Relationship of Optic Nerve Structure and Function to Peripapillary Vessel Density Measurements of Optical Coherence Tomography Angiography in Glaucoma

Abstract

The inferotemporal peripapillary vessel density showed the strongest association with the corresponding retinal nerve fiber layer thickness and visual sensitivity loss in the global and sectoral regions studied. The FP models were significantly better than linear models in describing these relationships.

Optical Coherence Tomography Angiography in Glaucoma: A Review

“…A significant correlation was found between the OCTA parameters and visual field MD, between OCTA parameters and glaucoma stage, and, as previously described, between the OCTA and OCT parameters in the peripapillary area [6, 17-20, 22-24, 26, 28-30, 33, 35, 36, 38, 39, 41, 45, 48, 50, 71-75], the optic disc [19, 23, 29, 36, 51-53, 57, 58], and the macular area [21, 36, 38, 61, 62, 64, 69, 75, 76]. As mentioned above, the results for the parafoveal area were not significant in some of the studies [38, 70].…”

“…In the peripapillary area, the greatest differences in OCTA parameters between the normal and glaucoma groups were found in the infero- and superotemporal sectors [6, 18, 25, 35, 37, 42]. This was expected since these 2 sectors are the ones that are the most vulnerable to glaucomatous damage at an early stage [65, 66].…”

“…Rao et al [35] showed that vessel density reached a base level beyond a visual sensitivity loss of –15 dB, while the RNFL reached that level at a visual sensitivity loss of –10 to –15 dB. Rao et al [35] showed, in another study, that in later stages of glaucoma (visual field MD between –20 and –30 dB), the diagnos tic ability of vessel density was better than that of the RNFL [7]. …”

“…Only a few publications, reporting on the peripapillary area, gave information about the occurrence of the floor effect in OCTA, when the parameters reached a base level beyond which little change was seen with increasing severity of glaucoma [7, 35]. Rao et al [35] showed that vessel density reached a base level beyond a visual sensitivity loss of –15 dB, while the RNFL reached that level at a visual sensitivity loss of –10 to –15 dB.…”

Optical Coherence Tomography Angiography in Glaucoma

“…In general, for both the Humphrey and Octopus perimetry systems a strong negative relationship was found between peripapillary, whole image, and macular vessel density parameters and the corresponding visual field deterioration. 19,20,21  It is even more interesting that in primary open-angle glaucoma, the relationship is particularly strong for superotemporal and inferotemporal peripaillary vessel density and the spatially corresponding visual field sectors, and this relationship can be significantly stronger than that seen for the spatially corresponding sector RNFL thickness value. 19,20  These results support the pathophysiological hypothesis which suggests a causative role of vascular dysregulation in the development and progression of primary open-angle glaucoma, particularly in the inferotemporal and superotemporal peripapillary areas, where glaucomatous RNFL loss appears early and progresses rapidly.…”