A comparison of the diagnostic ability of vessel density and structural measurements of optical coherence tomography in primary open angle glaucoma

Abstract

PurposeTo compare the diagnostic abilities of vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with primary open angle glaucoma (POAG) with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements.MethodsIn a cross sectional study, 78 eyes of 50 control subjects and 117 eyes of 67 POAG patients underwent vessel density and structural measurements with spectral domain OCT. POAG was diagnosed based on the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness.ResultsThe AUC (sensitivity at 95% specificity) of average vessel densities within the ONH, peripapillary and macular region were 0.77 (31%), 0.85 (56%) and 0.70 (18%) respectively. The same of ONH rim area, average RNFL and GCC thickness were 0.94 (83%), 0.95 (72%) and 0.93 (62%) respectively. AUCs of vessel densities were significantly lower (p<0.05) than that of the corresponding structural measurements. Pre-treatment IOP (coefficient: 0.08) affected (p<0.05) the AUC of ONH vessel density but not of any other vessel density or structural measurements.ConclusionsDiagnostic abilities of ONH, peripapillary and the macular vessel densities in POAG were significantly lower than ONH rim area, peripapillary RNFL and macular GCC measurements respectively. At fixed levels of glaucoma severity, the diagnostic ability of the ONH vessel density was significantly greater in eyes with higher pre-treatment IOP.

An Optical Coherence Tomography Angiography Study of the Relationship Between Foveal Avascular Zone Size and Retinal Vessel Density

“…Measurements of disc wiVD or cpVD correlated significantly with glaucoma severity, as previously reported. 26,27 In the present study, FAZ parameters also showed a significant correlation with glaucoma severity in that FAZ area and perimeter showed a significant negative correlation with cpRNFLT, mGCIPLT, and global/central VF MS (Table 4). Therefore, it is not surprising that there was a significant correlation between FAZ parameters and disc wiVD or cpVD, even though these measurements were derived from different retinal locations.…”

“…23 At present, although it is known that both FAZ size and retinal VD measurements are altered in glaucoma patients, the relationship between microvasculature changes in the FAZ and VD measurements at various retinal locations is unknown. 12,13,[24][25][26][27] We hypothesized that clarification of this relationship would provide an additional insight into the clinical utility of FAZ size (area or perimeter) in the detection and possible monitoring of glaucoma. In the present study, we have, therefore, investigated the relationships between the FAZ size and VD measurements obtained with OCTA at different retinal locations, including the circumpapillary, parafoveal, and foveal regions in a series of healthy and glaucomatous eyes.…”

Optical Coherence Tomography Angiography in Glaucoma: A Review

“…In all of those areas, the diagnostic abilities increased with increasing severity of glaucoma [32, 34, 52]. This illustrated that an increasing severity of glaucoma was correlated with more pronounced vascular and structural damage.…”

“…Significantly lower OCTA parameters (vessel density, blood flow index, and flow index) were found in glaucoma eyes in comparison with normal eyes in the peripapillary area [6, 16-50], the optic disc [19, 23, 25, 32, 36, 51-60] and the whole image macular area [16, 21, 32, 34, 36-38, 61-64]. In all of those areas, the diagnostic abilities increased with increasing severity of glaucoma [32, 34, 52].…”

“…The area under the curve (AUC) for the best discriminating OCTA parameter (vessel density and blood flow index) ranged between 0.75 and 1.00, while for the OCT parameter (RNFL) the values ranged between 0.76 and 0.97 [17, 19, 20, 22, 23, 25, 27, 31, 32, 34, 36, 37, 41, 49]. Most studies found an AUC above 0.850 both for the OCTA parameters [17, 20, 22, 23, 25, 31, 32, 37, 41] and for the RNFL [19, 20, 22, 25, 31, 34, 37, 49].…”