Choriocapillaris flow impairment in type 3 macular neovascularization: a quantitative analysis using swept-source optical coherence tomography angiography

Author: Hoang Mai Le (France)

Co-authors: Alexandra MIERE, Giuseppe QUERQUES, Enrico BORELLI, Riccardo SACCONI, Camille JUNG, Eric SOUIED

Purpose

To quantitatively analyze choriocapillaris alterations using swept-source optical coherence tomography angiography (SS-OCTA) in eyes presenting with type 3 macular neovascularization (MNV) and to compare these alterations with eyes presenting with intermediate AMD (iAMD).

Setting/Venue

Choriocapillaris is a key source of nutrition and oxygenation of the RPE. Retinal hypoxia and ischemia induced by a decreased choroidal perfusion could participate in retinal degeneration and lead to an increased secretion of vascular endothelial growth factor resulting in neovascularization. Hence, outer retinal ischemia and the integrity of the choriocapillaris may play a role in the development of type 3 MNV.

Methods

Macular 3x3 mm SS-OCTA scans were retrospectively analyzed in eyes with type 3 MNV and in eyes with iAMD. The choriocapillaris en face slabs were extracted from the SS-OCTA device after manual segmentation. En face choriocapillaris flow images were compensated with en face choriocapillaris structure images, followed by the Phansalkar local thresholding method using a window radius 4 and 8 pixels. Percentage of flow deficits (FD%), the number, size and total area of FDs were computed for comparison. A secondary analysis was performed in the 4 corners of the image to include equidistant regions in all eyes.

Results

Twenty-six type 3 MNV eyes of 21 patients and 26 eyes iAMD eyes of 17 patients were included. Compared to iAMD eyes, eyes with type 3 MNV displayed a higher FD% (41.37% +/-14.74 versus 19.80% +/-9.63 using radius 4 pixels (p<0.001); 45.24% +/-11.9 versus 26.63% +/-8.96 using radius 8 pixels (p<0.001)). Average size of FDs was significantly larger in type 3 MNV eyes compared with iAMD eyes (p<0.001), while the number of FDs was significantly lower in type 3 MNV compared to iAMD eyes (p<0.001).

Conlusions

Type 3 MNV eyes present with an increased choriocapillaris flow impairment compared to iAMD eyes. Reduced choriocapillaris perfusion may contribute to type 3 MNV development and pathogenesis.

Financial Disclosure

no financial relations

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