Factors Influencing Central Lamina Cribrosa Depth: A Multicenter Study

Diagnostic Performance for Detection of Glaucomatous Structural Damage Using Pixelwise Analysis of Retinal Thickness Measurements

Purpose

To compare the diagnostic accuracy of thickness measurements of individual and combined macular retinal layers to discriminate 188 glaucomatous and 148 glaucoma suspect eyes from 362 healthy control (HC) eyes on a pixel-by-pixel basis.

Methods

For this retrospective study, we manually corrected the segmentations of posterior pole optical coherence tomography (OCT) scans to determine the thickness of the nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), the ganglion cell complex (GCC), and the total neural retina (TR). For each eye, the total number of pixels with thickness values less than the fifth percentile of the HC distribution was used to create a receiver operating characteristic (ROC) curve for each layer and for layer combinations.

Results

Using total abnormal pixel count criteria to discriminate glaucoma from HC eyes, the individual layers with the highest area under the ROC curve (AUC) were the NFL and GCL; IPL performance was significantly lower (P < 0.05). GCC had a significant higher AUC (94.3%) than individual the AUC of the NFL (92.3%) (P = 0.0231) but not higher than AUC of the GCL (93.4%) (P = 0.3487). The highest AUC (95.4%) and sensitivity (85.1%) at 95% specificity was found for the Boolean combination of NFL or GCL. The highest AUC is not significantly higher (P = 0.0882) than the AUC of the GCC but the highest sensitivity is significantly higher than the sensitivity of the GCC. This pattern was similar for discriminating between suspect and HC eyes (P = 0.0356).

Conclusions

Using pixel-based methods, the diagnostic accuracy of NFL and GCL exceeded that of IPL and TR. GCC had equivalent performance as NFL and GCL. The specific spatial locations within the posterior pole that exhibit best performance vary depending on which layer is being assessed. Recognizing this dependency highlights the importance of considering multiple layers independently, as they offer complementary information for effective and comprehensive diagnosis.

Effect of Eye Globe and Optic Nerve Morphologies on Gaze-Induced Optic Nerve Head Deformations

Purpose

The purpose of this study was to investigate the effect of globe and optic nerve (ON) morphologies and tissue stiffnesses on gaze-induced optic nerve head deformations using parametric finite element modeling and a design of experiment (DOE) approach.

Methods

A custom software was developed to generate finite element models of the eye using 10 morphological parameters: dural radius, scleral, choroidal, retinal, pial and peripapillary border tissue thicknesses, prelaminar tissue depth, lamina cribrosa (LC) depth, ON radius, and ON tortuosity. A central composite face-centered design (1045 models) was used to predict the effects of each morphological factor and their interactions on LC strains induced by 13 degrees of adduction. Subsequently, a further DOE analysis (1045 models) was conducted to study the effects and potential interactions between the top five morphological parameters identified from the initial DOE study and five critical tissue stiffnesses.

Results

In the DOE analysis of 10 morphological parameters, the 5 most significant factors were ON tortuosity, dural radius, ON radius, scleral thickness, and LC depth. Further DOE analysis incorporating biomechanical parameters highlighted the importance of dural and LC stiffness. A larger dural radius and stiffer dura increased LC strains but the other main factors had the opposite effects. Notably, the significant interactions were found between dural radius with dural stiffness, ON radius, and ON tortuosity.

Conclusions

This study highlights the significant impact of morphological factors on LC deformations during eye movements, with key morphological effects being more pronounced than tissue stiffnesses.

Lamina Cribrosa Configurations in Highly Myopic and Non-Highly Myopic Eyes: The Beijing Eye Study

Purpose

The purpose of this study was to examine characteristics of lamina cribrosa (LC) configuration in highly myopic (HM) eyes.

Methods

Participants from the Beijing Eye Study 2011, free of optic nerve or retinal diseases, were randomly selected to examine LC depth (LCD) and LC tilt (LCT) using three-dimensional optical coherent tomography images of the optic nerve head (ONH). LCD and LCT were measured as the distance and angle between the LC plane with two reference planes, including the Bruch's membrane opening (BMO) plane and the peripapillary sclera (PPS) plane, respectively. Each parameter was measured in both horizontal and vertical B-scans.

Results

The study included 685 individuals (685 eyes) aged 59.6 ± 7.7 years, including 72 HM eyes and 613 non-HM eyes. LCD measurements showed no significant differences between HM eyes and non-HM eyes in both horizontal (LCD-BMO = 421.83 ± 107.86 µm for HM eyes vs. 447.24 ± 104.94 µm for non-HM eyes, P = 0.18; and LCD-PPS = 406.39 ± 127.69 µm vs. 394.00 ± 101.64 µm, P = 1.00) and vertical directions (LCD-BMO = 435.78 ± 101.29 µm vs. 450.97 ± 106.54 µm, P = 0.70; and LCD-PPS = 401.62 ± 109.9 µm vs. 379.85 ± 110.35 µm, P = 0.35). However, the LCT was significantly more negative (tilted) in HM eyes than in non-HM eyes horizontally (LCT-BMO = -4.38 ± 5.94 degrees vs. -0.04 ± 5.86 degrees, P < 0.001; and LCT-PPS = -3.16 ± 5.23 degrees vs. -0.94 ± 4.71 degrees, P = 0.003), but not vertically (P = 1.00).

Conclusions

Although LCD did not differ significantly between HM and non-HM eyes, LCT was more negative in HM eyes, suggesting that the temporal or inferior side of the LC was closer to the reference plane. These findings provide insights into morphological and structural changes in the LC and ONH between HM and non-HM eyes.

Effects of Deep Optic Nerve Head Structures on Bruch's Membrane Opening- Minimum Rim Width and Peripapillary Retinal Nerve Fiber Layer

PURPOSE

To explore the effects of deep optic nerve head (ONH) structures on Bruch's membrane opening (BMO)-minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (pRNFLT) in healthy eyes.

DESIGN

Prospective cross-sectional study.

METHODS

Two hundred five healthy eyes of 141 subjects (mean ± standard deviation of age and axial length (AXL): 46.9 ± 10.0 years and 24.79 ± 1.15 mm) were enrolled. Best fit multivariable linear mixed models identified factors associated with BMO-MRW and pRNFLT. Explanatory variables included age, gender, AXL, BMO and anterior scleral canal opening (ASCO) area and ovality, magnitude of BMO and ASCO shift, peripapillary choroidal thickness, lamina cribrosa (LC) parameters, prelaminar thickness, and peripapillary scleral (PPS) angle.

RESULTS

Thinner BMO-MRW was associated with older age, smaller ASCO/BMO offset magnitude, larger BMO area, thinner prelaminar thickness, deeper LC, and thinner pRNFLT (P = .011, <.001, .004, <.001, <.001, <.001 respectively). Thinner pRNFLT was associated with shorter AXL, smaller ASCO area, a more posteriorly bowed PPS, shallower LC and thinner BMO-MRW. (P = .030, .002, .035, .012, <.001 respectively) CONCLUSIONS: BMO-MRW and pRNFLT were influenced by several deep ONH structures such as BMO and ASCO position shift, BMO or ASCO area, prelaminar thickness, PPS bowing and LC depth in addition to patient characteristics such as age and AXL. The degree and/or direction of associations varied between deep ONH structures and BMO-MRW or pRNFLT. Despite both BMO-MRW and pRNFLT being surrogate parameters for RGC loss, a complex relationship with ONH deep-layer morphology was indicated.

Clinical Characteristics and Associated Factors to the Development of Glaucoma in Eyes With Myopic Optic Neuropathy

PURPOSE

To observe the development of glaucoma in myopic eyes with and without myopic optic neuropathy (MON) and analyze associated factors to the development of typical glaucomatous damage.

DESIGN

A prospective, observational, cohort study.

METHODS

A total of 233 myopic eyes with no definite evidence of glaucomatous damage were included. Myopic patients without any retinal nerve fiber layer (RNFL) or visual field (VF) abnormalities were classified as myopic eyes without MON. Myopic patients with decreased RNFL at the superonasal (SN) or nasal area, and with corresponding VF defects either in the temporal or inferotemporal (IT) region were classified as myopic eyes with MON. Myopic eyes that developed glaucoma were defined by the presence of glaucomatous VF in the SN region including defects in Bjerrum area, or a new localized RNFL defect in the IT region. Disc morphological features and optic nerve head (ONH) parameters of two groups were compared.

RESULTS

Myopic eyes with MON had a thinner average peripapillary RNFL thickness (P < 0.001), worse MD of the VF (P = 0.031), a higher percentage of IT VF defects (P < 0.001), smaller torsion degree (P = 0.047), and greater LCD (P = 0.022). Myopic eyes with MON who developed glaucoma had a thinner average peripapillary RNFL thickness (P = 0.009), greater PPA area (P = 0.049), greater LCD (P < 0.001), and thinner LCT (P < 0.001). Thinner baseline temporal RNFL thickness (HR, 0.956; 95% CI, 0.928-0.986; P = 0.004), greater baseline LCD (HR, 1.003; 95% CI, 1.000-1.005; P = 0.022), and greater PPA area (HR, 1.000; 95% CI, 1.000-1.003; P = 0.050) were significantly associated factors with glaucoma development.

CONCLUSIONS

Myopic eyes with MON have a greater risk to develop glaucoma compared to myopic eyes without MON. Structural weakness due to myopia, especially at the temporal side of the ONH and the peripapillary sclera, increases the risk of glaucoma in myopic eyes with MON.

Optical Coherence Tomographic Optic Nerve Head Morphology in Myopia III: The Exposed Neural Canal Region in Healthy Eyes-Implications for High Myopia

PURPOSE

To determine the prevalence and magnitude of optical coherence tomography (OCT) exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT), and exposed scleral flange (ESF) regions in 362 non-highly myopic (spherical equivalent -6.00 to 5.75 diopters) eyes of 362 healthy subjects.

DESIGN

Cross-sectional study.

METHODS

After OCT optic nerve head (ONH) imaging, Bruch membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented. BMO, ASCO, and SFO points were projected to the BMO reference plane. The direction and magnitude of BMO/ASCO offset as well as the magnitude of ENC, EOCBT, and ESF was calculated within 30° sectors relative to the foveal-BMO axis. Hi-ESF eyes demonstrated an ESF ≥100 µm in at least 1 sector. Sectoral peri-neural canal choroidal thickness (pNC-CT) was measured and correlations between the magnitude of sectoral ESF and proportional pNC-CT were assessed.

RESULTS

Seventy-three Hi-ESF (20.2%) and 289 non-Hi-ESF eyes (79.8%) were identified. BMO/ASCO offset as well as ENC, EOCBT, and ESF prevalence and magnitude were greatest inferior temporally where the pNC-CT was thinnest. Among Hi-ESF eyes, the magnitude of each ENC region correlated with the BMO/ASCO offset magnitude, and the sectors with the longest ESF correlated with the sectors with proportionally thinnest pNC-CT.

CONCLUSIONS

ONH BMO/ASCO offset, either as a cause or result of ONH neural canal remodeling, corresponds with the sectoral location of maximum ESF and minimum pNC-CT in non-highly myopic eyes. Longitudinal studies to characterize the development and clinical implications of ENC Hi-ESF regions in non-highly myopic and highly myopic eyes are indicated.

Association of Bergmeister Papilla and Deep Optic Nerve Head Structures With Prelaminar Schisis of Normal and Glaucomatous Eyes

PURPOSE

To investigate factors associated with the severity of prelaminar schisis (PLS) in heathy subjects and glaucoma patients.

DESIGN

Prospective cross-sectional study.

METHODS

A total of 217 eyes of 217 subjects (110 normal eyes and 107 open angle glaucoma eyes) were studied. Frequency and severity of PLS were compared between normal and glaucomatous eyes. Multivariate logistic models were used to assess factors associated with the severity of PLS. Factors considered were age, axial length, glaucomatous damage indices, Bruch membrane opening (BMO) and anterior scleral canal opening parameters, tractional forces (posterior vitreous staging and presence of Bergmeister papilla), circumpapillary choroidal thickness, lamina cribrosa (LC) parameters, and peripapillary scleral (PPS) angle.

RESULTS

The frequency of PLS was 70.9% in normal eyes and 72.0% in glaucomatous eyes. There was no difference in frequency and severity between the groups. The presence of Bergmeister papilla was the strongest predictor of a more severe PLS in both normal and glaucomatous eyes (odds ratio [OR] + 9.78, 12.5; both P < .001). A larger PPS angle in normal eyes (OR = 1.19; P = .003) and a larger BMO area and a deeper LC depth in glaucomatous eyes (OR = 1.08, 1.05; both P = .038) were associated with severity of PLS.

CONCLUSIONS

The severity of PLS was strongly associated with the presence of Bergmeister papilla, suggesting a traction-related phenomenon. Correlation of PLS severity with larger BMO area and deeper LC depth, which are optic nerve head structures associated with glaucoma, suggested its possible relationship with glaucomatous damage.

Displacement of the Lamina Cribrosa With Acute Intraocular Pressure Increase in Brain-Dead Organ Donors

Purpose

To examine deformations of the optic nerve head (ONH) deep tissues in response to acute elevation of intraocular pressure (IOP).

Methods

Research-consented brain-dead organ donors underwent imaging by spectral domain optical coherence tomography (OCT). OCT imaging was repeated while the eye was sequentially maintained at manometric pressures of 10, 30, and 50 mm Hg. Radial scans of the ONH were automatically segmented by deep learning and quantified in three dimensions by a custom algorithm. Change in lamina cribrosa (LC) depth and choroidal thickness was correlated with IOP and age by linear mixed-effect models. LC depth was computed against commonly utilized reference planes.

Results

Twenty-six eyes from 20 brain-dead organ donors (age range, 22-62 years; median age, 43 years) were imaged and quantified. LC depth measured against a reference plane based on Bruch's membrane (BM), BM opening, and an anterior sclera canal opening plane showed both a reduction and an increase in LC depth with IOP elevation. LC depth universally increased in depth when measured against a sclera reference plane. Choroidal (-0.5222 µm/mm Hg, P < 0.001) and retinal nerve fiber layer thickness (-0.0717 µm/mm Hg, P < 0.001) significantly thinned with increasing IOP. The magnitude of LC depth change with IOP was significantly smaller with increasing age (P < 0.03 for all reference planes).

Conclusions

LC depth changes with IOP reduce with age and are significantly affected by the reference plane of choice, which highlights a need for standardizing LC metrics to properly follow progressive remodeling of the loadbearing tissues of the ONH by OCT imaging and for the definition of a reference database.

OCT Optic Nerve Head Morphology in Myopia II: Peri-Neural Canal Scleral Bowing and Choroidal Thickness in High Myopia-An American Ophthalmological Society Thesis

PURPOSE

To use optical coherence tomography (OCT) to characterize optic nerve head (ONH) peri-neural canal (pNC) scleral bowing (pNC-SB) and pNC choroidal thickness (pNC-CT) in 69 highly myopic and 138 healthy, age-matched, control eyes.

DESIGN

Cross-sectional, case control study.

METHODS

Within ONH radial B-scans, Bruch membrane (BM), BM opening (BMO), anterior scleral canal opening (ASCO), and pNC scleral surface were segmented. BMO and ASCO planes and centroids were determined. pNC-SB was characterized within 30° foveal-BMO (FoBMO) sectors by 2 parameters: pNC-SB-scleral slope (pNC-SB-SS), measured within 3 pNC segments (0-300, 300-700, and 700-1000 μm from the ASCO centroid); and pNC-SB-ASCO depth relative to a pNC scleral reference plane (pNC-SB-ASCOD). pNC-CT was calculated as the minimum distance between the scleral surface and BM at 3 pNC locations (300, 700, and 1100 μm from the ASCO).

RESULTS

pNC-SB increased and pNC-CT decreased with axial length (P < .0133; P < .0001) and age (P < .0211; P < .0004) among all study eyes. pNC-SB was increased (P < .001) and pNC-CT was decreased (P < .0279) in the highly myopic compared to control eyes, and these differences were greatest in the inferior quadrant sectors (P < .0002). Sectoral pNC-SB was not related to sectoral pNC-CT in control eyes, but was inversely related to sectoral pNC-CT (P < .0001) in the highly myopic eyes.

CONCLUSIONS

Our data suggest that pNC-SB is increased and pNC-CT is decreased in highly myopic eyes and that these phenomena are greatest in the inferior sectors. They support the hypothesis that sectors of maximum pNC-SB may predict sectors of greatest susceptibility to aging and glaucoma in future longitudinal studies of highly myopic eyes. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Deep Optic Nerve Head Structures Associated With Increasing Axial Length in Healthy Myopic Eyes of Moderate Axial Length

PURPOSE

To elucidate which swept-source optical coherence tomography (OCT)-derived optic nerve head (ONH) parameters are associated with longer axial length (AXL) in healthy myopic eyes.

DESIGN

Prospective cross-sectional observational study.

METHODS

Two hundred eleven healthy eyes of 140 participants (96 emmetropic-mild myopic [AXL: 22.2-24.5 mm], 83 moderately myopic [24.5-26.0 mm], and 32 highly myopic [26.0-27.4 mm] eyes) were enrolled. Bruch membrane opening (BMO), anterior scleral canal opening (ASCO) area and ovality, minimum rim width, parameters defining misalignment between the BMO and ASCO planes, OCT-defined region of perineural canal retinal epithelium atrophy and externally oblique choroidal border tissue, circumpapillary retinal nerve fiber layer thickness (cpRNFLT), circumpapillary choroidal thickness (cpChT), lamina cribrosa parameters, and peripapillary scleral (PPS) angle were calculated from BMO-centered radial scans reconstructed from 3D raster scans. Multivariate linear mixed models were used to elucidate ONH parameters that are independently associated with AXL.

RESULTS

Longer AXL was associated with a greater misalignment between ASCO and BMO planes, larger region of externally oblique choroidal border tissue, thinner cpChT, larger PPS angle, larger ASCO area, and thicker cpRNFLT (all P < .040 after Bonferroni's correction for number of included explanatory variables).

CONCLUSIONS

A greater misalignment between BMO and ASCO planes, thinner choroid, a more posteriorly bowed PPS, an enlargement of ASCO, and thicker cpRNFLT were each associated with longer AXL. An enhanced understanding of these AXL-associated configurations should provide essential information to improve our ability to detect glaucoma-induced ONH morphology in myopic eyes.

Optical coherence tomography and optical coherence tomography — angiography used in endocrine ophthalmopathy

The literature review presents the results of optical coherence tomography and optical coherence tomography — angiography used for Graves’ orbitopathy. The data on the thickness of the inner layers of the retina, microcirculation in the peripapillary and macular regions, parameters of the choroid, lamina cribrosa and extraocular muscles were analyzed as possible diagnostic criteria of the condition.

Comparison of lamina cribrosa depth shallowing after trabeculectomy between primary open-angle glaucoma and exfoliation glaucoma

The lamina cribrosa (LC) becomes shallower as intraocular pressure (IOP) decreases after trabeculectomy. The LC in eyes with exfoliation syndrome has distinctive properties in the connective tissue and extracellular matrix, but how these affect the changes in LC depth in response to IOP reduction after trabeculectomy is unknown. We analyzed pre- and postoperative spectral-domain optical coherence tomography of exfoliation glaucoma (XFG) and primary open-angle glaucoma (POAG) patients who underwent trabeculectomy and investigated whether LC depth differed between XFG and POAG eyes after trabeculectomy. In total, 30 XFG eyes and 30 visual field mean deviation-matched POAG eyes were included. LC depth was determined at an average of 3.9 months after trabeculectomy. Postoperatively, the LC depth became shallower and the BMO-MRW became thicker in both XFG and POAG eyes. XFG eyes showed lesser amount of LC depth shallowing than POAG eyes. Greater preoperative LC depth, lower postoperative IOP, and absence of XFG were all associated with a greater degree of postoperative LC depth shallowing. These findings suggest that the LC of XFG eyes may inherently possess the distinctive properties of the connective tissue and extracellular matrix contained within it, which could affect the LC response to the reduction in IOP after trabeculectomy.

Detection of superficial and buried optic disc drusen with swept-source optical coherence tomography

Background

To detect the superficial and buried optic disc drusen (ODD) with swept-source optical coherence tomography (SS-OCT).

Methods

Retrospective cross-sectional study. Twenty patients (age 18–74 years) diagnosed with ODD via B-scan ultrasonography were analysed. All patients underwent color fundus photography (CFP), B-scan ultrasonography, fundus autofluorescence (FAF), and SS-OCT. We defined each hyporeflective signal mass of SS-OCT as an ODD, recorded its location and relationship with Bruch’s membrane opening (BMO), and other ophthalmic imaging characteristics.

Results

Twenty (33 eyes) patients had 54 ODDs in all, except one eye did not show abnormal optic disc findings on SS-OCT. We classified ODD into three categories: ODD above BMO, ODD across BMO, and ODD below BMO. The ODDs across BMO were the largest, followed by ODDs below BMO, and those above BMO. The location of the ODDs: One (1.9%) was in the border tissue of Elschnig, 6 (11.1%) might span across the lamina cribrosa, 16 (29.6%) were above BMO located in the neuroepithelial layer, 9 (16.7%) spanned across BMO located near the center of the optic disc, 18 (33.3%) were below BMO located near the center of the optic disc, 4 (7.4%) were below BMO located within the optic disc rim. When the anterior margin was ≥ 100 μm from the BMO, clear autofluorescence could be seen.

Conclusion

Multimodal imaging provided a deeper understanding of ODD. SS-OCT illustrated more details about the relationship between the posterior surface of ODD, BMO and the lamina cribrosa.

Are There Static-Structural Biomarkers for Glaucoma with OCT?

Glaucomas lead to uniform, specific and slowly developing atrophy of the optic nerve with progressing visual field defects in late stages. Early diagnosis is challenging, but necessary as optic nerve damage is irreparable. Biomarkers with structural optical coherence tomography (OCT) flag optic atrophy but do not prove to be specific in the differential diagnosis to other forms of optic atrophy. Combination of OCT parameters and their correlation to other variables facilitate glaucoma diagnosis. Use of artificial intelligence (AI) in structural OCT images may prove to be superior and as biomarker more specific to thickness measurements of neuronal tissues alone.

Nonlinear distortion correction for posterior eye segment optical coherence tomography with application to tree shrews

We propose an empirical distortion correction approach for optical coherence tomography (OCT) devices that use a fan-scanning pattern to image the posterior eye segment. Two types of reference markers were used to empirically estimate the distortion correction approach in tree shrew eyes: retinal curvature from MRI images and implanted glass beads of known diameter. Performance was tested by correcting distorted images of the optic nerve head. In small animal eyes, our purposed method effectively reduced nonlinear distortions compared to a linear scaling method. No commercial posterior segment OCT provides anatomically correct images, which may bias the 3D interpretation of these scans. Our method can effectively reduce such bias.

Offset of openings in optic nerve head canal at level of Bruch's membrane, anterior sclera, and lamina cribrosa

We compared the central retinal vascular trunk (CRVT) position, as a surrogate of lamina cribrosa (LC) offset, with the anterior scleral opening (ASCO) offset from the Bruch’s membrane opening (BMO). Based on the BMO-centered radial scans, the BMO and ASCO margins were demarcated, and each center was determined as the center of the best-fitted ellipse for each margin. The ASCO/BMO offset was defined as the offset between each center. Angular deviations and the extent of ASCO and CRVT offsets from the BMO center were compared directly. Incomplete demarcation of ASCO was found in 20%, which was associated with a larger BMO area and a larger ASCO offset from the BMO. The angular deviation of ASCO offset was associated with that of CRVT offset and that of the longest externally oblique border. The ASCO offset was smaller than the CRVT offset, and, unlike the CRVT offset, it was rarely deviated to the inferior side. The complete ASCO margin might not be demarcatable when determined on BMO-centered radial scans in the presence of an offset. Also, the ASCO, which reflects only the superficial scleral layer, might not reflect the LC position, because the LC might be shifted further from the ASCO.

Evaluation of Lamina Cribrosa by Using Enhanced Depth Imaging Optical Coherence Tomography in Ocular Sarcoidosis during Quiescent Phase

SIGNIFICANCE

Enhanced depth imaging optical coherence tomography is a useful method to allow for the evaluation of deep ocular structures, such as choroid and lamina cribrosa (LC), which are affected by ocular diseases. We hypothesized that choroidal and optic nerve inflammation in patients with ocular sarcoidosis (OS) might affect the LC structure.

PURPOSE

This study aimed to evaluate changes in the LC and anterior LC depth (ALCD) in patients with OS.

METHODS

Forty-eight eyes of 26 patients with OS who received the treatment of panuveitis and were in the quiescent phase for at least 6 months were included in the study. Thirty healthy subjects' randomly selected eyes were selected as a control group. Eyes with OS were divided into two subgroups according to the presence (OS eyes with glaucoma [OSWG], n = 23) or absence of glaucoma (OS eyes without glaucoma [OSWOG], n = 25). The LC thickness, ALCD, and peripapillary choroidal thickness were measured using enhanced depth imaging optical coherence tomography in eyes with OS and in controls.

RESULTS

The mean LC thickness was found significantly thinner in both OSWG and OSWOG eyes compared with the healthy controls (P < .001 and P = .001, respectively). The mean ALCD was found significantly higher in OSWG eyes (462 ± 65 μm) compared with OSWOG eyes (417 ± 58 μm) and the healthy control eyes (397 ± 59 μm; P = .03 and P = .001, respectively). The average peripapillary choroidal thickness was found to be significantly thinner in OSWG eyes compared with the control eyes (P = .05).

CONCLUSIONS

The present study revealed that OS is associated with a thinned LC independent of the presence of glaucoma. The degenerative changes in the LC, which is the transition point of the retinal nerve fibers, may cause long-term visual dysfunction in OS. These degenerative changes should be prevented by controlling inflammation with early diagnosis and treatment in patients with OS.

Association of Optic Nerve Head Prelaminar Schisis With Glaucoma

PURPOSE

To compare the frequency of observing optic nerve head (ONH) prelaminar schisis by optical coherence tomography (OCT) in glaucoma and glaucoma suspect (GL/S) eyes vs healthy control (HC) eyes and to assess its association with other markers of glaucoma severity.

METHODS

This cross-sectional study included 298 eyes of 150 GL/S patients and 88 eyes of 44 HCs. OCT scans were obtained, including 24 radial B-scans, each composed of 768 A-lines spanning 15°, centered on the ONH. Two reviewers masked to all other clinical, demographic, and ocular information independently graded the OCT scans for the presence of ONH prelaminar schisis on a 4-point scale of 0 (none) to 3 (severe). The probability of ONH schisis was compared between groups and against demographic and ocular factors, including structural and functional measures of glaucoma severity.

RESULTS

The frequency and severity of ONH prelaminar schisis were greater in GL/S than in HC (P = .009). Among the GL/S group, 165 eyes (55.4%) had no visible schisis (Grade 0), 71 (23.8%) had Grade 1, 46 (15.4%) had Grade 2 and 16 (5.4%) had Grade 3 schisis. Among HC eyes, 59 (67.0%) had Grade 0, 24 (27.3%) had Grade 1, 5 (5.7%) had Grade 2, none had Grade 3. ONH schisis was more common in eyes with thinner MRW and a deeper cup.

CONCLUSIONS

ONH prelaminar schisis may be a sign of glaucomatous deformation and reflect ongoing pathophysiological damage. ONH prelaminar schisis can impact OCT image segmentation and diagnostic parameters, resulting in substantial overestimation of the true rim tissue thickness and underestimation of cup depth.

Optical Coherence Tomography Imaging of the Lamina Cribrosa: Structural Biomarkers in Nonglaucomatous Diseases

The lamina cribrosa (LC) is an active structure that responds to the strain by changing its morphology. Abnormal changes in LC morphology are usually associated with, and indicative of, certain pathologies such as glaucoma, intraocular hypertension, and myopia. Recent developments in optical coherence tomography (OCT) have enabled detailed in vivo studies about the architectural characteristics of the LC. Structural characteristics of the LC have been widely explored in glaucoma management. However, information about which LC biomarkers could be useful for the diagnosis, and follow-up, of other diseases besides glaucoma is scarce. Hence, this literature review aims to summarize the role of the LC in nonophthalmic and ophthalmic diseases other than glaucoma. PubMed was used to perform a systematic review on the LC features that can be extracted from OCT images. All imaging features are presented and discussed in terms of their importance and applicability in clinical practice. A total of 56 studies were included in this review. Overall, LC depth (LCD) and thickness (LCT) have been the most studied features, appearing in 75% and 45% of the included studies, respectively. These biomarkers were followed by the prelaminar tissue thickness (21%), LC curvature index (5.4%), LC global shape index (3.6%), LC defects (3.6%), and LC strains/deformations (1.8%). Overall, the disease groups showed a thinner LC (smaller LCT) and a deeper ONH cup (larger LCD), with some exceptions. A large variability between approaches used to compute LC biomarkers has been observed, highlighting the importance of having automated and standardized methodologies in LC analysis. Moreover, further studies are needed to identify the pathologies where LC features have a diagnostic and/or prognostic value.

Optical Coherence Tomography Optic Nerve Head Morphology in Myopia I: Implications of Anterior Scleral Canal Opening Versus Bruch Membrane Opening Offset

PURPOSE

To measure the magnitude and direction of anterior scleral canal opening (ASCO) offset relative to the Bruch membrane opening (BMO) (ASCO/BMO offset) to characterize neural canal obliqueness and minimum cross-sectional area (NCMCA) in 69 highly myopic and 138 healthy, age-matched, control eyes.

DESIGN

Cross-sectional study.

METHODS

Using optical coherence tomography (OCT) scans of the optic nerve head (ONH), BMO and ASCO were manually segmented and their centroids and size and shape were calculated. ASCO/BMO offset magnitude and direction were measured after projecting the ASCO/BMO centroid vector onto the BMO plane. Neural canal axis obliqueness was defined as the angle between the ASCO/BMO centroid vector and the vector perpendicular to the BMO plane. NCMCA was defined by projecting BMO and ASCO points onto a plane perpendicular to the neural canal axis and measuring their overlapping area.

RESULTS

ASCO/BMO offset magnitude was greater (highly myopic eyes 264.3 ± 131.1 μm; healthy control subjects 89.0 ± 55.8 μm, P < .001, t test) and ASCO centroid was most frequently nasal relative to BMO centroid (94.2% of eyes) in the highly myopic eyes. BMO and ASCO areas were significantly larger (P < .001, t test), NCMCA was significantly smaller (P < .001), and all 3 were significantly more elliptical (P ≤ .001) in myopic eyes. Neural canal obliqueness was greater in myopic (65.17° ± 14.03°) compared with control eyes (40.91° ± 16.22°; P < .001, t test).

CONCLUSIONS

Our data suggest that increased temporal displacement of BMO relative to the ASCO, increased BMO and ASCO area, decreased NCMCA, and increased neural canal obliqueness are characteristic components of ONH morphology in highly myopic eyes.

Peripapillary Scleral Bowing Increases with Age and Is Inversely Associated with Peripapillary Choroidal Thickness in Healthy Eyes

PURPOSE

To use optical coherence tomography (OCT) to 3-dimensionally characterize the optic nerve head (ONH) in peripapillary scleral bowing in non-highly myopic healthy eyes.

DESIGN

Cross-sectional, multicenter study.

METHODS

A total of 362 non-highly myopic (+6 diopters [D] > spherical equivalent > -6D) eyes of 362 healthy subjects from 20-90 years old underwent OCT ONH radial B-scan imaging. Bruch's membrane (BM), BM opening (BMO), anterior scleral canal opening (ASCO), and the peripapillary scleral surface were segmented. BMO and ASCO planes were fit, and their centroids, major axes, ovality, areas and offsets were determined. Peripapillary scleral bowing was characterized by 2 parameters: peripapillary scleral slope (ppSS) of 3 anterior peripapillary scleral segments (0-300, 300-700, and 700-1,000 μm from the ASCO centroid); and ASCO depth relative to a peripapillary scleral reference plane (ASCOD-ppScleral). Peripapillary choroidal thickness (ppCT) was calculated relative to the ASCO as the minimum distance between the anterior scleral surface and BM.

RESULTS

Both ppSS and ASCOD-ppScleral ranged from slightly inward through profoundly outward in direction. Both parameters increased with age and were independently associated with decreased ppCT.

CONCLUSIONS

In non-highly myopic healthy eyes, outward peripapillary scleral bowing achieved substantial levels, was markedly increased with age, and was independently associated with decreased peripapillary choroidal thickness. These findings provide a normative foundation for characterizing this anatomy in cases of high myopia and glaucoma and in eyes with optic disc tilt, torsion, and peripapillary atrophy.

Clinical Assessment of Scleral Canal Area in Glaucoma Using Spectral-Domain Optical Coherence Tomography

PURPOSE

To investigate anterior scleral canal (ASC) area in the eyes with glaucoma using spectral-domain optical coherence tomography (SDOCT).

DESIGN

Cross-sectional study.

METHODS

This study included 206 eyes of 103 patients with glaucoma, classified as 66 eyes of 33 patients with unilateral glaucoma and 140 eyes of 70 patients with bilateral glaucoma. Radial scan enhanced depth imaging SDOCT centered on the optic disc was performed, and parameters that present ASC area such as ASC opening and the largest ASC area were obtained in each eye. The largest ASC area was the largest cross-sectional area of the ASC region identified between the ASC opening and anterior lamina cribrosa insertion. These parameters were compared between eyes with and without glaucoma in unilateral glaucoma, and eyes with worse and better visual field defect (VFD) in bilateral glaucoma.

RESULTS

In the patients with unilateral glaucoma, ASC opening and largest ASC area were significantly larger in the eyes with glaucoma than in those without glaucoma (both P < .001). In bilateral glaucoma, these parameters were significantly larger in the eyes with worse VFD than in those with better VFD (P = .0080 and P = .0018, respectively). Intereye differences of the ASC parameters in the glaucoma patients were significantly greater than that in the normal subjects.

CONCLUSIONS

Significantly larger ASC area was first observed in the living human eyes with glaucoma compared to the normal eyes. Further longitudinal studies are required to determine if the ASC area is useful in the prevention and treatment of glaucoma.

Determinants of lamina cribrosa depth in healthy Asian eyes: the Singapore Epidemiology Eye Study

AIM

To investigate the determinants of lamina cribrosa depth (LCD) in healthy eyes of Chinese and Indian Singaporean adults.

METHODS

The optic nerve head (ONH) of the right eye of 1396 subjects (628 Chinese and 768 Indian subjects) was imaged with optical coherence tomography (OCT, Spectralis, Heidelberg, Germany). LCD was defined as the distance from the Bruch's membrane opening (LCD-BMO) or the peripapillary sclera (LCD-PPS) reference plane to the laminar surface. A linear regression model was used to evaluate the relationship between the LCD and its determinants.

RESULTS

Both LCDs were significantly different between the two races (LCD-BMO: 421.95 (95% CI 365.32 to 491.79) µm in Chinese vs 430.39 (367.46-509.81) µm in Indians, p=0.021; and LCD-PPS: 353.34 (300.98-421.45) µm in Chinese vs 376.76 (313.39-459.78) µm in Indians, p<0.001). In the multivariable regression analysis, the LCD-PPS of the whole cohort was independently associated with females (β=-31.93, p<0.001), Indians subjects (β=21.39, p=0.004) (Chinese as the reference), axial length (Axl) (β=-6.68, p=0.032), retinal nerve fibre layer thickness (RNFL) (β=0.71, p=0.019), choroidal thickness (ChT) (β=0.41, p<0.001), vertical cup disc ratio (VCDR) (β=24.42, p<0.001) and disc size (β=-60.75, p=0.001). For every 1 year older in age, the LCD-PPS was deeper on average by 1.95 µm in Chinese subjects (p=0.01) but there was no association in Indians subjects (p=0.851).

CONCLUSIONS

The LCD was influenced by age, gender, race, Axl, RNFL, ChT, VCDR and disc size. This normative LCD database may facilitate a more accurate assessment of ONH cupping using OCT in Asian populations.

Optical Coherence Tomography Structural Abnormality Detection in Glaucoma Using Topographically Correspondent Rim and Retinal Nerve Fiber Layer Criteria

PURPOSE

This study evaluated the ability of topographically correspondent (TC) minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (pRNFLT) criteria to detect optical coherence tomography (OCT) structural abnormality in glaucoma (GL) and glaucoma suspect (GLS) eyes.

DESIGN

Retrospective cross-sectional study.

METHODS

A total of 196 GL eyes, 150 GLS eyes, and 303 heathy eyes underwent pRNFL and 24 radial optic nerve head OCT imaging and manual correction of the internal limiting membrane, Bruch's membrane opening (BMO), and outer pRNFL segmentations. MRW and pRNFLT were quantified in 6 Garway-Heath or 12 30-degree (clock-hour) sectors. OCT abnormality for each parameter was defined to be less than the 5th percentile of the healthy eye distribution. OCT abnormality for individual eyes was defined using global, sectoral, and combined parameter criteria that achieved ≥95% specificity in the healthy eyes. TC combination criteria required the sectoral location of MRW and pRNFLT abnormality to be topographically aligned and included comMR (a previously reported TC combination consisting of MRW and pRNFLT parameter: [MRW + pRNFLT × (average MRW healthy eyes/average pRNFLT healthy eyes) MRW].

RESULTS

TC sectoral criteria (1 Garway-Heath MRW + corresponding Garway-Heath RNFLT), (one 30-degree MRW + any 1 corresponding or adjacent 30-degree pRNFLT), 30-degree and Garway-Heath comMR-TI and global comMR were the best performing criteria, demonstrating (96%-99% specificity), 86%-91% sensitivity for GL, 80%-84% sensitivity for early GL (MD ≥ -4.0 dB) and 93%-96% sensitivity for moderate-to-advanced GL (MD < -4.0 dB).

CONCLUSIONS

Clinically intuitive TC MRW and pRNFLT combination criteria identified the sectoral location of OCT abnormality in GL eyes with high diagnostic precision.

Relationship of Corneal Hysteresis and Anterior Lamina Cribrosa Displacement in Glaucoma

PURPOSE

To investigate the relationship between corneal hysteresis (CH) and anterior lamina cribrosa surface (ALCS) displacement over time in a cohort of patients with glaucoma.

DESIGN

Prospective observational case series.

METHODS

In this study, 147 eyes from 96 glaucoma or glaucoma suspect patients were followed for a mean of 3.5 years and 7.9 visits. Baseline CH measurements were obtained using the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments Inc, Depew, New York, USA). The mean anterior lamina cribrosa surface depth (ALCSD) and choroidal thickness were by automated segmentation of spectral-domain optical coherence tomography (SD-OCT) scans. The rate of change of ALCSD was calculated using linear mixed effects models. Relationship between baseline CH and follow-up ALCSD rate of change was adjusted for confounding factors, including age, intraocular pressure (IOP), and choroidal thickness.

RESULTS

The mean baseline CH was 9.4 mm Hg (95% confidence interval [CI] 9.1-9.7). Overall, the ALCS was displaced posteriorly at a rate of 0.78 μm/y (95% CI -1.82, 0.26). Seventeen eyes (11.5%) showed a significant posterior displacement of ALCS, whereas 22 eyes (15.0%) showed a significant anterior displacement of ALCS. The choroidal thickness thinned at a rate of -1.09 μm/y during the follow-up (P = .001). Multivariable mixed modeling showed that choroidal thinning, lower IOP change, and lower corneal hysteresis were significantly associated with posterior ALCS displacement over time (P = .034, P = .037, and P = .048). Each 1 mm lower CH was associated with 0.66 μm/y posterior displacement of the ALCS.

CONCLUSIONS

Lower corneal hysteresis was significantly associated with posterior displacement of the anterior lamina cribrosa over time. These data provide additional support for lower corneal hysteresis being a risk factor for glaucoma progression.

OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness, and Minimum Cross-Sectional Area in Healthy Eyes

PURPOSE

To assess anterior scleral canal opening (ASCO) offset relative to Bruch's membrane opening (BMO) (ASCO/BMO offset) so as to determine neural canal direction, obliqueness, and minimum cross-sectional area (NCMCA) in 362 healthy eyes.

DESIGN

Cross-sectional study.

METHODS

After optical coherence tomography optic nerve head and retinal nerve fiber layer thickness (RNFLT) imaging, BMO and ASCO were manually segmented. Planes, centroids, size, and shape were calculated. Neural canal direction was defined by projecting the neural canal axis vector (connecting BMO and ASCO centroids) onto the BMO plane. Neural canal obliqueness was defined by the angle between the neural canal axis and the BMO plane perpendicular vector. NCMCA was defined by projecting BMO and ASCO points onto a neural canal axis perpendicular plane and measuring the area of overlap. The angular distance between superior and inferior peak RNFLT was measured, and correlations between RFNLT, BMO, ASCO, ASCO/BMO offset, and NCMCA were assessed.

RESULTS

Mean (SD) NCMCA was significantly smaller than either the BMO or ASCO area (1.33 (0.42), 1.82 (0.38), 2.22 (0.43) mm2, respectively), and most closely correlated to RNFLT (P < .001, R2 = 0.158). Neural canal direction was most commonly superior-nasal (55%). Mean neural canal obliqueness was 39.4° (17.3°). The angular distance between superior and inferior peak RNFLT correlated to neural canal direction (P ≤ .008, R2 = 0.093).

CONCLUSIONS

ASCO/BMO offset underlies neural canal direction, obliqueness, and NCMCA. RNFLT is more strongly correlated to NCMCA than to BMO or ASCO, and its peripapillary distribution is influenced by neural canal direction.

Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

Purpose

To quantify peripapillary choroidal thickness (PCT) and the factors that influence it in healthy participants who represent the racial and ethnic composition of the U.S. population.

Methods

A total of 362 healthy participants underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head with a 24 radial B-scan pattern aligned to the fovea to Bruch's membrane opening axis. Bruch's membrane, anterior scleral canal opening (ASCO), and the anterior scleral surface were manually segmented. PCT was measured at 100, 300, 500, 700, 900, and 1100 μm from the ASCO globally and within 12 clock-hour sectors. The effects of age, axial length, intraocular pressure, ethnicity, sex, sector, and ASCO area on PCT were assessed by ANOVA and univariable and multivariable regressions.

Results

Globally, PCT was thicker further from the ASCO border and thinner with older age, longer axial length, larger ASCO area, European descent, and female sex. Among these effectors, age and axial length explained the greatest proportion of variance. The rate of age-related decline increased further from the ASCO border. Sectorally, the inferior-temporal sectors were thinnest (10.7%-20.0% thinner than the thickest sector) and demonstrated a higher rate of age-related loss (from 15.6% to 20.7% faster) at each ASCO distance.

Conclusions

In healthy eyes, PCT was thinnest in the inferior temporal sectors and thinner PCT was associated with older age, European descent, longer axial length, larger ASCO area, and female sex. Among these associations, age had the strongest influence, and its effect was greatest within the inferior temporal sectors.

Lamina Cribrosa Depth and Shape in Glaucoma Suspects. Comparison to Glaucoma Patients and Healthy Controls

Purpose: To evaluate the lamina cribrosa depth and shape parameters in glaucoma suspects compared to glaucoma patients and healthy controls. Materials and Methods: A total of 325 subjects (120 with primary open-angle glaucoma, 103 glaucoma suspects and 102 healthy controls) were included. Serial horizontal B-scan images of optic nerve head were obtained using enhanced depth imaging of the optical coherence tomography. For each of the 325 subjects, lamina cribrosa position was measured manually in 16 horizontal B-scans, hence 5200 scans in total were analyzed. In particular, lamina cribrosa depth (LCD), lamina cribrosa deflection depth (LCDD), lamina cribrosa shape index (LCSI), and its horizontal equivalent (LCSI_H) were estimated. Along lamina cribrosa parameterization, intraocular pressure, visual field, central retinal thickness, retinal nerve fiber layer thickness, and disc and neuroretinal rim areas were also measured. Results: LCD was statistically significant different (P < .001) in glaucoma patients when compared to glaucoma suspects and heathy controls (603 ± 172 μm versus 554 ± 114 μm and 531 ± 115 μm, respectively). Similarly, LCDD was statistically significant different (P < .001) in glaucoma patients when compared to glaucoma suspects and heathy controls (250 ± 78 μm versus 213 ± 54 μm and 211 ± 58 μm, respectively). No statistically significant differences were found in LCSI (P = .957). However, LCSI_H showed statistically significant differences between healthy controls and glaucoma suspects (P = .003) and between healthy controls and glaucoma patients (P = .006). Conclusions: The deformation of LC in glaucoma suspects, in terms of LCSI_H, was not statistically different from that of glaucoma patients. LCD does not have the potential to discriminate glaucoma suspects from healthy controls.