Progressive Macula Vessel Density Loss in Primary Open-Angle Glaucoma: A Longitudinal Study

Abstract

Purpose To characterize the rate of macula vessel density loss in primary open angle glaucoma (POAG), glaucoma suspect, and healthy eyes. Design Longitudinal, observational cohort from the Diagnostic Innovations in Glaucoma Study. Methods One hundred eyes (32 POAG, 30 glaucoma suspect and 38 healthy) followed for at least one year with optical coherence tomography angiography (OCT-A) imaging on at least two visits were included. Vessel density was calculated in the macula superficial layer. The rate of change was compared across diagnostic groups using multivariate linear mixed-effects model. Results Baseline macula vessel density was highest in healthy eyes, followed by glaucoma-suspect and POAG eyes (P < 0.01). The rate of vessel density loss was significantly different from zero in the POAG, but not in the glaucoma suspect or healthy eyes. The mean rate of change in macula whole en-face vessel density was significantly faster in glaucoma eyes (−2.23 %/yr) than in glaucoma suspect (0.87%/yr, P = 0.001) or healthy eyes (0.29 %/yr, P = 0.004). Conversely, the rate of change in ganglion cell complex (GCC) thickness was not significantly different from zero in any diagnostic group, and no significant differences in the rate of GCC change among diagnostic groups were found. Conclusions With a mean follow-up of less than 14 months, eyes with POAG had significantly faster loss of macula vessel density than either glaucoma suspect or healthy eyes. Serial OCT-A measurements also detected glaucomatous change in macula vessel density in eyes without evidence of change in GCC thickness.

Optical Coherence Tomography Angiography in Glaucoma: A Review

“…In the macular area the results were less clear than in the peripapillary area. One study found a significantly lower vessel density in PrG eyes in comparison to normal eyes [63]; a second study found a significantly lower vessel density in the inferior sector [47]; and a third study found a significantly greater vessel density in GS in comparison with control eyes [69]. In the latter, this might be explained by the fact that the GS group was significantly younger than the control group [69].…”

“…Because OCTA is a recently developed technique, only limited research has been published about its ability to detect progression [63, 84]. …”

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

“…In this study, we set the cutoff value of OCTA image quality at SSI >48, as used in many previous studies. 23,25,26,36,[39][40][41][42] Venugopal et al recently reported that SSI value had a significant effect on the repeatability of VD measurement by OCTA. 43 The mean SSI values of our cohort were relatively high, being close to 60, and there was no significant difference among groups in terms of SSI values.…”

“…34,35,37,38 Thus, AL-related magnification factor can be corrected by Dt ¼ 3.460*0.01306*(AL À 1.82)*Dm. 34,35,37,38 Poor quality OCTA images were excluded from the analysis, including signal strength index (SSI) < 48 (minimum ¼ 1, maximum ¼ 100) 23,25,26,36,[39][40][41][42] ; poor-clarity images due to severe media opacities; motion artifacts or localized weak signal by vitreous floaters; residual motion artifacts visible as irregular vessel patterns or disc boundary on the en face angiogram; images not centered on the fovea for macular OCTA (fixation error); and segmentation failure.…”

“…Moreover, glaucomatous change in VD has been detected by serial OCTA measurements in the macular region in patients with primary open-angle glaucoma (POAG), suggesting the potential role of macular VD measurement to detect and monitor microvasculature changes in glaucoma. 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.…”