Effects of Myopia and Glaucoma on the Neural Canal and Lamina Cribrosa Using Optical Coherence Tomography.

PRCIS: Glaucoma was associated with axial bowing and rotation of Bruchs membrane opening (BMO) and anterior laminar insertion (ALI), skewed neural canal, and deeper anterior lamina cribrosa surface (ALCS). Longer axial length was associated with wider, longer, and more skewed neural canal and flatter ALCS. PURPOSE: Investigate the effects of myopia and glaucoma in the prelaminar neural canal and anterior lamina cribrosa using 1060-nm swept-source optical coherence tomography. PATIENTS: 19 control (38 eyes) and 38 glaucomatous subjects (63 eyes). MATERIALS AND METHODS: Participants were imaged with swept-source optical coherence tomography, and the images were analyzed for the BMO and ALI dimensions, prelaminar neural canal dimensions, and ALCS depth. RESULTS: Glaucomatous eyes had more bowed and nasally rotated BMO and ALI, more horizontally skewed prelaminar neural canal, and deeper ALCS than the control eyes. Increased axial length was associated with a wider, longer, and more horizontally skewed neural canal and a decrease in the ALCS depth and curvature. CONCLUSION: Our findings suggest that glaucomatous posterior bowing or cupping of lamina cribrosa can be significantly confounded by the myopic expansion of the neural canal. This may be related to higher glaucoma risk associated with myopia from decreased compliance and increased susceptibility to IOP-related damage of LC being pulled taut.

Diagnostic accuracy of point of care faecal immunochemical testing using a portable high-speed quantitative analyser for diagnosis in 2-week wait patients.

AIM: Laboratory-based faecal immunochemical testing (FIT) is the gold standard for detecting the presence of blood in the stool. The aim was to perform a diagnostic accuracy study to confirm if a point of care (POC) analyser for FIT could be safely used as an adjunct in the triage and management of 2-week wait (TWW) colorectal patients. METHODS: The Point of Care Faecal Immunochemical Testing (POC FIT) prospective observational cohort study was designed for TWW patients at a regional referral centre. Between July 2019 and March 2020, patients were invited to perform and bring a FIT sample to clinic. FIT was completed within the clinic appointment using a POC quantitative analyser that has a 2-min processing time (QuikRead go®). Patients and clinicians were blinded to results within the clinic appointment. The results were compared with subsequent diagnostic outcomes. Faecal haemoglobin of <10 µg haemoglobin/g of faeces was considered a negative result. Sensitivities for colorectal cancer (CRC) and combined serious bowel disease (SBD) were calculated using this pre-determined cut-off. RESULTS: A total of 553 patients were included for analytical comparison with diagnostic outcomes. There were 14 (2.5%) patients with CRC and 52 (9.4%) with SBD. The sensitivities for CRC and SBD were 92.9% (95% CI 68.5%-98.7%) and 76.9% (95% CI 63.9%-86.3%) respectively. 379 (68.5%) patients had a negative FIT result (negative predictive value for CRC was 99.7%). CONCLUSIONS: This POC FIT device is a useful adjunct to better manage TWW patients. The high observed sensitivity for CRC offers opportunities, within a single consultation, for improved triage and rationalization of investigation for those with bowel symptoms.

Protocolo ERAS® en cirugía colorrectal / ERAS® in Colorectal Surgery

RESUMEN El protocolo de recuperación optimizada Enhanced Recovery After Surgery (ERAS®) en cirugía colo rrectal promueve un retorno más rápido a la función orgánica siguiendo la evidencia de las últimas investigaciones dirigidas a disminuir el estrés quirúrgico. La vía perioperatoria recomendada está per feccionada, es dinámica y se ajusta a las últimas investigaciones basadas en la evidencia para mejorar todos los aspectos de la atención quirúrgica del paciente. En este artículo describiremos los cuatro aspectos de un paciente a quien se le realizará una cirugía colorrectal: preadmisión, preoperatorio, in traoperatorio y posoperatorio El tema recurrente es disminuir el estrés fisiológico general relacionado con la cirugía; para ello, las intervenciones se superponen a lo largo del recorrido que hace el paciente. Utilizando un enfoque multidisciplinario, la adherencia al protocolo ERAS® en cirugía colorrectal cum pliendo con el 70% o más de las intervenciones de ERAS® ha demostrado una reducción del riesgo de muerte relacionada con el cáncer del 42% a los 5 años. Las intervenciones óptimas no solo se determi nan mediante la publicación de investigaciones de alta calidad, sino que la colaboración internacional periódica permite compartir experiencias e investigaciones y estandarizar los cuidados.

ABSTRACT Enhanced Recovery After Surgery (ERAS®) in colorectal surgery is a protocol that promotes quicker return to function. It follows the latest evidence-based research to promote stress reduction related to surgery. The recommended perioperative pathway is fine-tuned, dynamic and in line with the latest evidence-based research to enhance all aspects of the patient's surgical care. We describe the four aspects for a patient undergoing colorectal surgery - pre-admission, pre-operative, intra-operative and post-operative. The running theme is to reduce overall physiological stress related to surgery and interventions overlap throughout the patient's pathway. Using a multidisciplinary approach, adheren ce to ERAS® in colorectal surgery with ≥70 % compliance to the ERAS interventions has shown a risk reduction of 5-year cancer-related death by 42%. The optimum interventions are not only determined through the publication of high-quality research, but regular international collaboration enables expe rience and research to be shared and care standardized.

Adoption of faecal immunochemical testing for 2-week-wait colorectal patients during the COVID-19 pandemic: an observational cohort study reporting a new service at a regional centre.

AIM: The COVID-19 pandemic has resulted in the near-complete loss of routine endoscopy services. We describe a major reorganization of service at a regional referral centre (Royal Surrey NHS Foundation Trust) to manage the crisis. Faecal immunochemical testing (FIT) was implemented for triage to make optimum use of limited diagnostic resources. Consultations were switched from face-to-face to telephone. Our aim was to evaluate the impact FIT had on resource allocation and patient diagnoses in the first 3 months of use. METHOD: All colorectal 2-week-wait patient referrals were posted a pack requesting FIT and notification of telephone consultation. A prepaid envelope was included for return of the samples. At consultation, FIT was incorporated with the presenting symptoms to guide the choice of investigation and triage urgency. FIT ≥10 µg/g was interpreted as positive. Outcome data were collected prospectively and compared with retrospective audit data from prepandemic levels across 3 months. RESULTS: From 26 March 2020 to 2 July 381 patients were referred who were invited to provide FIT samples and underwent telephone consultations. Three hundred and fifty eight FIT samples were returned (94%). Onward referral for colonoscopy reduced from 62% to 34% (P < 0.001). There were 14 colorectal cancers (CRC) (3.7%) diagnosed, which was not statistically different from the prepandemic level of 3.9% (P = 0.995). Twelve of the 14 patients with a CRC diagnosis had provided samples; all 12 had FIT ≥10 µg/g and were offered fast-track investigations. CONCLUSIONS: The incorporation of FIT optimized the allocation of limited resources to triage those who required urgent colonic investigation for detecting CRC.

Exascale applications: skin in the game.

As noted in Wikipedia, skin in the game refers to having 'incurred risk by being involved in achieving a goal', where 'skin is a synecdoche for the person involved, and game is the metaphor for actions on the field of play under discussion'. For exascale applications under development in the US Department of Energy Exascale Computing Project, nothing could be more apt, with the skin being exascale applications and the game being delivering comprehensive science-based computational applications that effectively exploit exascale high-performance computing technologies to provide breakthrough modelling and simulation and data science solutions. These solutions will yield high-confidence insights and answers to the most critical problems and challenges for the USA in scientific discovery, national security, energy assurance, economic competitiveness and advanced healthcare. This article is part of a discussion meeting issue 'Numerical algorithms for high-performance computational science'.

Longitudinal Analysis of Bruch Membrane Opening Morphometry in Myopic Glaucoma.

PRéCIS:: The Bruch membrane opening (BMO) was posteriorly bowed and the degree of nonplanarity increased in stable and progressive glaucoma subjects. BMO became more posterior relative to the Bruch membrane (BM) in control and both stable and progressive glaucoma subjects. PURPOSE: To investigate longitudinal changes in morphologic characteristics of the BMO in control and glaucomatous subjects. MATERIALS AND METHODS: A total of 53 myopic eyes (17 control, 6 suspect, 20 stable glaucoma, and 10 progressing glaucoma) were followed for an average of 4.2±1.4 years and imaged at the baseline and 2 follow-up appointments using a 1060 nm swept-source optical coherence tomography system. BM and BMO were segmented, and 4 morphometric BMO parameters (area, ellipse ratio, nonplanarity, and depth) were measured. RESULTS: There were no significant changes in BMO area or ellipse ratio for all groups. BMO nonplanarity was shown to increase in the glaucoma groups. BMO depth relative to BM increased in all groups except the suspects (control: 8.1 µm/y, P=0.0001; stable glaucoma: 3.5 µm/y, P=0.0001; progressing glaucoma: 14.0 µm/y, P=0.0026). In linear mixed-model analysis, axial length was positively associated with BMO area in all groups except for progressing glaucoma, and with BMO nonplanarity in stable glaucoma. It was not a significant factor to the slopes of the BMO parameters in the ANCOVA analysis of slopes. CONCLUSIONS: Longitudinally, BMO increased in nonplanarity in the glaucoma eyes, and its axial position relative to BM became more posterior in both control and glaucoma eyes.

Age and Glaucoma-Related Characteristics in Retinal Nerve Fiber Layer and Choroid: Localized Morphometrics and Visualization Using Functional Shapes Registration.

Optical coherence tomography provides high-resolution 3D imaging of the posterior segment of the eye. However, quantitative morphological analysis, particularly relevant in retinal degenerative diseases such as glaucoma, has been confined to simple sectorization and averaging with limited spatial sensitivity for detection of clinical markers. In this paper, we present point-wise analysis and visualization of the retinal nerve fiber layer and choroid from cross-sectional data using functional shapes (fshape) registration. The fshape framework matches two retinas, or generates a mean of multiple retinas, by jointly optimizing the surface geometry and functional signals mapped on the surface. We generated group-wise mean retinal nerve fiber layer and choroidal surfaces with the respective layer thickness mapping and showed the difference by age (normal, younger vs. older) and by disease (age-matched older, normal vs. glaucomatous) in the two layers, along with a more conventional sector-based analysis for comparison. The fshape results visualized the detailed spatial patterns of the differences between the age-matched normal and glaucomatous retinal nerve fiber layers, with the glaucomatous layers most significantly thinner in the inferior region close to Bruch's membrane opening. Between the young and older normal cases, choroid was shown to be significantly thinner in the older subjects across all regions, but particularly in the nasal and inferior regions. The results demonstrate a comprehensive and detailed analysis with visualization of morphometric patterns by multiple factors.

Anterior Segment Optical Coherence Tomography for Targeted Transconjunctival Suture Placement in Overfiltering Trabeculectomy Blebs.

PURPOSE: To demonstrate the utility of swept-source anterior segment optical coherence tomography (SS-AS-OCT) in guiding placement of transconjunctival sutures in hypotonous patients after a trabeculectomy. PATIENTS AND METHODS: This is a longitudinal case series of 10 eyes from 10 patients who required transconjunctival sutures after a trabeculectomy. SS-AS-OCT was used to aid in the placement of the sutures to improve the function of the overfiltering bleb. RESULTS: SS-AS-OCT reliably identified localized areas of overfiltering, allowing for targeted suture placement in 8 eyes. The 2 eyes in which localized areas of overfiltering were not found required further surgical intervention. CONCLUSIONS: SS-AS-OCT enhances transconjunctival suturing for overfiltering blebs when focal fluid accumulation is visualized.

Quantifying Variability in Longitudinal Peripapillary RNFL and Choroidal Layer Thickness Using Surface Based Registration of OCT Images.

PURPOSE: To assess within-subject variability of retinal nerve fiber layer (RNFL) and choroidal layer thickness in longitudinal repeat optical coherence tomography (OCT) images with point-to-point measurement comparison made using nonrigid surface registration. METHODS: Nine repeat peripapillary OCT images were acquired over 3 weeks from 12 eyes of 6 young, healthy subjects using a 1060-nm prototype swept-source device. The RNFL, choroid and the Bruch's membrane opening (BMO) were segmented, and point-wise layer thicknesses and BMO dimensions were measured. For each eye, the layer surfaces of eight follow-up images were registered to those of the baseline image, first by rigid alignment using blood vessel projections and axial height and tilt correction, followed by nonrigid registration of currents-based diffeomorphisms algorithms. This mapped all follow-up measurements point-wise to the common baseline coordinate system, allowing for point-wise statistical analysis. Measurement variability was evaluated point-wise for layer thicknesses and BMO dimensions by time-standard deviation (tSD). RESULTS: The intraclass correlation coefficients (ICCs) of BMO area and eccentricity were 0.993 and 0.972, respectively. Time-mean and tSD were computed point-wise for RNFL and choroidal thickness and color-mapped on the baseline surfaces. tSD was less than two coherence lengths of the system 2ℓ = 12 µm at most vertices. High RNFL thickness variability corresponded to the locations of retinal vessels, and choroidal thickness varied more than RNFL thickness. CONCLUSIONS: Our registration-based end-to-end pipeline produced point-wise correspondence among time-series retinal and choroidal surfaces with high measurement repeatability (low variability). Blood vessels were found to be the main sources contributing to the normal variability of the RNFL thickness measure. The computational pipeline with a measurement of normal variability can be used in future longitudinal studies to identify changes that are above the threshold of normal point-wise variability and track localized changes in retinal layers in high spatial resolution. TRANSLATIONAL RELEVANCE: Using the registration-based approach presented in this study, longitudinal changes in retinal and choroidal layers can be detected with higher sensitivity and spatial precision.

Quantitative Optical Coherence Tomography Angiography of Radial Peripapillary Capillaries in Glaucoma, Glaucoma Suspect, and Normal Eyes.

PURPOSE: To evaluate the quantitative characteristics of the radial peripapillary capillary (RPC) network in glaucoma, glaucoma suspect, and normal eyes using speckle variance optical coherence tomography angiography (OCT-A). To determine correlations between RPC density, nerve fiber layer (NFL) thickness, and visual field indices. DESIGN: Cross-sectional study. METHODS: OCT-A images of RPCs were acquired at a single institution using a custom-built 1060 nm system from 3 groups: unilateral glaucoma (10 eyes from 5 subjects), glaucoma suspects (6 eyes from 3 subjects), and normal control eyes (16 eyes from 9 normal subjects). Peripapillary NFL thickness measurements were determined using spectral-domain optical coherence tomography. Glaucoma and glaucoma suspects also underwent automated 30-2 Humphrey visual field analysis. Manual tracing techniques were used to quantify RPC density in the OCT-A images. Data were analyzed using a linear mixed model with 1 fixed-effect covariate. Correlations between main outcome measures (RPC density, NFL thickness, and visual field index) were determined. RESULTS: Mean age was not significantly different between the 3 groups (P = .25). The density of RPCs was significantly lower in glaucomatous eyes compared with matched-peripapillary regions in the fellow eye, glaucoma suspect group, and normal group (all P < .001). RPC density was strongly correlated with NFL thickness (P < .001) and visual field index (P < .001). CONCLUSIONS: Significant reductions in RPC density were correlated with sites of NFL decrease and visual field loss in glaucoma. Speckle variance OCT-A allows visualization and quantification of RPCs and may therefore be a useful tool for indirectly quantifying and monitoring retinal ganglion cell axonal injury in glaucoma.

Retinal optical coherence tomography at 1 µm with dynamic focus control and axial motion tracking.

High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the retina and optic nerve head, from which we extracted clinically relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

Quantitative Noninvasive Angiography of the Fovea Centralis Using Speckle Variance Optical Coherence Tomography.

PURPOSE: To demonstrate the utility of speckle variance optical coherence tomography (svOCT), a noninvasive angiographic technique, for evaluating the foveal vasculature. METHODS: Twelve normal human eyes were imaged with svOCT (1060-nm, 100-kHz custom-built system) and fluorescein angiography (FA; Topcon TRC-50DX with 5.0 megapixel resolution camera). Manual tracing techniques were used to quantify the foveal vasculature, including foveal avascular zone (FAZ) metrics (area, perimeter, greatest diameter, and lowest diameter). Reproducibility of these measurements was determined. The FAZ was imaged in 25 normal eyes using svOCT and 15 donor eyes using confocal scanning laser microscopy. Retinal capillary plexuses in donor eyes were perfusion-labeled with phalloidin conjugated to Alexa Fluor 546. RESULTS: Speckle variance OCT is able to stratify the foveal circulation into inner and deep capillary plexuses as well as reliably quantify and assess the morphometric dimensions of the human FAZ. Capillary density measurements were significantly greater in svOCT than FA (31.2 ± 1.6% vs. 19.3 ± 1.9% of total tissue area; P < 0.001). Measurements were highly reproducible (all P > 0.366). All FAZ metrics were significantly lower in histology than svOCT (all P < 0.001). CONCLUSIONS: Speckle variance OCT permits precise, reproducible, and noninvasive visualization of the human foveal vasculature. Speckle variance OCT may become an important adjunct in evaluating patients with retinal vascular diseases.

Label-Free Density Measurements of Radial Peripapillary Capillaries in the Human Retina.

Radial peripapillary capillaries (RPCs) comprise a unique network of capillary beds within the retinal nerve fibre layer (RNFL) and play a critical role in satisfying the nutritional requirements of retinal ganglion cell (RGC) axons. Understanding the topographical and morphological characteristics of these networks through in vivo techniques may improve our understanding about the role of RPCs in RGC axonal health and disease. This study utilizes a novel, non-invasive and label-free optical imaging technique, speckle variance optical coherence tomography (svOCT), for quantitatively studying RPC networks in the human retina. Six different retinal eccentricities from 16 healthy eyes were imaged using svOCT. The same eccentricities were histologically imaged in 9 healthy donor eyes with a confocal scanning laser microscope. Donor eyes were subject to perfusion-based labeling techniques prior to retinal dissection, flat mounting and visualization with the microscope. Capillary density and diameter measurements from each eccentricity in svOCT and histological images were compared. Data from svOCT images were also analysed to determine if there was a correlation between RNFL thickness and RPC density. The results are as follows: (1) The morphological characteristics of RPC networks on svOCT images are comparable to histological images; (2) With the exception of the nasal peripapillary region, there were no significant differences in RPC density measurements between svOCT and histological images; (3) Capillary diameter measurements were significantly greater in svOCT images compared to histology; (4) There is a positive correlation between RPC density and RNFL thickness. The findings in this study suggest that svOCT is a reliable modality for analyzing RPC networks in the human retina. It may therefore be a valuable tool for aiding our understanding about vasculogenic mechanisms that are involved in RGC axonopathies. Further work is required to explore the reason for some of the quantitative differences between svOCT and histology.

Quantitative Comparison of Retinal Capillary Images Derived By Speckle Variance Optical Coherence Tomography With Histology.

PURPOSE: The purpose of this study was to correlate human retinal capillary network information derived from a prototype speckle variance optical coherence tomography (svOCT) device with histology to determine the utility of this instrument for quantitative angiography. METHODS: A retina location 3 mm superior to the optic disk was imaged with svOCT in 14 healthy human eyes. Qualitative and quantitative features of capillary networks, including capillary diameter and density, were compared with perfusion-labeled histological specimens from the same eccentricity. Twelve human donor eyes with no history of eye disease were used for histological comparisons. RESULTS: svOCT was able to clearly distinguish the morphological features of the nerve fiber layer capillary network, the retinal ganglion cell (RGC) layer capillary network, the capillary network at the border of the inner plexiform layer and superficial boundary of the inner nuclear layer, and the capillary network at the boundary of the deep inner nuclear layer and outer plexiform layer. The morphological features of these networks were highly comparable to those in previous histological studies. There were no statistical differences in mean capillary diameter between svOCT images and histology for all networks other than the RGC capillary network. Capillary density measurements were significantly greater in svOCT images, except in the RGC capillary network. CONCLUSIONS: svOCT has the capacity to provide histology-like anatomical information about human retinal capillary networks in vivo. It may have great potential as a research and diagnostic tool in the management of retinal vascular diseases. Further work is required to clarify the cause of some quantitative differences between svOCT and histology.

In vivo optical imaging of human retinal capillary networks using speckle variance optical coherence tomography with quantitative clinico-histological correlation.

Retinal capillary networks are critically linked to neuronal health and disease. The ability to perform accurate in vivo examination of human retinal capillary networks is therefore valuable for studying mechanisms that govern retinal homeostasis and retinal vascular diseases. Speckle variance optical coherence tomography (svOCT) is a non-invasive imaging technique that has the capacity to provide angiographic information about the retinal circulation. The application of this technology for studying human retinal capillary networks however has not been validated in a quantifiable manner. We use a custom-built svOCT device to qualitatively and quantitatively study the various capillary networks in the human perifovea. Capillary networks corresponding to the nerve fibre layer (NFL), the retinal ganglion cell/superficial inner plexiform layer (RGC/sIPL), the deep inner plexiform layer/superficial inner nuclear layer (dIPL/sINL) and the deep inner nuclear layer (dINL) are imaged in 9 normal human subjects. Measurements of capillary diameter and capillary density are made from each of these networks and results are compared to post-mortem histological data acquired with confocal scanning laser microscopy. Additionally, retinal capillary measurements from high-resolution fundus fluorescein angiogram (FA) are directly compared with svOCT images from 6 eyes. We demonstrate that svOCT images of capillary networks are morphologically comparable to microscopic images of histological specimens. Similar to histological images in svOCT images, the capillaries in the NFL network run parallel to the direction of RGC axons while capillaries in the dINL network comprise a planar configuration with multiple closed loops. Capillaries in remaining networks are convoluted with a complex three-dimensional architecture. We demonstrate that there is no significant difference in capillary density measurements between svOCT and histology images for all networks. Capillary diameter was significantly greater in svOCT images compared to histology for all networks. Capillary density measurements were also higher in svOCT compared to FA. The results of this study suggest that in vivo svOCT imaging allows accurate morphometric assessment of capillary networks in the human perifovea and may provide an improved ability to render microvascular detail compared to FA. Therefore, svOCT may have broad clinical applications in the study of human retinal physiology and disease. The difference in quantitative measurements between svOCT and histology may reflect dynamic variations in the retinal microcirculation and warrants further investigation.

Retinal angiography with real-time speckle variance optical coherence tomography.

This report describes a novel, non-invasive and label-free optical imaging technique, speckle variance optical coherence tomography (svOCT), for visualising blood flow within human retinal capillary networks. This imaging system uses a custom-built swept source OCT system operating at a line rate of 100 kHz. Real-time processing and visualisation is implemented on a consumer grade graphics processing unit. To investigate the quality of microvascular detail acquired with this device we compared images of human capillary networks acquired with svOCT and fluorescein angiography. We found that the density of capillary microvasculature acquired with this svOCT device was visibly greater than fluorescein angiography. We also found that this svOCT device had the capacity to generate en face images of distinct capillary networks that are morphologically comparable with previously published histological studies. Finally, we found that this svOCT device has the ability to non-invasively illustrate the common manifestations of diabetic retinopathy and retinal vascular occlusion. The results of this study suggest that graphics processing unit accelerated svOCT has the potential to non-invasively provide useful quantitative information about human retinal capillary networks. Therefore svOCT may have clinical and research applications for the management of retinal microvascular diseases, which are a major cause of visual morbidity worldwide.

Comparison of the clinical disc margin seen in stereo disc photographs with neural canal opening seen in optical coherence tomography images.

PURPOSE: To compare neural canal opening (NCO) with the clinical optic disc margin (DM) seen and to investigate the planarity of the NCO in normal human optic nerve heads (ONH). METHODS: Sixteen eyes were imaged. Twelve healthy eyes were selected for planarity and 9 for NCO and DM correspondence. All subjects were subjected to a visual field examination, stereo disc photograph (SDP), scanning laser ophthalmoscopy, clinical examination with a fellowship trained glaucoma specialist, and optical coherence tomography imaging. Three reviewers delineated the NCO and inner limiting membrane on optical coherence tomography images. The clinical DM was delineated by a glaucoma specialist while viewing SDPs. Plane error was calculated for NCO and for Bruch membrane (BM) at distances 80 and 120 µm from NCO. RESULTS: The NCO segmentation interrater variability was low with an average coefficient of variation of 2.7%. A regional variation of the SDP and NCO correspondence was observed, wherein the temporal region had the largest coefficient of variation. The plane error of the NCO and BM were similar and was approximately 12 µm, which is small relative to an average DM diameter of 1.7 mm. CONCLUSIONS: The BM opening has a good correspondence with the clinical DM seen in SDPs. NCO delineation seemed to be reliable. The BM and NCO are relatively planar in normal humans and can be further evaluated for longitudinal studies to observe stability.

Optic nerve head and peripapillary morphometrics in myopic glaucoma.

PURPOSE: To investigate morphological characteristics of optic nerve head and peripapillary region with myopia and glaucoma. METHODS: Ten normal and 17 glaucomatous myopic participants were imaged with a custom 1060-nm swept-source optical coherence tomography system. The three-dimensional images were processed and segmented for inner limiting membrane (ILM), posterior border of retinal nerve fiber layer (RNFL), Bruch's membrane (BM), and posterior border of choroid. Seven shape parameters were measured: nerve fiber layer (NFL) thickness; Bruch's membrane opening (BMO) area, eccentricity, and planarity; BMO and BM depths; and choroidal thickness. The results were analyzed by group and regional sector, and multiple regression was performed on each shape parameter with age, axial length, and glaucoma severity, measured by mean deviation (MD). RESULTS: Bruch's membrane opening area (P < 0.001), eccentricity (P = 0.025), and planarity (P = 0.019) were correlated with axial length but not with MD, such that larger, more elliptical, and less planar BMO was associated with longer axial length. Several BMOs displayed a saddle-like shape configuration whose orientation appeared to be aligned with that of the BMO ellipse. All BM showed posterior deformation toward BMO such that BM closer to BMO was more posterior than that farther from BMO. Bruch's membrane depth was correlated with axial length (P = 0.014) and MD (P = 0.040) in intersubject regression, and BMO depth (P = 0.003) and BM depth (P = 0.006) were correlated with MD in intereye regression. Bruch's membrane depth was also associated with age. Choroidal thickness was negatively correlated with age (P = 0.001) and with axial length to a smaller degree (P = 0.034), but not with glaucoma severity. CONCLUSIONS: Axial length was a significant factor in BMO and BM shape in normal and glaucomatous myopic subjects. Posterior deformation of BM was observed in all eyes and significantly associated with functional glaucomatous damage and age.

An immunoglobulin G complexed form of thyroid-stimulating hormone (macro thyroid-stimulating hormone) is a cause of elevated serum thyroid-stimulating hormone concentration.

BACKGROUND: Macrocomplexes can be the cause of elevated serum hormone concentrations and may cause diagnostic confusion. This is well recognized for prolactin and commonly screened for using polyethylene glycol (PEG) precipitation. The phenomenon and a suitable screening method is less familiar with respect to thyroid-stimulating hormone (TSH). METHOD: Samples sent to the laboratory for routine analysis of thyroid function and found to have a TSH >10 mU/L were evaluated to determine the prevalence of macro-TSH in the Roche Elecsys assay, using PEG precipitation with confirmation by gel filtration chromatography. RESULTS: Of 495 samples tested, 3 (0.6%) were found to have macro-TSH. From the distribution of recoveries, a cut-off <25% was determined for identifying samples requiring further investigation for the presence of macro-TSH. CONCLUSION: The prevalence of elevated TSH due to macro-TSH was found to be 0.6%. Laboratories should be aware of this cause of assay interference.