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. 2022 Apr;13(4):668-676.
doi: 10.1111/jdi.13712. Epub 2021 Dec 6.

Measuring the foveal avascular zone in diabetes: A study using optical coherence tomography angiography

Ross T Aitchison  1 , Graeme J Kennedy  1 , Xinhua Shu  1 , David C Mansfield  2 , Rachel Kir  1 , Jasmine Hui  1 , Uma Shahani  1
Affiliations

Measuring the foveal avascular zone in diabetes: A study using optical coherence tomography angiography

Ross T Aitchison et al. J Diabetes Investig. 2022 Apr.

Abstract

Aims/introduction: Diabetes is a global issue that currently affects 425 million people worldwide. One observable microvascular complication of this condition is a change in the foveal avascular zone (FAZ). In this study, we used optical coherence tomography angiography to investigate the effect of diabetes on the FAZ.

Materials and methods: A total of 11 participants with diabetes and 11 participants without diabetes took part in this study. Participants in both groups were matched for age (P = 0.217) and sex (P = 0.338), and had no history of ocular disease. Macular optical coherence tomography angiography (OCT-A) scans of participants' right and left eyes were taken. Glycosylated hemoglobin (HbA1c ) and blood glucose levels were also measured. The FAZ area was manually segmented at the levels of the superficial capillary plexus (FAZSCP ) and deep capillary plexus (FAZDCP ).

Results: There was a strong relationship between the FAZ area of participants' right and left eyes (P ≤ 0.001) in both diabetes and non-diabetes groups. In the diabetes group, the FAZSCP (P = 0.047) and FAZDCP (P = 0.011) areas was significantly larger than in the non-diabetes group. Moreover, multiple linear regression analysis predicted a 0.07-mm2 increase in the FAZSCP and FAZDCP areas of individuals with diabetes for every 1% increase in their HbA1c level.

Conclusions: Our findings show that there is enlargement of the FAZ in individuals with diabetes compared with individuals without diabetes. In the diabetes group, this enlargement appears to be correlated with HbA1c level. OCT-A imaging could, therefore, be a useful tool to monitor the FAZ and identify potential early microvasculopathy in diabetes.

Keywords: Foveal avascular zone; Glycosylated hemoglobin; Optical coherence tomography angiography.

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Figures

Figure 1
Figure 1
Right en face macular images of the foveal avascular zone of a typical participant with diabetes and a typical participant without diabetes (pre‐processed). (a) Superficial capillary plexus of a participant with diabetes. (b) Superficial capillary plexus of a participant without diabetes. (c) Deep capillary plexus of a participant with diabetes. (d) Deep capillary plexus of a participant without diabetes.
Figure 2
Figure 2
Image processing and analysis of foveal avascular zone (FAZ) area, for each en face macular image. (a) Pre‐processed FAZ image; (b) en face FAZ image after Phansalkar binarization; (c) best‐fit oval (in yellow) of the FAZ area after binarization and manual outlining using the polygon tool.
Figure 3
Figure 3
Foveal avascular zone area manually segmented at the levels of the superficial capillary plexus in diabetes (dark gray solid) and non‐diabetes groups (dark gray striped), and foveal avascular zone area manually segmented at the levels of the deep capillary plexus in diabetes (light gray solid) and non‐diabetes groups (light gray solid). *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.
Figure 4
Figure 4
Partial regression plot of the foveal avascular zone area manually segmented at the level of the superficial capillary plexus against glycosylated hemoglobin in participants with diabetes, when controlling for participants’ age and sex.
Figure 5
Figure 5
Partial regression plot of FAZDCP area against HbA1c in diabetic participants when controlling for participants' age and sex.
See this image and copyright information in PMC

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