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Background Most neovascular age-related macular degeneration treatments involve long-term follow-up of disease activity. Home monitoring would reduce the burden on patients and those they depend on for transport, and release clinic appointments for other patients. The study aimed to evaluate three home-monitoring tests for patients to use to detect active neovascular age-related macular degeneration compared with diagnosing active neovascular age-related macular degeneration by hospital follow-up. Objectives There were five objectives: Estimate the accuracy of three home-monitoring tests to detect active neovascular age-related macular degeneration. Determine the acceptability of home monitoring to patients and carers and adherence to home monitoring. Explore whether inequalities exist in recruitment, participants’ ability to self-test and their adherence to weekly testing during follow-up. Provide pilot data about the accuracy of home monitoring to detect conversion to neovascular age-related macular degeneration in fellow eyes of patients with unilateral neovascular age-related macular degeneration. Describe challenges experienced when implementing home-monitoring tests. Design Diagnostic test accuracy cohort study, stratified by time since starting treatment. Setting Six United Kingdom Hospital Eye Service macular clinics (Belfast, Liverpool, Moorfields, James Paget, Southampton, Gloucester). Participants Patients with at least one study eye being monitored by hospital follow-up. Reference standard Detection of active neovascular age-related macular degeneration by an ophthalmologist at hospital follow-up. Index tests KeepSight Journal: paper-based near-vision tests presented as word puzzles. MyVisionTrack®: electronic test, viewed on a tablet device. MultiBit: electronic test, viewed on a tablet device. Participants provided test scores weekly. Raw scores between hospital follow-ups were summarised as averages. Results Two hundred and ninety-seven patients (mean age 74.9 years) took part. At least one hospital follow-up was available for 317 study eyes, including 9 second eyes that became eligible during follow-up, in 261 participants (1549 complete visits). Median testing frequency was three times/month. Estimated areas under receiver operating curves were < 0.6 for all index tests, and only KeepSight Journal summary score was significantly associated with the lesion activity (odds ratio = 3.48, 95% confidence interval 1.09 to 11.13, p = 0.036). Older age and worse deprivation for home address were associated with lower participation (χ2 = 50.5 and 24.3, respectively, p 6 and < 42 months earlier. We tried to recruit equal numbers by time since starting treatment in the first-treated study eye (6–17 months; 18–29 months; 30–41 months) to ensure test performance was estimated across this range of duration of nAMD. Patients were followed for at least 6 months. Reference standard The reference standard was the reviewing ophthalmologist’s decision about the activity status of a study eye at a HES monitoring visit, recorded as active, inactive or uncertain. There were no additional hospital visits for the study. Such decisions are usually based on clinical examination and the results of hospital-based retinal imaging investigations, for example, colour fundus photographs and ocular coherence tomograms (OCTs). The reference standard grouped uncertain with inactive judgements for analyses. Index tests Three home-monitoring (‘index’) tests were evaluated, spanning low to moderate cost and complexity. These were: KeepSight Journal (KSJ): a paper-based booklet of near-vision tests presented as word puzzles developed in the United States and adapted by the study team for use in the study. MyVisionTrack® (mVT®): electronic vision test, intended to be viewed on a tablet device. MultiBit (MBT): electronic vision test, intended to be viewed on a tablet device. Specific thresholds indicating a significant clinical change were not provided for any of index tests in advance by their developers. Outcomes The primary outcome was classification of a study eye at a monitoring visit as having active or inactive disease (active, inactive, uncertain), that is, the reviewing ophthalmologist’s decision. A secondary outcome (new reference standard) for Objective A was a change from inactive to active status from one management visit to the next. This was considered better to represent how home monitoring might be implemented. For Objective C, outcomes investigated were willingness in principle to participate; ability to carry out index tests; adherence to weekly testing. For Objective D, the outcome was conversion of a fellow eye to active nAMD as judged by an ophthalmologist, that is, same reference standard. For Objective E, the following outcomes were described as measures of the technical and logistical challenges identified during the study: Frequency and reason for incoming calls made to the helpline and outgoing calls made to participants. Frequency and duration of events leading to the digital tests being unavailable for testing. Other technical and logistical challenges. Objective B study recruitment and data collection Recruitment to the qualitative component began 3 months after the monitoring for neovascular age-related macular degeneration reactivation at home (MONARCH) study began recruiting. During the consent process for participation in the study, patients could consent to further contact from the qualitative research team to discuss participation in the qualitative study. Maximum variation sampling ensured a range of perspectives were captured in relation to: age (young-old 50–69 years and older-old > 70 years), gender, one or both eyes with nAMD, time since first treatment (defined as above) and adherence to home monitoring (test data from the two electronic tests were used to categorise participants into ‘regular’ testers and ‘irregular’ testers). Patients who declined to participate in MONARCH but provided consent to be contacted about the qualitative study, informal ‘carers’, supporters or significant others in the lives of patients and healthcare professionals who interacted with participants at study sites visits were also approached to gather their perspectives about the acceptability of home monitoring. Statistical analysis Objective A: The test accuracy of index tests was estimated by fitting a logistic regression model to predict the reference standard from summary test scores for the interval between monitoring visits, adjusting for participants’ baseline data. Accuracy was estimated for the primary outcome using all index test data, data only for the 4 weeks preceding the monitoring visit, the reference standard based on reading centre decisions made from OCT images and for the secondary outcome. Test scores were summarised as: means (MBT and mVT); median (KSJ reported near visual acuity (VA), ordinal six-point scale); proportions (KSJ reported VA, Amsler grid and household object appearance reported worse than baseline vs. same or better). All four scores were fitted in the KSJ model and a single area under the receiving operator curve (AUROC) was estimated. Separate models were fitted for each test for the primary outcome, the two sensitivity analyses and the secondary outcome. Model performance was quantified by the odds ratio (OR) for the index test summary score(s) and the estimate of the AUROC and their respective confidence intervals (CIs). AUROCs were based on predicted probabilities calculated using only the fixed effects in the models. Sensitivity, specificity, positive and negative predictive values and 95% CIs were calculated using cut-off thresholds corresponding to Youden’s index for each model, which minimises overall misclassifications. Average test scores above and below the thresholds were also calculated. Analyses took account of the structure within the data, that is, the nesting of visits and eyes within patients. Objective B: All interviews were audio-recorded and transcribed. A directed content analysis approach based on deductive and inductive coding was used. NVivo version 12 was used to manage data and facilitate the analysis process, which, in summary, included the following stages: (1) independent transcription, (2) data familiarisation, (3) independent coding, (4) development of an analytical framework, (5) indexing, (6) charting and (7) interpreting data. Objective C: Willingness in principle to participate was defined as an approached eligible patient agreeing to attend a research visit for training. Ability to perform an index test was defined as the proportion of monitoring visits for which some valid index test data were available. Adherence was defined as the proportion of weeks between monitoring visits for which some valid data for an index test were available. The ability and adherence models were performed for each test separately at the level of the patient. Regression models estimated associations of age, sex, Index of Multiple Deprivation (IMD), stratum of time since first diagnosis and baseline visual acuity at diagnosis on the outcomes of willingness to participate, ability to perform tests and adherence to weekly testing; models for the latter two outcomes were fitted for each index test. Associations were reported with 95% CIs. Analyses of adherence and ability took account of nesting of visits within participants. Objective D: The test accuracy of the index tests for the reference standard of an ophthalmologist’s classification of a fellow eye as having active disease at a monitoring visit, that is, conversion to active nAMD, was estimated by the same methods as described for Objective A. Two sensitivity analyses were carried out: (1) the same reference standard but using test data only for the 4 weeks preceding the management visit and (2) the alternative reference standard of classification of a fellow eye having active disease based on reading centre grading of OCTs carried out during the monitoring visits. Objective E: This objective used descriptive summary descriptive statistics only. Results The study recruited 297 patients (consented participants) between 21 August 2018 and 31 March 2020. Half of recruited participants were first treated for nAMD 6–17 months before consenting, 28% 18–29 months before consenting and 22% 30–41 months before consenting. At the end of the study, data for at least one monitoring visit after starting to use the index monitoring tests were available for 357 study eyes in 297 patients. Data were available for at least one complete monitoring visit after starting to use the index monitoring tests for 317 study eyes of 261 patients. More participants were women (58.6%). Participants’ mean age was 74.9 (6.6) years [standard deviation (SD)]. The mean visual acuity of study eyes (better seeing eyes if participants had two study eyes) was 0.2 (0.2) Logarithm of the minimum angle of resolution (LogMAR) (SD). Objective A: Median testing frequency was three times per month. In the primary analysis, estimated AUROCs were < 0.6 for all index tests, and only KSJ summary score was significantly associated with the lesion activity (OR = 3.48, 95% CI 1.09 to 11.13; p = 0.036). Estimated AUROCs were < 0.6 for all tests in both sensitivity analyses and for the secondary outcome of change from inactive to active status between adjacent management visits. Objective B: Two overarching meta-themes emerged from the qualitative studies related to acceptance or non-acceptance of home monitoring. Meta-theme 1 encompassed four main themes: (1) the role of home monitoring; (2) suitability of procedures and instruments; (3) experience of home monitoring; and (4) feasibility of home monitoring in usual practice. Meta-theme 2 consisted of one main theme covering key inhibitors to acceptability. The main factors influencing acceptability included a participant’s understanding about the purpose of home monitoring and their experience of using it. While home monitoring was generally seen as a relatively straightforward exercise to undertake and non-burdensome, training and ongoing support were regarded as essential to its success. Home monitoring was acceptable to patients and its potential to reduce clinic visits during non-active treatment phases was recognised. Objective C: A minority of patients who were approached were willing in principle to participate. Increasing age and worse deprivation index for home address were associated with being unwilling in principle to participate (χ2 = 50.5 and 24.3, respectively, both p ≤ 0.001). Recruiting site was also associated with willingness in principle to participate, believed to be due to sites adopting different strategies for approaching and recruiting patients. Increasing age and worse deprivation were not consistently associated with either being able to self-monitor with the index tests or adherence to weekly testing (χ2 for all tests 0.08 for ability and adherence, except for worse IMD being associated with better adherence for the KSJ, χ2 = 12.15, p = 0.016). Recruiting site was also associated with being able to test and adhering to weekly testing. Objective D: There were 132 fellow eyes with data from 544 monitoring visits, 17 of which (12.9%) had nAMD recorded at one or more management visits over about 100 participant-years. This rate of conversion was higher than expected based on epidemiological studies of conversion rates in unaffected fellow eyes, potentially due to study eyes having had nAMD longer ago. Some predictors could not be fitted in models and estimates of associations were imprecise. The no-test model predicted conversion better than for Objective A (AUROC = 0.73) and electronic tests did not increase this (AUROCs = 0.73 and 0.76 for MBT and mVT, respectively). The estimated AUROC for the KSJ was 0.85, due to a strong positive association of the household object summary score with conversion (OR 15.3, p = 0.036). Objective E: Despite two-thirds of the population having previously used a smartphone, there were still a variety of challenges experienced with the electronic devices while testing at home that contributed to both reduced adherence and ultimately withdrawals from the study. Strengths and limitations The study had several strengths. Estimates of the diagnostic test accuracy of index tests were at low risk of bias: the study population was appropriate for the intended use of the tests, and summary test scores were not available to ophthalmologists providing the reference standard, which was judged after the index test data were collected. Limitations A smaller-than-planned sample size (less than half the target number of monitoring visits); nonetheless, 95% CIs for AUROCs were narrow (± 0.04) and estimates were able to rule out tests providing adequate accuracy for diagnosing active nAMD to enable patients to be monitored without hospital review. Tests were sometimes not available for technical reasons that were beyond the control of the research team. The study had no control over monitoring visits and participants are likely to have reported their subjective visual experience to their consultants, which might have influenced the reference standard. We could not define test thresholds a priori, and instead estimated AUROCs. We did not compare AUROCs for tests due to their poor accuracy. The ways in which patients were approached and screened varied across sites, generating a site effect in analyses of potential inequalities; variations may have reflected the pre-conceptions of research staff regarding the capabilities of patients to use the electronic tests. Conclusions Based on the detection of lesion activity assessed by clinicians in the clinic, we have shown that none of the index tests provides acceptable test accuracy for home monitoring in this context. Associations of increasing age and deprivation index for home address with unwillingness in principle to participate despite provision of hardware highlight the potential for inequality with interventions of the kind evaluated. While a proportion of nAMD patients are willing and interested in the potential for home monitoring, substantial practical and technological issues are encountered in the implementation of such, requiring a significant support infrastructure, including a study helpline. Future work Future research should focus on the methodological challenge of efficiently evaluating mobile health technologies which deal with constantly emerging new technology. The clear evidence of inequalities in participation and retention should prompt future research on ways to encourage participant and adoption of mobile health technologies by underserved populations. Focus should also be placed on methods to improve adherence and retention in longitudinal studies involving electronic testing, particularly around the nature of feedback to participants. Trial registration This trial is registered as ISRCTN79058224. Funding This award was funded by the National Institute of Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 15/97/02) and is published in full in Health Technology Assessment; Vol. 28, No. 32. See the NIHR Funding and Awards website for further award information.

Abstract l-DOPA is deficient in the developing albino eye, resulting in abnormalities of retinal development and visual impairment. Ongoing retinal development after birth has also been demonstrated in the developing albino eye offering a potential therapeutic window in humans. To study whether human equivalent doses of l-DOPA/Carbidopa administered during the crucial postnatal period of neuroplasticity can rescue visual function, OCA C57BL/6 J-c2J OCA1 mice were treated with a 28-day course of oral l-DOPA/Carbidopa at 3 different doses from 15 to 43 days postnatal age (PNA) and for 3 different lengths of treatment, to identify optimum dosage and treatment length. Visual electrophysiology, acuity, and retinal morphology were measured at 4, 5, 6, 12 and 16 weeks PNA and compared to untreated C57BL/6 J (WT) and OCA1 mice. Quantification of PEDF, βIII-tubulin and syntaxin-3 expression was also performed. Our data showed impaired retinal morphology, decreased retinal function and lower visual acuity in untreated OCA1 mice compared to WT mice. These changes were diminished or eliminated when treated with higher doses of l-DOPA/Carbidopa. Our results demonstrate that oral l-DOPA/Carbidopa supplementation at human equivalent doses during the postnatal critical period of retinal neuroplasticity can rescue visual retinal morphology and retinal function, via PEDF upregulation and modulation of retinal synaptogenesis, providing a further step towards developing an effective treatment for albinism patients.

Abstract There are no disease-modifying treatments available for geographic atrophy (GA), the advanced form of dry age-related macular degeneration. Current murine models fail to fully recapitulate the features of GA and thus hinder drug discovery. Here we describe a novel mouse model of retinal degeneration with hallmark features of GA. We used an 810 nm laser to create a retinal lesion with central sparing (RLCS), simulating parafoveal atrophy observed in patients with progressive GA. Laser-induced RLCS resulted in progressive GA-like pathology with the development of a confluent atrophic lesion. We demonstrate significant changes to the retinal structure and thickness in the central unaffected retina over a 24-week post-laser period, confirmed by longitudinal optical coherence tomography scans. We further show characteristic features of progressive GA, including a gradual reduction in the thickness of the central, unaffected retina and of total retinal thickness. Histological changes observed in the RLCS correspond to GA pathology, which includes the collapse of the outer nuclear layer, increased numbers of GFAP + , CD11b + and FcγRI + cells, and damage to cone and rod photoreceptors. We demonstrate a laser-induced mouse model of parafoveal GA progression, starting at 2 weeks post-laser and reaching confluence at 24 weeks post-laser. This 24-week time-frame in which GA pathology develops, provides an extended window of opportunity for proof-of-concept evaluation of drugs targeting GA. This time period is an added advantage compared to several existing models of geographic atrophy.

Purpose: To study the individual course of retinal changes caused by healthy aging using deep learning. Design: Retrospective analysis of a large data set of retinal OCT images. Participants: A total of 85 709 adults between the age of 40 and 75 years of whom OCT images were acquired in the scope of the UK Biobank population study. Methods: We created a counterfactual generative adversarial network (GAN), a type of neural network that learns from cross-sectional, retrospective data. It then synthesizes high-resolution counterfactual OCT images and longitudinal time series. These counterfactuals allow visualization and analysis of hypothetical scenarios in which certain characteristics of the imaged subject, such as age or sex, are altered, whereas other attributes, crucially the subject’s identity and image acquisition settings, remain fixed. Main Outcome Measures: Using our counterfactual GAN, we investigated subject-specific changes in the retinal layer structure as a function of age and sex. In particular, we measured changes in the retinal nerve fiber layer (RNFL), combined ganglion cell layer plus inner plexiform layer (GCIPL), inner nuclear layer to the inner boundary of the retinal pigment epithelium (INL-RPE), and retinal pigment epithelium (RPE). Results: Our counterfactual GAN is able to smoothly visualize the individual course of retinal aging. Across all counterfactual images, the RNFL, GCIPL, INL-RPE, and RPE changed by −0.1 μm ± 0.1 μm, −0.5 μm ± 0.2 μm, −0.2 μm ± 0.1 μm, and 0.1 μm ± 0.1 μm, respectively, per decade of age. These results agree well with previous studies based on the same cohort from the UK Biobank population study. Beyond population-wide average measures, our counterfactual GAN allows us to explore whether the retinal layers of a given eye will increase in thickness, decrease in thickness, or stagnate as a subject ages. Conclusion: This study demonstrates how counterfactual GANs can aid research into retinal aging by generating high-resolution, high-fidelity OCT images, and longitudinal time series. Ultimately, we envision that they will enable clinical experts to derive and explore hypotheses for potential imaging biomarkers for healthy and pathologic aging that can be refined and tested in prospective clinical trials. Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Abstract To evaluate the influence AMD risk genomic variants have on macular thickness in the normal population. UK Biobank participants with no significant ocular history were included using the UK Biobank Resource (project 2112). Spectral-domain optical coherence tomography (SD-OCT) images were taken and segmented to define retinal layers. The influence of AMD risk single-nucleotide polymorphisms (SNP) on retinal layer thickness was analysed. AMD risk associated SNPs were strongly associated with outer-retinal layer thickness. The inner-segment outer segment (ISOS)-retinal pigment epithelium (RPE) thickness measurement, representing photoreceptor outer segments was most significantly associated with the cumulative polygenic risk score, composed of 33 AMD-associated variants, resulting in a decreased thickness (p = 1.37 × 10–67). Gene–gene interactions involving the NPLOC4-TSPAN10 SNP rs6565597 were associated with significant changes in outer retinal thickness. Thickness of outer retinal layers is highly associated with the presence of risk AMD SNPs. Specifically, the ISOS-RPE measurement. Changes to ISOS-RPE thickness are seen in clinically normal individuals with AMD risk SNPs suggesting structural changes occur at the macula prior to the onset of disease symptoms or overt clinical signs.

Age-related macular degeneration (AMD) is linked to 2 main disparate genetic pathways: a chromosome 10 risk locus and the alternative pathway (AP) of complement. Rare genetic variants in complement factor H (CFH; FH) and factor I (CFI; FI) are associated with AMD. FH acts as a soluble cofactor to facilitate FI’s cleavage and inactivation of the central molecule of the AP, C3b. For personalised treatment, sensitive assays are required to define the functional significance of individual AP genetic variants. Generation of recombinant FI for functional analysis has thus far been constrained by incomplete processing resulting in a preparation of active and inactive protein. Using an internal ribosomal entry site (IRES)-Furin-CFI expression vector, fully processed FI was generated with activity equivalent to serum purified FI. By generating FI with an inactivated serine protease domain (S525A FI), a real-time surface plasmon resonance assay of C3b:FH:FI complex formation for characterising variants in CFH and CFI was developed and correlated well with standard assays. Using these methods, we further demonstrate that patient-associated rare genetic variants lacking enzymatic activity (e.g. CFI I340T) may competitively inhibit the wild-type FI protein. The dominant negative effect identified in inactive factor I variants could impact on the pharmacological replacement of FI currently being investigated for the treatment of dry AMD.

Background: This report describes the study design and baseline characteristics of patients with Stargardt disease (STGD1) enrolled in the STArgardt Remofuscin Treatment Trial (STARTT). Methods: In total, 87 patients with genetically confirmed STGD1 were randomized in a double-masked, placebo-controlled proof of concept trial to evaluate the safety and efficacy of 20 milligram oral remofuscin for 24 months. The primary outcome measure is change in mean quantitative autofluorescence value of an 8-segment ring centred on the fovea (qAF8). Secondary efficacy variables are best corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), mesopic microperimetry (mMP), spectral domain optical coherence tomography (SD-OCT), reading speed on Radner reading charts, and patient-reported visual function as assessed by the National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25) and Functional Reading Independence (FRI) Index. Results: Mean age of participants was 35±11 years with 49 (56%) female. Median qAF8 value was 438 Units (range 210-729). Median BCVA and LLVA in decimal units were 0.50 (range 0.13-0.80) and 0.20 (range 0.06-0.63), respectively. The median of the mean retinal sensitivity with mMP was 20.4 dB (range 0.0-28.8). SD-OCT showed median central subfield retinal thickness of 142 µm (range 72-265) and median macular volume of 1.65 mm3 (range 1.13-2.19). Compared to persons without vision impairment, both reading performance and patient-reported visual function were significantly lower (p

Landmark genetic studies have revealed the effect of complement biology and its regulation on the pathogenesis of age-related macular degeneration (AMD). Limited phase 3 clinical trial data showing a benefit of complement inhibition in AMD raises the prospect of more complex mediators at play. Substantial evidence supports the role of para-inflammation in maintaining homeostasis in the retina and choroid. With increasing age, a decline in immune system regulation, known as immunosenescence, has been shown to alter the equilibrium maintained by para-inflammation. The altered equilibrium results in chronic, sterile inflammation with aging, termed ‘inflammaging’, including in the retina and choroid. The chronic inflammatory state in AMD is complex, with contributions from cells of the innate and adaptive branches of the immune system, sometimes with overlapping features, and the interaction of their secretory products with retinal cells such as microglia and retinal pigment epithelium (RPE), extracellular matrix and choroidal vascular endothelial cells. In this review, the chronic inflammatory state in AMD will be explored by immune cell type, with a discussion of factors that will need to be overcome in the development of curative therapies.

Primary open-angle glaucoma (POAG) is highly heritable, yet not well understood from a genetic perspective. Here, the authors perform a meta-analysis of genome-wide association studies in 34,179 POAG cases, identifying 44 previously unreported risk loci and mapping effects across multiple ethnicities.

Abstract Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of ‘real-world’ diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.

While anti-angiogenic therapies for wet age-related macular degeneration (AMD) are effective for many patients, they require multiple injections and are expensive and prone to complications. Gene therapy could be an elegant solution for this problem by providing a long-term source of anti-angiogenic proteins after a single administration. Another potential issue with current therapeutic proteins containing a fragment crystallizable (Fc) domain (such as whole antibodies like bevacizumab) is the induction of an unwanted immune response. In wet AMD, a low level of inflammation is already present, so to avoid exacerbation of disease by the therapeutic protein, we propose single-chain fragment variable (scFv) antibodies, which lack the Fc domain, as a safer alternative. To investigate the feasibility of this, anti-vascular endothelial growth factor (VEGF)-blocking antibodies in two formats were produced and tested in vitro and in vivo. The scFv transgene was then cloned into an adeno-associated virus (AAV) vector. A therapeutic effect in a mouse model of choroidal neovascularization (CNV) was demonstrated with antibodies in both scFv and immunoglobulin G1 (IgG1) formats (p < 0.04). Importantly, the scFv anti-VEGF antibody expressed from an AAV vector also had a significant beneficial effect (p = 0.02), providing valuable preclinical data for future translation to the clinic. Keywords: AAV, vector, gene therapy, AMD, CNV mouse model, anti-VEGF scFv antibodies, single-chain, angiogenesis

The retinal pigment epithelium (RPE) plays a key role in the pathogenesis of several blinding retinopathies. Alterations to RPE structure and function are reported in Age-related Macular Degeneration, Stargardt and Best disease as well as pattern dystrophies. However, the precise role of RPE cells in disease aetiology remains incompletely understood. Many studies into RPE pathobiology have utilised animal models, which only recapitulate limited disease features. Some studies are also difficult to carry out in animals as the ocular space remains largely inaccessible to powerful microscopes. In contrast, in-vitro models provide an attractive alternative to investigating pathogenic RPE changes associated with age and disease. In this article we describe the step-by-step approach required to establish an experimentally versatile in-vitro culture model of the outer retina incorporating the RPE monolayer and supportive Bruch’s membrane (BrM). We show that confluent monolayers of the spontaneously arisen human ARPE-19 cell-line cultured under optimal conditions reproduce key features of native RPE. These models can be used to study dynamic, intracellular and extracellular pathogenic changes using the latest developments in microscopy and imaging technology. We also discuss how RPE cells from human foetal and stem-cell derived sources can be incorporated alongside sophisticated BrM substitutes to replicate the aged/diseased outer retina in a dish. The work presented here will enable users to rapidly establish a realistic in-vitro model of the outer retina that is amenable to a high degree of experimental manipulation which will also serve as an attractive alternative to using animals. This in-vitro model therefore has the benefit of achieving the 3Rs objective of reducing and replacing the use of animals in research. As well as recapitulating salient structural and physiological features of native RPE, other advantages of this model include its simplicity, rapid set-up time and unlimited scope for detailed single-cell resolution and matrix studies.

Age-related macular degeneration (AMD) causes irreversible loss of central vision for which there is no effective treatment. Incipient pathology is thought to occur in the retina for many years before AMD manifests from midlife onwards to affect a large proportion of the elderly. Although genetic as well as non-genetic/environmental risks are recognized, its complex aetiology makes it difficult to identify susceptibility, or indeed what type of AMD develops or how quickly it progresses in different individuals. Here we summarize the literature describing how the Alzheimer's-linked amyloid beta (Aβ) group of misfolding proteins accumulate in the retina. The discovery of this key driver of Alzheimer's disease in the senescent retina was unexpected and surprising, enabling an altogether different perspective of AMD. We argue that Aβ fundamentally differs from other substances which accumulate in the ageing retina, and discuss our latest findings from a mouse model in which physiological amounts of Aβ were subretinally-injected to recapitulate salient features of early AMD within a short period. Our discoveries as well as those of others suggest the pattern of Aβ accumulation and pathology in donor aged/AMD tissues are closely reproduced in mice, including late-stage AMD phenotypes, which makes them highly attractive to study dynamic aspects of Aβ-mediated retinopathy. Furthermore, we discuss our findings revealing how Aβ behaves at single-cell resolution, and consider the long-term implications for neuroretinal function. We propose Aβ as a key element in switching to a diseased retinal phenotype, which is now being used as a biomarker for late-stage AMD.

Alzheimer’s disease-associated amyloid beta (Aβ) proteins accumulate in the outer retina with increasing age and in eyes of age-related macular degeneration (AMD) patients. To study Aβ-induced retinopathy, wild-type mice were injected with nanomolar human oligomeric Aβ1-42, which recapitulate the Aβ burden reported in human donor eyes. In vitro studies investigated the cellular effects of Aβ in endothelial and retinal pigment epithelial (RPE) cells. Results show subretinal Aβ-induced focal AMD-like pathology within 2 weeks. Aβ exposure caused endothelial cell migration, and morphological and barrier alterations to the RPE. Aβ co-localized to late-endocytic compartments of RPE cells, which persisted despite attempts to clear it through upregulation of lysosomal cathepsin B, revealing a novel mechanism of lysosomal impairment in retinal degeneration. The rapid upregulation of cathepsin B was out of step with the prolonged accumulation of Aβ within lysosomes, and contrasted with enzymatic responses to internalized photoreceptor outer segments (POS). Furthermore, RPE cells exposed to Aβ were identified as deficient in cargo-carrying lysosomes at time points that are critical to POS degradation. These findings imply that Aβ accumulation within late-endocytic compartments, as well as lysosomal deficiency, impairs RPE function over time, contributing to visual defects seen in aging and AMD eyes.

PURPOSE:To determine whether visual-tactile sensory substitution utilizing the Low-vision Enhancement Optoelectronic (LEO) Belt prototype is suitable as a new visual aid for those with reduced peripheral vision by assessing mobility performance and user opinions. METHODS:Sighted subjects (n = 20) and subjects with retinitis pigmentosa (RP) (n = 6) were recruited. The LEO Belt was evaluated on two cohorts: normally sighted subjects wearing goggles to artificially reduce peripheral vision to simulate stages of RP progression, and subjects with advanced visual field limitation from RP. Mobility speed and accuracy was assessed using simple mazes, with and without the LEO Belt, to determine its usefulness across disease severities and lighting conditions. RESULTS:Sighted subjects wearing most narrowed field goggles simulating most advanced RP had increased mobility accuracy (44% mean reduction in errors, p = 0.014) and self-reported confidence (77% mean increase, p = 0.004) when using the LEO Belt. Additionally, use of LEO doubled mobility accuracy for RP subjects with remaining visual fields between 10° and 20°. Further, in dim lighting, confidence scores for this group also doubled. By patient reported outcomes, subjects largely deemed the device comfortable (100%), easy to use (92.3%) and thought it had potential future benefit as a visual aid (96.2%). However, regardless of severity of vision loss or simulated vision loss, all subjects were slower to complete the mazes using the device. CONCLUSIONS:The LEO Belt improves mobility accuracy and therefore confidence in those with severely restricted peripheral vision. The LEO Belt's positive user feedback suggests it has potential to become the next generation of visual aid for visually impaired individuals. Given the novelty of this approach, we expect navigation speeds may improve with experience.