Vessel density in early-stage primary open angle glaucoma and pseudoexfoliation glaucoma: a comparative controlled optical coherence tomography angiography study.

Purpose: This study aimed to compare the vessel density of the optic nerve head and radial peripapillary capillary in the eyes with early-stage primary open angle glaucoma and pseudoexfoliation glaucoma and control eyes.

Methods: With visual field mean deviation scores >-6.0 dB, 54 eyes from 37 patients diagnosed with primary open angle glaucoma (n=18) and pseudoexfoliation glaucoma (n=18) and healthy controls (n=18) were enrolled in this cross-sectional observational study. Retrieved from optical coherence tomography angiography, vessel density for the optic nerve head and radial peripapillary capillary were analyzed according to the distribution of the data and appropriate tests. The diagnostic accuracy of vessel density parameters was also assessed.

Results: The whole-image vessel density of the radial peripapillary capillary and inside-disc vessel density of the optic nerve head were significantly lower in eyes with primary open angle glaucoma and pseudoexfoliation glaucoma compared to those in the control eyes (p<0.05). Compared to that in pseudoexfoliation glaucoma, the inside-disc vessel density of the optic nerve head was significantly lower in primary open angle glaucoma (p<0.05). Inferotemporal sector vessel density of the optic nerve head for both primary open angle glaucoma and pseudoexfoliation glaucoma was significantly lower than that of the controls (p=0.009). In discrimination of primary open angle glaucoma vs. control and pseudoexfoliation glaucoma vs. control, area under the receiver operating characteristic curve values for inside-disc vessel density of the optic nerve head were 0.855 and 0.731, respectively (p<0.001, p=0.018). However, in discrimination of primary open angle glaucoma vs. pseudoexfoliation glaucoma, area under the receiver operating characteristic curve values for whole-image and inside-disc vessel densities of the optic nerve head were 0.707 and 0.722 (p=0.034, p=0.023).

Conclusions: Vessel densities of the optic nerve head and radial peripapillary capillary were significantly lower in eyes with primary open angle glaucoma and pseudoexfoliation glaucoma compared to healthy control eyes. In the early stage of glaucoma, the inside-disc vessel density of the optic nerve head slab may be lower in eyes with primary open angle glaucoma eyes compared to eyes with pseudoexfoliation glaucoma.