Choroidal vascular changes in age-related macular degeneration: A protocol for systematic review and meta-analysis

Analyzing shifts in age-related macular degeneration research trends since 2014: A bibliometric study with triple-map Sankey diagrams (TMSD)

BACKGROUND

Age-related macular degeneration (AMD) is the primary cause of vision impairment in older adults, especially in developed countries. While many articles on AMD exist in the literature, none specifically delve into the trends based on document categories. While bibliometric studies typically use dual-map overlays to highlight new trends, these can become congested and unclear with standard formats (e.g., in CiteSpace software). In this study, we introduce a unique triple-map Sankey diagram (TMSD) to assess the evolution of AMD research. Our objective is to understand the nuances of AMD articles and show the effectiveness of TMSD in determining whether AMD research trends have shifted over the past decade.

METHODS

We collected 7465 articles and review pieces related to AMD written by ophthalmologists from the Web of Science core collection, accumulating article metadata from 2014 onward. To delve into the characteristics of these AMD articles, we employed various visualization methods, with a special focus on TMSD to track research evolution. We adopted the descriptive, diagnostic, predictive, and prescriptive analytics (DDPP) model, complemented by the follower-leading clustering algorithm (FLCA) for clustering analysis. This synergistic approach proved efficient in identifying and showcasing research focal points and budding trends using network charts within the DDPP framework.

RESULTS

Our findings indicate that: in countries, institutes, years, authors, and journals, the dominant entities were the United States, the University of Bonn in Germany, the year 2021, Dr Jae Hui Kim from South Korea, and the journal "Retina"; in accordance with the TMSD, AMD research trends have not changed significantly since 2014, as the top 4 categories for 3 citing, active, and cited articles have not changed, in sequence (Ophthalmology, Science & Technology - Other Topics, General & Internal Medicine, Pharmacology & Pharmacy).

CONCLUSION

The introduced TMSD, which incorporates the FLCA algorithm and features in 3 columns-cited, active, and citing research categories-offers readers clearer insights into research developments compared to the traditional dual-map overlays from CiteSpace software. Such tools are especially valuable for streamlining the visualization of the intricate data often seen in bibliometric studies.

Influence of scan direction on subfoveal choroidal vascularity index using optical coherence tomography

We investigated the influence of scan direction on subfoveal choroidal vascularity index (CVI) measurements using spectral-domain optical coherence tomography (SD-OCT) in young healthy subjects. Seventy-eight eyes of 41 healthy volunteers were included. Choroidal structures were obtained using SD-OCT with enhanced depth imaging (EDI) through radial scans at the center of the macula. The subfoveal choroidal images in the horizontal (0°), 45°, vertical (90°) and − 45° directions were recorded and CVIs were analyzed according to their respective directions using image binarization. Additionally, subfoveal choroidal thickness (SFCT), and axial eye length were measured. The SFCT and subfoveal CVI showed a negative correlation but were only significant for the 45° scan (Pearson’s r = − 0.262, P = 0.021). The axial eye length and subfoveal CVI had no significant correlation in any direction (all P > 0.05). In the Bland–Altman plot, the subfoveal CVI measurement showed high agreement among the four scan directions. When the SFCT was ≥ 300 µm, there was no difference in the measured values of the subfoveal CVI among the four scan directions; however, when the SFCT was < 300 µm, there was a significant difference in subfoveal CVI among the scan directions (one-way analysis of variance, F = 4.685, P = 0.004). In subfoveal CVI measurement, it is considered that the horizontal (0°) scan can represent the vertical (90°) or oblique (45°, − 45°) scans. However, when the SFCT is thinner, the subfoveal CVI in each direction of radial scan may vary significantly. Hence, caution is required in the interpretation.

OCT Biomarkers in Neovascular Age-Related Macular Degeneration: A Narrative Review

Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly people. Neovascular AMD (nAMD) is responsible for the majority of cases of severe visual loss in eyes with AMD. Optical coherence tomography (OCT) is the most widely used technology for the diagnosis and follow-up of nAMD patients, which is widely used to study and guide the clinical approach, as well as to predict and evaluate treatment response. The aim of this review is to describe and analyze various structural OCT-based biomarkers, which have practical value during both initial assessment and treatment follow-up of nAMD patients. While central retinal thickness has been the most common and one of the first OCT identified biomarkers, today, other qualitative and quantitative biomarkers provide novel insight into disease activity and offer superior prognostic value and better guidance for tailored therapeutic management. The key importance of retinal fluid compartmentalization (intraretinal fluid, subretinal fluid, and subretinal pigment epithelium (RPE) fluid) will be discussed firstly. In the second part, the structural alterations of different retinal layers in various stages of the disease (photoreceptors layer integrity, hyperreflective dots, outer retinal tubulations, subretinal hyperreflective material, and retinal pigment epithelial tears) will be analyzed in detail. The last part of the review will focus on how alterations of the vitreoretinal interface (vitreomacular adhesion and traction) and of the choroid (sub-RPE hyperreflective columns, prechoroidal clefts, choroidal caverns, choroidal thickness and choroidal volume, and choroidal vascular index) interact with nAMD progression. OCT technology is evolving very quickly, and new retinal biomarkers are continuously described. This up-to-date review article provides a comprehensive description on how structural OCT-based biomarkers provide a valuable tool to monitor the progression of the disease and the treatment response in nAMD patients. Thus, in this perspective, clinicians will be able to allocate hospital resources in the best possible way and tailor treatment to the individual patient's needs.