Costs and cost-effectiveness of the Kerala pilot screening programme for diabetic retinopathy in the public health system.

BACKGROUND/OBJECTIVES: The Government of Kerala initiated a pilot screening programme for diabetic retinopathy in 16 Family Health Centres in Thiruvananthapuram district in 2019 in collaboration with the ORNATE India project. The evaluation of this pilot included a study of its costs and cost-effectiveness to inform decisions about extending the programme throughout Kerala. SUBJECTS/METHODS: The participants comprise all 5307 people who were screened for diabetic retinopathy under the pilot programme for whom data could be collected. RESULTS: The costs of the pilot programme are estimated at INR 11.3 million (including INR 1.9 million costs to individuals) and the benefits at 514 QALYs, slightly over one QALY per person treated. The cost per QALY was INR 22,000, which is well below India's Gross National Income per person. CONCLUSIONS: Kerala's 2019 pilot screening programme for diabetic retinopathy was highly cost-effective.

A Comparison of Optical Coherence Tomography Angiography Metrics and Artifacts on Scans of Different Sizes in Diabetic Macular Ischemia: The effect of different size scans on DMI evaluation.

PURPOSE: Changes in the foveal avascular zone (FAZ) metrics over time are key outcome measures for clinical trials in diabetic macular ischemia (DMI). However, artifacts and automatically delineated FAZ measurements may influence the results. We aimed to compare the artifact frequency and FAZ metrics on 3 × 3 versus 6 × 6 mm optical coherence tomography angiography (OCTA) macular scans in patients with DMI. DESIGN: Prospective, comparative image quality analysis with one-year follow-up. METHODS: Patients with diabetic retinopathy (DR) were recruited if they presented with OCTA evidence of DMI, defined as an automated FAZ (aFAZ) ≥0.5 mm2 or parafoveal capillary nonperfusion (CNP) ≥1 quadrant if the aFAZ <0.5 mm2. Only those who had both size scans were included in the analysis. The types of artifacts and FAZ delineation errors were graded before manual correction. After excluding scans with poor quality, the aFAZ, corrected FAZ (cFAZ), whole image superficial vessel density (wiSVD), and whole image deep vessel density (wiDVD) were compared on both size scans. RESULTS: Fifty-seven patients (81 eyes) with paired OCTA 3 × 3 and 6 × 6 mm scans at baseline were included in the image quality analysis. The 6 × 6 mm scan presented with more severe motion artifact (P = .02). Conversely, the 3 × 3 mm scans were more susceptible to mild decentration (P = .009). After removing all the poor-quality images, 55 eyes with both size scans entered the longitudinal analysis. The 3 × 3 mm FAZ was significantly larger than the 6 × 6 mm FAZ using either aFAZ or cFAZ (both P < .05). In contrast, the 6 × 6 mm wiSVD and wiDVD were remarkably higher than those on the 3 × 3 mm scans (both P < .001). There was a steady increase in cFAZ over one year on both size scans (both P < .01). However, the 3 × 3 mm aFAZ decreased numerically at 52 weeks (P = .02). After reviewing all the scans, poor identification of parafoveal CNP was the most common reason for erroneous aFAZ delineation. CONCLUSIONS: In DMI, the FAZ metrics are best evaluated on the 3 × 3 scan due to better resolution. However, manual correction of the FAZ margin is needed. The frequency of artifacts and aFAZ delineation errors suggest that further technical refinement is required.

Correlation of gut microbial diversity to sight-threatening diabetic retinopathy.

PURPOSE: To determine the association of gut microbiome diversity and sight-threatening diabetic retinopathy (STDR) amongst patients with pre-existing diabetes. METHODS: A cross-sectional study was performed, wherein 54 participants selected in total were placed into cases cohort if diagnosed with STDR and those without STDR but had a diagnosis of diabetes mellitus of at least 10-year duration were taken as controls. Statistical analysis comparing the gut microbial alpha diversity between cases and control groups as well as patients differentiated based on previously hypothesized Bacteroidetes/Firmicutes(B/F) ratio with an optimal cut-off 1.05 to identify patients with STDR were performed. RESULTS: Comparing gut microbial alpha diversity did not show any difference between cases and control groups. However, statistically significant difference was noted amongst patients with B/F ratio ≥1.05 when compared to B/F ratio < 1.05; ACE index [Cut-off < 1.05:773.83 ± 362.73; Cut-off > 1.05:728.03 ± 227.37; p-0.016]; Chao1index [Cut-off < 1.05:773.63 ± 361.88; Cut-off > 1.05:728.13 ± 227.58; p-0.016]; Simpson index [Cut-off < 1.05:0.998 ± 0.001; Cut-off > 1.05:0.997 ± 0.001; p-0.006]; Shannon index [Cut-off < 1.05:6.37 ± 0.49; Cut-off > 1.05:6.10 ± 0.43; p-0.003]. Sub-group analysis showed that cases with B/F ratio ≥ 1.05, divided into proliferative diabetic retinopathy (PDR) and clinically significant macular edema (CSME), showed decreased diversity compared to controls (B/F ratio < 1.05). For PDR, all four diversity indices significantly decreased (p < 0.05). However, for CSME, only Shannon and Simpson indices showed significant decrease in diversity (p < 0.05). CONCLUSIONS: Based on clinical diagnosis, decreasing gut microbial diversity was observed among patients with STDR, although not statistically significant. When utilizing B/F ratio, the decreasing gut microbial diversity in STDR patients seems to be associated due to species richness and evenness in PDR when compared to decreasing species richness in CSME.

Pachychoroid disease: review and update.

The pachychoroid disease spectrum is a phenotype characterized by alterations in choroidal vasculature which result in outer retinal and choriocapillaris damage and visual loss. The presence of pachyvessels is one of the key features of the pachychoroid phenotype. Recent imaging studies suggest that pachyvessels may form because of choroidal venous congestion in one or more quadrants. The formation of intervortex anastomosis may function as a compensatory mechanism to dissipate the increased venous pressure, while outflow obstruction has been hypothesized to occur at the site of the vortex vein exiting the sclera. This review aims to summarize recent imaging findings and discuss evolution in the understanding of pathogenesis of the pachychoroid disease spectrum. We have summarized notable treatment trials in central serous chorioretinopathy and polypoidal choroidal vasculopathy and included an update of the current diagnostic and management strategies of the entities that are part of the pachychoroid disease spectrum.

Dual pathway inhibition with faricimab for previously treated neovascular age-related macular degeneration and diabetic macular oedema: guidance from a UK panel of retina specialists.

BACKGROUND/OBJECTIVES: Some eyes with neovascular age-related macular degeneration (nAMD) and centre-involving diabetic macular oedema (DMO) fail to respond sufficiently or lose response over time to standard of care intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy. This paper explores clinical scenarios for switching to dual action angiopoietin-2 (Ang-2)/VEGF-A inhibitor faricimab (Vabysmo, Roche Products Limited) in previously anti-VEGF-treated patients. METHODS: A national steering group meeting of UK retina specialists was held in London on 27 October 2023. Clinician practice and experience were reviewed together with pivotal clinical trial data and early findings from real-world settings. Roche Products Limited facilitated and funded the meeting. RESULTS: While there is no standardised protocol for identifying suboptimal response, the authors review relevant clinical biomarkers of disease activity used in routine clinical practice to determine patient response and guide treatment decisions. Common reasons identified for considering a change of treatment were lack of efficacy demonstrated by suboptimal anatomic or visual improvement and insufficient durability of response. The panel outline strategies for switching to faricimab among eligible patients with a prior anti-VEGF treatment history, with initial monthly loading doses or maintaining the previous treatment interval before attempting to extend, that may be integrated into current treat-and-extend (T&E) clinical pathways for treating patients with nAMD and DMO. General considerations for switching between treatments are also reviewed. CONCLUSION: Clinicians may consider a treatment switch to faricimab in nAMD and DMO patients who have suboptimal disease control or insufficient durability of response on initial anti-VEGF therapy.

Deep Learning-Based Clustering of OCT Images for Biomarker Discovery in Age-Related Macular Degeneration (PINNACLE Study Report 4).

Purpose: We introduce a deep learning-based biomarker proposal system for the purpose of accelerating biomarker discovery in age-related macular degeneration (AMD). Design: Retrospective analysis of a large data set of retinal OCT images. Participants: A total of 3456 adults aged between 51 and 102 years whose OCT images were collected under the PINNACLE project. Methods: Our system proposes candidates for novel AMD imaging biomarkers in OCT. It works by first training a neural network using self-supervised contrastive learning to discover, without any clinical annotations, features relating to both known and unknown AMD biomarkers present in 46 496 retinal OCT images. To interpret the learned biomarkers, we partition the images into 30 subsets, termed clusters, that contain similar features. We conduct 2 parallel 1.5-hour semistructured interviews with 2 independent teams of retinal specialists to assign descriptions in clinical language to each cluster. Descriptions of clusters achieving consensus can potentially inform new biomarker candidates. Main Outcome Measures: We checked if each cluster showed clear features comprehensible to retinal specialists, if they related to AMD, and how many described established biomarkers used in grading systems as opposed to recently proposed or potentially new biomarkers. We also compared their prognostic value for late-stage wet and dry AMD against an established clinical grading system and a demographic baseline model. Results: Overall, both teams independently identified clearly distinct characteristics in 27 of 30 clusters, of which 23 were related to AMD. Seven were recognized as known biomarkers used in established grading systems, and 16 depicted biomarker combinations or subtypes that are either not yet used in grading systems, were only recently proposed, or were unknown. Clusters separated incomplete from complete retinal atrophy, intraretinal from subretinal fluid, and thick from thin choroids, and, in simulation, outperformed clinically used grading systems in prognostic value. Conclusions: Using self-supervised deep learning, we were able to automatically propose AMD biomarkers going beyond the set used in clinically established grading systems. Without any clinical annotations, contrastive learning discovered subtle differences between fine-grained biomarkers. Ultimately, we envision that equipping clinicians with discovery-oriented deep learning tools can accelerate the discovery of novel prognostic biomarkers. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Predict and Protect: Evaluating the Double-Layer Sign in Age-Related Macular Degeneration.

INTRODUCTION: Advanced age-related macular degeneration (AMD) is a major cause of vision loss. Therefore, there is interest in precursor lesions that may predict or prevent the onset of advanced AMD. One such lesion is a shallow separation of the retinal pigment epithelium (RPE) and Bruch's membrane (BM), which is described by various terms, including double-layer sign (DLS). METHODS: In this article, we aim to examine and clarify the different terms referring to shallow separation of the RPE and BM. We also review current evidence on the outcomes associated with DLS: firstly, whether DLS is predictive of exudative neovascular AMD; and secondly, whether DLS has potential protective properties against geographic atrophy. RESULTS: The range of terms used to describe a shallow separation of the RPE and BM reflects that DLS can present with different characteristics. While vascularised DLS appears to protect against atrophy but can progress to exudation, non-vascularised DLS is associated with an increased risk of atrophy. Optical coherence tomography (OCT) angiography (OCTA) is the principal method for identifying and differentiating various forms of DLS. If OCTA is unavailable or not practically possible, simplified classification of DLS as thick or thin, using OCT, enables the likelihood of vascularisation to be approximated. Research is ongoing to automate DLS detection by applying deep-learning algorithms to OCT scans. CONCLUSIONS: The term DLS remains applicable for describing shallow separation of the RPE and BM. Detection and classification of this feature provides valuable information regarding the risk of progression to advanced AMD. However, the appearance of DLS and its value in predicting AMD progression can vary between patients. With further research, individualised risks can be confirmed to inform appropriate treatment.

Age-related macular degeneration (AMD) is an eye disease that may develop in older people, usually those aged over 60 years. Early in the disease, people often do not show any symptoms, but as the disease progresses, vision loss may occur. The advanced forms of AMD are called neovascular AMD (also called "wet" AMD) and advanced dry AMD (called geographic atrophy; GA). It is important to identify features and signs on eye scans that can help to predict if someone with AMD will develop an advanced form of the disease because this will help doctors plan the most appropriate treatment. One such feature on eye scans is the double-layer sign (DLS). In this article, we summarise the different names used for DLS, and assess if having a DLS increases the likelihood of someone with early AMD developing wet AMD or GA. We conclude that how DLS looks varies between people, which leads to DLS being called by various names. Someone with early AMD and a DLS containing blood vessels may be more likely to develop wet AMD; whereas someone with early AMD and a DLS without blood vessels may be more likely to develop GA. Taking photos of the eye using optical coherence tomography angiography imaging is the main method of identifying DLS and confirming whether it contains blood vessels.

Metadata-enhanced contrastive learning from retinal optical coherence tomography images.

Deep learning has potential to automate screening, monitoring and grading of disease in medical images. Pretraining with contrastive learning enables models to extract robust and generalisable features from natural image datasets, facilitating label-efficient downstream image analysis. However, the direct application of conventional contrastive methods to medical datasets introduces two domain-specific issues. Firstly, several image transformations which have been shown to be crucial for effective contrastive learning do not translate from the natural image to the medical image domain. Secondly, the assumption made by conventional methods, that any two images are dissimilar, is systematically misleading in medical datasets depicting the same anatomy and disease. This is exacerbated in longitudinal image datasets that repeatedly image the same patient cohort to monitor their disease progression over time. In this paper we tackle these issues by extending conventional contrastive frameworks with a novel metadata-enhanced strategy. Our approach employs widely available patient metadata to approximate the true set of inter-image contrastive relationships. To this end we employ records for patient identity, eye position (i.e. left or right) and time series information. In experiments using two large longitudinal datasets containing 170,427 retinal optical coherence tomography (OCT) images of 7912 patients with age-related macular degeneration (AMD), we evaluate the utility of using metadata to incorporate the temporal dynamics of disease progression into pretraining. Our metadata-enhanced approach outperforms both standard contrastive methods and a retinal image foundation model in five out of six image-level downstream tasks related to AMD. We find benefits in both a low-data and high-data regime across tasks ranging from AMD stage and type classification to prediction of visual acuity. Due to its modularity, our method can be quickly and cost-effectively tested to establish the potential benefits of including available metadata in contrastive pretraining.

Health transition and eye care policy planning for people with diabetic retinopathy in south Asia.

The prevalence of type 2 diabetes (T2D), associated systemic disorders, diabetic retinopathy (DR) and current health policies in south Asian countries were analysed to assess country-specific preparedness to meet the 2030 Sustainable Development Goals. The south Asian countries were classified by human development index, socio-demographic index, multidimensional poverty indices, and eye health resources for epidemiological resource-level analysis. In south Asia, the prevalence of diagnosed and undiagnosed T2D in adults aged 40 years or above, was higher in Pakistan (26.3%) and Afghanistan (71.4%), respectively; India has the highest absolute number of people with DR, and Afghanistan has the highest prevalence of DR (50.6%). In this region, out-of-pocket spending is high (∼77%). This Health Policy is a situational analysis of data available on the prevalence of DR and common eye diseases in people with T2D in south Asia and available resources to suggest tailored health policies to local needs. The common issues in the region are insufficient human resources for eye health, unequal distribution of available workforce, and inadequate infrastructure. Addressing these challenges of individuals with T2D and DR, a 10-point strategy is suggested to improve infrastructure, augment human resources, reduce out-of-pocket spending, employ targeted screening, and encourage public-private partnerships.

The effect of four loading intravitreal aflibercept injections on macular fluid in treatment-naïve neovascular age-related macular degeneration.

PURPOSE: To evaluate the effect of four versus three loading aflibercept injections on macular fluid resolution and visual acuity (VA) in exudative neovascular AMD (nAMD). METHODS: Multicentre, retrospective cohort study of treatment naïve nAMD eyes undergoing 3 versus 4 loading doses of aflibercept. Change in VA and fluid resolution on optical coherence tomography (OCT), were evaluated at 8 weeks post loading. The primary outcome was proportion of patients with no intraretinal (IRF) and/or subretinal (SRF) fluid at central 1 mm and whole macula at 8 weeks after loading. Data were summarised with mean ± SD for continuous variables, and n (%) for categorical variables. RESULTS: Data from 995 patients was analysed (355 patients - 4 loading doses and 640-3 loading doses). At 8 weeks post 4 loading doses proportion of eyes with neither IRF nor SRF, no IRF and no SRF were 62.8%, 88.7% and 79.2% at fovea versus 56.1%, 87.9% and 69.9% in the whole macula, respectively. Fluid resolution at both fovea and macula were significantly higher in eyes with 4 loading injections versus 3 (p = 0.0001). The mean VA change was +4.0 (±11.3) and +5.4(±13.3) letters for 3 and 4 loading doses groups (p = 0.09). CONCLUSION: Four loading dose injections of aflibercept results in higher proportion of eyes with total fluid resolution in the central subfield and total macular scan when compared to those receiving 3 loading dose injections at 8 weeks post loading phase. However, the better drying effect of 4th loading dose does not translate into better short-term VA outcomes.

Acceptability of Home Monitoring for Neovascular Age-Related Macular Degeneration Reactivation: A Qualitative Study.

This study formed part of a diagnostic test accuracy study to quantify the ability of three index home monitoring (HM) tests (one paper-based and two digital tests) to identify reactivation in Neovascular age-related macular degeneration (nAMD). The aim of the study was to investigate views about acceptability and explore adherence to weekly HM. Semi-structured interviews were held with 98 patients, family members, and healthcare professionals. A thematic approach was used which was informed by theories of technology acceptance. Various factors influenced acceptability including a patient's understanding about the purpose of monitoring. Training and ongoing support were regarded as essential for overcoming unfamiliarity with digital technology. Findings have implications for implementation of digital HM in the care of older people with nAMD and other long-term conditions.

A new population for primary prevention of retinal diseases; a step toward improved global eye health beyond diabetes and prediabetes.

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Exploring the fragility of meta-analyses in ophthalmology: a systematic review.

OBJECTIVE: The fragility index (FI) of a meta-analysis evaluates the extent that the statistical significance can be changed by modifying the event status of individuals from included trials. Understanding the FI improves the interpretation of the results of meta-analyses and can help to inform changes to clinical practice. This review determined the fragility of ophthalmology-related meta-analyses. METHODS: Meta-analyses of randomized controlled trials with binary outcomes published in a journal classified as 'Ophthalmology' according to the Journal Citation Report or an Ophthalmology-related Cochrane Review were included. An iterative process determined the FI of each meta-analysis. Multivariable linear regression modeling evaluated the relationship between the FI and potential predictive factors in statistically significant and non-significant meta-analyses. RESULTS: 175 meta-analyses were included. The median FI was 6 (Q1-Q3: 3-12). This meant that moving 6 outcomes from one group to another would reverse the study's findings. The FI was 1 for 18 (10.2%) of the included meta-analyses and was ≤5 for 75 (42.4%) of the included meta-analyses. The number of events (p < 0.001) and the p-value (p < 0.001) were the best predictors of the FI in both significant and non-significant meta-analyses. CONCLUSION: The statistical significance of meta-analyses in ophthalmology often hinges on the outcome of a few patients. The number of events and the p-value are the most important factors in determining the fragility of the evidence. The FI is an easily interpretable measure that can supplement the reader's understanding of the strength of the evidence being presented. PROSPERO REGISTRATION: CRD42022377589.