March 2014
Volume 55, Issue 3
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Glaucoma  |   March 2014
Lamina Cribrosa Depth in Healthy Eyes
Author Affiliations & Notes
  • Je Hyun Seo
    Department of Ophthalmology, Pusan National University Yangsan Hospital, Pusan, Korea
  • Tae-Woo Kim
    Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
  • Robert N. Weinreb
    Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, California
  • Correspondence: Tae-Woo Kim, Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-dong, Bundang-gu, Seongnam, Gyeonggi-do 463-707, Korea; twkim7@snu.ac.kr
Investigative Ophthalmology & Visual Science March 2014, Vol.55, 1241-1251. doi:10.1167/iovs.13-12536
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      Je Hyun Seo, Tae-Woo Kim, Robert N. Weinreb; Lamina Cribrosa Depth in Healthy Eyes. Invest. Ophthalmol. Vis. Sci. 2014;55(3):1241-1251. doi: 10.1167/iovs.13-12536.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose.: To investigate the characteristics of the lamina cribrosa (LC) depth in healthy eyes using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT).

Methods.: Serial horizontal B-scans of the optic nerve head were obtained using EDI SD-OCT for both eyes of 150 healthy subjects. Anterior LC surface (ALCS) depths were measured with B-scan images from equidistant planes in each eye and defined as the distance from the Bruch's membrane opening plane to the anterior LC surface. The ALCS depths were compared between eyes within each subject. A linear mixed model was used to identify factors associated with the ALCS depth.

Results.: The average ALCS depth was 402.06 ± 101.46 μm (range, 193.08–826.81). The ALCS depth was not significantly different between the right and left eyes (Ps > 0.05 at all planes). There was a strong intereye correlation within subjects (Rs ≥ 0.808 at all planes, Ps < 0.0001 at all planes). The ALCS depth was largest in the superior periphery and smallest in the central inferior plane. ALCS depth was larger in males (P < 0.05) and also larger in eyes with shorter axial length (P = 0.029).

Conclusions.: This study reports the range of ALCS depth in healthy subjects. These data suggest that ALCS depth is related to sex and axial length.

Introduction
The lamina cribrosa (LC) is considered to be the putative site of primary axonal injury in glaucoma. 14 Distortions within the LC are thought to contribute to or in some instances initiate the blockade of axoplasmic flow within the retinal ganglion cell axons that lead to glaucomatous vision loss. 47  
Numerous experimental studies have shown the posterior displacement of the anterior LC surface (ALCS) after IOP elevation with respect to the neural canal opening reference level. 811 Recently, our group demonstrated that the LC moves anteriorly (reduction of LC depth) after IOP lowering in glaucoma patients using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). 12,13 These findings together indicate that increase of the ALCS depth, which is attributable to posterior displacement and/or thinning of the LC, is a principal component of glaucomatous optic neuropathy, and the ALCS depth may vary in relation to IOP-related stress in human glaucoma patients. Moreover, it has been demonstrated that the displacement of the LC may precede early surface-detected structural damage and early retinal nerve fiber layer loss in experimental glaucoma. 1417  
Features of the LC, including LC depth, may provide an additional index to diagnose glaucoma, and also may be potentially useful to assess the IOP-related stress on the optic nerve head. To evaluate the value of LC depth as a clinical index, it is essential to know the LC depth in a healthy population. Such knowledge should provide a basis for the recognition of glaucomatous LC change in patients. The purpose of the present study was to investigate the ALCS depth in healthy subjects and to determine the factors associated with the LC depth. 
Methods
This study was conducted on healthy subjects attending the Seoul National University Bundang Hospital Glaucoma Clinic from June 2010 to May 2011. The study was approved by the Seoul National University Bundang Hospital Institutional Review Board and conformed to the Declaration of Helsinki. Informed consent was obtained from all of the subjects. 
Study Subjects
The subjects were enrolled by advertisement. All participants underwent complete ophthalmic examinations, including visual acuity measurement, Goldmann applanation tonometry, refraction, slit-lamp biomicroscopy, gonioscopy, stereoscopic disc photography, SD-OCT, central corneal thickness (CCT) measurement (Orbscan II; Bausch & Lomb Surgical, Rochester, NY), axial length (AXL) measurement (IOL Master version 5; Carl Zeiss Meditec, Dublin, CA), and standard automated perimetry (Humphrey Field Analyzer II 750; 24-2 Swedish interactive threshold algorithm; Carl Zeiss Meditec). 
To be included, the eyes were required to have IOP less than 21 mm Hg without antiglaucomatous medication, normal-appearing optic discs, and normal visual fields. Normal-appearing optic disc was defined as the absence of glaucomatous optic neuropathy (i.e., focal thinning, notching, and disc hemorrhage) and absence also of pallor or swelling of the optic disc. Normal visual field was defined as the absence of glaucomatous or neurologic visual field defects. Glaucomatous visual field defect was defined as (1) outside normal limit on glaucoma hemifield test; (2) three abnormal points with P less than 5% probability of being normal, one with P less than 1% by pattern deviation; or (3) pattern SD less than 5%, confirmed on two consecutive tests. A visual field measurement was considered as reliable when false-positive/negative results were less than 25% and fixation losses were less than 20%. 
Exclusion criteria were best-corrected visual acuities worse than 20/40, spherical refraction greater than +5.0 diopters (D) and less than −8.0 D, cylinder correction greater than +3.0 D, anisometropia (intereye diopter difference > 2 D), or poor image quality as described below (see enhanced depth imaging OCT section). Subjects with a history of ocular surgery other than uncomplicated cataract surgery, intraocular disease (e.g., diabetic retinopathy or retinal vein occlusion), or neurologic disease (e.g., pituitary tumor) that could cause visual field loss were also excluded from this study. Both eyes were included for comparison of ALCS depth symmetry. 
Enhanced Depth Imaging OCT
The optic nerve image was acquired by the Spectralis OCT (Heidelberg Engineering GmbH, Heidelberg, Germany) using the EDI technique. The details and advantages of this technology to evaluate the LC have been described previously. 18 In brief, the imaging was performed using a 10 × 15-degree rectangle covering the optic disc. This rectangle was scanned with approximately 65 sections, which were 30 to 34 μm apart (the slicing distance is determined automatically by the machine). Each section had 42 OCT frames averaged, which provided the best trade-off between the image quality and patient cooperation. Using Spectralis OCT, the images are obtainable only when the quality score is higher than 15. When the quality score does not reach 15, the image acquisition process automatically stops and image of the respective section remains missing. Eyes were also excluded when a good-quality image (i.e., quality score > 15) could not be obtained at more than five sections. Moreover, when the image did not allow clear delineation of anterior border of the central LC, the subject was further excluded. Three-dimensional (3D) volumetric images were reconstructed from the B-scan images and en face images were constructed from the 3D images using image-processing software (Amira 5.2.2; Visage Imaging, Berlin, Germany). 
Measurement of LC Depth
After the 3D image was reconstructed, seven B-scan images that divided the optic disc diameter into eight equal parts vertically were selected for each eye. These seven B-scan lines (red lines) were defined as plane 1 to plane 7 (top to bottom). In this model, plane 4 corresponds to the mid-horizontal plane, and planes 2 and 6 correspond to the superior and inferior mid-periphery, respectively (Fig. 1). The ALCS depth was measured at each plane, and defined as the distance from the Bruch's membrane opening level to the anterior LC surface. 
Figure 1
 
Measurement of the anterior lamina cribrosa surface depth. (A) Three-dimensional image was reconstructed using EDI SD-OCT files. Then, seven equidistant planes were determined and named as plane 1 to plane 7 (top to bottom). (B) The LC depth was measured as the distance from the line connecting the two Bruch's membrane edges (reference line) to the anterior surface of the LC. Lamina cribrosa depth was measured at three points: the maximum depth point and two additional points (100 and 200 μm apart from the maximum depth point to temporal direction). The average of three measurements (452, 448, 448 μm) was taken as the ALCS depth (449.3 μm) of the plane.
Figure 1
 
Measurement of the anterior lamina cribrosa surface depth. (A) Three-dimensional image was reconstructed using EDI SD-OCT files. Then, seven equidistant planes were determined and named as plane 1 to plane 7 (top to bottom). (B) The LC depth was measured as the distance from the line connecting the two Bruch's membrane edges (reference line) to the anterior surface of the LC. Lamina cribrosa depth was measured at three points: the maximum depth point and two additional points (100 and 200 μm apart from the maximum depth point to temporal direction). The average of three measurements (452, 448, 448 μm) was taken as the ALCS depth (449.3 μm) of the plane.
To do this, a line connecting the Bruch's membrane edges was set as a reference plane, then the ALCS depth was measured in the direction perpendicular to the reference plane at three points: the maximum depth point and two additional points (100 and 200 μm apart from the maximum depth point to temporal direction). Only the temporally adjacent points were selected because the maximally depressed point was often close to the central vessel trunk, which had a shadow that obscured the LC (Fig. 1). The average of three measurements was taken as the ALCS depth of each plane. The average of the LC depths from the seven planes was defined as the mean ALCS depth of the eye. 
Each B-scan image was enlarged on the computer screen so that each pixel was clearly visible when the caliper tool was used. The ALCS depth was measured by a single experienced observer (JHS) who was masked to the clinical information. Our previous study had shown that interobserver intraclass correlation coefficient (ICC) of this method was more than 0.998. 13  
Data Analysis
Paired t-test was performed for intereye comparison of the ALCS depth within subjects. A Pearson correlation coefficient was calculated to examine the correlation between right and left eyes within subjects. A linear mixed model was used to assess the association of clinical factors with the ALCS depth (univariate and multivariate), including both eyes of each patient. The factors included were age, sex, refractive error, IOP at the time of disc scanning, CCT, AXL, and disc area, which was measured on infrared fundus photography. For multivariate analysis, interaction terms of some parameters (CCT and IOP, AXL and refractive error) were also included. A false discovery rate (FDR) was controlled using the Benjamini-Hochberg step-up procedure. 19,20 P values of less than 0.05 were considered to indicate statistical significance. Univariate and multivariate linear regression analyses were also performed for left eyes from each patient. 
Data analysis was performed using the Statistical Package for Social Sciences (version 18.0; SPSS, Inc., Chicago, IL). 
Results
The study initially involved 328 eyes of 164 subjects who were willing to participate in the study. Of these, three subjects were excluded because they were suspected for glaucoma or another optic neuropathy. Eleven subjects were further excluded because of low image quality that disabled the clear delineation of either the anterior border of the LC, leaving a final sample of 300 eyes of 150 subjects. 
The mean age was 48.31 ± 14.31 years (Table 1). Ninety-six subjects were female and 54 subjects were male. The IOP, refractive error (spherical equivalent), AXL, CCT, and mean deviation (MD) value of visual field were not different between the right and left eyes (P > 0.05). 
Table 1
 
Demographic Characteristics of Study Subjects
Table 1
 
Demographic Characteristics of Study Subjects
Variables Participants, n = 150 Right Eyes, n = 150 Left Eyes, n = 150 P Value* Correlation Coefficient(P Value)
Age, y 48.31 ± 14.31 (range, 18–83)
Age distribution 150
 <40, n (%) 40 (26.7)
 41–50, n (%) 32 (21.3)
 51–60, n (%) 48 (32.0)
 ≥61, n (%) 30 (20.0)
Male/female 54/96
Diabetes mellitus, n (%) 8 (5.3)
Systemic hypertension, n (%) 25 (16.7)
IOP at the time of disc scanning, mm Hg 12.51 ± 2.77 12.59 ± 2.62 0.675 0.688 (<0.0001)
Spherical equivalent, D −0.91 ± 2.22 −0.98 ± 2.25 0.247 0.944 (<0.0001)
AXL, mm 23.87 ± 1.22 23.89 ± 1.26 0.588 0.964 (<0.0001)
CCT, μm 554.97 ± 36.14 554.39 ± 36.66 0.594 0.934 (<0.0001)
Visual field MD, dB −0.41 ± 1.24 −0.40 ± 1.31 0.874 0.965 (<0.0001)
ALCS Depth Variation Between Subjects
The mean ALCS depth was 402.06 ± 101.46 μm. The mean frequency distribution of the ALCS depth showed a Gaussian curve (P = 0.114, Fig. 2) ranging from 193.08 to 826.81 μm. 
Figure 2
 
Histogram showing the distribution of the ALCS depth in right and left eyes among healthy subjects (n = 150). The ALCS depth distribution showed a normal curve (Gaussian curve) (P = 0.114 by Kolmogorov-Smirnov test).
Figure 2
 
Histogram showing the distribution of the ALCS depth in right and left eyes among healthy subjects (n = 150). The ALCS depth distribution showed a normal curve (Gaussian curve) (P = 0.114 by Kolmogorov-Smirnov test).
There was no significant difference between the right (404.86 ± 102.04 μm) and left eyes (399.31 ± 101.08 μm) (Ps > 0.05) and there was a strong intereye correlation (correlation coefficients ≥ 0.808, all Ps < 0.0001; Table 2, Fig. 3). 
Figure 3
 
Scatterplot of anterior laminar cribrosa surface depth in right and left eyes. Solid line indicates trend line and dotted lines indicate 95% confidential interval. The extreme value over 95% confidence intervals of ALCS depth ranged from 198.69 to 310.42 μm.
Figure 3
 
Scatterplot of anterior laminar cribrosa surface depth in right and left eyes. Solid line indicates trend line and dotted lines indicate 95% confidential interval. The extreme value over 95% confidence intervals of ALCS depth ranged from 198.69 to 310.42 μm.
Table 2
 
Anterior LC Surface Depth in Right and Left Eyes in Healthy Subjects According to Plane
Table 2
 
Anterior LC Surface Depth in Right and Left Eyes in Healthy Subjects According to Plane
Plane Number All, n = 300, Mean ± SD (Range) Right Eyes, n = 150, Mean ± SD (Range) Left Eyes, n = 150, Mean ± SD (Range) P Value* Correlation Coefficient(P Value) Absolute Difference
1 LC depth, μm 425.65 ± 113.47 (177.52–888.33) 428.34 ± 113.37 (177.52–888.33) 422.96 ± 113.87 (183.64–840.67) 0.503 0.825 (<0.0001) 53.99 ± 40.32
2 LC depth, μm 420.08 ± 113.18 (209.72–842.33) 422.91 ± 111.87 (209.72–842.33) 417.26 ± 114.78 (216.44–825.00) 0.503 0.814 (<0.0001) 54.58 ± 42.70
3 LC depth, μm 405.80 ± 111.75 (174.57–844.33) 406.94 ± 113.91 (174.57–844.33) 404.66 ± 109.92 (207.66–755.67) 0.661 0.839 (<0.0001) 47.30 ± 42.52
4 LC depth, μm 391.09 ± 104.21 (166.08–802.00) 395.09 ± 107.50 (166.08–802.00) 387.08 ± 101.02 (168.00–760.67) 0.424 0.814 (<0.0001) 49.03 ± 41.44
5 LC depth, μm 384.69 ± 103.32 (166.00–850.33) 386.47 ± 109.32 (166.00–850.33) 382.91 ± 97.27 (190.33–773.00) 0.575 0.808 (<0.0001) 52.53 ± 38.28
6 LC depth, μm 389.08 ± 102.14 (192.20–815.00) 393.82 ± 102.46 (192.20–815.00) 384.54 ± 101.43 (201.00–794.33) 0.424 0.828 (<0.0001) 50.47 ± 34.18
7 LC depth, μm 398.04 ± 99.81 (195.29–745.33) 400.27 ± 96.50 (205.73–745.33) 395.81 ± 103.29 (195.29–728.67) 0.503 0.811 (<0.0001) 48.90 ± 37.74
Average LC depth, μm 402.06 ± 101.46 (193.08–826.81) 404.84 ± 102.04 (193.08–826.81) 399.31 ± 101.08 (228.43–771.00) 0.424 0.890 (<0.0001) 37.88 ± 29.51
ALCS Depth Variation Within Eyes
The mean ALCS depth showed a significant variation between planes. In general, the ALCS depth was largest in the superior periphery and smallest in the central inferior plane (plane 5) (Fig. 4). 
Figure 4
 
Graph showing the variation of anterior lamina cribrosa surface depth among different planes. With both eyes from all subjects included (n = 300 eyes), paired t-test showed significant difference between planes. The depth was smallest at the central-inferior plane (plane 5).
 
*Statistically significant changes after controlling the FDR for multiple comparison adjusted P (a P value of <0.05 was considered significant).
Figure 4
 
Graph showing the variation of anterior lamina cribrosa surface depth among different planes. With both eyes from all subjects included (n = 300 eyes), paired t-test showed significant difference between planes. The depth was smallest at the central-inferior plane (plane 5).
 
*Statistically significant changes after controlling the FDR for multiple comparison adjusted P (a P value of <0.05 was considered significant).
Association of Sex, Age, Refractive Errors, IOP, CCT, AXL, and Disc Area With LC Depths
The univariate analysis using linear mixed model with controlling the FDR for multiple comparison showed a significant association of sex (all Ps ≤ 0.05) with ALCS depth at all planes (Table 3). Axial length was associated with ALCS depth at plane 1 (P = 0.077) and at plane 7 (P = 0.052) with marginal significance. Disc area was significantly associated with ALCS depth at all planes (Ps ≤ 0.048). On multivariate analysis, sex was associated with ALCS depth at all planes (Ps ≤ 0.007) and AXL was significantly associated with ALCS depth at plane 1 (P = 0.024), plane 2 (P = 0.027), plane 6 (P = 0.029), and plane 7 (P = 0.026), and for average ALCS depth (P = 0.029). Disc area was significantly associated with ALCS depth at planes 1, 2, and 3 (Ps = 0.043) (Table 4). 
Table 3
 
Univariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Table 3
 
Univariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Plane Number Age Coefficient, P Value Sex Coefficient, P Value Refractive Error Coefficient, P Value IOP Coefficient, P Value CCT Coefficient, P Value AXL Coefficient, P Value Disc Area Coefficient, P Value
1 0.344, P = 0.743 46.885, P = 0.028 2.633, P = 0.637 1.570, P = 0.821 −0.165, P = 0.585 −11.821, P = 0.077 47.634, P = 0.018
2 0.459, P = 0.743 43.838, P = 0.028 2.526, P = 0.637 0.194, P = 0.928 −0.193, P = 0.585 −8.056, P = 0.227 45.203, P = 0.018
3 0.303, P = 0.743 44.679, P = 0.028 3.212, P = 0.637 −1.204, P = 0.821 −0.126, P = 0.625 −5.969, P = 0.362 45.782, P = 0.018
4 0.061, P = 0.915 40.478, P = 0.028 1.459, P = 0.749 −0.642, P = 0.851 −0.065, P = 0.743 −4.706, P = 0.444 34.329, P = 0.035
5 0.256, P = 0.743 35.433, P = 0.038 −0.213, P = 0.948 −2.387, P = 0.680 −0.366, P = 0.507 −0.761, P = 0.901 30.035, P = 0.048
6 0.709, P = 0.743 36.675, P = 0.036 2.646, P = 0.637 −2.159, P = 0.680 −0.291, P = 0.524 −7.718, P = 0.199 30.978, P = 0.046
7 0.942, P = 0.664 30.320, P = 0.031 3.727, P = 0.637 −2.166, P = 0.680 −0.229, P = 0.585 −11.408, P = 0.052 37.400, P = 0.018
Average LC depth 0.439, P = 0.743 39.758, P = 0.028 3.113, P = 0.637 −0.807, P = 0.821 −0.167, P = 0.585 −8.869, P = 0.126 38.784, P = 0.018
Table 4
 
Multivariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Table 4
 
Multivariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Plane Num-ber Age Coefficient, P Value Sex Coefficient, P Value Refractive Error Coefficient, P Value IOP Coefficient, P Value CCT Coefficient, P Value AXL Coefficient, P Value AXL*Refractive Error Coefficient, P Value IOP*CCT Coefficient, P Value Disc Area Coefficient, P Value
1 0.194, P = 0.967 −52.403, P = 0.0008 27.922, P = 0.462 35.895, P = 0.377 0.436, P = 0.756 −27.481, P = 0.024 −1.530, P = 0.311 −0.061, P = 0.417 41.664, P = 0.043
2 0.317, P = 0.991 −48.489, P = 0.0016 45.215, P = 0.462 31.061, P = 0.402 0.314, P = 0.777 −24.262, P = 0.027 −2.173, P = 0.311 −0.055, P = 0.417 40.619, P = 0.043
3 0.207, P = 0.967 −44.604, P = 0.0016 44.852, P = 0.462 55.437, P = 0.339 0.963, P = 0.653 −16.546, P = 0.075 −2.001, P = 0.311 −0.099, P = 0.334 41.266, P = 0.043
4 0.060, P = 0.991 −41.018, P = 0.0023 29.771, P = 0.462 47.505, P = 0.339 0.824, P = 0.653 −16.202, P = 0.073 −1.438, P = 0.342 −0.085, P = 0.334 30.588, P = 0.083
5 0.379, P = 0.967 −34.756, P = 0.0070 17.234, P = 0.576 57.751, P = 0.339 1.022, P = 0.653 −11.637, P = 0.162 −0.914, P = 0.439 −0.106, P = 0.334 25.831, P = 0.109
6 0.610, P = 0.967 −42.796, P = 0.0016 28.387, P = 0.462 37.428, P = 0.347 0.572, P = 0.653 −19.529, P = 0.029 −1.414, P = 0.311 −0.069, P = 0.334 23.126, P = 0.131
7 0.510, P = 0.967 −38.596, P = 0.0023 31.734, P = 0.462 20.496, P = 0.486 0.168, P = 0.802 −20.567, P = 0.026 −1.454, P = 0.311 −0.039, P = 0.464 26.985, P = 0.093
Average LC depth 0.327, P = 0.967 −43.215, P = 0.0016 31.801, P = 0.462 40.984, P = 0.346 0.623, P = 0.653 −19.300, P = 0.029 −1.547, P = 0.311 −0.074, P = 0.334 32.911, P = 0.062
Tables 5 and 6 show the results of the univariate and multivariate linear regression analysis for left eyes from each patient. Sex was significantly associated with the ALCS depth both in the univariate and multivariate analysis (all Ps ≤ 0.05). Disc area was associated with the ALCS depth at planes 1, 2, 3, and 7 with marginal significance in the univariate analysis (all Ps = 0.099). On multivariate analysis, AXL was significantly associated the ALCS depth at planes 1, 2, 4, 5, 6, and 7 with marginal significance (P = 0.086–0.098). Disc area was significantly associated at plane 1 (P = 0.023), and was associated with marginal significance at planes 2, 3, and 7 (P = 0.089–0.092). There was a significant difference in the ALCS depth between male and female subjects (Ps ≤ 0.025; Table 7, Fig. 5). 
Figure 5
 
Relationship between AXL and average LC depth.
Figure 5
 
Relationship between AXL and average LC depth.
Table 5
 
Univariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT AXL, and Disc Area (n = 150 eyes)*†
Table 5
 
Univariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT AXL, and Disc Area (n = 150 eyes)*†
Plane Number Age β Coefficient, P Value Sex β Coefficient, P Value Refractive Error β Coefficient, P Value IOP β Coefficient, P Value CCT β Coefficient, P Value AXL β Coefficient, P Value Disc Area β Coefficient, P Value
1 0.440, P = 0.529 −45.360, P = 0.049 0.152, P = 0.981 2.786, P = 0.988 −0.300, P = 0.240 −6.756, P = 0.703 59.546, P = 0.099
2 0.582, P = 0.529 −45.912, P = 0.049 −0.275, P = 0.981 0.573, P = 0.988 −0.378, P = 0.188 −4.573, P = 0.703 46.320, P = 0.099
3 0.480, P = 0.529 −42.682, P = 0.049 −0.333, P = 0.981 0.679, P = 0.988 −0.296, P = 0.240 −2.741, P = 0.703 45.261, P = 0.099
4 0.366, P = 0.529 −36.696, P = 0.049 −0.355, P = 0.981 −0.048, P = 0.988 −0.340, P = 0.188 −3.140, P = 0.703 34.676, P = 0.112
5 0.549, P = 0.529 −33.279, P = 0.049 0.084, P = 0.981 −1.650, P = 0.988 −0.457, P = 0.188 −4.101, P = 0.703 35.924, P = 0.112
6 0.873, P = 0.529 −35.670, P = 0.049 2.112, P = 0.981 −2.198, P = 0.988 −0.411, P = 0.188 −7.621, P = 0.703 34.891, P = 0.112
7 1.217, P = 0.529 −29.992, P = 0.048 4.177, P = 0.981 −2.823, P = 0.988 −0.419, P = 0.188 −11.461, P = 0.703 48.688, P = 0.099
Average LC depth 0.641, P = 0.529 −38.376, P = 0.049 0.780, P = 0.981 −0.386, P = 0.988 −0.374, P = 0.188 −5.776, P = 0.703 43.539, P = 0.099
Table 6
 
Multivariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 150 eyes)*†
Table 6
 
Multivariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 150 eyes)*†
Plane Number Age β Coefficient, P Value Sex β Coefficient, P Value Refractive Error β Coefficient, P Value IOP β Coefficient, P Value CCT β Coefficient, P Value AXL β Coefficient, P Value AXL*Refractive Error β Coefficient, P Value IOP*CCT β Coefficient, P Value Disc Area β Coefficient, P Value
1 0.337, P = 0.676 −47.424, P = 0.044 19.847, P = 0.766 75.688, P = 0.235 1.120, P = 0.492 −32.203, P = 0.086 −1.339, P = 0.596 −0.127, P = 0.256 57.035, P = 0.023
2 0.563, P = 0.659 −48.661, P = 0.044 41.848, P = 0.766 72.987, P = 0.235 1.120, P = 0.492 −27.503, P = 0.086 −2.128, P = 0.596 −0.126, P = 0.256 43.035, P = 0.092
3 0.585, P = 0.659 −41.628, P = 0.046 32.259, P = 0.766 96.070, P = 0.235 1.740, P = 0.492 −20.342, P = 0.113 −1.639, P = 0.596 −0.169, P = 0.256 41.812, P = 0.089
4 0.351, P = 0.676 −38.260, P = 0.046 23.076, P = 0.766 61.073, P = 0.235 0.928, P = 0.492 −20.436, P = 0.098 −1.261, P = 0.596 −0.106, P = 0.256 31.293, P = 0.169
5 0.490, P = 0.659 −35.240, P = 0.046 28.649, P = 0.766 62.880, P = 0.235 0.915, P = 0.492 −20.915, P = 0.086 −1.486, P = 0.596 −0.112, P = 0.256 32.452, P = 0.134
6 0.751, P = 0.659 −41.974, P = 0.044 19.637, P = 0.766 38.956, P = 0.442 0.484, P = 0.695 −22.642, P = 0.086 −1.127, P = 0.596 −0.070, P = 0.442 26.381, P = 0.246
7 0.983, P = 0.659 −36.739, P = 0.046 13.734, P = 0.766 34.420, P = 0.448 0.408, P = 0.695 −24.028, P = 0.086 0.903, P = 0.610 −0.063, P = 0.442 38.799, P = 0.091
Average LC depth 0.575, P = 0.659 −41.290, P = 0.044 25.586, P = 0.766 63.158, P = 0.235 0.956, P = 0.492 −24.078, P = 0.086 −1.413, P = 0.596 −0.110, P = 0.256 38.673, P = 0.085
Table 7
 
Comparison of Anterior Lamina Cribrosa Surface Depth Between Male and Female Groups
Table 7
 
Comparison of Anterior Lamina Cribrosa Surface Depth Between Male and Female Groups
Plane Number Male, n = 108 eyes Female, n = 192 eyes P Value*
Coefficient SE Coefficient SE
1 LC depth, μm 466.56 14.90 402.65 11.04 0.006
2 LC depth, μm 456.00 14.79 399.88 10.94 0.009
3 LC depth, μm 439.90 14.82 386.61 10.97 0.009
4 LC depth, μm 422.63 13.78 373.34 10.20 0.009
5 LC depth, μm 409.72 13.61 370.61 10.07 0.025
6 LC depth, μm 419.12 13.38 372.18 9.90 0.009
7 LC depth, μm 426.06 12.97 382.28 9.59 0.010
Average LC depth 436.89 13.58 383.59 10.06 0.003
Discussion
The optic nerve head (ONH) is composed of neural, vascular, and connective tissues. Glaucomatous optic neuropathy involves damage and remodeling of these tissues. Previous histological study revealed that the backward bowing as well as compression of LC sheets are principal features in glaucoma. 2 Further, it has been demonstrated that the displacement of the LC may be the earliest change in experimental nonhuman primate glaucoma models. 1417 Hence, LC depth may be potentially useful as an index for predicting the development of glaucoma in suspected patients. To use the LC depth as a clinical index, it is essential to know its normative profile and factors associated with LC depth variation. In the present study, we report the range of ALCS depth in healthy subjects. The LC depths in the right and left eyes were not different within subjects and were strongly correlated. Both sex and AXL were associated with LC depth. To our knowledge, this is the first report that investigated depth and factors related to the ALCS depth in healthy subjects using EDI SD-OCT. 
We observed that males had significantly larger ALCS depth than females. This finding is in line with ONH parameters measured by Heidelberg retina tomograph or SD-OCT, 2125 which showed that males had larger mean cup depth than females. Assuming that prelaminar neural tissue thickness is not highly variable among subjects, one may expect that eyes with deep LC may have larger cup volume. Thus, the sex difference in the ALCS depth may provide an explanation for the sex difference in cup-related parameters. 
Axial length had a significant negative correlation with ALCS depth in the present study. This relationship may be related to the change in the optic disc configuration in myopic eyes observed during childhood. 26 As the globe grows axially, temporal sclera moves back and flattens. 26 In this process, the optic nerve is pulled toward the temporal direction and the connection of the temporal disc and the sclera becomes flattened, leading to an oblique (or tilted) appearance of the optic disc. This may result in shorter LC depth, which is measured using the Bruch's membrane opening level as the reference (Fig. 6). 
Figure 6
 
Sample cases showing the different ALCS depths according to axial length in plane 6. (A) ALCS depth for the right of a female subject with AXL of 22.35 mm. The ALCS depths at the three locations were 499, 495, and 503 μm. (B) ALCS depth for the right eye of a female subject with AXL of 26.44 mm. The LC depths at three locations were 309, 320, and 298 μm.
Figure 6
 
Sample cases showing the different ALCS depths according to axial length in plane 6. (A) ALCS depth for the right of a female subject with AXL of 22.35 mm. The ALCS depths at the three locations were 499, 495, and 503 μm. (B) ALCS depth for the right eye of a female subject with AXL of 26.44 mm. The LC depths at three locations were 309, 320, and 298 μm.
Age was not associated with ALCS depth. One may consider the possibility that age is related to ALCS depth because the choroidal thickness decreases with age. 2731 The thinning of the choroidal thickness would reduce the ALCS depth, which is measured from the Bruch's membrane opening (BMO) plane. Although we do not have a clear answer about the absence of association between age and ALCS depth, we speculate that the LC depth from the anterior scleral canal opening (ASCO) plane may increase with age, which may offset the effect of choroidal thinning. This idea may be confirmed by measuring the ALCS depth using the ASCO plane as the reference. However, we could not perform this because the ASCO plane was often invisible in the EDI-OCT image. 
Recently, the concept of fovea-BMO center axis has been introduced. 32 It is known that the positions of the fovea and ONH shown in the fundus image may vary among subjects and even within the same individual from day to day because of cyclotorsion. 33 Therefore, it would be ideal if the B-scan images could be obtained parallel to the fovea-BMO center axis. In our patients, the angles of this axis ranged from −19.8 degrees to 6.5 degrees (mean, −6.40 ± 3.60), which is similar to that in a previous report. 32  
It is known that the ALCS depth is positively associated with the IOP level in glaucoma patients. 12,13 However, IOP was not significantly associated with the ALCS depth in the present study. We speculate that this may be because our study enrolled only healthy subjects with IOP lower than 21 mm Hg. 
Recently, Park et al. 34 examined the LC configuration in 30 healthy subjects and demonstrated that the LC has a horizontal central ridge with the smallest LC depth. We confirm this finding in a much larger sample of healthy subjects. In our population, the plane of the smallest ALCS depth was found slightly inferior from the center. 
The ALCS depth was 402.06 ± 101.46 μm in the present study. This result is similar to that of a previous study. 35 Furlanetto et al. 35 compared the ALCS depth of the lamina cribrosa in glaucoma and healthy eyes. The averaged maximum depth, which was measured at one point in each of 11 B-scans, was 453 ± 81 μm in their study. In addition, both studies demonstrated that the ALCS depth is largest in the superior mid-periphery. 
The shape of the LC determined in the present study was not a U or W shape that has been typically depicted in the literature. 57,16,34,35 This may be because we did not include the LC at the border of the optic disc, as the ALCS often was not clearly visible in this area. In some cases, the ALCS was visible at the superior or inferior optic disc border, and the ALCS depth in that region was typically shallower than in planes 1 and 7. Thus, the LC curvature would be W-shaped, if the LC at that border of the optic disc was included. 
Our study has limitations. First, all subjects included were Korean. Given the ethnic difference in the optic disc topography, 36 it is likely that there is an ethnic variation in the LC depth. Further study is needed in other ethnic groups. Second, the ALCS depth measurement was obtained only in the central three points in each B-scan due to the limitation of current technology. However, as there is posterior bowing in the LC with glaucoma, 811 the central portion of the LC in each plane in fact may be the area of interest. The depth variation in the peripheral LC near its insertion into the peripapillary sclera flange remains to be examined. Third, we excluded 11 subjects whose images did not allow clear delineation of anterior border of the central LC due to low image quality. One may consider that this criterion may lead to exclusion of the eyes with thick prelaminar tissue having large ALCS depth, and may be related to the positive skew of the ALCS depth, as shown in Figure 2. However, 10 of the 11 eyes excluded had a broken image or blood vessel shadow obscuring the LC. The thick prelaminar tissue was relevant only in one eye. Thus, the effect of this exclusion criterion may be negligible regarding the positive skew of the LC depth. Fourth, previous studies using finite element modeling have demonstrated that sclera thickness affect the mechanical stress given to the optic nerve head 37 and the strains in the LC. 38 These findings suggest that the sclera thickness may have significant influence on the ALCS depth. However, sclera thickness was not evaluated in the present study. This was because sclera thickness was not measurable using EDI-OCT due to invisibility of the posterior (outer) surface of the sclera using this device. Fifth, the association of the disc area with the ALCS depth was evaluated. It would be ideal if the association of the ASCO area was evaluated instead of the disc area; however, it is not possible to measure the ASCO area using EDI-OCT due to the lack of visibility of ASCO with this technology. Last, ALCS depth can be measured by using different methods. 34,35,3941 In particular, researchers at Devers Eye Institute 3941 have delineated the ALCS using 48 radial B-scans. Their method may provide a more robust characterization of the ALCS and BMO reference plane, 3941 whereas our method may be more convenient for clinical practice due to its simplicity. Further study is needed to examine whether seven-section laminar sampling provides results that are equivalent to 24 or 48 radial B-scans. 
In conclusion, this report presents the profile of normality for ALCS depth evaluated using EDI-OCT. Lamina cribrosa depths are not different and are strongly correlated between right and left eyes. Given the significant association of sex and axial length with the LC depth, ALCS depth evaluation should consider these factors. 
Acknowledgments
Disclosure: J.H. Seo, None; T.-W. Kim, None; R.N. Weinreb, Heidelberg Engineering (F) 
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Figure 1
 
Measurement of the anterior lamina cribrosa surface depth. (A) Three-dimensional image was reconstructed using EDI SD-OCT files. Then, seven equidistant planes were determined and named as plane 1 to plane 7 (top to bottom). (B) The LC depth was measured as the distance from the line connecting the two Bruch's membrane edges (reference line) to the anterior surface of the LC. Lamina cribrosa depth was measured at three points: the maximum depth point and two additional points (100 and 200 μm apart from the maximum depth point to temporal direction). The average of three measurements (452, 448, 448 μm) was taken as the ALCS depth (449.3 μm) of the plane.
Figure 1
 
Measurement of the anterior lamina cribrosa surface depth. (A) Three-dimensional image was reconstructed using EDI SD-OCT files. Then, seven equidistant planes were determined and named as plane 1 to plane 7 (top to bottom). (B) The LC depth was measured as the distance from the line connecting the two Bruch's membrane edges (reference line) to the anterior surface of the LC. Lamina cribrosa depth was measured at three points: the maximum depth point and two additional points (100 and 200 μm apart from the maximum depth point to temporal direction). The average of three measurements (452, 448, 448 μm) was taken as the ALCS depth (449.3 μm) of the plane.
Figure 2
 
Histogram showing the distribution of the ALCS depth in right and left eyes among healthy subjects (n = 150). The ALCS depth distribution showed a normal curve (Gaussian curve) (P = 0.114 by Kolmogorov-Smirnov test).
Figure 2
 
Histogram showing the distribution of the ALCS depth in right and left eyes among healthy subjects (n = 150). The ALCS depth distribution showed a normal curve (Gaussian curve) (P = 0.114 by Kolmogorov-Smirnov test).
Figure 3
 
Scatterplot of anterior laminar cribrosa surface depth in right and left eyes. Solid line indicates trend line and dotted lines indicate 95% confidential interval. The extreme value over 95% confidence intervals of ALCS depth ranged from 198.69 to 310.42 μm.
Figure 3
 
Scatterplot of anterior laminar cribrosa surface depth in right and left eyes. Solid line indicates trend line and dotted lines indicate 95% confidential interval. The extreme value over 95% confidence intervals of ALCS depth ranged from 198.69 to 310.42 μm.
Figure 4
 
Graph showing the variation of anterior lamina cribrosa surface depth among different planes. With both eyes from all subjects included (n = 300 eyes), paired t-test showed significant difference between planes. The depth was smallest at the central-inferior plane (plane 5).
 
*Statistically significant changes after controlling the FDR for multiple comparison adjusted P (a P value of <0.05 was considered significant).
Figure 4
 
Graph showing the variation of anterior lamina cribrosa surface depth among different planes. With both eyes from all subjects included (n = 300 eyes), paired t-test showed significant difference between planes. The depth was smallest at the central-inferior plane (plane 5).
 
*Statistically significant changes after controlling the FDR for multiple comparison adjusted P (a P value of <0.05 was considered significant).
Figure 5
 
Relationship between AXL and average LC depth.
Figure 5
 
Relationship between AXL and average LC depth.
Figure 6
 
Sample cases showing the different ALCS depths according to axial length in plane 6. (A) ALCS depth for the right of a female subject with AXL of 22.35 mm. The ALCS depths at the three locations were 499, 495, and 503 μm. (B) ALCS depth for the right eye of a female subject with AXL of 26.44 mm. The LC depths at three locations were 309, 320, and 298 μm.
Figure 6
 
Sample cases showing the different ALCS depths according to axial length in plane 6. (A) ALCS depth for the right of a female subject with AXL of 22.35 mm. The ALCS depths at the three locations were 499, 495, and 503 μm. (B) ALCS depth for the right eye of a female subject with AXL of 26.44 mm. The LC depths at three locations were 309, 320, and 298 μm.
Table 1
 
Demographic Characteristics of Study Subjects
Table 1
 
Demographic Characteristics of Study Subjects
Variables Participants, n = 150 Right Eyes, n = 150 Left Eyes, n = 150 P Value* Correlation Coefficient(P Value)
Age, y 48.31 ± 14.31 (range, 18–83)
Age distribution 150
 <40, n (%) 40 (26.7)
 41–50, n (%) 32 (21.3)
 51–60, n (%) 48 (32.0)
 ≥61, n (%) 30 (20.0)
Male/female 54/96
Diabetes mellitus, n (%) 8 (5.3)
Systemic hypertension, n (%) 25 (16.7)
IOP at the time of disc scanning, mm Hg 12.51 ± 2.77 12.59 ± 2.62 0.675 0.688 (<0.0001)
Spherical equivalent, D −0.91 ± 2.22 −0.98 ± 2.25 0.247 0.944 (<0.0001)
AXL, mm 23.87 ± 1.22 23.89 ± 1.26 0.588 0.964 (<0.0001)
CCT, μm 554.97 ± 36.14 554.39 ± 36.66 0.594 0.934 (<0.0001)
Visual field MD, dB −0.41 ± 1.24 −0.40 ± 1.31 0.874 0.965 (<0.0001)
Table 2
 
Anterior LC Surface Depth in Right and Left Eyes in Healthy Subjects According to Plane
Table 2
 
Anterior LC Surface Depth in Right and Left Eyes in Healthy Subjects According to Plane
Plane Number All, n = 300, Mean ± SD (Range) Right Eyes, n = 150, Mean ± SD (Range) Left Eyes, n = 150, Mean ± SD (Range) P Value* Correlation Coefficient(P Value) Absolute Difference
1 LC depth, μm 425.65 ± 113.47 (177.52–888.33) 428.34 ± 113.37 (177.52–888.33) 422.96 ± 113.87 (183.64–840.67) 0.503 0.825 (<0.0001) 53.99 ± 40.32
2 LC depth, μm 420.08 ± 113.18 (209.72–842.33) 422.91 ± 111.87 (209.72–842.33) 417.26 ± 114.78 (216.44–825.00) 0.503 0.814 (<0.0001) 54.58 ± 42.70
3 LC depth, μm 405.80 ± 111.75 (174.57–844.33) 406.94 ± 113.91 (174.57–844.33) 404.66 ± 109.92 (207.66–755.67) 0.661 0.839 (<0.0001) 47.30 ± 42.52
4 LC depth, μm 391.09 ± 104.21 (166.08–802.00) 395.09 ± 107.50 (166.08–802.00) 387.08 ± 101.02 (168.00–760.67) 0.424 0.814 (<0.0001) 49.03 ± 41.44
5 LC depth, μm 384.69 ± 103.32 (166.00–850.33) 386.47 ± 109.32 (166.00–850.33) 382.91 ± 97.27 (190.33–773.00) 0.575 0.808 (<0.0001) 52.53 ± 38.28
6 LC depth, μm 389.08 ± 102.14 (192.20–815.00) 393.82 ± 102.46 (192.20–815.00) 384.54 ± 101.43 (201.00–794.33) 0.424 0.828 (<0.0001) 50.47 ± 34.18
7 LC depth, μm 398.04 ± 99.81 (195.29–745.33) 400.27 ± 96.50 (205.73–745.33) 395.81 ± 103.29 (195.29–728.67) 0.503 0.811 (<0.0001) 48.90 ± 37.74
Average LC depth, μm 402.06 ± 101.46 (193.08–826.81) 404.84 ± 102.04 (193.08–826.81) 399.31 ± 101.08 (228.43–771.00) 0.424 0.890 (<0.0001) 37.88 ± 29.51
Table 3
 
Univariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Table 3
 
Univariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Plane Number Age Coefficient, P Value Sex Coefficient, P Value Refractive Error Coefficient, P Value IOP Coefficient, P Value CCT Coefficient, P Value AXL Coefficient, P Value Disc Area Coefficient, P Value
1 0.344, P = 0.743 46.885, P = 0.028 2.633, P = 0.637 1.570, P = 0.821 −0.165, P = 0.585 −11.821, P = 0.077 47.634, P = 0.018
2 0.459, P = 0.743 43.838, P = 0.028 2.526, P = 0.637 0.194, P = 0.928 −0.193, P = 0.585 −8.056, P = 0.227 45.203, P = 0.018
3 0.303, P = 0.743 44.679, P = 0.028 3.212, P = 0.637 −1.204, P = 0.821 −0.126, P = 0.625 −5.969, P = 0.362 45.782, P = 0.018
4 0.061, P = 0.915 40.478, P = 0.028 1.459, P = 0.749 −0.642, P = 0.851 −0.065, P = 0.743 −4.706, P = 0.444 34.329, P = 0.035
5 0.256, P = 0.743 35.433, P = 0.038 −0.213, P = 0.948 −2.387, P = 0.680 −0.366, P = 0.507 −0.761, P = 0.901 30.035, P = 0.048
6 0.709, P = 0.743 36.675, P = 0.036 2.646, P = 0.637 −2.159, P = 0.680 −0.291, P = 0.524 −7.718, P = 0.199 30.978, P = 0.046
7 0.942, P = 0.664 30.320, P = 0.031 3.727, P = 0.637 −2.166, P = 0.680 −0.229, P = 0.585 −11.408, P = 0.052 37.400, P = 0.018
Average LC depth 0.439, P = 0.743 39.758, P = 0.028 3.113, P = 0.637 −0.807, P = 0.821 −0.167, P = 0.585 −8.869, P = 0.126 38.784, P = 0.018
Table 4
 
Multivariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Table 4
 
Multivariate Linear Mixed Model Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 300 eyes)*
Plane Num-ber Age Coefficient, P Value Sex Coefficient, P Value Refractive Error Coefficient, P Value IOP Coefficient, P Value CCT Coefficient, P Value AXL Coefficient, P Value AXL*Refractive Error Coefficient, P Value IOP*CCT Coefficient, P Value Disc Area Coefficient, P Value
1 0.194, P = 0.967 −52.403, P = 0.0008 27.922, P = 0.462 35.895, P = 0.377 0.436, P = 0.756 −27.481, P = 0.024 −1.530, P = 0.311 −0.061, P = 0.417 41.664, P = 0.043
2 0.317, P = 0.991 −48.489, P = 0.0016 45.215, P = 0.462 31.061, P = 0.402 0.314, P = 0.777 −24.262, P = 0.027 −2.173, P = 0.311 −0.055, P = 0.417 40.619, P = 0.043
3 0.207, P = 0.967 −44.604, P = 0.0016 44.852, P = 0.462 55.437, P = 0.339 0.963, P = 0.653 −16.546, P = 0.075 −2.001, P = 0.311 −0.099, P = 0.334 41.266, P = 0.043
4 0.060, P = 0.991 −41.018, P = 0.0023 29.771, P = 0.462 47.505, P = 0.339 0.824, P = 0.653 −16.202, P = 0.073 −1.438, P = 0.342 −0.085, P = 0.334 30.588, P = 0.083
5 0.379, P = 0.967 −34.756, P = 0.0070 17.234, P = 0.576 57.751, P = 0.339 1.022, P = 0.653 −11.637, P = 0.162 −0.914, P = 0.439 −0.106, P = 0.334 25.831, P = 0.109
6 0.610, P = 0.967 −42.796, P = 0.0016 28.387, P = 0.462 37.428, P = 0.347 0.572, P = 0.653 −19.529, P = 0.029 −1.414, P = 0.311 −0.069, P = 0.334 23.126, P = 0.131
7 0.510, P = 0.967 −38.596, P = 0.0023 31.734, P = 0.462 20.496, P = 0.486 0.168, P = 0.802 −20.567, P = 0.026 −1.454, P = 0.311 −0.039, P = 0.464 26.985, P = 0.093
Average LC depth 0.327, P = 0.967 −43.215, P = 0.0016 31.801, P = 0.462 40.984, P = 0.346 0.623, P = 0.653 −19.300, P = 0.029 −1.547, P = 0.311 −0.074, P = 0.334 32.911, P = 0.062
Table 5
 
Univariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT AXL, and Disc Area (n = 150 eyes)*†
Table 5
 
Univariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT AXL, and Disc Area (n = 150 eyes)*†
Plane Number Age β Coefficient, P Value Sex β Coefficient, P Value Refractive Error β Coefficient, P Value IOP β Coefficient, P Value CCT β Coefficient, P Value AXL β Coefficient, P Value Disc Area β Coefficient, P Value
1 0.440, P = 0.529 −45.360, P = 0.049 0.152, P = 0.981 2.786, P = 0.988 −0.300, P = 0.240 −6.756, P = 0.703 59.546, P = 0.099
2 0.582, P = 0.529 −45.912, P = 0.049 −0.275, P = 0.981 0.573, P = 0.988 −0.378, P = 0.188 −4.573, P = 0.703 46.320, P = 0.099
3 0.480, P = 0.529 −42.682, P = 0.049 −0.333, P = 0.981 0.679, P = 0.988 −0.296, P = 0.240 −2.741, P = 0.703 45.261, P = 0.099
4 0.366, P = 0.529 −36.696, P = 0.049 −0.355, P = 0.981 −0.048, P = 0.988 −0.340, P = 0.188 −3.140, P = 0.703 34.676, P = 0.112
5 0.549, P = 0.529 −33.279, P = 0.049 0.084, P = 0.981 −1.650, P = 0.988 −0.457, P = 0.188 −4.101, P = 0.703 35.924, P = 0.112
6 0.873, P = 0.529 −35.670, P = 0.049 2.112, P = 0.981 −2.198, P = 0.988 −0.411, P = 0.188 −7.621, P = 0.703 34.891, P = 0.112
7 1.217, P = 0.529 −29.992, P = 0.048 4.177, P = 0.981 −2.823, P = 0.988 −0.419, P = 0.188 −11.461, P = 0.703 48.688, P = 0.099
Average LC depth 0.641, P = 0.529 −38.376, P = 0.049 0.780, P = 0.981 −0.386, P = 0.988 −0.374, P = 0.188 −5.776, P = 0.703 43.539, P = 0.099
Table 6
 
Multivariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 150 eyes)*†
Table 6
 
Multivariate Linear Regression Analysis of Lamina Cribrosa Depth for Age, Sex, Refractive Error, IOP, CCT, AXL, and Disc Area (n = 150 eyes)*†
Plane Number Age β Coefficient, P Value Sex β Coefficient, P Value Refractive Error β Coefficient, P Value IOP β Coefficient, P Value CCT β Coefficient, P Value AXL β Coefficient, P Value AXL*Refractive Error β Coefficient, P Value IOP*CCT β Coefficient, P Value Disc Area β Coefficient, P Value
1 0.337, P = 0.676 −47.424, P = 0.044 19.847, P = 0.766 75.688, P = 0.235 1.120, P = 0.492 −32.203, P = 0.086 −1.339, P = 0.596 −0.127, P = 0.256 57.035, P = 0.023
2 0.563, P = 0.659 −48.661, P = 0.044 41.848, P = 0.766 72.987, P = 0.235 1.120, P = 0.492 −27.503, P = 0.086 −2.128, P = 0.596 −0.126, P = 0.256 43.035, P = 0.092
3 0.585, P = 0.659 −41.628, P = 0.046 32.259, P = 0.766 96.070, P = 0.235 1.740, P = 0.492 −20.342, P = 0.113 −1.639, P = 0.596 −0.169, P = 0.256 41.812, P = 0.089
4 0.351, P = 0.676 −38.260, P = 0.046 23.076, P = 0.766 61.073, P = 0.235 0.928, P = 0.492 −20.436, P = 0.098 −1.261, P = 0.596 −0.106, P = 0.256 31.293, P = 0.169
5 0.490, P = 0.659 −35.240, P = 0.046 28.649, P = 0.766 62.880, P = 0.235 0.915, P = 0.492 −20.915, P = 0.086 −1.486, P = 0.596 −0.112, P = 0.256 32.452, P = 0.134
6 0.751, P = 0.659 −41.974, P = 0.044 19.637, P = 0.766 38.956, P = 0.442 0.484, P = 0.695 −22.642, P = 0.086 −1.127, P = 0.596 −0.070, P = 0.442 26.381, P = 0.246
7 0.983, P = 0.659 −36.739, P = 0.046 13.734, P = 0.766 34.420, P = 0.448 0.408, P = 0.695 −24.028, P = 0.086 0.903, P = 0.610 −0.063, P = 0.442 38.799, P = 0.091
Average LC depth 0.575, P = 0.659 −41.290, P = 0.044 25.586, P = 0.766 63.158, P = 0.235 0.956, P = 0.492 −24.078, P = 0.086 −1.413, P = 0.596 −0.110, P = 0.256 38.673, P = 0.085
Table 7
 
Comparison of Anterior Lamina Cribrosa Surface Depth Between Male and Female Groups
Table 7
 
Comparison of Anterior Lamina Cribrosa Surface Depth Between Male and Female Groups
Plane Number Male, n = 108 eyes Female, n = 192 eyes P Value*
Coefficient SE Coefficient SE
1 LC depth, μm 466.56 14.90 402.65 11.04 0.006
2 LC depth, μm 456.00 14.79 399.88 10.94 0.009
3 LC depth, μm 439.90 14.82 386.61 10.97 0.009
4 LC depth, μm 422.63 13.78 373.34 10.20 0.009
5 LC depth, μm 409.72 13.61 370.61 10.07 0.025
6 LC depth, μm 419.12 13.38 372.18 9.90 0.009
7 LC depth, μm 426.06 12.97 382.28 9.59 0.010
Average LC depth 436.89 13.58 383.59 10.06 0.003
×
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