Macular vessel density and foveal avascular zone parameters in patients after acute primary angle closure determined by OCT angiography

Abstract

This study analyzed the optical coherence tomography angiography (OCTA) macular parameters in primary angle-closure glaucoma (PACG) patients after acute primary angle closure (APAC) episodes. Thirty-three patients with 33 APAC eyes and 33 primary angle closure suspect (PACS) eyes and 33 age-matched normal subjects (controls) were enrolled. Macular vessel density (VD) in central, inner, outer and full regions and foveal avascular zone (FAZ) parameters (area, perimeter and circularity index) were compared between APAC, PACS, and control eyes. For resolved APAC eyes, the VD in each macular region was significantly lower than that in control eyes, with less central and inner macular VD than PACS eyes. The central macular VD was significantly lower in PACS eyes than in controls. There was no difference in FAZ area and perimeter between APAC, PACS, and control eyes. FAZ circularity was highest in control eyes, followed by PACS eyes, and lowest in APAC eyes. The AUC, sensitivity and specificity of FAZ circularity were 0.944, 93.9% and 84.8%, respectively, in APAC eyes and 0.881, 84.8% and 81.8%, respectively, in PACS eyes. Therefore, FAZ circularity had the best discrimination capability for detecting both APAC and PACS eyes. Macular assessment with OCTA could provide an accurate early-stage diagnostic tool for PACG.

Figure 1

Macular area measurement map, the central area is the center 1 mm diameter range, the inner ring and the outer ring are respectively 3 mm, 6 mm diameter range. The yellow zone is foveal avascular zone.

Figure 2

ROC curve analysis of macular vessel density and foveal avascular zone parameters between (A) APAC and control eyes, and (B) PACS and control eyes. Ctr control, APAC acute primary angle closure, PACS primary angle closure suspect, SSI signal strength index, VLD vessel length density, VPD vessel perfusion density, FAZ foveal avascular zone, AUC area under the receiver operating characteristic curve.

Figure 3

Representative cases with different macular VD and FAZ metrics. (A) An APAC eye has the lowest circularity index and irregular shape. (B) A PACS eye has the higher circularity index than APAC eyes and distorted FAZ shape. (C) A control eye has highest circularity index and regular shape. APAC acute primary angle closure, PACS primary angle closure suspect, cVLD vessel length density in central macular region, cVPD vessel perfusion density in central macular region, iVLD vessel length density in inner macular region, iVPD vessel perfusion density in inner macular region, oVLD vessel length density in outer macular region, oVPD vessel perfusion density in outer macular region, fVLD vessel length density of all regions, fVPD vessel length density of all regions, FAZ foveal avascular zone.