Nerve Fiber Bundles Research Articles

Irritation of Dental Sensory Nerves Promotes the Occurrence of Pulp Calcification

IntroductionPulp calcification (PC) often appears in strong association with nerve fiber bundles, which indicates the important role of dental nerves in the formation of PC. Additionally, given that sensory nerves and calcitonin gene-related peptide (CGRP) secreted from sensory nerve fibers are involved in physiological and pathological bone formation, we aimed to determine whether chronic irritation of sensory nerves can promote the occurrence of PC. MethodsA sensory nerve irritation rat model was established via ligation of the inferior alveolar nerve (IAN), and face grooming behavior was analyzed as a measure of pain sensation. Two months post-surgery, PC was determined by imaging and histologic analyses. ResultsRats in the IAN-chronic constriction injury (IAN-CCI) group showed spontaneous pain-associated behavior after the operations and pain tolerance on the 60th postoperative day. The imaging and histological analysis showed more calcified particles in the IAN-innervated first and second molars after day 60 of the dental sensory nerve irritation. These calcified masses had a dentin-like structure that contained sparse, irregularly oriented tubules. Compared to the control and sham groups, the odontoblasts located in the periphery of radicular pulp aligned along a thicker layer of predentin; which expressed more nestin with longer and stouter processes in the IAN-CCI group. Additionally, more CGRP-positive nerves were observed in the IAN-CCI group. ConclusionsIrritation of sensory nerves promotes PC formation, and the increased density of CGRP-immunolabeled fibers probably contributes to this process. This highlights the significance of dental sensory nerves in the formation of PC.

Three-dimensional nanofibrous sponges with aligned architecture and controlled hierarchy regulate neural stem cell fate for spinal cord regeneration.

Background: Spinal cord injury (SCI) induces neuronal death and disrupts the nerve fiber bundles, which leads to severe neurological dysfunction and even permanent paralysis. A strategy combining biomimetic nanomaterial scaffolds with neural stem cell (NSC) transplantation holds promise for SCI treatment. Methods: Innovative three-dimensional (3D) nanofibrous sponges (NSs) were designed and developed by a combination of directional electrospinning and subsequent gas-foaming treatment. Immunofluorescence, mRNA sequencing, magnetic resonance imaging, electrophysiological analysis, and behavioral tests were used to investigate the in vitro and in vivo regenerative effects of the 3D NSs. Results: The generated 3D NSs exhibited uniaxially aligned nano-architecture and highly controllable hierarchical structure with super-high porosity (99%), outstanding hydrophilicity, and reasonable mechanical performance. They facilitated cell infiltration, induced cell alignment, promoted neuronal differentiation of NSCs, and enhanced their maturation mediated through cellular adhesion molecule pathways. In vivo, the NSC-seeded 3D NSs efficiently promoted axon reinnervation and remyelination in a rat SCI model, with new "neural relays" developing across the lesion gap. These histological changes were associated with regain of function, including increasing the neurological motor scores of SCI rats, from approximately 2 to 16 (out of 21), and decreasing the sensing time in the tape test from 140 s to 36 s. Additionally, the scaffolds led to restoration of ascending and descending electrophysiological signalling. Conclusion: The as-fabricated 3D NSs effectively regulate NSC fates, and an advanced combination of 3D NS design and transplanted NSCs enables their use as an ideal tissue-engineered scaffold for SCI repair.

Histological and Molecular Evaluation of Raw Meatball Products

Meat is an important source of protein with high biological value. Due to this importance, the production and consumption of meat and meat products such as minced meat, salami, sausage, meatballs and roasted meat has been increasing rapidly in recent years. In order to earn more money, some companies sell animal meats that are not consumed by the society by mixing them into meat products without considering the health, habits, ethical and cultural values of people. In this study, it is aimed to examine whether there are undesirable tissues and muscle tissue belonging to different species in meat products by making histological and molecular evaluations in raw meatball products offered for sale. Evaluations were made by taking samples of raw meatball products offered for sale by 6 different well known supermarkets. In the results we obtained, it was observed that the integrity of the muscle tissue was not impaired in sample 1, but the presence of cartilage fragments in places. In sample 2, different sizes of tendon fragments and nerve fiber bundles were detected, with less muscle tissue. In sample number 3, it was observed that the integrity of the muscle tissue was not impaired and the spice pieces were excessive. In sample number 4, it was observed that the integrity of the muscle tissue was partially damaged. In sample 5, large tendon fragments and abundant connective tissue were detected. In sample 6, an image was detected, suggesting that it was caused by too much use of the additive. In the RT-PCR results, no tissue belonging to different species was found in any of the 6 samples we received. These results, in addition to being inappropriate in terms of public health and consumer rights, also appear as attempts to gain unfair financial gain.

Microstructural changes of white matter assessed with diffusional kurtosis imaging in extremely preterm infants with severe intraventricular hemorrhage.

Intraventricular hemorrhage (IVH) is a serious neurological complication in premature infants. This study aimed to investigate the white matter impairments and neurodevelopmental outcomes of severe IVH in extremely preterm infants with gestation age less than 28 weeks. We retrospectively evaluated the extremely preterm infants between 2017 and 2020. Neurodevelopmental outcomes were evaluated with the Bayley Scales of Infant and Toddler Development-III at 2 years of corrected age. Diffusional kurtosis imaging (DKI) was employed to evaluate the microstructural changes in white matter tracts. Mean kurtosis (MK) and fractional anisotropy (FA) values of DKI were measured in the brain regions including posterior limbs of the internal capsule (PLIC) and the corpus callosum at term equivalent age. Of 32 extremely preterm infants with severe IVH during the follow-up period, 18 cases were identified as neurodevelopmental impairments. The delay rates of motor and language were 58.4% and 52.7%. The cases with neurodevelopmental impairments had lower MK and FA values in both bilateral PLIC and the corpus callosum. The analysis of multivariable regression models predicting motor and language outcomes at 2 years of corrected age, showed that the decreases of MK values in both PLIC and the corpus callosum at the term equivalent age contributed to a significantly increased risk of neurodevelopmental impairments (all p < 0.05). During follow-up period, obvious loss of nerve fiber bundles was observed with DKI tractography. Motor and language abilities at age 2 years were associated with MK values of DKI at the term equivalent age in both PLIC and the corpus callosum of extremely preterm infants with severe IVH. The evaluation of white matter microstructural changes with MK values might provide feasible indicators of neurodevelopmental outcomes of extremely preterm infants with severe intraventricular hemorrhage.

Diffusion tensor imaging combined with nerve fiber bundle tracing in acute cerebral infarction

ObjectiveThe early diagnosis and judgment of clinical prognosis directly affect the treatment effect and rehabilitation of cerebral infarction. This study aims to observe the corticospinal tract (CST) condition and its relationship with motor function in patients with acute cerebral infarction. MethodsA total of 21 patients with unilateral acute cerebral infarction diagnosed by conventional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were included in this study. The fractional anisotropy (FA) and diffusion tensor tractography (DTT) maps were reconstructed to determine the specific FA and DCavg values. The correlation between the FA and DCavg value and the modified Edinburgh Scandinavian scale score (MESSS) was analyzed. ResultsThe FA and DCag values in the cerebral infarction area were (0.18 ± 0.09) and (5.16 ± 1.06) 10−3 mm2/s, respectively. These values were significantly lower than that of corresponding parts on the healthy side (P < 0.05). The FA and DCavg values in bilateral cerebral peduncles have no statistical significance (P > 0.05). The CST on the lesion side shows compression, displacement, deformation, and interruption. The degree of injury of the CST is related to clinical neurological symptoms. The FA (r = 0.772) and DCag values (r = 0.827) in the cerebral infarction area had a high positive correlation with the MESSS. ConclusionThe DTI can noninvasively display the injury degree of the CST in cerebral infarction, which helps judge the impairment of motor function and predict the prognosis.

Regeneration of sensory nerve branches in extraction socket and surrounding alveolar bone in rat: immunohistochemical observation of the axon and myelin sheath changes

The purpose of this study was to investigate the process and derivation of the distribution of the sensory nerves that appear in the extraction socket and surrounding alveolar bone following tooth extraction. The right mandibular first molar of rats and periodontal ligament were extracted as a single mass, and the mandible was harvested after days 1, 3, 5, and 7 after extraction. Serial sections of 7 µm thickness were prepared for the proximal root (Section A), buccolingual root (Section B), and centrifugal root (Section C) of the first molar. H–E staining and immunohistochemical staining with anti-S100 antibody and anti-NF-L antibody were carried out. The presence of nerve fiber bundles in the blood clot was already evident on post-extraction day 3, and on post-extraction day 7. On day 3, the number of axons in Sections B and C had greatly decreased, indicating that, after extraction, the connection between peripheral nerve tissue and the trigeminal ganglion was temporarily markedly reduced in the region of the alveolar branch. Although the myelin sheaths were regenerating on day 5, the majority of the axons of the alveolar branches extending from the inferior alveolar nerve were seen to be extremely thin and scattered, despite their further regeneration. The above results suggest that the newly myelinated nerves are actually derived from the bone marrow to the extraction socket, so few nerves, rather than being derived from the alveolar branches that had innervated the extracted tooth.

Characterisation of parasympathetic ascending nerves in human colon.

In the human large bowel, sacral parasympathetic nerves arise from S2 to S4, project to the pelvic plexus ("hypogastric plexus") and have post-ganglionic axons entering the large bowel near the rectosigmoid junction. They then run long distances orally or aborally within the bowel wall forming "ascending nerves" or "shunt fascicles" running in the plane of the myenteric plexus. They form bundles of nerve fibres that can be distinguished from the myenteric plexus by their straight orientation, tendency not to merge with myenteric ganglia and greater width. To identify reliable marker(s) to distinguish these bundles of ascending nerves from other extrinsic and intrinsic nerves in human colon. Human colonic segments were obtained with informed consent, from adult patients undergoing elective surgery (n = 21). Multi-layer immunohistochemical labelling with neurofilament-H (NF200), myelin basic protein (MBP), von Willebrand factor (vWF), and glucose transporter 1 (GLUT1), and rapid anterograde tracing with biotinamide, were used to compare ascending nerves and lumbar colonic nerves. The rectosigmoid and rectal specimens had 6-11 ascending nerves spaced around their circumference. Distal colon specimens typically had 1-3 ascending nerves, with one located near the mesenteric taenia coli. No ascending nerves were observed in ascending colon specimens. GLUT1 antisera labelled both sympathetic lumbar colonic nerves and ascending nerves in the gut wall. Lumbar colonic nerves joined the myenteric plexus and quickly lost GLUT1 labelling, whereas GLUT1 staining labelled parasympathetic ascending nerves over many centimetres. Ascending nerves can be distinguished in the colorectum of humans using GLUT1 labelling combined with NF200.

Inhibitory Actions of Clinical Analgesics, Analgesic Adjuvants, and Plant-Derived Analgesics on Nerve Action Potential Conduction

The action potential (AP) conduction in nerve fibers plays a crucial role in transmitting nociceptive information from the periphery to the cerebral cortex. Nerve AP conduction inhibition possibly results in analgesia. It is well-known that many analgesics suppress nerve AP conduction and voltage-dependent sodium and potassium channels that are involved in producing APs. The compound action potential (CAP) recorded from a bundle of nerve fibers is a guide for knowing if analgesics affect nerve AP conduction. This entry mentions the inhibitory effects of clinically used analgesics, analgesic adjuvants, and plant-derived analgesics on fast-conducting CAPs and voltage-dependent sodium and potassium channels. The efficacies of their effects were compared among the compounds, and it was revealed that some of the compounds have similar efficacies in suppressing CAPs. It is suggested that analgesics-induced nerve AP conduction inhibition may contribute to at least a part of their analgesic effects.

Histomorphology and Chemical Constituents of Interdigital Gland of Vembur Sheep, Ovis aries.

The interdigital gland is a specialized skin gland located between the digits of Artiodactyla (i.e., even-toed ungulates). Its secretion participates in semiochemical communication, and protects from ultraviolet radiation as well as fungal and bacterial infections of the feet. The present study aimed at finding if there are male-female differences in the anatomy, morphology, and volatile compounds of the interdigital gland of the South Indian breed of Vembur sheep. A total of 24 sheep (12 each of male and female) were spotted at the slaughterhouse and the interdigital gland was removed for examination. The anatomical examination revealed it to resemble a tobacco pipe and to consist of a body, flexure, and excretory duct with an external orifice located at the cleft of the digits. Morphometrically, the interdigital glands differed between males and females. The gland possesses a distinct fibrous capsule, epidermis, and dermis. The fibrous capsule contains several parallel bundles of collagen fibers, nerve fibers, and blood vessels, etc. The epidermis consists of keratinized squamous epithelium formed of stratum basale, stratum granulosum and stratum spinosum. The dermis consists of hair follicles, nerve plexuses, arrector pili muscles, and apocrine and sebaceous glandular lobules. The latter, lined by a simple cuboidal epithelium, are arranged in clusters of acini in the upper portion of the dermis. The apocrine secretory lobules, made up of parenchymal cells, are found in the lower portion of the dermis. The density and diameter of the apocrine and sebaceous secretory lobules were significantly higher in the males than females. Scanning electron microscopic (SEM) analysis confirmed the apocrine and sebaceous secretory components. Twenty-three major compounds were identified in the interdigital gland postings of male and female sheep, among which butanoic acid, 2-methylpropanoic acid, 1-heptanol and octadecanoic acid were present only in the male glandular post, whereas octane, 7-hexyl-tridecane, tetradecane, heptadecane and decanoic acid were present only in the female glandular post. Tetradecanol, tetradecanoic acid and hexadecanol peaks, reportedly antibacterial compounds in pronghorn antelopes, were highly prominent in both male and female sheep. Thus, the interdigital gland of Vembur sheep has two major secretory lobules, namely, sebaceous and apocrine, larger in males than females, which secrete a variety chemical compounds that may serve as chemical communication systems and protect the sheep from foot-borne diseases.

A new approach to delineating clinical target volume for radiotherapy of glioblastoma: A phase II trial.

No consensus has currently been reached regarding the optimal radiation volume for radiotherapy of glioblastoma. Here, we have proposed a new delineation approach to delineating clinical target volume based on the relationship between the growth patterns of glioblastoma and neural pathways. Its safety and efficacy were evaluated in a phase II clinical trial. A total of 69 patients with histologically confirmed glioblastoma were enrolled. All patients underwent tumor resection, followed by focal radiotherapy and concomitant temozolomide (TMZ), and then received six cycles of adjuvant TMZ. The gross tumor volume (GTV) was defined as the surgical resection cavity plus any residual enhancing tumor, on contrast enhanced T1-weighted MRI. The clinical target volume (CTV) was delineated through our new approach. The median recurrence-free survival (RFS) and overall survival (OS) were 11.4 months and 18.2 months, which were better than the previous reports. Relapse was found in 47 patients, of whom 41 patients (87.2%) failed in central, two patients (4.3%) failed in field, and four patients (8.5%) failed in distance. No marginal recurrence was found. Our regimen showed a trend of lower rates of marginal recurrence, and the brain volume of high-dose radiation fields in our regimen was similar to that of EORTC (p = 0.257). We have proposed a novel method for the delineation of clinical target volume by referencing the nerve fiber bundles for radiotherapy of glioblastoma. The results of the present phase II clinical trial suggest that this approach may be feasible and effective.

Goblet cell adenocarcinoma in the digestive system: a clinicopathological analysis of 22 cases

Objective: To investigate the clinical features, morphological characteristics, immunophenotype, and differential diagnosis of goblet cell adenocarcinoma (GCA) in the digestive system. Methods: The clinicopathological data, morphological characteristics, immunophenotypes of 22 cases of GCA in the digestive system diagnosed from January 2010 to January 2021 were collected. Meanwhile, 25 cases of neuroendocrine neoplasm (NEN) and 24 cases of adenocarcinoma were used as controls. Relevant literature was also reviewed. Results: There were 16 males and 6 females, aged from 36 to 79 years with an average of 56 years. The anatomical sites of the 22 GCA were mostly appendix (17 cases) and occasionally extra-appendix (5 cases), including 3 cases in stomach, 1 case in duodenum and 1 case in anal. All 17 cases of appendiceal GCA were pure GCA. Among the 5 cases of extra-appendiceal GCA, One case of gastric GCA was pure, two cases of gastric GCA with NEN or adenocarcinoma, duodenal GCA with NEN and adenocarcinoma, anal GCA with NEN.Low-grade GCAs were composed of goblet, Paneth and neuroendocrine cells, which were arranged in intestinal crypt tubular or cluster structures and distributed in the wall of digestive system. The tubular and cluster structures lacked adhesion. Goblet cells were columnar, located in the base, with clear cytoplasm, small nuclei, inconspicuous atypia, and uncommon mitoses. Extracellular mucus and signet-ring cells with nuclear variations could be seen in some cases. Nerve fiber bundle invasion and tumor thrombus in vessels were often present. High-grade GCAs lacked tubular and cluster structures, and their histological structures were more complex. Tumor cells expressed mixed neuroendocrine and glandular epithelial markers. Similar to the expression patterns of synaptophysin and chromogranin A, CD200 and INSM1 were also dot-like or patch-positive in GCA. Conclusions: GCA is an infrequent tumor of the digestive system and shows the bi-directional differentiation characteristics of neuroendocrine and glandular epithelium. Accurate diagnosis and staging are related to its prognosis.

Moving Stimulus Perimetry: A New Functional Test for Glaucoma.

PurposeStatic pointwise perimetric sensitivities of less than approximately 19 dB are unreliable in glaucoma owing to excessive variability. We propose using moving stimuli to increase detectability, decrease variability, and hence increase this dynamic range.MethodsA moving stimulus was designed to travel parallel to the average nerve fiber bundle orientation at each location, and compared against an otherwise identical static stimulus. To assess dynamic range, psychometric functions were measured at 4 locations of each of 10 subjects. To assess clinically realistic test–retest variability, 34 locations of 94 subjects with glaucoma and glaucoma suspects were tested twice, 6 months apart. Pointwise sensitivity estimates were compared using generalized estimating equation regression models. The test–retest limits of agreement for each stimulus were assessed, adjusted for within-eye clustering.ResultsUsing static stimuli, 9 of the 40 psychometric functions had less than a 90% maximum response probability, suggesting being beyond the dynamic range. Eight of those locations had asymptotic maximum of more than 90% with moving stimuli. Sensitivities were higher for moving stimuli (P < 0.001); the difference increased as sensitivity decreased (P < 0.001). Test-retest limits of agreement were narrower for moving stimuli (−6.35 to +6.48 dB) than static stimuli (−12.7 to +7.81 dB). Sixty-two percent of subjects preferred using moving stimuli versus 19% who preferred static stimuli.ConclusionsUsing a moving stimulus increases perimetric sensitivities in regions of glaucomatous loss. This extends the effective dynamic range, allowing reliable testing later into the disease. Results are more repeatable, and the test is preferred by most subjects.Translational RelevanceMoving stimuli allow reliable testing in patients with more severe glaucoma than currently possible.

Cervical Spine Injuries Most Commonly Occur in Traffic Accidents

The spine is made up of vertebrae, ring-shaped bones that line up in a row to form the spinal canal. Inside the spinal canal is the spinal cord - a bundle of nerve fibers and cells that conduct nerve impulses from the brain to various parts of the body and vice versa. The individual nerves that exit the spinal canal are separated from the spinal cord. In vertebral fractures, bone fragments can injure the spinal cord, leading to partial or complete muscle loss and loss of sensation below the level of the injury. The spinal cord can be damaged at the very moment of the vertebral injury, but also later when moving and carrying the injured person. Injuries occur when direct physical force damages the vertebrae, ligaments or discs of the spine, causing crushing, crushing or rupture of brain tissue, and penetrating brain injuries. Such injuries can also lead to vascular damage leading to ischemia or hematoma causing additional damage. All types of injuries can cause brain edema which further reduces blood flow and oxygenation

Peculiar endoneurial myxomatous matrix-collagen nodule in a patient with neurofibromatosis type 1.

An 8-year-old girl presented with an 18-month history of right buttock gradual swelling, accompanied by increased urination and defecation frequency for 2 weeks. A physical examination revealed a cafe au lait spot from the lumbosacral region to the right buttock (Fig. 1A). Magnetic resonance imaging (MRI) demonstrated multiple ring or half-ring nodules in the pelvic cavity and the right buttock, which formed the target sign (Fig. 1B–D). Some nodules were distributed along the nerve fiber bundle directions.

Innervation of human superficial fascia.

The superficial fascia has only recently been recognized as a specific anatomical structure. Furthermore, whereas it is actually recognized that the innervation of the deep/muscular fascia plays a key role in proprioception and nociception, there are very few studies that have analyzed these characteristics in the superficial fascia. In this work, our group analyzed two different anatomical districts (abdomen and thigh), from volunteer patients, undergoing surgery procedures. Each sample was processed for histological analysis by Hematoxylin&Eosin, and by immunohistochemistry stainings (in 5-micron-paraffin embedded section and in cryosectioned free floating samples), with antibodies specific for nerve fibers: S100 antibody for myelinating and non-myelinating Schwann cells, PGP9.5 antibody as pan-neuronal marker, tyrosine hydroxylase for autonomic innervation. The results revealed a huge innervation: the nervous structures were found above all around blood vessels and close to adipocytes, but they penetrated also in the connective tissue itself and are found in the midst of fibro-adipose tissue. The tissue is pervaded by both thin (mean diameter of 4.8 ± 2.6 μm) and large nerve fiber bundles of greater diameter (21.1 ± 12.2 μm). The ratio S100/TH positivity was equal to 2.96, with a relative percentage of autonomic innervation with of 33.82%. In the light of these findings is evident that the superficial fasciae have a clear and distinct anatomical identity and a specific innervation, which should be considered to better understand their role in thermoregulation, exteroception and pain perception. The knowledge of the superficial fascia may improve grading and developing of different manual approach for treatments of fascial dysfunctions, and the understanding of how some factors like temperature or manual therapies can have an impact on sensitivity of the fascia.

Comparing evolvement of visual field defect in neuromyelitis optica spectrum disorder-optic neuritis and idiopathic optic neuritis: a prospective study

PurposeTo compare the evolvement of visual field (VF) defect in neuromyelitis optica spectrum disorder-optic neuritis (NMOSD-ON) and idiopathic optic neuritis (IDON).MethodsThis prospective study involved 104 optic neuritis (ON) patients followed up for ≥ 6 months (33 patients with NMOSD-ON and 71 patients with IDON). The pattern and recovery pattern of VF defect, mean defect (MD) and pattern standard deviation (PSD) of VF, as well as BCVA at onset, 1 month (1 m), 3 months (3 m), and ≥ 6 months (6 m) after onset were compared between two groups. Analysis of these indicators in first episode patients was also done.ResultsDiffuse abnormalities and nerve fiber bundle abnormalities were the two most common patterns in both groups. The percentage of neurologic abnormality of VF defect in NMOSD-ON was higher than that of IDON. Compared with the IDON group, the MD and PSD of NMOSD-ON group were significantly worse at each follow-up. While a positive correlation in BCVA was found between 1 m and ≥ 6 m in the NMOSD-ON group only, a positive correlation was found between 1 m and ≥ 6 m in MD and PSD of both groups. A positive correlation was found between 3 m and ≥ 6 m in MD, PSD and BCVA of both groups. The quadrant recovery pattern was the most common pattern in both groups (57.1% in NMOSD-ON and 57.4% in IDON). The analysis of the first episode subgroup further confirmed the observation above.ConclusionsThe NMOSD-ON patients tended to suffer more severe VF damage, VF irregularity and worse prognosis than that of IDON patients. Diffuse abnormalities and nerve fiber bundle abnormalities were the two most common types in both groups, while neurologic abnormality more common in NMOSD-ON and central scotoma more common in IDON. The visual functions of 1 m in NMOSD-ON and 3 m in IDON were related to its prognosis.

Test of a Retinal Nerve Fiber Bundle Trajectory Model Using Eyes With Glaucomatous Optic Neuropathy.

PurposeTo test a model of retinal nerve fiber bundle trajectories that predicts the arcuate-shaped patterns seen on optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) probability/deviation maps (p-maps) in glaucomatous eyes.MethodsThirty-one glaucomatous eyes from a database of 250 eyes had clear arcuate-shaped patterns on RNFL p-maps derived from an OCT cube scan. The borders of the arcuate patterns were extracted from the RNFL p-maps. Next, the trajectories from an arcuate model were compared against these borders via a normalized root-mean-square difference analysis. The model's parameter, β, was varied, and the best-fitting, initial clock-hour position of the trajectory to the border was found for each β. Finally, the regions, as determined by the arcuate border's best-fit, initial clock-hour positions, were compared against the abnormal regions on the circumpapillary retinal nerve fiber layer (cpRNFL) profile.ResultsThe arcuate model's mean βSup and βInf parameters minimized large differences between the trajectories and the arcuate borders on the RNFL p-maps. Furthermore, on average, 68% of the cpRNFL regions defined by the arcuate border's best-fit, initial clock-hour positions were abnormal (i.e., below the ≤5% threshold).ConclusionsThe arcuate model performed well in predicting the borders of arcuate patterns seen on RNFL p-maps. It also predicted the associated abnormal regions of the cpRNFL thickness plots.Translational RelevanceThis model should prove useful in helping clinicians understand topographical comparisons among different OCT representations and should improve structure-structure, as well as structure-function agreement analyses.

Concordance of Objectively Detected Retinal Nerve Fiber Bundle Defects in En Face OCT Images with Conventional Structural and Functional Changes in Glaucoma

To assess how objectively detected defects in retinal nerve fiber bundle (RNFB) reflectance on en face OCT images relate to circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and visual field defects. Cross-sectional study. Sixteen participants with early glaucoma and 29 age-matched healthy controls, of whom 22 had usable en face images for the establishment of normative levels of RNFB reflectance. All the participants underwent cpRNFLT scans, visual field examination, and wide-field OCT. En face reflectivity was assessed objectively using the Summary of Multiple Anatomically Adjusted Slabs method. En face defects were deemed concordant with cpRNFLT when they had at least 1 cpRNFLT point with P < 0.01, within ± 15° of the predicted insertion on the optic disc. Visual fields were examined using custom suprathreshold perimetry and SITA Standard 24-2. For each visual field location, the corresponding reflectance was deemed abnormal if any en face superpixel within ± 1° was abnormal. The overall, positive, and negative agreements were measured in each participant. Proportion of concordant defects between en face reflectance analysis and cpRNFLT (%) as well as overall, positive, and negative agreements between en face reflectance analysis and visual field results. Most en face abnormalities had concordant cpRNFLT defects in the mapped sector (median proportion concordant, 0.85; interquartile range, 0.74-0.95). In eyes with glaucoma, a median of 8.1% (range, 2.4%-23.7%) and 14.9% (range, 3.5%-29.1%) locations showed corresponding en face and visual field defects using 24-2 and custom perimetry, respectively. Both the perimetric strategies had moderate-to-good raw agreement with en face analysis (0.66-0.68), with stronger agreement on normal findings than on defects (0.77-0.78 and 0.4-0.44). Objectively extracted reflectance defects showed strong concordance with conventional cpRNFLT damage and good agreement with perimetry, which could be enhanced by further minimization of image artifacts.

Visual Field Defect Patterns Associated With Lesions of the Retrochiasmal Visual Pathway.

Perimetry is widely used in the localization of retrochiasmal visual pathway lesions. Although macular sparing, homonymous paracentral scotomas, and quadrantanopias are regarded as features of posterior retrochiasmal visual pathway lesions, incongruous hemianopia is regarded as a hallmark of anterior lesions. Recent studies have questioned the specificity of these defect patterns. Retrospective record review conducted in a single, academic, medical center using an electronic search engine with the terms ""homonymous hemianopia," "optic tract," "temporal lobectomy," "visual field defect," and "MRI." Patients were included if they had reliable, automated, static visual fields, high-quality reviewable MRI scans, and pertinent lesions. MRI lesions were assigned to 1 of 6 retrochiasmal visual pathway segments by the study neuroradiologist. Two study authors independently reviewed the visual fields and designated 10 different defect patterns. From an original cohort of 256 cases, only 83 had MRI-defined lesions that were limited to particular retrochiasmal segments and had visual field defect patterns that allegedly permitted localization to those particular segments. The 5 contralateral nerve fiber bundle defects were exclusive to optic tract tumors with rostral extension. Pie-in-the-sky defects were exclusive to Meyer loop lesions. Among 22 fields with macular sparing, 86% arose from the visual cortex or posterior optic radiations. Among 31 fields with homonymous quadrantanopias, 77% arose from Meyer loop, visual cortex, or posterior optic radiations. Among 13 fields with homonymous paracentral scotomas, 69% arose from visual cortex or posterior optic radiations. Optic tract lesions accounted for 70% of incongruous hemianopias but that pattern occurred uncommonly. In correlating discrete MRI-defined retrochiasmal lesions with visual field defect patterns identified on static perimetry, this study showed that macular sparing, homonymous paracentral scotomas, and quadrantanopias localized to the visual cortex and posterior optic radiations segments but not exclusively. It has differed from an earlier study in showing that incongruous hemianopias occur predominantly from optic tract lesions.

Case of Legal Blindness Secondary to Optic Nerve Head Drusen

Optic nerve head drusen are relatively infrequent abnormalities of the optic disc that are usually discovered as incidental findings during a routine eye examination. While typically considered to be benign, visual field loss due to the drusen is not uncommon. Visual field defects are more prevalent in superficial drusen than buried drusen, and can present as nerve fiber bundle defects, generalized concentric constriction, or enlargement of the blind spot. The extent of damage is variable, but it is rare that the degree of field loss leads to substantial functional impairment. This case presents a patient with significant bilateral concentric field loss secondary to optic nerve drusen that caused severe visual impairment and disability.