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. 2017 Oct 18;10(10):1545-1551.
doi: 10.18240/ijo.2017.10.11. eCollection 2017.

Foveal avascular zone area and parafoveal vessel density measurements in different stages of diabetic retinopathy by optical coherence tomography angiography

Rodolfo Mastropasqua  1 , Lisa Toto  2 , Alessandra Mastropasqua  2 , Raffaella Aloia  2 , Chiara De Nicola  2 , Peter A Mattei  2 , Guido Di Marzio  2 , Marta Di Nicola  3 , Luca Di Antonio  2
Affiliations

Foveal avascular zone area and parafoveal vessel density measurements in different stages of diabetic retinopathy by optical coherence tomography angiography

Rodolfo Mastropasqua et al. Int J Ophthalmol. .

Abstract

Aim: To investigate foveal avascular zone (FAZ) and parafoveal vessel densities (PRVD) by means of optical coherence tomography angiography (OCTA) in diabetic patients with or without diabetic retinopathy (DR) and to assess the reproducibility of FAZ and PRVD measurements.

Methods: Sixty diabetic patients (60 eyes) with different stage of DR (graded according to the International Clinical Severity Scale for DR) and 20 healthy subjects underwent FAZ area and PRVD measurements using OCTA by two experienced examiners. FAZ area in all patients was also assessed using fluorescein angiography (FA).

Results: In subject with proliferative DR and with moderate-severe non proliferative DR, FAZ area was significantly increased compared to healthy controls (P=0.025 and P=0.050 respectively measured with OCTA and P=0.025 and P=0.048 respectively measured with FA). OCTA showed significantly less inter-observer variability compared to FA. Concordance correlation coefficient (CCC) for FAZ area measurements was 0.829 (95%CI: 0.736-0.891) P<0.001 with FA and 1.000 (95%CI: 0.999-1.000) P<0.001 with OCTA. CCC was 0.834 (95%CI: 0.746-0.893) P<0.001 and 0.890 (95%CI: 0.828-0.930) P<0.001 for parafoveal superficial and deep vessel density measurements, respectively.

Conclusion: OCTA shows progressive increase of FAZ area and reduction of PRVD in both superficial and deep plexus at increasing DR severity. FAZ area and PRVD measurements using OCTA are highly reproducible.

Keywords: diabetic retinopathy; fluorescein angiography; optical coherence tomography angiography.

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Figures

Figure 1
Figure 1. Bland-Altman plot of difference in FAZ area measurements between observers against their mean
FA [panel A; mean difference 0.02 (95% limits of agreement -0.12; 0.16) ] OCT [panel B; mean difference -0.0007 (95% limits of agreement -0.01; 0.009)].
Figure 2
Figure 2. OCTA images of DR patients
There is a reduction of parafoveal superficial and deep retinal vessel density in mild NPDR (A, B), severe NPDR (C, D) and PDR (E, F).
Figure 3
Figure 3. Bland-Altman plot of difference in superficial vessel density [panel A; mean difference -0.68 (95% limits of agreement -11.57; 10.20)] deep vessel density [panel B; mean difference -1.16 (95% limits of agreement -12.15; 9.8)] measurements between observers against their mean.
See this image and copyright information in PMC

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