Fig 1.
Optical coherence tomography angiography (OCTA) microvasculature images of optic nerve head in glaucoma eye without microvasculature dropout inside the optic disc.
OCTA en face projection images in the retinal nerve fiber layer (RNFL) (Top left), superficial layer (Top right), and the whole-depth (Second row). The red ellipse indicates the optic disc boundary and red lines show the boundaries of evaluation areas. Superotemporal and inferotemporal regions were used for evaluation of microvasculature dropout. The yellow and green lines indicate the location of the B-scans in the bottom row. Bottom, Cross-sectional angiogram images overlying the B-scan images. Microvasculature in the anterior portion of lamina cribrosa is visualized in the area shown by orange arrowheads, while the anterior lamina cribrosa and microvasculature cannot be detected because of vessel shadowing in the area shown by aqua arrowheads. Yellow and aqua borders show the inner limiting membrane (ILM) and 80 μm below the ILM, respectively.
Fig 2.
Flowchart determining the classification based on microvasculature dropout inside the optic disc (Mvd-D).
Fig 3.
Examples of eyes with microvasculature dropout (Mvd) inside the optic disc (Mvd-D), pseudo-Mvd-D, and no Mvd-D.
A, The Mvd-D and Mvd in the parapapillary region (Mvd-P) are enclosed by yellow and aqua border, respectively. A3, Anterior lamina cribrosa (LC) surface is well visualized as shown by yellow dotted line. Yellow arrows indicate the borders of the Mvd-D. It should be noted that the area between 2 yellow arrows does not contain any microvasculature signal in the prelaminar tissue and anterior portion of LC. B,C, Pseudo-Mvd-Ds are shown by yellow dotted border. Anterior LC could not be observed between 2 yellow arrows, which indicate the borders of the pseudo-Mvd-D, because of shadowing by neuroretinal rim (B3) and large retinal vessel (B4, C3). D, No Mvd-D is observed in the temporal side of the optic disc. Optic disc border is shown by red ellipse and the border for evaluation is shown by red lines (A2―D2).
Table 1.
Comparison of the demographic and test results between primary open-angle glaucoma patients with and without microvasculature dropout inside the optic disc (Mvd-D).
Table 2.
Logistic regression testing factors associated with the presence of microvasculature dropout inside the optic disc in glaucoma eyes (Total 123 eyes of 123 patients).
Fig 4.
Representative cases of eyes with microvasculature dropout (Mvd) inside the optic disc (Mvd-D).
A―G, Left eye of a 74-year-old man with primary open-angle glaucoma (POAG). A, Neuroretinal rim thinning is observed at the temporal area of the optic disc. B, Humphrey Visual Field Analyzer with the 24–2 Swedish interactive threshold algorithm standard (HFA24-2) grayscale image showing severe visual field defects (visual field mean deviation [MD], -16.91 dB). C, Optical coherence tomography (OCT) angiography (OCTA) en face projection image with whole-signal-mode. Red ellipse indicates optic disc border. Yellow and aqua borders indicate Mvd-D and Mvd in the parapapillary area (Mvd-P), respectively. D, E, B-scan OCT images and cross-sectional angiogram images overlying the B-scan image acquired at the yellow (D) and green line (E) in C2. Microvasculature is observed in the prelaminar tissue and anterior lamina cribrosa (LC) in D, while no microvasculature is seen in the Mvd area of E. Yellow arrows indicate the borders of Mvd-D. Yellow dotted lines show anterior LC surface. Red arrow indicates focal LC defect. F, G, En face (F) and horizontal section of volume scan (G) of swept-source OCT images. Red dotted line indicates anterior LC surface, and red arrow shows focal LC defect. H―N, Right eye of a 62-year-old woman with POAG. H, Inferotemporal rim thinning is observed. I, HFA24-2 grayscale image showing mild visual field defects (visual field MD, -1.72 dB). J, OCTA en face projection image with whole-signal-mode. Red ellipse indicates optic disc border. Yellow and aqua borders indicate Mvd-D and Mvd-P, respectively. K, L, B-scan OCT images and cross-sectional angiogram images overlying the B-scan image acquired at the yellow (K) and green line (L) in J2. Microvasculature is observed in prelaminar tissue and anterior LC in K, while no microvasculature is seen in the Mvd area of L. Yellow and aqua arrows indicate the borders of Mvd-D and Mvd-P, respectively. Yellow dotted lines show anterior LC surface, and red arrow indicates focal LC defect. M, N, En face (M) and horizontal section of volume scan (N) of swept-source OCT images. Red dotted line indicates anterior LC surface, and red arrow shows focal LC defect.
Table 3.
Topographic characteristics of lamina cribrosa defect and parapapillary microvasculature dropout (Mvd-P) in eyes with microvasculature dropout inside the optic disc (Mvd-D).