Fig 1.
A fundus photograph and horizontal cross-sectional B-scan images of the optic nerve head obtained using swept-source optical coherence tomography showing measurement of lamina cribrosa thickness.
The lamina cribrosa thickness is measured at the mid-superior, central, and mid-inferior levels of the optic nerve head (A). At each level, the thickness is measured at three points (center, 100 μm nasally, and 100 μm temporally), along a line perpendicular to a reference line connecting the two ends of Bruch’s membrane (B).
Fig 2.
B-scan images of the optic nerve (left) and peripapillary vessels (right) obtained using swept-source optical coherence angiography showing measurement of peripapillary vessel density.
The peripapillary vessel density is measured in the superficial capillary plexus, which comprises the inner capillary layer of the retina (A); the deep capillary plexus, which makes up the outer capillary layer (B); and the choriocapillaris (C).
Fig 3.
Segmental valuation of the peripapillary vessel density.
The optic nerve was indicated as a circle, and the outer margin was set at 750 μm from this circle margin. The donut-shaped portion between the outer margin and the optic nerve margin was divided into four segments, namely the superotemporal, inferotemporal, superonasal, and inferonasal segments (A); each segment was extracted as a region of interest (ROI) (B); large vessels were detected and deleted (C); and finally, the binary ROI of the peripapillary vessels, with large vessels excluded, was retained (D). ON, optic nerve; ST, superotemporal; IT, inferotemporal; SN, superonasal; IN, inferonasal.
Table 1.
Baseline characteristics of BRVO and NTG patients.
Table 2.
Comparing anterior lamina depth between BRVO and NTG patients.
Table 3.
Comparing lamina cribrosa thickness between BRVO and NTG patients.
Table 4.
Mean difference of anterior lamina depth from mid-superior to mid-inferior portion of central lamina cribrosa.
Fig 4.
Swept-source optical coherence angiography findings for the peripapillary vessel density in different layers in eyes with branch retinal vein occlusion (BRVO) and those with normal-tension glaucoma (NTG) (A, Superiotemporal; B, Inferotemporal; C, Superonasal; D Inferonasal area).
The vessel density in the superotemporal segment of the superficial capillary plexus is significantly lower in BRVO than in NTG (P = 0.008) (A). The vessel density in all segments in the choriocapillaris is significantly lower in NTG than in BRVO (P < 0.05) (A–D) (Error bar = standard deviation).
Fig 5.
Lamina cribrosa properties and the peripapillary vessel density for representative cases of branch retinal vein occlusion (BRVO) and normal-tension glaucoma (NTG) (A–E). The left eye of a patient with BRVO, showing a mean deviation (Humphrey visual field [HVF]) of −5.21 dB (F–J). The right eye of a patient with NTG, showing a mean deviation (HVF) of −5.41 dB. The eye with BRVO shows superior disc notching (A) and a superior retinal nerve fiber layer (RNFL) defect (B). The peripapillary vessel density in the superotemporal segment of the superficial capillary plexus has decreased (C), with more superior disc cupping seen on a vertical B-scan (white arrow, E). The vessel density in the choriocapillaris is lower in the eye with NTG (I) than in the eye with BRVO. Moreover, the eye with NTG shows greater disc cupping and a more uniform LC (J) than does the eye with BRVO.