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Special Communication
November 27, 2019

Assessing the Use of Incorrectly Scaled Optical Coherence Tomography Angiography Images in Peer-Reviewed Studies: A Systematic Review

Author Affiliations
  • 1School of Medicine, Medical College of Wisconsin, Milwaukee
  • 2Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee
  • 3Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia
  • 4Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
  • 5Department of Ophthalmology, Perth Children’s Hospital, Nedlands, Western Australia, Australia
  • 6Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee
JAMA Ophthalmol. 2020;138(1):86-94. doi:10.1001/jamaophthalmol.2019.4821
Key Points

Question  What percentage of articles using optical coherence tomography angiography report scaling their images to account for individual differences in retinal magnification?

Findings  In this systematic review of articles retrieved from PubMed, 509 articles required knowledge of the lateral scale of the optical coherence tomography angiography images used for their measurements, and 41 (8.0%) appeared to use axial length to derive the lateral scale of individual images.

Meaning  Readers should exercise caution when interpreting some results from studies that may be relying on inaccurate optical coherence tomography angiography measurements; these inaccuracies can confound comparisons of data between studies and decrease the sensitivity and specificity of biomarkers based on optical coherence tomography angiography.


Importance  Individual differences in axial length affect the lateral magnification of in vivo retinal images and as a result can affect the accuracy of quantitative measurements made from these images. As measurements from optical coherence tomography angiography (OCTA) images are becoming increasingly used in the diagnosis and monitoring of a wide range of diseases, evaluating which studies use correctly scaled images is crucial to their interpretation.

Objective  To perform a systematic literature review to assess the percentage of articles that report correcting the scale of their OCTA images for individual differences in retinal magnification.

Evidence Review  A PubMed (MEDLINE) search was conducted for articles on OCTA retinal imaging published between June 1, 2015, and June 1, 2018. Initial results included 7552 articles. Initial exclusion criteria removed studies of animal models, as well as reviews, letters, replies, comments, and image-based or photographic essays. Articles not written in English and those that required purchase from non–English language websites were excluded. Articles that did not use OCTA for imaging the retina were also excluded. Remaining articles were reviewed in detail to assess whether the OCTA measurements required correct lateral scaling, and if so, whether axial length was reported or used to scale the images. We also determined the number of articles that mentioned the lack of correct lateral scaling as a limitation of the study.

Findings  A total of 989 articles were included in the detailed review. Of these, 509 were determined to require correct image scaling for their analyses, but only 41 (8.0%) report measuring and using axial length to correct the lateral scale of their OCTA images. Furthermore, of the 468 articles that did not correctly scale their images, only 18 (3.8%) mentioned this as a limitation to their study.

Conclusions and Relevance  These findings suggest that most peer-reviewed articles in PubMed that use quantitative OCTA measurements use incorrectly scaled images. This could call into question the conclusions of such studies and warrants consideration by OCTA manufacturers, physicians, authors, journal reviewers, and journal editors.

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