Comparison of peripapillary vessel density between preperimetric and perimetric glaucoma evaluated by OCT-angiography

Abstract

PurposeTo determine peripapillary vessel density in eyes with perimetric glaucoma (PG) or preperimetric glaucoma (PPG) compared to normal controls using optical coherence tomography-angiography (OCT-A).MethodsWe recruited 13 patients with unilateral perimetric normal-tension glaucoma (NTG) and fellow preperimetric NTG showing only inferotemporal retinal nerve fiber layer (RNFL) defect in red-free RNFL photography in both eyes. We also enrolled 9 healthy controls. Using OCT-A, radial peripapillary capillary densities at inferotemporal and superotemporal regions were evaluated. Paired comparison of peripapillary vessel density was performed for PG eye, PPG eye, and normal eye.ResultsA total of 26 eyes of the 13 patients with unilateral PG and fellow PPG eyes and 18 eyes of 9 normal controls were analyzed. Vessel densities at the whole peripapillary region and inferotemporal region in PG eyes were significantly lower than those in PPG eyes (P = 0.001, P<0.001, respectively). Comparison between PPG and normal eyes showed no significant difference in the whole peripapillary region or the inferotemporal region (P = 0.654, P = 0.174, respectively). There was no significant (P = 0.288) difference in vessel density at superotemporal region among the three types of eyes (PG eye, PPG eye, and normal eye).ConclusionPPG eyes and normal eyes were found to have the similar densities of peripapillary microvasculature at the area with nerve fiber layer defect, whereas in PG eye, there was a significant decrease in vessel density at the area of RNFL thinning. This provides evidence that microvascular compromise in the retina might be a secondary change to nerve fiber layer degeneration in the pathogenesis of NTG.

Diagnostic Ability and Discriminant Values of OCT-Angiography Parameters in Early Glaucoma Diagnosis

“…As evidence for this speculation, the same authors studied the vessel densities in the area with RNFL defects. PPG eyes were found to have higher vessel densities than those in glaucomatous eyes but similar to those in normal eyes [33]. Our study seems to support this hypothesis.…”

<p>Peripapillary Vessel Density In Unilateral Preperimetric Glaucoma</p>

“…Rolle et al 27 reported that RPC VD was not significantly different between PPG and healthy eyes. Kim et al 31 found that in unilateral normal tension glaucoma the perimetrically unaffected eyes had similar peripapillary capillary densities with normal eyes at the area with a RNFL defect. Chung et al 26 considered vessel density parameters of limited diagnostic value in early glaucoma stage.…”

“…However, it is still under discussion whether the assessment of RPC density could help in preperimetric glaucoma (PPG) detection. 13,15,20,[26][27][28][29][30][31] The aim of the present study was to investigate the vascular status of the optic disc and peripapillary area in association with the structural changes in patients with unilateral PPG.…”

Correlation between Basal Macular Circulation and Following Glaucomatous Damage in Progressed High-Tension and Normal-Tension Glaucoma

“…While comparing OCTA examination to traditional methods, previous studies have demonstrated that OCTA is a reliable tool for the analysis of retinal vasculature, similar to fluorescein angiography [21, 22], and that the retinal vasculature layers can be imaged more precisely compared to fluorescein angiography and indocyanine green angiography [23, 24]. With regard to glaucoma, HTG, after evaluation by OCTA, showed decreased peripapillary vessels that correlate with the RNFL and VF defects and impaired macular VD [9, 14, 17, 18, 25-28], while the OCTA evaluation in NTG subjects showed similar results and precision in the peripapillary and macular vasculature [10, 15, 17, 18, 29]. In addition, the spilt-layer function of OCTA can appropriately separate the different retinal layers and analyze each vasculature in more detail than the traditional approach [4].…”