Lamina Cribrosa Morphology Research Articles

Evaluation of lamina cribrosa and peripapillary vascular density in thyroid orbitopathy and effect of intravenous methylprednisolone therapy

ObjectifÉvaluer les modifications de la tête du nerf optique en présence d'orbitopathie thyroïdienne (OT) et examiner les effets de l'administration intraveineuse (i.v.) de méthylprednisolone (MTP) sur ces modifications. MéthodesOnt été inclus 82 yeux de 41 patients présentant une OT avec ou sans neuropathie optique dysthyroïdienne (NOD) et 40 yeux de 40 sujets témoins en bonne santé. L’épaisseur et la profondeur de la lame criblée (ELC et PLC, respectivement), l’épaisseur de la couche de fibres nerveuses rétiniennes péripapillaires (pRNFLT, pour peripapillary retinal nerve fiber layer thickness) et la densité vasculaire dans le réseau capillaire péripapillaire radial ont été mesurées à l'aide de la tomographie par cohérence optique (OCT) et de l'angiographie-tomographie par cohérence optique (OCTA). On a également réalisé un examen du champ visuel et de l'exophtalmie. Les patients qui présentaient une NOD de même qu'une atteinte évolutive autre que la NOD ont reçu la MTP par voie i.v. pendant 12 semaines, après quoi l'effet du traitement a été évalué. RésultatsLa densité vasculaire péripapillaire a diminué en présence de NOD, comparativement aux autres groupes (p < 0,001 dans tous les cas); aucune différence n'a été enregistrée entre les groupes quant à la pRNFLT (totale, de l'hémisecteur supérieur et de l'hémisecteur inférieur). L'ELC a diminué dans le groupe OT (p < 0,001). Après l'administration i.v. de MTP, on a noté une hausse de l'ELC et de la meilleure acuité visuelle corrigée. Le taux d'anticorps anti-récepteurs de la TSH, la pression intraoculaire, la pRNFLT de l'hémisecteur supérieur et l'exophtalmie ont tous diminué, comparativement à ce qui a été enregistré chez les témoins (p = 0,012; p = 0,008; p = 0,043 et p < 0,001, respectivement). ConclusionsLa pRNFLT n'augmente pas nécessairement en présence de NOD. On peut observer une modification de la morphologie de la lame criblée dans l'OT. L'administration i.v. de MTP a eu un effet positif sur l'ELC mais pas sur la densité vasculaire dans le réseau capillaire péripapillaire radial ni sur la PLC.

Impact of obesity on peripapillary choroidal thickness, macular choroidal thickness, and lamina cribrosa morphology

BackgroundObesity is known to be a significant risk factor for many ocular diseases. In order to understand the mechanism of obesity-related ocular diseases, we examined the lamina cribrosa morphology, peripapillary choroidal thickness (PPCT), and macular choroidal thickness (MCT) in obese women using optical coherence tomography (OCT). MethodsThis comparative cross-sectional study included the right eyes of 72 obese women and 63 healthy women classified based on body mass index (BMI). Each participant underwent a thorough ophthalmological examination and enhanced depth (EDI) OCT imaging, including measurements of PPCT from a total of 12 regions, MCT from a total of 7 regions, Bruch's membrane opening (BMO), lamina cribrosa thickness (LCT), lamina cribrosa depth (LCD), intraocular pressure (IOP), and central corneal thickness (CCT). ResultsThe mean age and BMI of the obese group were 32.36±7.38 years and 35.11±4.39 kg/m², while those of the control group were 31.64±7.78 years and 20.88±1.72 kg/m² (p = 0.658, and p<0.001, respectively). PPCT N1000, PPCT N1500, PPCT S1500, and PPCT T1500 were statistically significantly thinner in the obese group than the control group (p values were 0.039, 0.012, 0.027, and 0.036, respectively). IOP and CCT were significantly higher in the obese group than the control group (p = 0.016, and p = 0.019, respectively). There was no statistically significant difference between the two groups in terms of MCT, BMO, LCT, and LCD. ConclusionWe discovered thinning in the PPCT, which indicates microvascular abnormalities in the optic disc head. Microvascular alteration in the peripapillary region may be a potential initial event in the pathogenesis of several obesity-related ocular diseases, especially glaucoma.

Lamina Cribrosa Morphology in Normal-tension Glaucoma According to the Location of Visual Field Defects.

The morphological alterations in lamina cribrosa may be related to the location of visual field defects. The aim of this study was to investigate morphologic differences in the lamina cribrosa (LC) in normal-tension glaucoma (NTG) according to the location of visual field (VF) defects. This study was a retrospective, cross-sectional study. Ninety-six eyes of 96 patients with NTG were included in this study. The patients were divided into two groups according to the location of VF defects (parafoveal scotoma [PFS] and peripheral nasal step [PNS]). All patients underwent an optical coherence tomography (OCT) of the optic disc and macula using swept-source OCT (DRI-OCT Triton; Topcon, Tokyo, Japan). The parameters of the optic disc, macula, LC, and connective tissues were compared between the groups. The relationships between the LC parameters and other structures were analyzed. The temporal peripapillary retinal nerve fiber layer, average macular ganglion cell-inner plexiform layer, and average macular ganglion cell complex were significantly thinner in the PFS than in the PNS group (P<0.001, P<0.001, and P=0.012, respectively). The PFS group showed a more glaucomatous LC morphology with a smaller lamina cribrosa-global shape index (LC-GSI, P=0.047), more LC defects (P=0.034), and thinner LC (P=0.021) than the PNS group. LC-GSI was significantly correlated with LC thickness (P=0.011) but not with LC depth (P=0.149). In patients with NTG, those with initial PFS showed a more glaucomatous LC morphology than those with initial PNS. The morphological differences in LC may be related to the location of the VF defects.

Effect of pseudoexfoliation syndrome on lamina cribrosa morphology after uneventful phacoemulsification.

To evaluate the behavior of the lamina cribrosa (LC) following successful phacoemulsification (PE) surgery in non-glaucomatous PXS cases with cataract. A total of 25 bilateral PXS and 56 non-PXS cataract patients were included in this prospective, interventional, and controlled study. The lamina cribrosa thickness (LCt) and anterior laminar depth (ALD) were measured horizontally and vertically from two sections using EDI-OCT. The measurements were taken preoperatively, and the LCt and ALD measurements were repeated at week one (W1), month one (M1), month two (M2), and month three (M3) postoperatively. The baseline horizontal and vertical LCt values were found to be significantly thinner in the PXS group (p = 0.001, p = 0.006 respectively). The horizontal section ALD values were 463.32 ± 98.82µm and 383.88 ± 85.8µm (p < 0.001) for the PXS and non-PXS groups, respectively, and this significance continued during follow-up. The vertical ALD values were 469.64 ± 117.83µm and 390.3 ± 98.1µm (p = 0.002) in the PXS and non-PXS groups, respectively. There was no significant change in the PXS group for the depth following PE, but a statistically significant depth increase response was observed in the non-PXS group during follow-up. It is possible to conclude that the bending capacity of the lamina cribrosa may be lower than seen in the normal population, but we do not know how this lack of flexibility will affect the eye.

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.

Differentiation of Nonarteritic Anterior Ischemic Optic Neuropathy from Normal Tension Glaucoma by Comparison of the Lamina Cribrosa.

PurposeTo compare lamina cribrosa (LC) morphology between eyes with nonarteritic anterior ischemic optic neuropathy (NAION) and eyes with normal tension glaucoma (NTG) in the Korean population.MethodsThis retrospective study included 48 eyes with NAION, 48 eyes with NTG, and 48 healthy control eyes matched by age, intraocular pressure, axial length, and optic disc area. Eyes with NAION and NTG were also matched by retinal nerve fiber layer (RNFL) thickness in the affected sector. Optic nerve heads were scanned using enhanced depth imaging spectral-domain optical coherence tomography. LC depth (LCD) and the LC curvature index (LCCI) were measured at seven locations spaced equidistantly across the vertical optic disc diameter. LCD and the LCCI were compared in the three groups.ResultsRNFL thicknesses of the matched affected sectors did not differ between the NAION and NTG groups (P = 0.347). LCD and the LCCI were significantly larger in the NTG group than in the NAION and healthy control groups at all seven planes (P < 0.001 each), but were comparable in the NAION and healthy control groups. The LCCI was larger in the affected than in the unaffected sector of NTG eyes (P = 0.010) but did not differ in NAION eyes (P = 1.000). LCD did not differ between affected and unaffected sectors in either NAION (P = 0.600) or NTG (P = 0.098) eyes.ConclusionsLC morphology differed in eyes with NAION and NTG, despite a similar degree of RNFL damage. Evaluation of LC morphology may help to understand the distinctive pathophysiology of NAION and to differentiate NAION from NTG eyes.

Investigation of the Optic Nerve Head Morphology Influence to the Optic Nerve Head Biomechanics - Population Specific Model.

Glaucoma is an eye disorder potentially leading to permanent blindness through the damage of optic nerves at the optic nerve head (ONH). As a critical region of optic nerve damage, the porous Lamina Cribrosa (LC) in the ONH plays a critical role in determining whether optic nerves passing through will experience apoptosis in response to shear stress. The primary cause of shear stress to the LC is the increase in intraocular pressure (IOP). Since morphology governs how mechanical stresses distributes, LC morphology could be an important factor in determining the risks of glaucoma development and progression. The current project aims at investigating how anterior LC surface morphology impacts its response to shear stress caused by IOP. Results of the current study show that steeper LC morphologies could be associated with increased average shear stress on the anterior LC surface. The effect of LC morphology was comparable to that of IOP. This highlights the potential significance of LC morphology on the distribution of IOP-induced shear stress and calls for further investigation in this area.

Investigation of the Optic Nerve Head Morphology Influence to the Optic Nerve Head Biomechanics - Patient Specific Model.

Glaucoma is associated with damage and death of optic nerve fibers within the Lamina Cribrosa (LC) region of the Optic Nerve Head. The pathogenesis of the disease is unclear, and the anterior LC surface morphology of different individuals can be one of the possible contributor of glaucoma development and progression. The current study evaluates the relationship between the LC surface curvature and distribution of shear stresses on the LC surface. The patient-specific reconstructed ocular model was developed and analyzed in a finite element analysis software. In addition, the effect of elastic modulus of both sclera and LC on the shear stress was examined. Results showed that there is a correlation between the shear stress distribution and the curvature of the anterior LC surface. This finding highlights the potential significance of the LC morphology on the distribution of LC shear stress and require further investigation.

Changes in the Anterior Lamina Cribrosa Morphology with Glaucoma Severity

This study was designed to evaluate if primary open angle glaucoma (POAG) and its severity are associated with the shape of the lamina cribrosa (LC) as measured by a global shape index (LC-GSI), or other indices of LC curvature or depth. Optical coherence tomography (OCT) scans of the optic nerve head (OHN) were obtained from subjects with POAG (n = 99) and non-glaucomatous controls (n = 76). ONH structures were delineated, the anterior LC morphology reconstructed in 3D, and the LC-GSI calculated (more negative values denote greater posterior concavity). Anterior LC depth and 2D-curvature were also measured. Severity of glaucoma was defined by the extent of visual field loss, based on the Hodapp-Parrish-Anderson grading. Linear regression analyses compared LC characteristics between controls, mild-moderate, and advanced POAG groups. After adjusting for age, gender, ethnicity, intraocular pressure, axial length and corneal curvature, the LC-GSI was most negative in the advanced POAG group (mean [standard error] = −0.34 [0.05]), followed by the mild-moderate POAG group (−0.31 [0.02]) and then controls (−0.23 [0.02], PTrend = 0.01). There was also a significant trend of increasing LC depth and greater LC horizontal curvature with increasing severity of glaucoma (PTrend = 0.04 and 0.02, respectively). Therefore, with more severe glaucoma, the LC-GSI was increasingly more negative, and the anterior LC depth and curvature greater. These observations collectively correspond to greater cupping of the ONH at the level of the LC. As the LC-GSI describes the 3D anterior LC morphology, its potential usage may be complementary to existing ONH parameters measured on OCT.

Lamina Cribrosa Curvature in Healthy Korean Eyes

Given that posterior bowing of the lamina cribrosa (LC) is a principle event in the development of glaucomatous damage, assessment of the LC morphology may have clinical utility in diagnosing and managing glaucoma patients. LC curvature has been suggested as an index to evaluate the LC morphology. To apply LC morphology in clinical practice, it is necessary to know normal profiles of LC curvature in healthy population. This study was performed to investigate the characteristics of LC curvature in healthy eyes using enhanced depth imaging spectral-domain optical coherence tomography in a total of 250 eyes of 125 healthy Korean subjects. The lamina cribrosa curvature index (LCCI) values at seven locations spaced equidistantly across the vertical optic disc diameter were measured on serial horizontal B-scan images. The mean value of the seven measurements was defined as the average LCCI. The average LCCI was 7.46 ± 1.22 (range, 4.29–10.48) and did not differ significantly between the right and left eyes. There was a strong inter-eye correlation within subjects. LCCI was significantly larger in eyes with shorter axial length (P < 0.001). The observed range of LCCI in healthy subjects may be used as a reference for evaluating LC curvature in glaucomatous eyes.

Lamina Cribrosa Morphology in Glaucomatous Eyes with Hemifield Defect in a Korean Population

To compare regional variations in lamina cribrosa (LC) curvature and depth between healthy eyes (group 1) and naïve eyes with primary open-angle glaucoma (POAG) having superior (group 2), inferior (group 3), and both (group 4) hemifield retinal nerve fiber layer (RNFL) defects. Cross-sectional study. Each group consisted of 39 eyes of 39 Korean patients who were matched for age, sex, and axial length. The LC curvature index (LCCI) and LC depth (LCD) were measured in B-scan images obtained using enhanced depth imaging OCT at 7 locations spaced equidistantly across the vertical optic disc diameter. Superior and inferior LCCI and LCD were compared by calculating the superior-to-inferior (Sup/Inf) ratios. Comparisons of LCCI, LCD, and Sup/Inf ratio among the 4 groups. Compared with healthy eyes (group 1), LCCIs were larger at the superior and middle planes in group 2, at the inferior and middle planes in group 3, and at all planes in group 4 (P ≤ 0.003). The LCD showed similar results, but there was no difference in superior planes between groups 1 and 2. The Sup/Inf ratio of LCCI differed significantly between groups 1 (1.03) and 2 (1.20), groups 1 and 3 (0.79), groups 2 and 3, groups 2 and 4 (0.96), and groups 3 and 4 (all P < 0.001), but not between groups 1 and 4 (P= 0.273). The Sup/Inf ratio of LCD differed only between groups 2 and 3 (P= 0.002). Eyes with POAG showed regional differences in LC morphology, corresponding with the location of RNFL defects. The regional variations in LCCI suggest that LC morphology in POAG would be better assessed on a regional basis than by a global index.

Ocular and Clinical Characteristics Associated with the Extent of Posterior Lamina Cribrosa Curve in Normal Tension Glaucoma

Although normal-tension glaucoma (NTG) is pathogenetically heterogenous, there have been few attempts to subclassify NTG patients according to the mechanism and anatomy of optic nerve damage. This cross-sectional study was performed to investigate differences in the clinical and ocular characteristics between NTG patient groups stratified according to the degree of posterior lamina cribrosa (LC) curve which was assessed by calculating LC curvature index (LCCI). A total of 101 eyes of 101 treatment naïve NTG patients were included. The optic nerve head was imaged using enhanced-depth-imaging spectral-domain optical coherence tomography in three horizontal B-scan images in each eye. The patients were divided into two groups based on the magnitude of LCCI using a cutoff of known upper 95 percentile value in healthy subjects: a steeply curved LC group (Group 1, 75 eyes, 74.3%) and a relatively flat LC group (Group 2, 26 eyes, 25.7%). NTG eyes with relatively flat LC had lower intraocular pressure, and were associated with greater parapapillary structural alternation and systemic risk factors. These data suggest that assessment of LC morphology may help clinicians seek additional risk factors and make inferences about the mechanism of optic nerve damage in individual patients.

Lamina Cribrosa Morphology Predicts Progressive Retinal Nerve Fiber Layer Loss In Eyes with Suspected Glaucoma

Although early diagnosis and treatment reduce the risk of blindness from glaucoma, the decision on whether or not to begin treatment in patients with suspected glaucoma is often a dilemma because the majority of patients never develop definite glaucoma. A growing body of evidences suggests that posterior bowing of the lamina cribrosa (LC) is the earliest structural change preceding the retinal nerve fiber layer (RNFL) loss in glaucomatous optic neuropathy. Based on this notion, we conducted a prospective study enrolling 87 eyes suspected of having glaucoma to investigate whether the future rate of RNFL loss is associated with the baseline LC curve evaluated by measuring the LC curve index (LCCI) using enhanced depth imaging optical coherence tomography. A faster rate of RNFL loss was significantly associated with greater LCCI (P < 0.001;standardized coefficient beta = −0.392), older age (P = 0.008;beta = −0.314), and greater vertical cup-to-disc ratio (P = 0.040;beta = −0.233). Assessment of LC morphology may help predict the disease outcome in eyes with suspected glaucoma.

Positional and shape changes of lamina cribrosa after trabeculectomy in pseudoexfoliative and primary open angle glaucoma

PurposeTo evaluate positional and shape changes of anterior lamina cribrosa (LC) after trabeculectomy and compare them between eyes with pseudoexfoliative (PEXG) and primary open angle glaucoma (POAG).MethodsThe prospective study included 99 eyes (78 PEXG and 21 POAG) planned for trabeculectomy. The morphological parameters of LC and intraocular pressure (IOP) were measured pre‐ and postoperatively (1 week and 1, 3, 6 and 9 months after the surgery). LC was imaged using enhanced depth imaging spectral domain optical coherence tomography. The mean and sectoral LC depth (LCD), global shape index (GSI), curvedness and curvatures in main meridians were calculated using Morphology 1.0 software. LC parameters were compared across the follow‐up visits and in‐between PEXG and POAG groups.ResultsThe mean IOP reduced in PEXG and POAG eyes after the trabeculectomy at all follow‐up visits (p &lt; 0.001). There was a decrease in mean and sectoral LCD (p &lt; 0.001), curvedness (p &lt; 0.001), nasal‐temporal (N‐T) and superior‐inferior (S‐I) curvatures (p &lt; 0.001, p = 0.045, respectively) during whole postoperative period. LC GSI did not change significantly postoperatively and stayed in‐between a trough and rut shape (p = 0.065). There were no differences in the changes of LC morphology between PEXG and POAG eyes (p &gt; 0.05); however a tendency of greater reduction in LCD and curvature was observed. The decrease in LCD, N‐T and S‐I curvatures correlated positively with IOP reduction(ρ = 0.326, ρ = 0.3, ρ = 0.261, p &lt; 0.01 after 1 week, respectively).ConclusionsTrabeculectomy induced a long term mean and sectoral anterior displacement as well as flattening of LC. However, the overall shape of LC was not affected postoperatively. Despite a potential elastinopathy of pseudoexfoliative syndrome PEXG and POAG eyes did not show differences in positional and shape behaviour of LC after the surgery.

Lamina cribrosa in glaucoma.

This article presents, summarizes, and interprets the most recent advances in the study and understanding of the lamina cribrosa in glaucoma, in the context of previous work. The lamina is an active living structure that responds to strain by changing morphology at the micro-scale and macro-scale in glaucoma. Changes in lamina cribrosa morphology in glaucoma include posteriorization of the laminar insertion into the sclera, increased cupping or depth of the lamina cribrosa, and the development of focal lamina cribrosa defects. These lamina cribrosa changes are associated with disk hemorrhages and visual field damage, and are detectable with clinical imaging techniques such as optical coherence tomography. Glaucomatous changes in the lamina cribrosa are thought to be driven by cellular processes mediated by focal cyclical mechanical strain. Strain is eye specific and mediated by intraocular pressure, cerebrospinal fluid pressure, scleral and lamina cribrosa morphology, and structural stiffness; deleterious lamina cribrosa strains can occur at all levels of mean intraocular pressure. Laminar morphology is ever changing in health and disease, and recent studies have identified several promising morphological changes that are indicative of glaucoma susceptibility, onset, and progression.

Evaluation of the lamina cribrosa morphology in correlation to retinal nerve fiber layer thickness

Aim The aim of this study was to assess the correlation between lamina cribrosa (LC) morphology and glaucoma severity using spectral domain optical coherence tomography. Patients and methods This is a comparative cross-sectional study that included 40 eyes divided into 20 eyes having primary open-angle glaucoma and 20 normal control eyes. Serial horizontal B-scan images of the optic nerve head were obtained using enhanced depth imaging optical coherence tomography. Images were analyzed using the Cirrus HD software. Statistical analysis was conducted to compare the lamina cribrosa depth (LD) and lamina cribrosa thickness (LT) with retinal nerve fiber layer (RNFL) thickness and visual field mean deviation. Results The mean±SD values of the LD, LT, and visual field mean deviation were 533.5±66.8, 188.4±15.8 µm, and −4.3±3.4 dB, respectively. On linear regression analysis, LD, LT, and intraocular pressure were significantly correlated with RNFL thickness (P Conclusion There was a generalized decrease in LT and posterior displacement of the LC in the glaucomatous patients compared with healthy controls. Thus, the LC morphology can help differentiate glaucomatous from normal eyes.

A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes.

Lamina cribrosa (LC) morphology could be implicated in the progression of glaucoma. To date, no established, quantifiable parameter to assess LC shape in vivo exists. We aim to introduce a new global shape index for the anterior LC (LC-GSI) and to identify associations with ocular factors in a healthy Indian population. Optical coherence tomography (OCT) scans of the optic nerve head (ONH) were performed on 162 healthy subjects. Optic nerve head structures were delineated and a geometric characterization of anterior LC morphology was obtained by measuring curvature along 180 LC cross sections and representing it as LC-GSI ranging from -1 to +1. Lamina cribrosa depth and curvature were also reported. Linear regression was used to identify factors associated with LC morphology. The typical healthy LC had a saddle rut-like appearance, with a central ridge visible in superior-inferior cross sections. A more prominent central ridge (larger LC-GSI) was associated with shorter axial length (P < 0.001), smaller Bruch's membrane opening (BMO) area (P = 0.020), smaller vertical cup-to-disc ratio (VCDR) (P = 0.007), and larger minimum rim width (BMO-MRW) (P = 0.001). A deeper LC was associated with male sex (P < 0.001), shorter axial length (P = 0.003), larger VCDR (P < 0.001), and smaller BMO-MRW (P = 0.002). Age and IOP were not significantly associated with LC morphology in healthy eyes. The LC-GSI is a single index that quantifies overall LC shape in an intuitive way. Ocular determinants of LC-GSI in healthy eyes included risk factors for glaucoma (axial length, VCDR, and BMO-MRW), highlighting the potential role of LC morphological characterization in the diagnosis and monitoring of glaucoma.

Imaging of the Lamina Cribrosa using Swept-Source Optical Coherence Tomography.

ABSTRACTThe lamina cribrosa (LC) is the presumed site of axonal injury in glaucoma. Its deformation has been suggested to contribute to optic neuropathy by impeding axoplasmic flow within the optic nerve fibers, leading to apoptosis of retinal ganglion cells. To visualize the LC in vivo, optical coherence tomography (OCT) has been applied. Spectral domain (SD)-OCT, used in conjunction with recently introduced enhanced depth imaging (EDI)-OCT, has improved visualization of deeper ocular layers, but in many individuals it is still limited by inadequate resolution, poor image contrast and insufficient depth penetrance. The posterior laminar surface especially is not viewed clearly using these methods. New generation high-penetration (HP)-OCTs, also known as swept-source (SS)-OCT, are capable to evaluate the choroid in vivo to a remarkable level of detail. SS-OCTs use a longer wavelength (1,050 nm instead of 840 nm) compared to the conventional techniques. We review current knowledge of the LC, findings from trials that use SD-OCT and EDI-OCT, and our experience with a prototype SS-OCT to visualize the LC in its entirety.Key PointsWhat is known?• The LC is the presumed site of axonal injury in glaucoma• Compared to spectral domain-OCT, enhanced depth imaging-OCT improves imaging of the LC• Even so, currently used SD-OCT techniques are restricted by poor wavelength penetrance of the deeper ocular layersWhat our findings add?• SS-OCT may be a superior imaging modality for deep ocular structures• Prior studies used SS-OCT to evaluate choroidal thickness in both healthy and ‘normal tension glaucoma’ eyes• SS-OCT enables good evaluation of three-dimension (3D) lamina cribrosa morphology.How to cite this article: Nuyen B, Mansouri K, Weinreb RN. Imaging of the Lamina Cribrosa using Swept-Source Optical Coherence Tomography. J Current Glau Prac 2012;6(3): 113-119.

The Optic Nerve Head inMyocilinGlaucoma

Approximately 1 in 30 unselected patients with open-angle glaucoma (OAG) have a mutation in the myocilin gene. The purpose of this study was to describe the morphologic features of the optic nerve head (ONH) in myocilin glaucoma. A case-control design was adopted. Sixty-six patients heterozygous for a range of myocilin mutation (cases) were matched in disease severity to 105 patients with OAG known not to have a myocilin mutation (controls), using visual field findings. Quantifiable analysis of the ONH was undertaken of stereoscopic photographs, by using custom software with a z-screen. Subjective grading of the cup depth, lamina cribrosa pore shape and orientation, and the slope of the neuroretinal rim was performed by an examiner masked to the subject's mutation status. Mutation screening was conducted using either direct sequencing or single-stranded conformation polymorphism analysis. Patients with a myocilin mutation had glaucoma diagnosed earlier (P < 0.001) and had higher maximum recorded intraocular pressures (P < 0.001) than did the control OAG subjects. There was no significant (P > 0.05) difference in global disc area, global neuroretinal rim area, alpha-parapapillary atrophy, beta-parapapillary atrophy, slope of neuroretinal rim, or visible lamina cribrosa morphology between myocilin mutation carriers and patients with nonmyocilin glaucoma. Disc hemorrhages were identified more frequently in those without mutations (14/209 vs. 1/129), though this was not significant after correction for multiple hypothesis testing. No major structural or morphologic difference of the ONH was detected in pooled data from subjects who had myocilin mutations compared with data from individuals with nonmyocilin glaucoma.