Optical coherence tomography angiography of the peripapillary capillaries in primary open-angle and normal-tension glaucoma

Abstract

ObjectivesTo evaluate the vascular architecture of the radial peripapillary capillaries (RPCs) and its relation with visual function in patients with open-angle glaucoma (OAG) and normal-tension glaucoma using spectral-domain optical coherence tomography (SD-OCT) angiography.Subjects and methodsClear OCT angiography images of blood vessels in the optic disc and peripapillary retina were obtained from 52 patients (52 eyes) aged 55.42±10.64 (range 28–72) years with primary OAG. The mean spherical equivalent was -3.19±2.31 diopters, and the mean deviation (MD) of the central 24/30-2 threshold test using the Humphrey Field Analyzer (HFA) was -10.47±7.99 dB. The correlations between the disappearance angle of the RPCs on OTC images, flow density (FD) and the circumpapillary retinal nerve fiber layer (cpRNFL) thickness, the angle of retinal nerve fiber layer (RNFL) defect, the MD and pattern standard deviation (PSD) values of the HFA central 24/30-2 threshold test using the Swedish interactive thresholding algorithm, the sensitivity threshold, age, corneal thickness, and refractive value were analyzed. In addition, the correlation between FD and the cpRNFL thickness was analyzed at FD measurement points.ResultsFD was significantly correlated with cpRNFL thickness, PSD value, MD value, and sensitivity threshold, whereas the disappearance angle of the RPCs was significantly correlated with the angle of the RNFL defect (P<0.001), MD value (P<0.01), and sensitivity threshold (P<0.01). There was a negative correlation between FD and age (P<0.05). The Pearson correlation coefficient of FD and cpRNFL thickness in the area surrounding the optic disc revealed the most significant correlation in the inferior visual field (r = 0.851, P<0.001), followed by the superior visual field (r = 0.803, P<0.001) and then the temporal visual field (r = 0.653, P<0.001).ConclusionSD-OCT angiography enabled thorough observation of the RPCs. FD and the disappearance angle of the RPCs were significantly and independently correlated with glaucoma-related functional and morphological changes in the optic nerve, suggesting that these two factors are novel functional and morphological indicators of visual defects due to glaucoma.

Correlation of the Retinal Parapapillary Perfusion and the Retinal Vessel Oxygen Saturation in Glaucoma Patients

“…26,27 Global NFL thickness was also correlated with the global VD and PD as shown in many studies. 28,29 Although this correlation showed a reduced PD with increasing tissue loss and progressing disease, the reduced perfusion as a cause of the tissue loss and reduction of NFL thickness still cannot be ruled out. The NFL correlated inversely with the venous O2S and directly with the AV-D, which has been previously reported.…”

Foveal Avascular Zone in Normal Tension Glaucoma Measured by Optical Coherence Tomography Angiography

“…Bojikian et al investigated optic disc perfusion differences in healthy subjects, POAG, and NTG and showed that optic disc perfusion was significantly reduced in POAG and NTG groups compared to normal controls, but no difference was seen between POAG and NTG groups with similar levels of VF damage [ 20 ]. Igarashi et al published that flow density and the disappearance angle of the radial peripapillary capillaries were significantly and independently correlated with glaucoma-related functional and morphological changes in the optic nerve in POAG and NTG [ 31 ].…”

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].…”

“…Although a correlation was found between declined peripapillary and macular VD and structural and functional parameters in HTG and NTG patients [10, 15-18], whether lower macular VD precedes or follows glaucoma development is still unclear. Additionally, while previous research has revealed a decrease in total VD [15], vascular alteration in different macular layers has not been evaluated.…”