Figure 1.
Measurement of the anterior lamina cribrosa insertion (ALI) position and marginal anterior laminar cribrosa depth (mALCSD).
A. SS-OCT image without labels. B. SS-OCT image after adaptive compensation. C. Measurement of ALI distance (ALID). The yellow line indicates the anterior lamina cribrosa surface, and the white lines indicate the choroidoscleral interface. ALID (red arrow lines) was defined as the distance from the anterior scleral canal opening (green dots) to the meeting point of the anterior laminar surface and the scleral canal wall (yellow dots). D. mALCSD (red arrow lines) was defined as the perpendicular distance from the anterior scleral canal opening plane (green dashed line) to the anterior lamina cribrosa surface (yellow line) at the location of the anterior scleral canal opening (green dots). E. Alignment of the SS-OCT scans to the fovea–Bruch's membrane opening center axis (foBMO axis), obtained using Spectralis infrared (IR) fundus photography (upper left). The SS-OCT IR fundus photography (upper right), which contains 12 lines indicating the location of the scan, was overlapped with the Spectralis IR fundus photograph (lower). The SS-OCT radial scan line that was closest to the foBMO axis (thin arrow) was defined as the 9 o′clock meridian (thick arrow). Note that the numbers in the SS-OCT IR fundus photography represent the serial number of the scans, not the clock-hour meridian.
Figure 2.
Schematic diagram and sample images for detecting the anterior scleral canal opening (ASCO) in various types of border tissue of Elschnig (BTE).
(A,B) non-oblique BTE, (C,D) externally oblique BTE, (E,F) internally oblique BTE. B, D, F. Left column is SS-OCT image without label, and right column is SS-OCT image with label. Anterior scleral surface (red dashed lines) is followed to the optic nerve head, and projected to define the ASCO (green dots).
Table 1.
Characteristics of the patients with primary open-angle glaucoma (POAG) and the normal healthy (control) subjects.
Figure 3.
ALID measurement in eyes with an acquired pit.
A. SS-OCT image without labels. Note that the lamina cribrosa is disinserted from the adjacent sclera. B. SS-OCT image after adaptive compensation. C. ALI was defined using an imaginary extension line (yellow dashed line) in eyes with a pit.
Table 2.
Number of cases for which either the anterior lamina cribrosa insertion distance (ALID) or the marginal anterior laminar cribrosa depth (mALCSD) was not measurable in each meridian.
Table 3.
Inter and intraobserver reliability of measuring ALID and mALCSD.
Figure 4.
Comparison of ALI positions between eyes from a patient with primary open-angle glaucoma (POAG) and a normal control (both aged 62 years).
The images are for the right eye in both patients. White arrows in the central circle indicate the meridians of the scans. The upper and lower images in each pair are from the normal control and POAG eyes, respectively. Yellow lines indicate the lamina cribrosa surface and white lines indicate the choroidoscleral interface. Note that ALID is greater in the POAG eye, with the most prominent differences being observed in the superotemporal and inferotemporal areas.
Figure 5.
Comparison of ALID (A) and mALCSD (B) between subjects with POAG and healthy controls in each meridian.
Significant differences after Bonferroni correction (p<0.002) are indicated with asterisks.
Table 4.
Comparison of ALID between POAG patients and normal healthy (control) subjects.
Table 5.
Comparison of mALCSD between POAG patients and normal healthy (control) subjects.
Table 6.
Factors affecting ALI in normal healthy subjects.
Table 7.
Factors affecting anterior laminar cribrosa insertion in primary open angle glaucoma.
Figure 6.
Comparison of ALID and mALCSD based on Bruch's membrane opening (white dashed line) and the anterior scleral canal opening (green dashed line) in a glaucomatous eye (A, B, C) and a normal eye (D, E, F).
A, D. SS-OCT images without labels. B, E. SS-OCT images after adaptive compensation. C, F. Yellow lines indicate the lamina cribrosa surface, and green lines indicate the anterior scleral surface. ALID measured from Bruch's membrane opening would be α (red dashed line) +β (red line), while ALID from the anterior scleral canal opening would be α. Note that α+β is similar between C and F; however, α is noticeably smaller in F than in C. Similarly, mALCSD is much larger in F when it is measured from the level of BMO (longer double arrows), although the depths from the ASCO (shorter double arrows) are smaller in F than in C.