PERIPAPILLARY AND MACULAR VASCULAR DENSITY IN DIFFERENT STAGES OF PSEUDOEXFOLIATION GLAUCOMA AND PRIMARY OPEN-ANGLE GLAUCOMA: A COMPARATIVE STUDY

To compare the changes in peripapillary and macular vascular density (VD) in different stages of pseudoexfoliation glaucoma (PXG) and primary open-angle glaucoma (POAG) with control group.

Cross-sectional observational study

The study included 142 eyes of 142 participants, 56 PXG, 56 POAG (30 early, 26 moderate/advanced stages in each group), matched according to age, visual field mean deviation (MD), and retinal nerve fiber layer (RNFL) thickness, and 30 healthy participants. Optical coherence tomography angiography (OCTA) imaging was performed in all cases. Peripapillary vascular density (ppVD) and RNFL thickness were evaluated in 8 sectors, superficial macular VD was evaluated in perifoveal and parafoveal regions. 

In the early stage PXG and POAG groups, visual field MD was -2.51±1.43 and -2.60±1.44 dB (p=0.994), and in the moderate/advanced stage, MD was -16.71±8.13 and -16.41±8.29, (p=0.862), respectively. In the early PXG and POAG groups, there was significant loss of ppVD in all sectors (except temporal sectors) compared to the control group, and there was no difference between the two groups (global ppVD: 48.8±4.8% and 48.3±4.3% and 53.7±2.3, p=0.975, p<0.001, respectively). In the moderate/advanced POAG, the rate of ppVD in the temporal inferior sector was lower than in PXG (44.85±6.92% vs. 39.22±8.52%, p=0.012), and there was no significant difference in other sectors.  While perifoveal VD did not differ between the early PXG and POAG groups (p=0.154), it was significantly reduced compared to the control group (p<0.001-0.005). Parafoveal VD was lower in early POAG compared to control and PXG group (p=0.013-0.019), and there was no difference between early PXG and control group (p=0.706). In the moderate and advanced stage there was no difference perifoveal and parafoveal VD between the PXG and POAG groups.

There was no difference in ppVD between PXG and POAG, except in the temporal inferior sector in the moderate/advanced stage.  Although POAG had lower parafoveal VD in the early stage, this difference was not observed in the moderately/advanced stage. The effects of PXG and POAG on peripapillary and macular VD appear to be similar. The observed lower parafoveal VD in POAG in the early stage may indicate initial compromise in microvascular perfusion in these patients. However, the lack of significant differences in more advanced stages suggests that disease progression in both PXG and POAG leads to similar patterns of vascular changes.