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Fractal analysis of polypoidal choroidal neovascularisation in age-related macular degeneration
  1. Rita Serra1,2,3,4,
  2. Florence Coscas3,4,
  3. Antonio Pinna5,
  4. Diogo Cabral6,
  5. Gabriel Coscas3,4,
  6. Eric H Souied4
  1. 1 Department of Surgical and Biomedical Sciences, University of Sassari, Sassari, Italy
  2. 2 Istituto di Ricerca Genetica e Biomedica (IRGB), CNR, Cittadella Universitaria di Cagliari, 09042, Monserrato (CA), Cagliari, Italy
  3. 3 Centre Ophtalmologique de l’Odéon, 113 bd Saint Germain, Paris, France
  4. 4 Department of Ophthalmology, Centre Hospitalier Intercommunal de Creteil University Paris Est Créteil, Créteil, France
  5. 5 Department of Medical, Surgical, and Experimental Sciences,, University of Sassari, Sassari, Italy
  6. 6 Instituto de Oftalmologia Dr. Gama Pinto, Lisboa, Portugal
  1. Correspondence to Florence Coscas, Centre Hospitalier Intercommunal de Créteil, Université Paris Est, 40 Avenue Verdun, 94010 Créteil, France; coscas.f{at}


Aim To describe optical coherence tomography angiography (OCTA) features of polypoidal choroidal neovascularisation (PCNV) secondary to age-related macular degeneration.

Methods A retrospective consecutive series of 51 patients with a diagnosis of PCNV, based on clinical and multimodal imaging, was analysed. All patients with PCNV underwent a comprehensive ophthalmological examination, including fluorescein and indocyanine green angiography, structural optical coherence tomography (OCT) and OCTA. Two blinded retinal specialists carefully reviewed OCTA slabs in order to assess the morphological patterns of PCNV lesions. Furthermore, fractal analysis of PCNV en face images on OCTA, including vascular perfusion density (VPD), fractal dimension (FD) and lacunarity (LAC), was performed.

Results Fifty-one PCNV eyes were included in the study. In all, the branching vascular network appeared hyper-reflective. Polyps showed two different patterns: in 34/51 (67%) eyes, they corresponded to hypo-reflective structures, whereas in the remaining 17 (33%) eyes, they appeared as hyper-reflective lesions. In all PCNV eyes, mean VPD, FD and LAC were 0.76±0.17%, 1.46±0.12 and 2.4±0.87, respectively. No significant difference was found between PCNVs showing a different OCTA pattern, in terms of quantitative OCTA parameters.

Conclusion Fractal analysis provides quantitative parameters demonstrating that PCNVs with different OCTA patterns share the same neovascular architecture and branching complexity. These new findings improve our ability to interpret OCTA slabs, opening new areas of discussion about this type of neovascular lesion.

  • Retina

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  • Correction notice This paper has been amended since it was published online. The first author's name was incorrectly transposed.

  • Contributors RS: research design, data acquisition, data analysis, manuscript preparation. FC: data acquisition, data analysis, research design, manuscript preparation. AP: data analysis, manuscript preparation. DC: data acquisition, data analysis. GC and EHS: research design, manuscript preparation.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Ethics approval This study was conducted in compliance with the tenets of the Declaration of Helsinki for research involving human subjects and was approved by the Paris and Creteil Institutional Review Committees (IRCs). No number/ID of the approval is provided because this was a retrospective study conducted on already available data. Included patients signed a written informed consent to participate in this observational study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplemental information.

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