Optic Ganglion Research Articles

A Novel Approach To Predict Glaucomatous Impairment in the Central 10° Visual Field, Excluding the Effect of Cataract.

Our previous study predicted genuine glaucomatous visual field (VF) impairment in the central 10° VF, excluding the effect of cataract, using visual acuity (VA) and global indexes of VF more accurately than pattern deviation (PD). This study aimed to improve the accuracy by using pointwise total deviation (TD) values with the machine-learning method of random forest model (RFM) and to investigate whether incorporating optical coherence tomography-measured ganglion cell-inner plexiform layer (GCIPL) thickness is useful. This retrospective study included 89 eyes with open-angle glaucoma that underwent successful cataract surgery (with or without iStent implantation or ab interno trabeculotomy). Postoperative TD in each of the 68 VF points was predicted using preoperative (1) PD, (2) VA and VF with a linear regression model (LM), and (3) VA and VF with RFM, and averaged as predicted mean TD (mTDpost). Further prediction was made by incorporating the preoperative GCIPL into the best model. The mean absolute error (MAE) between the actual and predicted mTDpost with RFM (1.25 ± 1.03 dB) was significantly smaller than that with PD (3.20 ± 4.06 dB, p < 0.01) and LM (1.42 ± 1.06 dB, p < 0.05). The MAEs with the model incorporating GCIPL into RFM (1.24 ± 1.04 dB) and RFM were not significantly different. Accurate prediction of genuine glaucomatous VF impairment was achieved using pointwise TD with RFM. No merit was observed by incorporating the GCIPL into this model. This pointwise RFM could clinically reduce cataract effect on VF.

Expression profile and immunomodulatory roles of methionine-enkephalin and delta opioid receptor in Octopus ocellatus

In this study, the expressions and distributions of methionine-enkephalin (Met-enk) and δ opioid receptor in the nervous system of Octopus ocellatus, and the immune regulatory mechanisms of Met-enk on O. ocellatus were explored. The distributions and expressions of Met-enk and δ opioid receptor were assessed by immunohistochemistry and enzyme-linked immunosorbent assay. UV-spectrophotometer, microplate reader, and flow cytometer were used to examine the effects of different concentrations of Met-enk on phagocytosis, antioxidant effects, and body surface mucus immunity of O. ocellatus hemocytes. The data were used to study the mechanisms of Met-enk immunity regulation in O. ocellatus. According to the results, the expression levels of Met-enk and δ opioid receptor in O. ocellatus lymphocytes were higher than those in hemocytes. The expression levels of Met-enk in the ganglia of O. ocellatus decreased in the following order: pedal ganglia > cerebral ganglia > visceral ganglia > optic ganglia > stellate ganglia. Moreover, the phagocytic activity of O. ocellatus hemocytes was enhanced with increasing Met-enk concentration. With increasing Met-enk concentration, the expressions of nitric oxide, total nitric oxide synthase, inducible nitric oxide synthase, catalase, hydrogen peroxide, myeloperoxidase, reduced glutathione, α-naphthy acetate esterase, and methionine aminopeptidases decreased in serums of O. ocellatus in the experimental group compared to the blank group. Similarly, the content of reduced glutathione in the hemocytes of O. ocellatus was also lower in the experimental group than in the blank group; however, the expressions of other substances were higher compared to the blank group. Furthermore, α-naphthy acetate esterase, myeloperoxidase, and hydrogen peroxide expressions in mucus immunity trials of the body surface were lower in the experimental group compared to the blank group. These results indicate that the distributions and expressions of Met-enk and δ opioid receptor in the nervous system of O. ocellatus were related to axoplasmic transport and immune regulation mechanisms. Met-enk participates in cellular immunity, humoral immunity, and mucus immunity in the form of neurotransmitters, thereby regulating the immune response of O. ocellatus.

Retinal Structure of Poecilia sphenops: Photoreceptor Mosaics, Synaptic Ribbon Patterns, and Glial Cell Expressions.

The specific arrangement and distribution of photoreceptors in the retina can vary among different fish species, with each species exhibiting adaptations related to its habitat, behavior, and visual requirements. Poecilia sphenops, a diurnal fish, was the focus of this study. The retinas of a total of eighteen Molly fish were investigated utilizing light and electron microscopy. The retina exhibited a square mosaic pattern of the inner segments of cones. This pattern comprised double cones positioned along the sides of a square, with two types of single cones situated at the center and corners of the square arrangement across the entire retina. The corner cones were slightly shorter than the central ones. Additionally, the outer plexiform layer contained both cone pedicles and rod spherules. The rod spherule consisted of a single synaptic ribbon arranged in a triad or quadrat junctional arrangement within the invaginating free ends of the horizontal and bipolar cell processes. On the other hand, cone pedicles have more than one synaptic ribbon in their junctional complex. The inner nuclear layer consisted of the amacrine, bipolar, Müller, and horizontal cell bodies. Müller cell processes, expressing GFAP, extended across all retinal layers, segmenting the deeper retina into alternating fascicles of optic axons and ganglion cells. The outer and inner plexiform layers showed many astrocyte cell processes expressing GFAP. In conclusion, the current study is the first record of the retinal structures of Molly fish. This study illustrated the mosaic arrangement of photoreceptors and GFAP expression patterns of astrocytes and Müller cells. The presence of three cone types, coupled with a sufficient number of rods, likely facilitates motion awareness for tasks like finding food and performing elaborate mating ceremonies.

The effect of macular visual field test density on central structure-function concordance in glaucoma

ABSTRACT Clinical relevance Central visual field (VF) testing often requires focussed high-density test grids. The critical number of test locations for maximising structure-function concordance in the macula is not known. Purpose The aim of this work is to determine the impact of the number of test locations in the central VF on binarized structure-function concordance in glaucoma. Methods Humphrey Field Analyser (HFA) 10–2 test grid and Cirrus optical coherence tomography Ganglion Cell Analysis (GCA) results from one eye of 155 glaucoma patients were extracted. Following anatomical correction for retinal ganglion cell displacement, the pointwise results of the central 36 locations of the 10–2 pattern deviation map and their corresponding locations within the GCA deviation map were recorded. The number of test locations was systematically reduced from 36 (4 locations per step) and added from 1 (1 location per step) and binarized structure-function concordance (p < 0.05 for both) at each step was evaluated. Eleven test point subtraction and addition models were developed. Concordance rates (proportion) were plotted as a function of number of test locations, and were fitted using segmental nonlinear regression to identify the critical point of inflection at which concordance was maximised and discordance minimised. Results Subtractive and additive approaches returned two-way estimates of the critical number, with, on average 8–14 test locations being the range at which structure-function concordance was optimised in the present cohort across all models. A randomised approach to subtracting or adding test locations returned critical numbers that were similar to systematic and empirical models, suggesting that specific test location was not as critical in optimising structure-function concordance compared to the number of test locations. Conclusion There is a potential critical number (8–14) in macular visual field testing where binarized structure-function concordance is optimised, providing a framework for guiding the development of integrated macular test locations in VF testing for glaucoma.

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury.

JOURNAL/nrgr/04.03/01300535-202502000-00034/figure1/v/2024-05-28T214302Z/r/image-tiff Several studies have found that transplantation of neural progenitor cells (NPCs) promotes the survival of injured neurons. However, a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical application. Small extracellular vesicles (sEVs) contain bioactive molecules for neuronal protection and regeneration. Previous studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye diseases. In this study, we intravitreally transplanted sEVs derived from human induced pluripotent stem cells (hiPSCs) and hiPSCs-differentiated NPCs (hiPSC-NPC) in a mouse model of optic nerve crush. Our results show that these intravitreally injected sEVs were ingested by retinal cells, especially those localized in the ganglion cell layer. Treatment with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration, and regulated the retinal microenvironment by inhibiting excessive activation of microglia. Component analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells, which had protective effects on RGCs after optic nerve injury. These findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

Morphology and spectral sensitivity of long visual fibers and lamina monopolar cells in the butterfly Papilio xuthus.

Extensive analysis of the flower-visiting behavior of a butterfly,Papilio xuthus, has indicated complex interaction between chromatic, achromatic, and motion cues. Their eyes are spectrally rich with six classes of photoreceptors, respectively sensitive in the ultraviolet, violet, blue, green, red, and broad-band wavelength regions. Here, we studied the anatomy and physiology of photoreceptors and second-order neurons ofP. xuthus, focusing on their spectral sensitivities and projection terminals to address where the early visual integration takes place. We thus found the ultraviolet, violet, and blue photoreceptors and all second-order neurons terminate in the distal region of the second optic ganglion, the medulla. We identified five types of second-order neurons based on the arborization in the first optic ganglion, the lamina, and the shape of the medulla terminals. Their spectral sensitivity is independent of the morphological types but reflects the combination of pre-synaptic photoreceptors. The results indicate that the distal medulla is the most plausible region for early visual integration.

BAFF deficiency aggravated optic nerve crush-induced retinal ganglion cells damage by regulating apoptosis and neuroinflammation via NF-κB-IκBα signaling

Loss of retinal ganglion cells (RGCs) is a primary cause of visual impairment in glaucoma, the pathological process is closely related to neuroinflammation and apoptosis. B-cell activating factor (BAFF) is a fundamental survival factor mainly expressed in the B cell lineage. Evidence suggests its neuroprotective effect, but the expression and role in the retina have not yet been investigated. In this study, we adopt optic nerve crush (ONC) as an in vivo model and oxygen-glucose deprivation/reoxygenation (OGD/R) of RGCs as an in vitro model to investigate the expression and function of BAFF. We found that BAFF and its receptors were abundantly expressed in the retina and BAFF inhibition exacerbated the caspase 3-mediated RGCs apoptosis, glial cell activation and pro-inflammatory cytokines expression, which may be caused by the activation of the NF-κB pathway in vivo. In addition, we found that BAFF treatment could alleviate RGCs apoptosis, pro-inflammatory cytokines expression and NF-κB pathway activation, which could be reversed the effect by blockade of the NF-κB pathway in vitro. Meanwhile, we found that microglia induced to overexpress BAFF in the inflammatory microenvironment in a time-dependent manner. Taken together, our results indicated that BAFF deficiency promoted RGCs apoptosis and neuroinflammation through activation of NF-κB pathway in ONC retinas, suggesting that BAFF may serve as a promising therapeutic target for the treatment of glaucoma.

A newly identified enzyme from Japanese common squid Todarodes pacificus has the ability to biosynthesize d-aspartate

Amino acids exist in two chiral forms, namely L and D. Although l-amino acids are predominant in vivo, certain limited circumstances have reported the usage of d-amino acids. d-aspartate (Asp), among them, plays crucial physiological roles in living organisms and is biosynthesized from L-Asp by the enzyme named aspartate racemase (AspRase). D-Asp is known to accumulate in large amounts in the nervous system of cephalopods. To understand the function of D-Asp in nervous system in more detail, it is necessary to elucidate its metabolic pathway; however, AspRase gene has not been identified in cephalopods as in the case of mammals. In this study, we successfully identified a novel gene encoding AspRase from the optic ganglion of Japanese common squid Todarodes pacificus. Our discovery of the squid AspRase challenges the prevailing assumption that AspRases across different animals share similar structures. Surprisingly, the squid AspRase is a unique enzyme that differs significantly from known AspRases, being structurally and phylogenetically related to aspartate aminotransferase (AST) and possessing both AspRase and AST activities. The optimum pH and temperature for AspRase activity using L-Asp as a substrate are approximately 7.0 and 20 °C, respectively. Moreover, we have found that AspRase activity is enhanced in the presence of 2-oxoacids. These findings have far-reaching implications for the understanding of enzymology and suggest that yet-to-be-identified mammalian AspRases may also be phylogenetically related to AST, rather than conventional AspRases. Furthermore, our results provide valuable insights into the evolution of the D-Asp biosynthetic pathway.

Leber Hereditary Optic Neuropathy Gene Therapy: Longitudinal Relationships Among Visual Function and Anatomical Measures

To assess longitudinal relationships among visual function and anatomical measures of gene therapy in G11778A Leber hereditary optic neuropathy (LHON). Phase 1 clinical trial. This was a single-institution study of patients with G11778A LHON. Patients with chronic bilateral visual loss >12 months (group 1, n=11), acute bilateral visual loss <12 months (group 2, n=9), or unilateral visual loss (group 3, n=8) were administered unilateral intravitreal AAV2(Y444,500,730F)-P1ND4v2 injection with low, medium, high, and higher doses to worse eye for groups 1 and 2 and better eye for group 3. Oucome measures were best-corrected visual acuity (BCVA), visual field mean deviation (VF MD), steady-state pattern electroretinogram (SS-PERG), optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness and ganglion cell+inner plexiform layer (GCIPL) thickness, and National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) scores. Mean follow-up was 33.6 months (range=18-36 months). Baseline SS-PERG amplitude was much reduced in both eyes of all groups including asymptomatic eyes of group 3, and showed no appreciable changes irrespective of disease stage and treatment. Significant and progressive GCIPL and RNFL thinning occurred in all eyes; BCVA and VF MD fluctuated in treated and fellow eyes, with some eyes having modest improvement that may be related to natural history or to gene therapy. Mean NEI-VFQ-25 scores declined in group 3 subjects (P=.023), CONCLUSION: Asymptomatic eyes in LHON patients with unilateral visual loss may be beyond the window of effective neuroprotection given reduced GCIPL and SS-PERG. Randomization of patients to an untreated control group would help to assess treatment effect by accounting for variable natural history. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Lycii Fructus, a medicine food homology material, attenuates retinal damage in sodium iodate-induced retinal degeneration mice and inhibits oxidation-induced apoptosis of Müller cells via regulating Nrf2-HO1 signaling pathway

Lycii Fructus (LF) is a medicinal-edible homology material frequently used for treating age-related macular degeneration (AMD) in Chinese medicine. Abundant of literatures verified the retina protection effect of LF on AMD-like animal models. However, previous studies on LF attenuating retinal damage mainly focused on its protection effect on pigment epithelial cells and optic ganglion cells while few reports on Müller cells. In the current study, we found that LF extracts attenuated oxidation damages and inhibited cell apoptosis of retina on a mouse retinal injury model induced by sodium iodate. LF extracts also increased expressions of Müller cell biomarker glutamine synthetase of eyeballs of model mice, which indicated that LF extract protected Müller cell from oxidation injury induced by sodium iodate. In Müller cell MIO-M1 cultures, LF also significantly inhibited cellular apoptosis induced by NaIO3 by regulating Nrf2/HO-1 signaling pathway and the aqueous extracts exerted better active tendency than ethanol extracts. These data implied that the antioxidant effect of LF on protecting Müller cell might contribute to its retina repair function, thereby providing more scientific evidences for the development of LF as an alternative therapy or preventive measures for AMD.

Evaluation of Retinal Nerve Fiber Layer and Macular Ganglion Cell Layer Thickness in Relation to Optic Disc Size.

To investigate whether optic nerve ganglion cell amount is dependent on optic disc size, this trial analyzes the correlation between Bruch's membrane opening area (BMOA) and retinal nerve fiber layer (RNFL) thickness as well as macular ganglion cell layer thickness (mGCLT). Additionally, differences in RNFL and mGCLT regarding various optic disc cohorts are evaluated. This retrospective, monocentric study included 501 healthy eyes of 287 patients from the University Hospital Münster, Germany, who received macular and optic disc optical coherence tomography (OCT) scans. Rank correlation coefficients for clustered data were calculated to investigate the relationship between BMOA and thickness values of respective retinal layers. Furthermore, these values were compared between different optic disc groups based on BMOA. Statistical analysis did not reveal a significant correlation between BMOA and RNFL thickness, nor between BMOA and mGCLT. However, groupwise analysis showed global RNFL to be significantly decreased in small and large discs in comparison to medium discs. This was not observed for global mGCLT. This study extends existing normative data for mGCLT taking optic disc size into account. While the ganglion cell amount represented by the RNFL and mGCLT seemed independent of BMOA, mGCLT was superior to global RNFL in displaying optic nerve integrity in very small and very large optic discs.

The Importance of Optical Coherence Tomography in the Diagnosis of Atypical or Subclinical Optic Neuritis: A Case Series Study

Background: Optic neuritis (ON) is an inflammatory condition of the optic nerve. ON is associated with development of demyelinating diseases of the central nervous system (CNS). CNS lesions visualized by magnetic resonance imaging (MRI) and the finding of oligoclonal IgG bands (OB) in the cerebrospinal fluid (CSF) are used to stratify the risk of MS after a "first" episode of ON. However, the diagnosis of ON in absence of typical clinical manifestations can be challenging. Methods and Materials: Here we present three cases with changes in the optic nerve and ganglion cell layer in the retina over the disease course. (1) A 34-year-old female with a history of migraine and hypertension had suspect amaurosis fugax (transient vision loss) in the right eye. This patient developed MS four years later. Optical coherence tomography (OCT) showed dynamic changes of the thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) over time. (2) A 29-year-old male with spastic hemiparesis and lesions in the spinal cord and brainstem. Six years later he showed bilateral subclinical ON identified using OCT, visual evoked potentials (VEP) and MRI. The patient fulfilled diagnosis criteria of seronegative neuromyelitis optica (NMO). (3) A 23-year-old female with overweight and headache had bilateral optic disc swelling. With OCT and lumbar puncture, idiopathic intracranial hypertension (IIH) was excluded. Further investigation showed positive antibody for myelin oligodendrocyte glycoprotein (MOG). Conclusions: These three cases illustrate the importance of using OCT to facilitate quick, objective and accurate diagnosis of atypical or subclinical ON, and thus proper therapy.

Altered dynamic functional connectivity in the primary visual cortex in patients with primary angle-closure glaucoma.

Glaucoma is the main blindness-causing disease in the world. Previous neuroimaging studies demonstrated that glaucoma not only causes the loss of optic ganglion cells but also leads to the abnormal function of the optic nerve pathway and the visual cortex. However, previous studies also reported that patients with glaucoma have dysfunction in the visual cortex in a static state. Whether or not patients with primary angle-closure glaucoma (PACG) were accompanied by dynamic functional connectivity (FC) changes in the primary visual cortex (V1) remains unknown. A total of 34 patients with PACG (23 men and 11 women) and 34 well-matched healthy controls (HCs) were enrolled in the study. The dynamic functional connectivity (dFC) with the sliding window method was applied to investigate the dynamic functional connectivity changes in the V1. Compared with HCs, patients with PACG showed increased dFC values between left V1 and bilateral calcarine (CAL). Meanwhile, patients with PACG showed increased dFC values between right V1 and bilateral CAL. Our study demonstrated that patients with PACG showed increased dFC within the visual network, which might indicate the increased variability FC in the V1 in patients with PACG.

Diagnostic performance of optical coherence tomography macular ganglion cell inner plexiform layer and retinal nerve fiber layer thickness in glaucoma suspect and early glaucoma patients at St. Paul's hospital millennium medical college, Addis Ababa, Ethiopia.

To evaluate glaucoma diagnostic performance of ganglion cell inner plexiform layer and retinal nerve fiber layer parameters measured with cirrus HD optical coherence tomography (OCT). Total of 188 eyes were included in our study. 49 eyes of healthy controls, 70 glaucoma suspect eyes and 69 early glaucomatous eyes. Complete ophthalmic examination was done including visual field test (with Humphrey field analyzer) and OCT scanning of ganglion cell inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) in different quadrants. Sensitivity, specificity and area under the receiver operating characteristic curve (AUROC) of each parameter was calculated to provide diagnostic ability between normal controls, glaucoma suspects or early glaucoma. GCIPL and RNFL parameters had strong power in discriminating early glaucoma from healthy controls with all having AUROC of above 0.76. Of all the GCIPL and RNFL parameters, the only variable that could discriminate between glaucoma suspect and healthy controls was the combined parameter by OR-logic approach. Of all the parameters, the average and nasal RNFL parameters had the strongest power in discriminating between the two with AUROC of 0.81. All parameters had an overall good diagnostic performance with excellent sensitivity but the specificity was relatively poor. The combined parameter had the best specificity (62.2%) with excellent sensitivity (93.5%). Nasal RNFL parameters had the strongest power in discriminating between glaucoma suspect and healthy controls and the OR-logic combination of RNFL and GCIPL provides better diagnostic performance than single GCIPL, RNFL or ONH parameter.

Mass spectrometry imaging reveals the spatial distribution of essential lipids in Daphnia magna – potential implications for trophic ecology

ABSTRACT Lipids and fatty acids are key dietary components for the nutrition of organisms at all trophic levels. They are required to build cellular structures such as cell membranes, serve as energy storage, and take part in signal transduction cascades. For decades, ecological research investigated how dietary fatty acid availability contributes to the fitness of individuals and their populations. The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) is of particular interest because its dietary availability determines the fitness of many aquatic consumers. Because of the small body size of zooplankton, only bulk tissue fatty acid analysis was previously performed, and thus the tissue-specific importance of EPA for zooplankton remained elusive. We used matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI-MSI) to reveal the tissue-specific distribution of functional phospholipids in the herbivorous zooplankton Daphnia magna. We demonstrate several lipid species for heart, egg, gut, gonad, somatic, and neurological tissues of D. magna, including the compound eye as well as the optical and cerebral ganglion. The compound eye revealed a large diversity in lipid species containing EPA, which were also found in other neurological tissues and eggs. Such knowledge of tissue-specific fatty acid requirements is essential to investigate how selective allocation of dietary fatty acids within this key grazer affects processes on a functional and molecular level from the individual to food web scales. This methodological advancement will facilitate investigations on how invertebrate physiology and behaviour adjust to changing environmental conditions and potentially affect food web structures, including the trophic transfer of dietary fatty acids.

Optical Coherence Tomography Retinal Nerve Fibre Layer and Ganglion Cell Complex Measurements in Normal Southern Nigerian Eyes.

Introduction Glaucoma is the leading cause of irreversible blindness worldwide. It is more severe in people with African heritage, and intraocular pressure remains the only modifiable risk factor in managing glaucoma. Attempts to improve the diagnosis and monitoring of glaucoma are ongoing. One of those attempts is the development of optical coherence tomography (OCT). However, there is a theoretical possibility of a delayed or wrong diagnosis of glaucoma using the OCT because of racial, age, and sex differences in the RNFL (retina nerve fibre layer), GCL (ganglion cell layer), and GCL+IPL (ganglion cell layer and inner plexiform layer) thickness. Objective This study aims to provide the measurements of RNFL, GCL, and GCL+IPL in normal eyes of southern Nigerian patients and specifically to evaluate the relationship of these measurements to gender, age, intra-eye variability, and the Topcon SD-OCT normative database. Method Three hundred and four eyes of 152 patients who had normal OCT scans using the 6x6 RNFL (four sectors) and Macula scans of the Topcon OCT-1 3D Maestro OCT machine were included for analysis. Parametric tests were used to interrogate the relationship between normally distributed parameters and gender, age, and the Topcon reference database. Non-parametric tests were used for non-normally distributed data. Results The male-to-female ratio was 1:1, and ages ranged between 18 and 71 for both genders. The average RNFL values were 111.49 ± 10.44 (right eye - RE) and 111.96 ± 9.66 (left eye - LE). For the GCL, average values were 66.23 ± 4.4 (RE) and 66.34 ± 4.19 (LE). GCL+IPL values were 104.02 ± 6.71 (RE) and 103.89 ± 6.66 (LE). There was no difference between genders (X2 = 56.467; df = 46; p = 0.160), and RNFL, GCL, and GCL+IPL values showed a significant reduction as the age of the respondents increased. There was a significant difference between RNFL, GCL, and GCL+IPL values and the Topcon reference database, p < 0.001. Conclusion Significant differences exist between the Southern Nigerian eyes' RNFL, GCL, and GCL+ IPL values and the Topcon OCT-1 3D Maestro reference database. While randomised control trials and extensive multi-centre studies have not been conducted to determine the possible effects of these differences between measured values and reference databases of the OCTs, they need to be considered while diagnosing and managing glaucoma with the OCT.

Optic disc, macula and ganglion cell layer measurements obtained with optical coherence tomography in patients with thyroid disorder

Purpose: The aim of this study was to compare retinal nerve layer thickness, central macula thickness and ganglion cell layer measurements using optical coherence tomography (OCT) between thyroid patients and age- and sex-matched healthy controls.&#x0D; Materials and Methods: Eighty eyes of 80 patients in the thyroid patient group and 48 eyes of 48 patients in the control group were included in the study. After evaluating the exclusion criteria, visual acuity, anterior segment biomicroscopy, intraocular pressure, fundoscopy and spectral field optic coherence tomography (SF-OCT) imaging tests were performed on all patients included in the study. These data have been recorded. Central macular thickness (CMT), retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) measurements were evaluated by statistical methods for both groups.&#x0D; Results: There was no statistically significant difference between the demographic data of the groups included in the study. IOP measurements were found to be statistically significantly higher in the patient group compared to the control group. CMT values were 258.2±16.1 µm in the patient group and 273.1±23.8 µm in the control group, and statistically significant differences were observed between the groups. &#x0D; Conclusion: The findings supports that changes in the optic nerve and macula develop before vision loss in TO patients compared to the healthy control group. We can follow TO patients more objectively and reliably and make treatment planning more accurately by adding OCT, which is a noninvasive test, to our clinical practice, since structural changes develop before functional deterioration in TO patients.

Association of Vitamin D Polygenic Risk Scores and Disease Outcome in People With Multiple Sclerosis.

Observational studies suggest low levels of 25-hydroxyvitamin D (25[OH]D) may be associated with increased disease activity in people with multiple sclerosis (PwMS). Large-scale genome-wide association studies (GWAS) suggest 25(OH)D levels are partly genetically determined. The resultant polygenic scores (PGSs) could serve as a proxy for 25(OH)D levels, minimizing potential confounding and reverse causation in analyses with outcomes. Herein, we assess the association of genetically determined 25(OH)D and disease outcomes in MS. We generated 25(OH)D PGS for 1,924 PwMS with available genotyping data pooled from 3 studies: the CombiRx trial (n = 575), Johns Hopkins MS Center (n = 1,152), and Immune-Mediated Inflammatory Diseases study (n = 197). 25(OH)D-PGS were derived using summary statistics (p < 5 × 10-8) from a large GWAS including 485,762 individuals with circulating 25(OH)D levels measured. We included clinical and imaging outcomes: Expanded disability status scale (EDSS), timed 25-foot walk (T25FW), nine-hole peg test (9HPT), radiologic activity, and optical coherence tomography-derived ganglion cell inner plexiform layer (GCIPL) thickness. A subset (n = 935) had measured circulating 25(OH)D levels. We fitted multivariable models based on the outcome of interest and pooled results across studies using random effects meta-analysis. Sensitivity analyses included a modified p value threshold for inclusion in the PGS (5 × 10-5) and applying Mendelian randomization (MR) rather than using PGS. Initial analyses demonstrated a positive association between generated 25(OH)D-PGS and circulating 25(OH)D levels (per 1SD increase in 25[OH]D PGS: 3.08%, 95% CI: 1.77%, 4.42%; p = 4.33e-06; R2 = 2.24%). In analyses with outcomes, we did not observe an association between 25(OH)D-PGS and relapse rate (per 1SD increase in 25[OH]D-PGS: 0.98; 95% CI: 0.87-1.10), EDSS worsening (per 1SD: 1.05; 95% CI: 0.87-1.28), change in T25FW (per 1SD: 0.07%; 95% CI: -0.34 to 0.49), or change in 9HPT (per 1SD: 0.09%; 95% CI: -0.15 to 0.33). 25(OH)D-PGS was not associated with new lesion accrual, lesion volume or other imaging-based outcomes (whole brain, gray, white matter volume loss or GCIPL thinning). The results were similarly null in analyses using other p value thresholds or those applying MR. Genetically determined lower 25(OH)D levels were not associated with worse disease outcomes in PwMS and raises questions about the plausibility of a treatment effect of vitamin D in established MS.

Diagnostic evaluation of optical coherence tomography parameters in normal, preperimetric and perimetric glaucoma patients.

To compare the diagnostic ability of glaucoma parameters measured by the optical coherence tomography (OCT) in normal, preperimetric glaucoma (PPG) and perimetric glaucoma (PG) patients. This cross-sectional observational study includes 127 eyes of 127 subjects. Patients were divided into PPG (51 eyes), PG (46 eyes), and normal controls (30 eyes) based on clinical optic disc assessment and Humphrey visual field changes. The Heidelberg Spectralis OCT machine using Glaucoma Module Premium Edition software was used to measure the retinal nerve fiber layer (RNFL) and Bruch's membrane opening-minimum rim width (BMO-MRW) to assess the optic nerve head and ganglion cell layer (GCL) thickness in the macula. RNFL, MRW, and GCL thickness were all significantly thinner in PG compared to PPG and the normal group. The BMO-MRW parameters showed better specificity (>70%) at 90% specificity compared to both RNFL and GCL parameters to discriminate normal, PPG, and PG patients. All BMO-MRW parameters showed higher area under curves (AUC) compared to RNFL and GCL parameters with the highest AUC observed in the superotemporal sector of the BMO-MRW (AUC=0.819 and and 0.897 between normal and PPG and PG groups respectively). While the BMO-MRW best discriminates PPG and PG against normal eyes, GCL parameters poorly differentiate the three groups.

Motion-sensitive neurons activated by chromatic contrast in a butterfly visual system.

A pattern of two equally bright colours contains only chromatic contrast. Unlike in flies, such a pattern elicits strong optokinetic responses in the butterfly Papilio xuthus. To investigate the neural basis of chromatic motion vision, we performed single-cell electrophysiology. We found spiking neurons exhibiting direction-selective motion sensitivity in the second optic ganglion, the medulla. We analysed the response characteristics of these neurons using two-colour stripe patterns moving vertically. We systematically manipulated the intensities of the colours so that the set of presented patterns included an isoluminant condition for the butterfly. Moving patterns containing only chromatic contrast still elicited a response in the neurons. The neurons' sensitivity profile is similar to that of the behavioural responses. Post-recording dye injection revealed that the neurons have dendrites in the ventral lateral protocerebrum and axonal processes in the medulla, suggesting a feedback role. Presumably, the neurons contribute to subtracting wide-field motion to facilitate the detection of small moving targets. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.