Experimental Eye Research

Cone photoreceptors are essential for daylight vision, and their degeneration has more profound visual consequences than rod loss in retinal degenerative diseases. Metabolic dysfunction is closely associated with cone degeneration, however the relatively small population of cones in mice and humans have limited our understanding of cone-specific metabolism. Here, we leveraged cone-dominant and cone-degeneration mouse models including Nrl-/-, Cnga3-/-, and high-dose Triiodothyronine (T3) treatment to investigate cone-specific metabolism and their metabolic impacts on the retinal pigment epithelium (RPE). Across models, cone-dominant retinas consistently showed lower pyruvate abundance alongside increases in glutathione, purines, pentose phosphate pathway intermediates, and one-carbon metabolites. Increases in several key amino acids were also associated with higher cone abundance, such as proline, arginine, alanine, valine, leucine, and hypotaurine. Strikingly, aminoadipate, an intermediate in lysine catabolism, was the most robustly changed metabolite in the retina, showing highly consistent increases across models. Relative cone increases were also associated with metabolic changes in the RPE/choroid. Like the retina, RPE/choroids showed consistent increases in aminoadipate, proline, and hypotaurine, as well as xanthosine and betaine, alongside decreases in uracil. Moreover, proteomic analysis of Nrl-/- mice showed decreases in many key metabolite transporters in the RPE/choroid, including carriers for glucose, lactate, aspartate, glutamate, serine, lysine, taurine, and proline. Collectively, these findings further our understanding of cone-specific metabolism and highlight potential cone-specific metabolic vulnerabilities in retinal degeneration.

Activated leukocyte cell adhesion molecule A (Alcama) plays a role in axonal guidance, cell differentiation, and retinal lamination in a developing retina and was identified as a marker for activated Muller glial cells in adult zebrafish. However, its spatiotemporal localization and its involvement in retina regeneration remains unclear. Here we induced focal photoreceptor damage in zebrafish using laser photocoagulation and examined the expression and localization of Alcama at different time points post lesion. Immunohistochemistry in wild type fish and Tg(kdrl-EGFP) fish showed Alcama localized to the blood retina barrier with increased expression in Muller glial end feet and radial processes in a regenerating retina. To confirm its role in retina regeneration, alcama expression was transiently knocked down using morpholinos in adult fish. Scanning laser ophthalmoscopy, Zpr1 immunostaining and EdU staining showed delayed retina regeneration in alcama knockdown fish, indicating a possible role for Alcama in zebrafish retina regeneration.

Purpose: Oxidative stress is thought to contribute to the development of age-related cataracts (ARCs), but the mechanisms by which oxidative damage leads to the opacification of the lens remain unclear. Previous studies suggest that oxidative stress can disrupt lens proteostasis. Therefore, it was hypothesized that ARCs arise from proteomic changes driven by an age-associated decline in oxidative stress defenses that interact with the lens proteostatic state. To test this hypothesis, proteomic analyses of lenses exposed to oxidative stress were performed to examine oxidative and proteostatic stress responses in vivo. Methods: Cataract formation was induced by injecting hydrogen peroxide into the aqueous humor of adult zebrafish. nrf2fh318/fh318 zebrafish were used to model the reduced oxidative stress protection observed in aged human lenses, while cryaba-/- zebrafish were used to model impaired lens proteostasis. Resulting opacities in WT, cryaba-/-, nrf2fh318/fh318, and cryaba-/-; nrf2fh318/fh318 lenses were quantified and proteomic changes in the cortex were analyzed using data independent acquisition Parallel Accumulation Serial Fragmentation mass spectrometry. Results: Hydrogen peroxide treatment induced the formation of cortical cataracts. Proteomic results showed that, dependent on genotype and day, oxidative stress activates the unfolded and mitochondrial unfolded protein responses. Additional changes were also observed in energy metabolism, Ca2+ homeostasis, protein degradation, and cytoskeletal and extracellular matrix remodeling pathways. Conclusions: Treated zebrafish lenses successfully model ARC and mass spectrometry proteomics identified the unfolded and mitochondrial unfolded protein responses as potential therapeutic targets for ARC.

PurposeFuchs endothelial corneal dystrophy (FECD) is a progressive disease, causing premature death of corneal endothelial cells (CECs). Iron-dependent lipid peroxidation and ferroptosis mediate cell death in FECD. We aimed to determine whether FECD progression is mediated by derangements in ferritinophagy - a form of autophagy that degrades ferritin to release labile ferrous iron - and whether ultraviolet A (UVA) exposure drives FECD progression by activating ferritinophagy. MethodsEndothelium-Descemet membrane (EDM) tissues were collected from patients with end-stage FECD undergoing endothelial keratoplasty and from healthy age-matched donor corneas. Separately, immortalized FECD and healthy control CEC lines were cultured. Cellular levels of NCOA4 production and LC3 activation, both markers of ferritinophagy, were quantified using western blotting and PCR. UVA-exposed immortalized cells were plated on coverslips, stained for immunohistochemistry (IHC), and analyzed using confocal microscopy. Corneal endothelial peels were stained and analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). ResultsSurgically explanted FECD CECs showed significantly increased levels of NCOA4 compared to healthy controls. LC3 activation was increased in FECD immortalized CECs; UV exposure further increased LC3 activation. Additionally, UVA exposure showed trends of increased expression of NCOA4 in immortalized FECD and healthy CECs. On IHC of FECD surgical explant tissue, ferritin was decreased markedly, NCOA4 localized in a dramatic punctate pattern, and both ferritin and LC3 localized within cell nuclei. Spectrometry images showed higher iron levels correlating with areas of higher FECD disease burden. ConclusionsOur results demonstrate ferritinophagy in FECD indicated by the increase of NCOA4 and LC3 ferritinophagy markers in FECD patient and cell culture models. Our finding that UVA activates ferritinophagy implicates this mechanism in UVA-mediated FECD progression. Altogether, aberrant iron dysregulation associated with FECD and ferroptosis may be mediated by ferritinophagy, providing a biomarker to assess disease severity as well as a potential target for future medical therapeutics.

Traumatic optic neuropathy (TON) occurs due to direct or indirect injury to the optic nerve and is a significant cause of visual disability. So far, there is no effective treatment. The lack of understanding of the cellular mechanisms by which trauma induces inflammation and damage in retinal neurons is a critical knowledge gap in developing effective therapies. We have studied the role of the arginase 1 (A1) enzyme in this pathology. We have found previously that treatment with a long-acting form of human recombinant A1, pegylated A1 (PEG-A1) after optic nerve crush limits activation of retinal microglia and macrophages (M{Phi}) and reduces inflammation, thereby decreasing injury and protecting visual function. Here we report on studies designed to demonstrate the therapeutic efficacy of PEG-A1 in mouse models of direct and indirect TON and to elucidate the underlying mechanisms. We used ONC to model direct TON and sonication-induced trauma to the supraorbital rim to model indirect TON (SI-TON). At different times after injury, mice were treated with PEG-A1 which was delivered systemically by i.p. injection or locally by intravitreal injection. In order to assess the role of A1-induced activation of the ornithine/polyamine pathway in the protective effects of PEG-A1, some mice were treated with the ornithine decarboxylase (ODC) inhibitor, difluoromethylornithine (DFMO) immediately after the PEG-A1 treatment. Retinal function was determined by OptoMotry and electroretinography. Retinal injury and microglia/M{Phi} activation were assessed by immunofluorescence imaging. Expression of inflammatory cytokines was determined by Western blotting and quantitative RT PCR. Liquid chromatography mass spectrometry was used to analyze changes in arginase/ODC pathway metabolites. Results showed that PEG-A1 treatment improved neuronal survival and visual function whether delivered systemically or intravitreally. This neuroprotection was associated with decreased microglia/M{Phi} activation, decreased inflammatory cytokine expression, and increased formation of L-ornithine and putrescine. Furthermore, DFMO treatment blocked these effects, indicating that PEG-A1 limits retinal injury and preserves vision after ocular injury by activating ODC. ODC processes the arginase product L-ornithine to form polyamines which are known to promote reparative functions. Thus, PEG-A1 therapy offers a new strategy to limit trauma-induced vision loss and promote repair after TON.

Background/Aims: Neovascular glaucoma (NVG) is a severe, secondary glaucoma. This study aimed to identify factors associated with vision, intraocular pressure (IOP), and ocular pain outcomes. Methods: The cohort included all patients diagnosed with NVG during 2008-2024 at Helsinki University Hospital, Finland. Linear mixed-effects models used pre-specified covariates, whereas machine learning was given the full longitudinal data with biomicroscopic findings as an exploratory approach. Results: 626 patients were analysed. Worse baseline vision and a closed angle were associated with worse follow-up vision. Treatments were associated with lower IOP and less pain rather than better vision. Age, sex and comorbidity were largely not associated with the outcomes. Glaucoma drainage devices showed the greatest initial IOP reduction (-10.2 mmHg, 95% confidence interval, CI -11.9 to -8.6 mmHg), followed by transscleral cyclophotocoagulation (TSCPC, -4.7 mmHg, 95% CI -5.8 to -3.7 mmHg) and peripheral retinal cryotherapy (-2.2 mmHg, 95% CI -3.1 to -1.4 mmHg). TSCPC and cryotherapy were also associated with reduced pain (odds ratio 0.51 and 0.46). Pan-retinal photocoagulation and anti-VEGF showed smaller IOP reductions, with a pain reduction for pan-retinal photocoagulation only. Both methods agreed, and machine learning added no novel clinical findings. Conclusions: Vision in this cohort was largely set by the state of the eye at diagnosis. IOP control and pain relief therefore remain realistic goals even when sight cannot be saved. Peripheral retinal cryotherapy stood out, linked to both lower IOP and less pain, seldom reported in NVG. These associations from a large, unselected cohort identify treatments worth comparing prospectively.

PurposeTo evaluate associations between green autofluorescence (GAF) and structural and functional measures relevant to retinal and optic neuropathies, and to establish normative GAF values across the optic nerve head (ONH), macula, and papillofoveal bundle (PFB) in rhesus macaques. MethodsEighty-two macaques with normal ONH morphology by spectral-domain optical coherence tomography (SD-OCT) were included with a mean {+/-} SD age of 12.76 {+/-} 7.18 (range 0.11-29.39) years. The GAF images were acquired in the ONH, macula and PFB with the OcuMet Beacon. In a subset of macaques (n=19), pattern electroretinogram (PERG) and photopic full-field ERG including the photopic negative response (PhNR) were recorded. ResultsThe GAF significantly increased with age in the ONH, macula and PFB. After adjusting by age, there were no sex differences, but IOP showed a positive association with macular GAF. At the ONH, higher GAF correlated with thinner retinal nerve fiber layer, inner and outer segment complex, and total retinal thickness. In the macula, inner nuclear layer thickness was positively associated with GAF, whereas outer plexiform layer and inner and outer segment complex were inversely associated. The PERG amplitudes inversely tracked ONH GAF. ConclusionsGAF rises with age and IOP, couples to retinal structure, and at the ONH, aligns with inner-retinal functional indices. This study provides a regional reference for GAF in rhesus macaques. Translational RelevanceNormative GAF data in healthy rhesus macaques provide a framework for interpreting this noninvasive signal in translational studies of retinal and optic nerve disease.

Purpose: To validate an automated pipeline to detect and quantify focal retinal and choroidal pulsation areas that are synchronous with the cardiac cycle in video indocyanine green angiography (ICGA). Design: Retrospective, observational, hypothesis-generating validation study Subjects, Participants: Consecutive patients with a diagnosis of central serous chorioretinopathy (CSCR) in one or both eyes. Methods: Videos were acquired on Heidelberg HRA+OCT. The pipeline consisted of three steps: signal extraction, foci detection, and quantification. After registration of the constituent frames, each pixel's intensity signal was analyzed at the presumed cardiac frequency (tested from a sample of three detectable frequencies). A synchrony score combining local phase coherence with oscillation amplitude was then derived and computed using a standard deviation ({sigma}) above each video's background oscillation value. Two masked graders marked the retinal and choroidal pulsation areas twice. We compared detection of the pulsation areas against grader consensus using a receiver operating characteristic curve (using multiple grid sizes to divide the scan area) and, separately, using a signal-based area-reduction method to obtain an optimum {sigma} value. Main Outcome Measures: Agreement between the automated algorithm and human graders in detection of pulsation foci, and the optimum threshold multiplier ({sigma}). Results: We studied 20 ICGA videos from 20 eyes. At the 16-pixel grid size, the pipeline achieved a mean area under the curve (AUC) of 0.914, sensitivity of 0.86, and specificity of 0.80. Grader agreement improved with larger grid size, reaching substantial-to-strong levels for choroidal annotations. The two independent validation methods demonstrated similar {sigma} values that differed by 0.62{sigma}, supporting {sigma}=4.0 as the optimum value. Conclusions: We report the first automated method to quantify retinal and choroidal vascular pulsation on video ICGA. It measures pixels that oscillate over time with the presumed cardiac cycle and works reliably at the spatial scale (grid level) where experts agree. Pulsatile hemodynamics may add a new vascular biomarker for glaucoma, diabetes, hypertension, and pachychoroid diseases.

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in older adults. It is characterised by early retinal pigment epithelium (RPE) dysfunction followed by progressive photoreceptor degeneration. Cigarette smoking is a major environmental risk factor for AMD, and hydroquinone (HQ), a redox-active cigarette smoke component, induces oxidative stress and apoptosis in RPE cells. To analyse how RPE stress contributes to photoreceptor degeneration, we employed a retinal co-culture model composed of human induced pluripotent stem cell-derived RPE (iPSC-RPE) cells in conjunction with porcine neuroretina explants. Exposure to HQ induced oxidative stress in iPSC-RPE cells as well as retinal photoreceptors (RPR), resulting in apoptosis, executed at least in part by caspase activation. Concomitantly, HQ caused endoplasmic reticulum (ER) stress (ERAD) in RPR followed by their degeneration, evidenced by reduced outer nuclear layer (ONL) rows and shortened RPR outer segments (OS). Based on earlier results, which suggest a perturbation of proteostasis due to HQ, we tested whether ML240, a bona fide inhibitor of valosin-containing protein (VCP), would influence the degree of degenerative activities. ML240 did not prevent HQ-induced apoptosis in iPSC-RPE cells. However, it significantly preserved photoreceptor integrity, retaining OS length and cone density in HQ-stressed co-cultures. Proteomic analysis suggested that ML240 reshapes stress response patterns of the HQ-exposed neuroretina, as evidenced by a reduction in ERAD-associated markers, increased levels of antioxidant response proteins, and the preservation of cytochrome c enrichment in photoreceptor inner segments, which indicates improved mitochondrial integrity consistent with the observed preservation of photoreceptor structure. Together, these findings establish the iPSC-RPE/neuroretina co-culture as a platform to analyse pathophysiological features of AMD, dissect cell type-specific retinal responses to environmental stress and test neuroprotective pharmacological approaches to protect photoreceptors in oxidative stress-associated retinal degeneration.

Individuals with inherited retinal dystrophies (IRDs) undergo a slow, genetically heterogeneous loss of vision, yet how the visual cortex and non-visual sensory, motor, and psychological systems adapt to this deprivation remains poorly characterized. Existing evidence comes mainly from single-modality, cross-sectional studies that rarely account for genetic heterogeneity, making it hard to distinguish adaptive change from a direct, non-retinal mutation effect, since several IRD genes are not retina-specific. To address this gap, we designed an observational, longitudinal, multimodal protocol that combines ophthalmological, genetic, and in silico characterization with electrophysiological (steady-state visual evoked potentials and TMS-EEG), chemosensory, sensorimotor, and psycho-personological assessments. Patients aged 18 to 75 years with rod-cone (retinitis pigmentosa, Usher syndrome) or cone and cone-rod dystrophies will be assessed at baseline (T0) and at an 18-month follow-up (T1); sighted controls, matched for age, sex, and handedness, will complete the same battery once. Importantly, pairing genotypic with phenotypic data allows changes in non-visual domains to be interpreted against, rather than independently of, each patient's molecular background. We expect individuals with IRDs to differ from controls in visual cortical responsiveness and in selected non-visual sensory and sensorimotor measures, with genotype-related differences explored where sample size permits. Given the rarity of IRDs, the design is exploratory and emphasizes effect sizes and individual variability over large-sample inference. The protocol was approved by the Ethics Committee of the University of Verona (CARP 08.R1/2024) and follows the Declaration of Helsinki and the GDPR; findings will be disseminated through peer-reviewed publications and shared with patients and IRD patient associations.

It is clear that the human retina and its underlying retinal pigment epithelium and choroid (RPE/choroid) form an interdependent metabolic ecosystem, but how metabolism differs between the cone-rich macula and rod-rich periphery remains unclear. Using targeted metabolomics, we quantified 133 metabolites in paired macular and peripheral neural retina and RPE/choroid explants from human donor eyes following short-term culture to restore metabolic activity. Distinct metabolic differences were identified between retinal regions and between tissues. Compared with the peripheral retina, the macula showed metabolic features consistent with greater glycolytic activity, increased NADH availability and higher levels of the neurotransmitter-associated metabolites N-acetyl-aspartate (NAA) and N-acetyl-aspartyl-glutamate (NAAG), consistent with increased energetic and neuronal activity. Compared with peripheral RPE/choroid, the macular RPE/choroid had higher levels of the flavin cofactor FAD together with NAD-related metabolites, including NAD, NADP and NAAD. Comparisons between the neural retina and RPE/choroid further showed that the neural retina was primarily associated with energy production and neurotransmission, whereas the RPE/choroid was associated with cofactor metabolism, nucleotide salvage and lipid metabolism. These findings are consistent with metabolic coupling between the neural retina and RPE/choroid. The macula has metabolic features consistent with high energetic demand, providing a potential metabolic basis for its selective vulnerability in macular disease.

Inherited retinal disorders are significant contributors of blindness worldwide. Mutations in Peripherin-2 (PRPH2), a highly conserved vertebrate tetraspanin membrane protein responsible for formation and maintenance of OS morphology, have been shown to cause diverse types of inherited photoreceptor cell (PRC) disorders including but not limited to Leber congenital amaurosis, cone-rod dystrophy, and retinitis pigmentosa. In this study we used a cone-rich diurnal zebrafish model to characterize the loss of PRPH2 function. Of the four PRPH2 zebrafish orthologs only prph2a and prph2b were found to be expressed in PRCs. CRISPR-mediated single mutants of prph2a and prph2b did not yield striking rod or cone phenotypes. Double prph2a/2b mutants exhibited early loss of all cone cells, preceded by cone outer segment disorganization in the form of whorls akin to the phenotypes observed in PRPH2+/- mice. Surprisingly rod photoreceptor cells were not affected and in fact exhibited a striking lengthening of rod OSs with normal disc formation. Overgrowth of rod OSs proceeded up to 1 year, but no degeneration was observed. To determine how rod OS can persist without prhp2a/b we targeted rom1a and rom1b using CRISPR. Injection of rom1a/b crRNA resulted in complete loss of both rod and cone OSs in the prph2a/b double mutants. Surprisingly, inhibition of rom1a/b alone resulted in the loss of rod but not cone OSs. These findings suggest that unlike in mammals, zebrafish rom1a/b is essential for rod OS formation while prph2a/b is essential for cone OSs.

Introduction: Community outreach eye camps extend eye care to underserved rural populations across South Asia, but published data mostly describe surgical yield rather than the full range of presenting conditions. This study described the pattern of ocular diagnoses among patients attending community eye camps in Bangladesh and examined how these patterns varied by year, age, and sex. Methodology: This was a retrospective, registry-based study of patients screened through the outreach eye-camp programme of Bashundhara Eye Hospital and Research Institute, Bangladesh, between 2020 and 2024 (2021 excluded due to COVID-19). Age, sex, and provisional diagnosis were recorded for every patient and grouped into five categories: cataract and lens disorders, refractive errors and presbyopia, ocular surface inflammatory disorders, lacrimal system disorders, and miscellaneous disorders. Multivariable logistic regression models estimated the adjusted odds and predicted prevalence of each diagnostic category by calendar year (adjusted for age group and sex) and by age group and sex (adjusted for calendar year). Results: Among 7,267 patients, refractive errors and presbyopia were the most common category (51.31%), followed by cataract and lens disorders (23.54%), miscellaneous disorders (13.86%), ocular surface inflammatory disorders (8.59%), and lacrimal disorders (2.70%). Ocular surface disorders declined significantly over time (adjusted OR: 0.80/year; p-value<0.001). Cataract showed a borderline decline (adjusted OR: 0.94; p-value=0.065). Cataract prevalence rose steeply with age, from 3-6% below 18 years to 49-55% at 60 and older, while refractive errors/presbyopia peaked at 40-59 years (64-68%) before declining thereafter (30-37%). Ocular surface disorders were most frequent among children. Lacrimal disorders remained uncommon (2-5%), with no significant interaction. Conclusion: Refractive errors and presbyopia were the leading reason for presentation, with distinct age patterns across diagnostic categories. Outreach eye camps should be resourced for both comprehensive refraction, primary eye care and cataract-surgical referral, reflecting actual community-level diagnostic needs.

Objective: To describe trends in cataract surgical volume, district-level surgical burden, and early postoperative visual outcomes among patients treated through a multi-district outreach programme in Bangladesh. Methods and Analysis: This retrospective study was conducted using data from patients undergoing cataract surgery through the outreach eye-camp programme of Bashundhara Eye Hospital and Research Institute across eight districts of Bangladesh, between 2016 and 2025 (excluding 2021 because of COVID-19). Annual surgical volume trend was assessed using Poisson regression. Postoperative visual outcome on day 1 was categorized as good, borderline, or poor per WHO criteria. Univariable and multivariable ordinal logistic regression identified predictors of worse outcome. Results: 1,929 cataract-surgery records were included. Surgical volume rose from 34 cases in 2016 to a peak of 677 in 2023 (IRR = 1.20; 95% CI: 1.180, 1.220; p-value< 0.001). Small incision cataract surgery (SICS) was used in 99.43% cases. On postoperative day 1, 70.09% of eyes had a good outcome, 19.44% borderline, and 10.47% poor. Increasing age was independently associated with worse outcome, with 2 to 3 times higher odds among patients over 70. District was independently associated with outcome, with Chapainawabganj and Kushtia having lower odds of worse outcome than Brahmanbaria. Sex was significant only in unadjusted analysis. Conclusion: Surgical volume rose substantially over time. About seven in ten eyes achieved a good outcome on day 1, with age and district as the main predictors of worse outcome. Limitations include a single early assessment, exclusion of incomplete records, no standardized refraction, and unmeasured predictors.

Purpose: Pupil examination is a routine examination of patients presenting with ophthalmological or neurological symptoms. Our purpose was to determine the sensitivity of pupillometry using HP Reverb G2 Omnicept virtual reality (VR) headset for detecting anisocoria and relative afferent pupillary defect (RAPD). Methods: Twenty-nine patients were included; Group I with asymmetric optic neuropathy (N=21) and Group II with suspected pathological anisocoria (N=8); alongside 19 controls. VR pupillometry consisted of Pupil symmetry test and Swinging light test. Pathological thresholds were established using upper limits of controls. Results were compared with routine pupil exam. Correlations with functional ophthalmological test results were analyzed. Results: RAPD was detected in 16/21 Group 1 patients using both VR pupillometry and standard exam. Remaining 5 had relative afferent pupillary asymmetry (RAPA) within the control range (0.1-0.2 mm). Significant correlation was found between RAPA/RAPD and inter-eye difference in visual acuity and visual field defect (MD) (R=0.58 and 0.68, p<0.01). All patients with >5,8 dB inter-eye MD difference had RAPD. In Group II, pathological anisocoria (>0.8 mm) was detected using VR pupillometry and 1/8 on standard exam. Qualitative differences in pupillary constriction were observed. In control group anisocoria (0.4-0.8 mm) was detected in 37% (7/19); in all greater in the dark (mean 0.2 mm). Conclusion: In comparison to conventional exam VR pupillometry matched detection rate of RAPD and surpassed detection rate of pathological anisocoria. Longitudinal data on pupillary constriction characteristics could significantly contribute to patient diagnosis and monitoring in clinical studies as well as understanding physiological variability.

In his seminal 1920s studies, Otto Warburg found the retina to generate large amounts of lactate. However, it was unclear what retinal cells produced lactate and whether it was a metabolic waste product or used further. Here, we show that lactate produced by rod photoreceptors fuels the energy-intensive function and viability of cone photoreceptors. In an initial expression analysis, we found monocarboxylate transporter-1 (MCT1), lactate-producing lactate-dehydrogenase-A (LDHA), and pyruvate carboxykinase-1 (PCK1) localized to rod photoreceptors, while high-affinity MCT2, pyruvate-producing LDHB, and PCK2 were expressed in cones. We then exposed retina to defined media containing either glucose or lactate as caloric component, and applied specific MCT inhibitors. In glucose-containing medium, 1H-NMR metabolomics showed rod MCT1 inhibition to increase retinal lactate, suggesting rods as a major source of lactate. In lactate-only medium, functional recordings using micro-electroretinography showed decreased rod function, while cone function was maintained. In glucose-containing medium, blocking rod MCT1 abolished cone function. Long-term treatment with MCT inhibitors selectively decreased photoreceptor viability. Conversely, supplementing the defined medium with lactate preserved cone viability in the rd1 mouse model for Retinitis Pigmentosa. Together, our data suggest that lactate shuttling from rods is crucial for cone function and viability. This may explain cone degeneration seen in various retinal diseases and provides an entirely new avenue for metabolism-based treatment development. The discovery of a lactate-shuttle between two functionally similar, yet distinct types of neurons may have far-reaching implications for our understanding of the central nervous system in general.

Purpose The direct effect of iStent inject on intraocular pressure (IOP) in patients with glaucoma is difficult to quantify in pragmatic trials where rates of post-surgical IOP-lowering therapy differ between intervention groups. We aimed to quantify the causal effect of iStent inject on unmedicated IOP at 12- and 24-months post-surgery. Methods Adults with mild-to-moderate glaucoma were 1:1 randomised to receive cataract surgery with iStent inject or cataract surgery alone at an Australian hospital (2017-2020, NCT03106181). IOP-lowering medications were prescribed as per clinician discretion. An exploratory analysis was used to estimate the controlled direct effect of iStent inject on IOP, analogous to the effect expected if all participants had undergone medication washout prior to assessment. Results Ninety-five eyes from 80 people were included (67.4% male, mean age 73.0 years, mean baseline IOP 17.1 mmHg). IOP-lowering medication was required for 53% of eyes in each group at 12 months (n=76); at 24 months (n=86) it was required for 43% and 64% in the active and control groups, respectively. Mean IOP was similar between intervention groups at each outcome visit. The controlled direct effect favoured the iStent inject group at 12 months (-2.1-mmHg difference, 95% CI -4.0,-0.3) but was attenuated at 24 months (-0.5 mmHg-difference, 95% CI -2.6,1.6). Conclusion Although the iStent inject was estimated to have an effect on lowering unmedicated IOP at 12 months, this effect had largely disappeared by 24 months. Medication washout is recommended when safe and practical in future trials to estimate these direct effects with more certainty.

Background: An estimated 826 million people have avoidable near vision impairment (NVI) due to lack of access to near vision glasses for presbyopia. Glasses use, uptake and replacement is essential to sustained NVI correction. Here we explore the uptake of second and subsequent pairs of near vision glasses and the willingness to pay. Methods: In this cross-sectional survey, 276 individuals who received near vision glasses through eye health screening programs in Punjab province, Pakistan from 2020 to 2022, were surveyed between February and July 2025, i.e. 3-5 years later. Results: 92.0% (n=254) of respondents were still using near vision glasses: a purchased replacement (41.3%, n=114), a free replacement (30.8%, n=85), or the original pair (19.9%, n=55). Male gender, higher age, and personal income were strongly associated with purchasing additional pairs, while women and those economically dependent on others relied more on free provision (all p values <0.05). Accessibility, indicated by shorter travel times and awareness of supply sources, also played a significant role in sustained replacement. Over 98% of participants expected to obtain (purchase or receive) a new pair of glasses in the future, and over 94% of participants expected to purchase their next pair. The mean willingness-to-pay (WTP) was 353 PKR (95% CI: 327-379) // 1.25 USD (95% CI: 1.16-1.34), while the average reported price paid was 416.67 PKR // 1.47 USD (95% CI: 351.39-481.94)). Conclusion: Sustained use of near vision glasses remained high 3-5 years after initial provision. Many recipients had purchased replacements, and willingness and ability to pay were high among participants, suggesting potential for sustained demand beyond initial subsidized distribution.

Purpose: To evaluate whether initiation of GLP-1 receptor agonists (GLP-1RAs) is associated with anti-VEGF treatment burden in type 2 diabetes patients with diabetic macular edema (DME) in the IRIS(R) Registry (Intelligent Research in Sight). Methods: Incident GLP-1RA initiators were matched 1:1 with controls via Mahalanobis distance matching (9,896 pairs; N=19,792) on sociodemographics, DME risk factors, and factors influencing GLP-1RA prescription including hypertension, obesity, chronic kidney disease. A longitudinal mixed-effects event-study model evaluated monthly anti-VEGF injection frequency over a 36-month window (12 months before through 24 months after initiation), adjusting for DME duration. Visual acuity (VA) and central subfield thickness (CST) were secondary outcomes. Results: Following GLP-1RA initiation, anti-VEGF injection trajectories did not significantly differ between the matched GLP-1RA and control cohorts (interaction coefficients -0.18 to 1.59, P>0.05). Likewise, no differences in VA were observed between cohorts (-0.05 to 0.04 logMAR, P>0.05) or CST (-14.12 to 33.58 {micro}m, P>0.05). Conclusion: In these matched cohorts, GLP-1RA initiation was not associated with the trajectory of anti-VEGF use or changes in VA or CST. Precis We used the American Academy of Ophthalmology IRIS(R) Registry (Intelligent Research in Sight) to identify patients with DME. In 19,792 matched patients, there was no significant reduction in injection frequency post GLP1-RA initiation and no significant change in VA or CST.

The outer blood-retinal barrier (OBRB) is the primary interface through which systemically circulating drugs reach the retina. A tool that measures delivery across this barrier would support the development of targeted therapies as alternatives to repeated intravitreal injection, and the screening of drugs that reach the retina as an off-target toxicity. Such a tool should deliver drugs fluidically through a vascular compartment, measure transport across the retinal pigment epithelium (RPE), and display disease phenotypes relevant to efficacy. Here we adapt the SiM platform, which places epithelium and endothelium in direct juxtaposition across a permeable, optically transparent silicon nitride nanomembrane. ARPE-19 and human umbilical vein endothelial cells (HUVECs) were used as development cell sources. ARPE-19 monocultures reached a transepithelial electrical resistance of 68 {+/-} 26 {Omega} cm2 by 28 days, and ARPE-19 + HUVEC co-cultures reached a small-molecule permeability of 6.34 {+/-} 1.3 x 10-4 cm min-1 within 14 days, a state reported elsewhere only after longer culture. The barriers developed an intervening basement membrane. Drugs perfused through the basal vascular channel crossed into an open apical well, where sampling and mass spectrometry showed transport correlating with lipophilicity, as reported in vivo. The device also displayed two clinically relevant phenotypes. Digoxin at a clinically toxic concentration reduced viability in the co-barrier by about half and doubled permeability. In a vascularized configuration, VEGF drove endothelial invasion of the RPE layer, as seen in neovascular AMD. The SiM-OBRB therefore satisfies basic design criteria for measurement of drug bioavailability, toxicity, and efficacy.