support further evaluation in larger studies.

PurposeTo investigate whether the geometric shape of the globe, sagittal length (SL) and Posterior Radius of curvature (rPC), differ between patients with rhegmatogenous retinal detachment (RD) and macular hole (MH), and to determine if these parameters offer better diagnostic differentiation than axial length (AL) alone. MethodsThis retrospective study included 20 MH and 20 RD patients. Groups were axial-length matched. Ocular biometry was performed with ultrasound to measure AL and SL. The PR was calculated. Due to the non-normal distribution of the data, the Mann-Whitney U test was used for continuous variables and Fishers Exact Test for gender distribution. ResultsThere was no significant difference between the MH and RD groups in terms of age (median: 33.8 vs 32.6 years; p=1.00), gender (p=0.341), or AL (27.65 mm vs 28.58 mm; p=0.39). However, RD eyes showed significantly higher SL (median: 25.70 mm vs 22.90 mm; p=0.001) and a significantly flatter rPC (median: 28.25 mm vs 24.30 mm; p < 0.001). ConclusionRD eyes exhibit a distinct vertical equatorial expansion and posterior flattening that is not present in MH eyes, despite similar axial lengths. These geometric differences suggest that SL and PR are structural risk factors in vitreoretinal disease.

PurposeHyperosmolar stress (HOS) is a major contributor to corneal epithelial cell damage in dry eye disease. We have previously shown that HOS damages mitochondria and impairs cell metabolism in corneal epithelial cells. Small extracellular vesicles (sEVs) are cell-derived lipid envelopes that are present in all body fluids, including tears. Prior studies suggest that sEV release and composition may be linked with changes in cell metabolism. In this study, we tested the effects of HOS on sEV release and composition, and found that sEV cargo may reflect early, underlying changes in dry eye disease. MethodsTelomerase-immortalized human corneal epithelial (hTCEpi) cells were treated with 450 mOsm NaCl for five days to induce chronic HOS. sEVs were isolated using differential centrifugation followed by iodixanol density gradient flotation. Particle number was determined using Nanoparticle Tracking Analysis (NTA). Mass spectrometry was used to assess the sEV proteome, and selected proteins were validated by immunoblot. Proteome pathways were analyzed using KEGG and CORUM. ResultsPathway analysis revealed an increase in metabolic proteins and proteasome components in sEV cargo released from hTCEpi cells exposed to HOS. These proteins were increased more than fourfold in HOS-sEVs. Examination of proteins involved in the endosomal pathway and NTA further confirmed an increase in HOS-sEV release. ConclusionOur findings suggest a potential mechanism whereby corneal epithelial cells exposed to HOS retain proteins involved in maintaining tissue integrity, while simultaneously releasing unneeded proteins involved in cell metabolism. The presence of metabolic proteins in sEVs may serve as early indicators of dry eye disease.

Purpose: To highlight the roles of intraoperative optical coherence tomography (iOCT) in managing acute corneal hydrops (ACH) and outcomes of iOCT-guided pneumodescemetopexy and corneal compression sutures. Methods: This was a retrospective, consecutive, interventional case series of patients with keratoconus who presented with significant ACH and underwent iOCT-guided pneumodescemetopexy (18% sulfur hexafluoride gas) and compression sutures at Birmingham and Midland Eye Centre, UK, between Aug 2023 and May 2025. Results: Five patients were included; mean age was 32.3+/-6.6 years old and 3 (60%) were male. The mean follow-up duration was 16.3+/-5.6 months. At presentation, the mean corrected-distance-visual-acuity (CDVA) was 1.90+/-0.67 logMAR, central corneal thickness (CCT) was 1187.6+/-372.6um, maximal corneal thickness was 1624.0+/-383.5um and maximal height and diameter of pre-Descemet layer/Descemet membrane (PDL/DM) detachment was 1014.6+/-366.4um and 4456.0+/-839.4um, respectively. The surgery successfully achieved complete PDL/DM attachment in all cases, with a mean time from surgery to ACH resolution of 17.8+/-8.0 days. iOCT successfully visualized the area of PDL/DM break/detachment, revealed the involvement of PDL (evidenced by a persistent taut type 1 DM detachment after gas tamponade), and guided the placement of compression sutures. Compared to preoperative, there was a significant improvement in the mean CDVA (0.52+/-0.32 logMAR; p=0.014) at last follow-up. One patient required a repeat procedure to fully attach the PDL/DM. Conclusions: This study demonstrated favorable outcomes of iOCT-guided pneumodescemetopexy and corneal compression sutures. iOCT revealed the involvement of PDL in ACH and provided plausible explanations why pneumodescemetopexy alone may not be able to resolve significant ACH rapidly in certain cases.

Background and Objective As optical coherence tomography (OCT) has enabled the identification of an expanding set of age related macular degeneration (AMD) risk biomarkers and become central to routine clinical practice, there remains a need for a simplified grading scheme that allows physicians to communicate and synchronize AMD grading directly from standard OCT imaging rather than relying on traditional color fundus imaging. This study aims to establish a standardized OCT based AMD classification that balances diagnostic accuracy with practicality for use across clinical and research settings. Patients and Methods Spectral domain optical coherence tomography scans were independently graded by two retinal specialists following the newly proposed Stanford OCT Based AMD Classification (SOAC). Discrepancies were adjudicated by a third independent retinal specialist. Intergrader agreement was assessed using weighted kappa coefficients. Results Among the 109 eyes from 108 patients, AMD staging based on SOAC was distributed as follows: normal aging in 9 patients (8.3%), early AMD in 16 (14.7%), intermediate AMD in 32 (29.4%), neovascular AMD (nAMD) in 18 (16.5%), geographic atrophy (GA) in 20 (18.3%), and combined nAMD and GA in 14 (12.8%). The overall intergrader agreement demonstrated robust consistency, with a weighted kappa value of 0.95 (95% CI: 0.92 to 0.98), signifying excellent intergrader reliability and reinforcing the validity of SOAC. Conclusion SOAC provides a standardized, OCT based framework for AMD grading that demonstrates high intergrader agreement. By enabling consistent classification from commonly acquired OCT scans, SOAC supports reliable disease staging and facilitates integration across clinical studies and translational research. As imaging and molecular data continue to expand, SOAC can serve as a common OCT based reference for phenotype refinement and longitudinal AMD studies.

PurposeMachine learning approaches for automated quantification of optic nerve histology have emerged as potential tools for objective assessment of axonal injury in experimental glaucoma models. However, the generalizability of these models to independent datasets remains unclear. Guided by a scoping review of the literature, this study performed independent validation testing of publicly available models on a novel rat optic nerve dataset to assess their generalizability. MethodsWe conducted a scoping review following PRISMA-ScR guidelines. PubMed, EMBASE, Scopus, and Cochrane CENTRAL were searched from 2000 through 2025. Two reviewers independently screened records and extracted data on model characteristics and performance metrics. Additionally, we performed independent validation of three models (AxoNet, AxonDeepSeg, AxoNet 2.0) on a novel rat optic nerve dataset comprising 57 images with 9,514 manually annotated axons. Because AxonDeep is not publicly available, we instead evaluated AxonDeepSeg, a separate publicly available deep learning-based tool that, while not previously applied to optic nerve tissue, is widely used for nerve fiber segmentation. ResultsFrom 2,036 records, four manuscripts describing three deep learning models met inclusion criteria. Published correlation coefficients between model predictions and reference counts ranged from 0.959 to 0.99. On independent validation, performance was reduced: AxoNet 2.0 achieved the highest correlation (r = 0.89), followed by AxonDeepSeg (r = 0.86) and AxoNet (r = 0.79). Segmentation quality metrics revealed high precision (>0.94) but low recall (0.18 to 0.27), with Dice coefficients of 0.29 to 0.40, substantially below published benchmarks of 0.81. ConclusionsDeep learning models for optic nerve histology demonstrate strong within-study performance but show meaningful performance decrements when applied to independent datasets. The observed generalizability gap (correlations 0.07 to 0.182 points below published values) demonstrates the need for standardized validation datasets and multi-center testing before widespread adoption of these tools.

PurposeQuantitative metrics obtained from retinal fundus images (such as vessel length, tortuosity and other scale-dependent measures) are increasingly used as potential biomarkers for systemic diseases, including cardio- and neurovascular conditions. However, with the increasing prevalence of myopia and related axial growth, this study aims to evaluate if axial length scaling significantly alters the overall distributions of the inferred biomarkers when compared to biomarker data obtained without axial length scaling and if these effects can be corrected. Methods2,309 clinic visits from patients aged [&le;]21 years were analysed and extracted for axial-length scaling analysis (range) 20 to 28 mm). The retinal fundus photographs were automatically segmented using Automorph to extract biometric data, including vascular metrics. The parameters were further corrected for axial length using correction factors based on the Bennett-Littmann formula and true axial length. ResultsAxial length significantly influenced biometric parameters (vessel metrics) derived from fundus photography. The magnitude of error in diameter and length of blood vessels was approximately 4-5% for each 1 mm deviation from the reference axial length of 24 mm, whereas the error in vessel area was approximately 9-10% per 1 mm, consistent with the geometric expectation that area scales with the square of linear dimensions. The scaling corrections for different axial lengths are presented. ConclusionsAxial-length-related magnification introduces systematic bias into retinal vascular metrics from fundus photographs. Bennett-Littmann correction using true axial length reduces these errors and should be adopted in quantitative fundus imaging and Al biomarker development.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in ageing populations, with oxidative stress recognised as a key pathogenic driver. The dietary antioxidant and cytoprotectant, L-ergothioneine (ET), is avidly accumulated in many tissues, especially the eye. However its relationship to AMD has not been investigated. Here, we examined ETs distribution in ocular tissue and assessed circulating and intraocular ET levels in patients with neovascular AMD. Compared with ocularly-normal age-matched individuals, AMD patients exhibited significantly lower serum ET; elevated levels of ET metabolites, hercynine and ETSO, which may be generated by oxidative stress; and elevated levels of serum allantoin, a product of oxidative damage to urate in humans. Levels of ET in aqueous humour in AMD patients were marginally lower than cataractous patients who are already known to have significantly lower ET levels than healthy eyes. High ET levels were seen in human ocular tissues concentrating in regions vulnerable to oxidative injury, including the lens, retina, retinal pigment epithelium, and choroid, supporting a physiological protective role of ET in the eye. These findings identify the strong association between low ET levels and AMD, warranting further studies to determine whether ET supplementation can modify AMD risk or progression.

Purpose: To identify the ocular biometric parameters associated with refractive outcomes in Chinese Primary angle closure glaucoma (PACG) patients receiving phacoemulsification and intraocular lens (IOL) implantation (PEI) surgery. Methods: 165 Chinese PACG patients receiving PEI and goniosynechialysis (GSL) and 53 cataract patients as controls only receiving PEI surgery were recruited. The prediction accuracy of IOL power calculation was assessed by the prediction error (PE), mean absolute error (MAE), median absolute error (MedAE), and proportions of eyes with a PE within {+/-} 0.25 diopters (D), {+/-} 0.50 D, {+/-} 0.75 D, and {+/-} 1.00 D. The association of different ocular biometric parameters with the PE of IOL calculation were evaluated. Results: The PACG patients had significantly higher absolute of PE as compared to the control subjects, especially the acute PACG patients. The axial length (AL), changes in aqueous depth pre- and post-surgery ({bigtriangleup}AD), and the ratio of {bigtriangleup}AD/AL were significantly associated with the PE in acute PACG patients. The association of {bigtriangleup}AD with the PE of IOL power calculation was found in PACG patients with AL [&ge;] 22 mm. Conclusions: This study revealed the association of AL and {bigtriangleup}AD with the PE of IOL calculation in Chinese PACG patients. Precisely predict the {bigtriangleup}AD is necessary for acute PACG patients, especially for those with AL [&ge;] 22 mm, to improve the refractive outcomes.

The retinal pigment epithelium (RPE) consists of polarized epithelial cells, serving as a support system for photoreceptor maintenance, where the polarity is contributed by the distribution of syntaxins (STX) within the cell. STX3, a known regulator of apical trafficking in epithelial cells, was previously understood to be absent in human RPE cells, with its functions thought to be compensated by STX1A. However, our results on SNARE mRNA expression profile in RPE detected the presence of 2 splice variants of STX3. Further investigation in donor retina, primary hRPE, and ARPE-19 cells revealed detectable levels of STX3 mRNA and protein. STX3 knockdown in ARPE19 resulted in a significant reduction of tight junction (TJ) proteins, compromising TJ assembly, highlighting the critical role of STX3 in maintaining RPE integrity. In addition, immunoprecipitation followed by LC-MS/MS analysis revealed that STX3 and STX1A have a distinct novel protein interactome in RPE. This study identified unique and shared interactants for STX3 and STX1A, suggesting a broader role for RPE beyond its traditional photoreceptor support function. This further emphasises the biological significance of STX1A and STX3 in maintaining retinal homeostasis, which could facilitate the development of novel therapeutic strategies for retinal disorders. SignificanceThis study identified the presence of STX3 in the human RPE cells, which was previously reported to be absent. Further, we demonstrated that STX3 knockdown in ARPE19 cells disrupted TJ assembly, highlighting its potential role in preserving RPE cell polarity and structural integrity, challenging the notion that STX3 functions were thought to be compensated by STX1A. Moreover, immunoprecipitation followed by LC-MS/MS analysis in RPE identified the protein interaction networks of both STX1A and STX3. Interestingly, unique and shared interactants, including proteins associated with neuronal plasticity, indicated unidentified functions of STX3 and STX1A in RPE. This suggests that they might perform both overlapping and distinct functions for maintaining RPE cell integrity and thus retinal homeostasis. Overall, our preliminary findings challenge the established view that STX3 is non-existent in RPE cells and initiate new directions for exploring the multifaceted and potentially non-redundant functions of STX3 in RPE.

Background: Mitochondrial dysfunction is an emerging metabolic hallmark of age-related diseases, yet tools to directly profile mitochondrial pathways and test metabolic interventions in the living human eye remain limited. Multi-omics ocular liquid biopsy enables real-time proteomic and metabolomic profiling of the intraocular microenvironment, complementing systemic biomarkers and imaging surrogates. Here, we used this approach to define mitochondrial and tricarboxylic acid (TCA) cycle dysregulation in geographic atrophy (GA) and to assess whether oral -ketoglutarate (-KG) supplementation can modulate mitochondrial metabolites within the eye. Methods: Mitochondrial and TCA cycle-related proteins were profiled in aqueous humor (AH) samples from patients with GA using DNA-aptamer-based proteomics. In a phase 0 study, a second cohort undergoing sequential cataract surgery provided paired AH samples collected at first-eye surgery and at second-eye surgery after interim -KG supplementation. These samples underwent targeted metabolomic profiling using hydrophilic interaction liquid chromatography coupled with mass spectrometry. Results: In GA, 64 mitochondrial proteins were differentially expressed, including coordinated TCA-cycle deficiencies marked by reduced expression of enzymes regulating TCA entry and flux, including PDHB and DLST. In the phase 0 cohort, oral -KG supplementation significantly increased intraocular -KG levels and the -KG-to-succinate ratio (P < 0.05), with coordinated shifts across TCA intermediates consistent with enhanced TCA cycle flux. Conclusions: AH proteomics demonstrated mitochondrial pathway depletion in GA, consistent with reduced oxidative bioenergetic capacity. AH metabolomics provided first-in-human in vivo evidence that systemic -KG supplementation can modify intraocular metabolites and may enhance intraocular energy metabolism. These findings support ocular liquid biopsy as a precision-health framework for per-patient biomarker-guided metabolic trials in GA.

Age-related macular degeneration (AMD) is a common, complex disease affecting older individuals that can lead to severe vision loss. It is characterized by early anatomical changes in the retina, retinal pigment epithelium (RPE), and choroid, especially in the central (macular) region. AMD can progress to severe atrophy and/or pathologic angiogenesis that leads to visual decline. Over 30 genetic loci have been identified as contributing to AMD risk; however, the mechanisms by which genetic variants affect pathology has not been thoroughly explored. In this report we examined single-nucleus gene expression in the retina, RPE and choroid of 88 individuals categorized by AMD stage, as well as 37 previously published samples. Genotyping was performed on 1.8 million SNPs, with additional SNPs imputed, on each donor to identify expression quantitative trait loci (eQTLs). We found that two AMD-risk loci (PILRB and ARMS2/HTRA1) affected the expression of PILRB and HTRA1, respectively. The risk allele of PILRB was associated with increased PILRB RNA in cones, fibroblasts, choroidal macrophages, and RPE, whereas the HTRA1 risk locus was associated with decreased HTRA1 RNA in the RPE. We also identified an age-related decrease in complement inhibitors in the choriocapillaris, a tissue susceptible to complement mediated damage in AMD.

Emerging evidence implicates retinal microglia and inflammation as important components impacting the outcome of retinal regeneration, which is spontaneously achieved in zebrafish retina following acute damage but is limited or blocked in mammals. In this paper, we describe the regenerative response in the larval zebrafish retina following ablation of cone photoreceptors. To investigate the role of microglia in the regenerative response, we used both irf8st95 heterozygote (microglia-sufficient) and irf8st95 homozygous mutant (microglia-deficient) zebrafish. We compared multiple aspects of the regenerative response in irf8+/- and irf8-/- larval retinas, including entry of the Muller glia (MG) into the cell cycle, the amplification of MG-derived progenitor cell (MGPC) proliferation, inflammatory and glial reactivity-associated gene expression, and the regeneration of cones. We found only modest impacts to early and late stages of MGPC proliferation and to inflammatory gene expression in irf8 mutants, with no obvious impacts to the regeneration of cones. Notably, we detected a population of immune cells in irf8 mutants that emerged following cone ablation, which expanded in number then were reduced over time, following a trajectory similar to microglia-sufficient siblings but at markedly reduced abundance. The immune cells detected in irf8 mutants included a subset with L-plastin/4C4 antibody staining patterns different than those in microglia-sufficient siblings, suggesting distinct origins and/or phenotype compared to resident microglia in controls. Though strong conclusions about the role of microglia were limited due to the presence of such immune cell populations in irf8 mutants, our results are consistent with several reports that indicate a role for microglia and inflammation in regulating MGPC proliferation in the regenerating retina. Collectively considered with other reports, our results further indicate that compensatory responses, which may include different immune cells and/or signaling from other retinal cell types such as the Muller glia, are elicited in microglia-deficient retinas upon neuronal damage.

PurposeThe aim of this clinical investigation was to evaluate the safety and effectiveness of iota-carrageenan (I-C) eye drops in the treatment of mild-to-moderate dry eye disease (DED). MethodsIn this prospective, single arm, open label clinical investigation, thirty adult participants with mild-to-moderate DED applied I-C eye drops three times daily for four weeks. Before start and after end of treatment, participants rated DED symptoms (foreign body sensation, burning/stinging, itching, pain, sticky feeling, blurred vision and photophobia), both after exposure to a normal controlled environment (NCE) and to an adverse controlled environment (ACE). Additional endpoints were changes in ocular surface disease index (OSDI), Change in Dry Eye Symptoms Questionnaire (CDES-Q), corneal and conjunctival surface damage, tear film break-up time, tear evaporation and production. Tolerability was assessed by participants at start and end of treatment. Safety, including visual acuity and intraocular pressure, was monitored throughout the investigation. ResultsAfter four weeks of treatment with I-C eye drops, the mean total DED score after ACE was significantly reduced by -11.89 points (95% CI: -15.11, -8.67), p<0.001. The mean score reduction between baseline and final visit after NCE was slightly less pronounced, with -8.07 points (95% CI: -10.71; -5.43), p<0.001. The vast majority of participants (93% after ACE and 89% after NCE exposure) recorded a reduction in total DED score between baseline and final visit. Mean OSDI score significantly decreased by -7.75 points (95% CI: -10.85, -4.63), p<0.001. ACE-induced deterioration of tear film stability as well as corneal and conjunctival damage were reduced following treatment. All adverse events were mild and transient in nature. 93% of the patients described I-C eye drops as well or very well tolerated. Treatment did not negatively impact any of the safety parameters. ConclusionI-C eye drops are effective, safe and well tolerated. Treatment with I-C eye drops alleviates DED symptoms, stabilizes tear film and protects the ocular surface in patients with mild-to-moderate DED even under adverse environmental conditions. Trial RegistrationNCT06262100.

Conventional assays (questionnaires, acuity, visual fields) may be insufficient to assess the real-world impact of new glaucoma treatments. Here, we report a novel virtual reality shopping task, and assess its sensitivity to differences in mild visual field loss. Eight glaucoma patients were asked to freely navigate a virtual grocery store and place items from a shopping list into a trolley. Across a range of metrics (time, head/body movements), performance was associated with variations in binocular visual field loss [r238=0.35, P<.001]. This indicates promise for using virtual reality tasks to evaluate the benefits of new treatments. Improvements and use-cases are discussed. ONLINE ONLY SUPPLEMENTARY MATERIALThe article contains supplementary material which will be provided as a single stand-alone PDF document.