Parapapillary deep‐layer microvasculature dropout is only found near the retinal nerve fibre layer defect location in open‐angle glaucoma

Purpose We aimed to investigate the topographic correspondence between deep‐layer microvasculature dropout (MvD) and retinal nerve fibre layer (RNFL) defects in eyes with open‐angle glaucoma (OAG) using spectral‐domain optical coherence tomography (SD‐OCT) and optical coherence tomography angiography (OCT‐A). Methods Microvasculature dropout width and location were determined using OCT‐A, RNFL thickness, RNFL defect width and location were revealed using SD‐OCT. The association between MvD and RNFL widths and that between the location of the MvD and RNFL defects were investigated. In addition, patients with OAG were divided into two groups: the RNFL defect in one hemiretina (RNFLD‐HR) group (n = 24 eyes) and the RNFL defects in both hemiretinas (RNFLD‐BR) group (n = 25 eyes). The presence, width and location of MvDs were compared between the two groups. Results Forty‐nine eyes were included. In 24 RNFLD‐HR eyes, all MvDs were found in the inferior area, corresponding with the location of the RNFL defect. Meanwhile, in 25 RNFLD‐BR eyes, 18 MvDs (72%) were found in the inferior hemiretina, two (8%) were found in the superior hemiretina, and five (20%) were found in both hemiretinas. In RNFLD‐BR eyes, the average RNFL thickness was thinner in a location with MvD than a location without MvD. Conclusion Considering that MvD is only observed at the location of the RNFL defect in RNFLD‐HR eyes and is usually found in the location of more severe RNFL defects in RNFLD‐BR eyes, MvD seems to be a sign that accompanies glaucomatous damage in OAG eyes.