Novel biomarker of sphericity and cylindricity indices in volume-rendering optical coherence tomography angiography in normal and diabetic eyes: a preliminary study

  • Peter M. MalocaEmail author
  • Richard F. Spaide
  • Emanuel Ramos de Carvalho
  • Harald P. Studer
  • Pascal W Hasler
  • Hendrik P. N. Scholl
  • Tjebo F. C. Heeren
  • Julia Schottenhamml
  • Konstantinos Balaskas
  • Adnan Tufail
  • Catherine Egan
  • IOB study group
Retinal Disorders



Preliminary to evaluate geometric indices (vessel sphericity and cylindricity) for volume-rendered optical coherence tomography angiography (OCTA) in healthy and diabetic eyes.


Twenty-six eyes of 13 healthy subjects and 12 eyes of patients with central ischemic, non-proliferative diabetic retinopathy were included. OCTA volume and surface area of the foveal vessels were measured and compared to determine OCTA sphericity and cylindricity indices and surface efficiency (SE).


The overall average OCTA volume in healthy was 0.49 ± 0.09 mm3 (standard deviation [SD]), compared to 0.44 ± 0.07 mm3 (SD) in the diabetic eyes (difference in means 0.06 mm3, p = 0.054). The overall average OCTA surface area in the healthy eyes was 87.731 ± 9.51 mm2 (SD), compared to 76.65 ± 13.67 mm2 (SD) in the diabetic eyes (difference in means 11.08 mm2, p = 0.021). In relation to total foveolar tissue volume, the proportion of blood vessels was 22% in healthy individuals and only 20% in diabetics. The difference between the groups was more pronounced with respect to the total OCTA surface area, with a decrease of 13% in diabetics. A diabetic eye was most likely using geometric vessel indices analysis if the sphericity value was ≥ 0.190, with a cylindricity factor of ≥ 0.001. Reproducibility of the method was good.


A method for OCTA surface area and volume measurements was developed. The application of the novel OCTA sphericity and cylindricity indices could be suitable as temporal biomarker to characterize stable disease or disease progression and may contribute to a better understanding in the evolution of diabetic retinopathy.


Diabetes Retina Optical coherence tomography angiography Volume-rendering Sphericity Cylindricity 


Compliance with ethical standards

Conflict of interest

Peter Maloca is a consultant at ZEISS FORUM. Catherine Egan and Adnan Tufail received a financial grant from the National Institute for Health Research (NIHR) Biomedical Research Centre, based at Moorfields Eye Hospital, and also from the NHS Foundation Trust and the UCL Institute of Ophthalmology. Adnan Tufail is employed is a consultant for Heidelberg Engineering and Optovue. Richard Spaide and Peter Maloca are consultant for Topcon. Richard Spaide holds the patent for Frangi vessel segmentation. The funding organizations had no role in the design or conduct of the current study. The views expressed are those of the authors and not necessarily those of the National Eye Institute, the NHS, the NIHR, or the Department of Health.

Dr. Hendrik Scholl is supported by the Foundation Fighting Blindness Clinical Research Institute (FFB CRI); Shulsky Foundation, New York, NY; National Centre of Competence in Research (NCCR) Molecular Systems Engineering (University of Basel and ETH Zürich); Swiss National Science Foundation; and Wellcome Trust.

Dr. Scholl is a paid consultant of the following entities: Boehringer Ingelheim Pharma GmbH & Co. KG; Gerson Lehrman Group; and Guidepoint.

Dr. Scholl is member of the Scientific Advisory Board of the Astellas Institute for Regenerative Medicine; Gensight Biologics; Intellia Therapeutics, Inc.; Ionis Pharmaceuticals, Inc.; ReNeuron Group Plc/Ora Inc.; Pharma Research & Early Development (pRED) of F. Hoffmann-La Roche Ltd.; and Vision Medicines, Inc.

Dr. Scholl is member of the Data Monitoring and Safety Board/Committee of the following entities: Genentech Inc./F. Hoffmann-La Roche Ltd. and ReNeuron Group Plc/Ora Inc. Dr. Scholl is member of the steering committee of the following entities: Novo Nordisk (FOCUS trial).

Dr. Scholl is co-director of the Institute of Molecular and Clinical Ophthalmology Basel (IOB) which is constituted as a nonprofit foundation and receives funding from the University of Basel, the University Hospital Basel, Novartis, and the government of Basel-Stadt.

These arrangements have been reviewed and approved by the Johns Hopkins University in accordance with its conflict of interest policies. Johns Hopkins University and Bayer Pharma AG have an active research collaboration and option agreement. These arrangements have also been reviewed and approved by the University of Basel (Universitätsspital Basel, USB) in accordance with its conflict of interest policies.

Dr. Hendrik Scholl is principal investigator of grants at the USB sponsored by the following entity: Acucela Inc.; Aegerion Pharmaceuticals (Novelion Therapeutics); Kinarus AG; NightstaRx Ltd.; Ophthotech Corporation; and Spark Therapeutics England, Ltd. Grants at USB are negotiated and administered by the institution (USB) which receives them on its proper accounts. Individual investigators who participate in the sponsored project(s) are not directly compensated by the sponsor but may receive salary or other support from the institution to support their effort on the project(s).

Others: None. This does not alter our adherence to Graefe’s policies on sharing data and materials. The mentioned institutions had no role in the design or conduct of this study.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2020

Authors and Affiliations

  • Peter M. Maloca
    • 1
    • 2
    • 3
    • 4
    Email author
  • Richard F. Spaide
    • 5
  • Emanuel Ramos de Carvalho
    • 4
  • Harald P. Studer
    • 2
  • Pascal W Hasler
    • 2
    • 3
  • Hendrik P. N. Scholl
    • 1
    • 2
    • 3
    • 7
  • Tjebo F. C. Heeren
    • 8
  • Julia Schottenhamml
    • 6
  • Konstantinos Balaskas
    • 4
    • 8
  • Adnan Tufail
    • 4
  • Catherine Egan
    • 4
  • IOB study group
  1. 1.Institute of Molecular and Clinical Ophthalmology Basel (IOB)BaselSwitzerland
  2. 2.Department of Ophthalmology, OCTlabUniversity Hospital BaselBaselSwitzerland
  3. 3.Department of OphthalmologyUniversity of BaselBaselSwitzerland
  4. 4.Moorfields Eye HospitalLondonUK
  5. 5.Vitreous Retina Macula ConsultantsNew York CityUSA
  6. 6.Pattern Recognition LabUniversity Erlangen-NürnbergErlangenGermany
  7. 7.Wilmer Eye InstituteJohns Hopkins UniversityBaltimoreUSA
  8. 8.Moorfields Ophthalmic Reading CentreLondonUK

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