Eye And Brain[JOURNAL]
Sun
183 papers
Impact of Forms of Visual Attenuation on Short-Term Eye Changes Under Controlled Reading Visibility.
Su H, Chun RKM, De Lestrange-Anginieur E
Eye Brain · 2024 · PMID 39651424 · Full text
PURPOSE: Animal studies have suggested that visual degradation impacts eye growth due to the attenuation of high spatial frequencies. However, the influence of perceptual visibility remains unclear in humans. The aim of...
PURPOSE: Animal studies have suggested that visual degradation impacts eye growth due to the attenuation of high spatial frequencies. However, the influence of perceptual visibility remains unclear in humans. The aim of this study was to investigate the impact of visibility on visual attenuation-related eye changes during reading. METHODS: Axial length (AxL) and choroidal thickness (ChT) changes associated with reading tasks were measured in two separate experiments. In the first experiment, the reading task was conducted under different forms of visual attenuation (contrast, resolution, defocus, noise, and crowding). For each form of visual attenuation, the text was set at a sub-threshold level of visibility, evaluated via prior measurement of reading performance, and kept constant via adaptive control of the intensity of the stimulation. Each sub-threshold reading condition was compared with a supra-threshold reading text, serving as control. In the second experiment, the effect of visibility on lens-induced defocus was further examined by comparing the effect of text stimulation with an equivalent dioptric of 5.5 D under sub- and supra-threshold levels of resolution. RESULTS: Near distance reading with supra-threshold texts caused eye elongation (AxL: +12.942 µm ± 2.147 µm; ChT: -3.192 µm ± 1.158 µm). Additional defocusing failed to exacerbate axial elongation under sub-threshold text visibility (mean difference: -0.135 µm ± 2.783 µm), revealing a clear inhibitory effect of lowering visibility on eye changes. Other forms of visual degradation, including crowding (mean difference: 6.153 µm ± 2.127 µm) and noise (mean difference: 5.02 µm ± 2.812 µm) also showed an inhibitory effect on eye elongation. The significant effect of crowding indicated that post-retinal mechanisms, involving attentional processes related to crowded characters, may play a role in the influence of visibility. CONCLUSION: Although the featural composition of visual stimulation can drastically influence eye changes, this study revealed an important mediating role of visibility, previously underscored in chick studies, which warrants further explorations of the impact of post-retinal processes in eye growth.
Microphthalmia and Disrupted Retinal Development Due to a Knock-in/Knock-Out Allele at the Locus.
Napoli FR, Li X, Hurtado AA … +1 more , Levine EM
Eye Brain · 2024 · PMID 39610658 · Full text
PURPOSE: Visual System Homeobox 2 () is a transcription factor expressed in the developing retina that regulates tissue identity, growth, and fate determination. Several mutations in the gene exist in mice, including a...
PURPOSE: Visual System Homeobox 2 () is a transcription factor expressed in the developing retina that regulates tissue identity, growth, and fate determination. Several mutations in the gene exist in mice, including a spontaneous nonsense mutation and two targeted missense mutations originally identified in humans. Here, we expand the genetic repertoire to include a reporter allele ( ) designed to express beta-Galactosidase (bGal) and simultaneously disrupt function (knock-in/knock-out). METHODS: We generated a reporter allele with an in-frame fusion to the coding sequence immediately following exon 2. Germline transmission was assessed with genomic DNA PCR and Western blot analysis was used to describe VSX2 expression from the mutant allele (). Eye size quantification and immunohistology were used to describe the embryonic and postnatal retinal phenotypes of homozygous and heterozygous mice. The contribution of to mutant microphthalmia was probed with the semi-dominant negative allele. RESULTS: The retinal expression pattern of bGal is concordant with VSX2, and the mutant allele is recessive. homozygous mice have congenital bilateral microphthalmia accompanied by defects in retinal development including ectopic expression of non-retinal genes, reduced proliferation, delayed neurogenesis, aberrant tissue morphology, and an absence of bipolar interneurons - all hallmarks of loss-of-function. The allele reduced the severity of microphthalmia caused by the allele. Unexpectedly, the mutant VSX2 protein is stably expressed, and there are subtle differences in eye size and early retinal neurogenesis when compared to the null mutant, . CONCLUSION: The perdurance of the mutant VSX2 protein combined with subtle deviations from the null phenotype leaves open the possibility that allele is not a complete knock-out. The allele exhibits loss-of-function characteristics and adds to the genetic toolkit for understanding function.
Peripapillary Retinal Nerve Fiber Layer (pRNFL) Thickness - A Novel Biomarker of Neurodegeneration in Late-Infantile CLN2 Disease.
Gkalapis N, Dulz S, Grohmann C … +6 more , Nickel M, Schwering C, Wibbeler E, Spitzer MS, Schulz A, Atiskova Y
Eye Brain · 2024 · PMID 39559345 · Full text
PURPOSE: To investigate the presence of peripapillary retinal nerve fiber layer (pRNFL) degeneration in patients with late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease and to evaluate the role of optica...
PURPOSE: To investigate the presence of peripapillary retinal nerve fiber layer (pRNFL) degeneration in patients with late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease and to evaluate the role of optical coherence tomography (OCT) assessed pRNFL thickness as a biomarker for CLN2 disease progression. PATIENTS AND METHODS: Forty eyes of 20 patients with genetically and enzymatically confirmed diagnosis of late-infantile CLN2 disease were included in this retrospective cohort study. All patients received 300 mg of intracerebroventricular enzyme replacement treatment (cerliponase alfa) once every two weeks. OCT imaging was performed under general anesthesia using spectral domain OCT (Heidelberg Engineering, Heidelberg, Germany). PRNFL thickness and central retinal thickness (CRT) values were manually confirmed with the Heidelberg Eye Explorer software. Corresponding pediatric data were extracted from the DEM-CHILD database. Spearman correlation coefficient values (rs) were calculated between pRNFL and CRT values, age at examination, the Weill Cornell Late Infantile Neuronal Ceroid Lipofuscinosis (Weill Cornell LINCL) Scale and the Hamburg Motor and Language (HML) Scale. RESULTS: Fourteen of 20 patients underwent serial examinations resulting in a total of 84 OCT Scans and 42 Weill Cornell LINCL and HML Scale scores. Mean age was 6.90 years and mean follow-up time was 1.38 years. Mean global pRNFL (G-pRNFL) thickness was 77.02 μm presenting a significant decrease compared to normative values from healthy children (106.45 μm; p < 0.0001). G-pRNFL displayed significant correlations towards age at examination = - 0.557, p < 0.01), the Weill Cornell LINCL Scale = 0.849, p < 0.01), and the HML Scale = 0.833, p < 0.01). Repeated measurements indicated decreases in pRNFL thickness over time in most patients. CONCLUSION: Patients with late-infantile CLN2 disease exhibit early onset progressive pRNFL loss regardless of outer retinal degeneration, highlighting the potential of pRNFL as an independent ocular biomarker for retinal pathology in late-infantile CLN2 disease.
Correlations Between Disability Score, Optical Coherence Tomography and Microperimetry in Patients with Multiple Sclerosis.
Guantay CD, Mena-García L, Tola-Arribas MÁ … +4 more , Garea García-Malvar MJ, Yugueros Fernández MI, Mayo-Iscar A, Pastor JC
Eye Brain · 2024 · PMID 39553841 · Full text
PURPOSE: To characterize ocular motility disturbances through Microperimetry (MP) in patients with Multiple Sclerosis (MS) trying to detect those capable of influencing the disability to improve the accuracy of assessing...
PURPOSE: To characterize ocular motility disturbances through Microperimetry (MP) in patients with Multiple Sclerosis (MS) trying to detect those capable of influencing the disability to improve the accuracy of assessing visual impact in EDSS scale. MP results were compare with some structural parameters obtained by OCT. PATIENTS AND METHODS: Cross-sectional analytical and correlational case-control study approved by Ethical Committee. A total of 82 eyes (41 patients) and 30 healthy eyes (15 subjects) were enrolled after informed consent. All participants underwent ophthalmological evaluation with MP and OCT. Variables included MS disease duration, Expanded Disability Status Scale (EDSS) score; in OCT: central macular thickness (CMT), ganglion cell-inner plexiform layer thickness (GCIPL), and peripapillary retinal nerve fiber layer thickness (pRNFL); and in MP: test duration, reaction time, average macular threshold (AT), and 4 fixation stability indexes (P1, P2, BCEA63, BCEA95). RESULTS: MS group showed a significant decrease in GCIPL (p < 0.001) and pRNFL thickness (p < 0.001) compared to the control group. Furthermore, patients demonstrated a longer examination (p < 0.001) and reaction (p < 0.001) times, reduced AT (p < 0.001), more unstable fixation indexes (P1 p <0.004, P2 p = 0.018, BCEA63 p = 0.005 and BCEA95 p = 0.007), measured by MP. In addition, patients with a history of ON (n=16) demonstrated longer examination times in MP (p = 0.049) compared to MS patients without ON, but they were not correlations with OCT measurements, EDSS score correlated with the CMT (p = 0.023, r = -0.25), MP duration (p = 0.043, r = 0.22), and fixation indexes (P1 p = 0.049, r = -0.22, BCEA63 p = 0.041, r = 0.23, BCEA95 p = 0.049, r = 0.22). CONCLUSION: Our study emphasizes the complementary utility of MP and OCT in assessing MS patients. Additionally, it highlights that using MP for objective measurements of oculomotor dysfunction could improves accuracy in disability assessment on the EDSS scale.
Impact of transcranial Direct Current Stimulation on stereoscopic vision and retinal structure in adult amblyopic rodents.
Martinez-Navarrete G, Castaño-Castaño S, Morales-Navas M … +3 more , Nieto-Escámez F, Sánchez-Santed F, Fernandez E
Eye Brain · 2024 · PMID 39498234 · Full text
PURPOSE: The impact of visual deprivation on retinal structure is widely debated. Experimental models, like monocular deprivation through lid suture, provide insights into the consequences of lacking visual experience du...
PURPOSE: The impact of visual deprivation on retinal structure is widely debated. Experimental models, like monocular deprivation through lid suture, provide insights into the consequences of lacking visual experience during development. This deprivation delays primary visual cortex (CV1) maturation due to improper neural connection consolidation, which remains plastic beyond the critical period. However, few studies have used Optical Coherence Tomography (OCT) to investigate structural alterations in the retina of animal models following monocular deprivation. Instead, some studies have focused on the ganglion cell layer using post-mortem histological techniques in amblyopia models induced by monocular deprivation. METHODS: In this study, we used Cliff test to assess stereoscopic vision and spectral domain optical coherence tomography (SD-OCT) to evaluate retinal changes in an in vivo model of visual deprivation treated with Transcranial Direct Current Stimulation (tDCS). RESULTS: The depth perception test initially revealed differences between individuals with amblyopia and the control group. However, after 8 tDCS sessions, amblyopic subjects matched the control group's performance, which remained stable Additionally, significant changes were observed in retinal structures post-tDCS treatment. Specifically, the thickness of the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) increased significantly in amblyopic eyes (p<0.001). Moreover, significant retinal thickening, including the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) and the entire retina, was observed post-tDCS treatment (p<0.05), highlighting the critical role of tDCS in ameliorating amblyopia. Additionally, treated animals exhibited reduced thickness in the Inner Nuclear Layer (INL) and Outer Nuclear Layer (ONL). CONCLUSION: tDCS treatment effectively restores amblyopic individuals' stereoscopic vision, aligning their performance with controls, while impacting retinal structure, highlighting its potential in ameliorating amblyopia's visual deficits.
Accuracy of Diagnosing Optic Neuritis Using DANTE T1-SPACE Imaging.
Shimada A, Suda K, Nakano E … +10 more , Tagawa M, Miyata M, Kashii S, Hinoda T, Fushimi Y, Kimura K, Nishigori R, Ahn S, Grinstead J, Tsujikawa A
Eye Brain · 2024 · PMID 39493624 · Full text
PURPOSE: To evaluate the use of delay alternating with nutation for tailored excitation-prepared T1-weighted turbo spin echo (DANTE T1-SPACE) imaging for diagnosing optic neuritis and to analyze its correlation with clin...
PURPOSE: To evaluate the use of delay alternating with nutation for tailored excitation-prepared T1-weighted turbo spin echo (DANTE T1-SPACE) imaging for diagnosing optic neuritis and to analyze its correlation with clinical findings before and after treatment. PATIENTS AND METHODS: Patients diagnosed with optic neuritis or non-arteritic anterior ischemic optic neuropathy (NA-AION) were evaluated at the Ophthalmology Department of Kyoto University Hospital. All patients underwent magnetic resonance (MR) studies before treatment initiation and ophthalmic examinations before and after treatment. Three ophthalmologists independently reviewed the MR scans for abnormalities. The magnetic resonance imaging (MRI) assessments included post-contrast DANTE T1-SPACE, post-contrast volumetric interpolated breath-hold examination (VIBE), and short T1 inversion recovery (STIR) scans. The presence of abnormalities in each sequence was determined. RESULTS: Of 36 eyes from 30 patients, 21 eyes from 17 patients were diagnosed with optic neuritis, and 15 eyes from 13 patients were diagnosed with NA-AION. DANTE T1-SPACE sequences showed better sensitivity for detecting optic neuritis than STIR sequences (100% vs 67%, p = 0.009). VIBE images did not confirm enhancement of lesions in some cases with optic neuritis. No differences were observed among the sequences for NA-AION. Lesion length evaluated by DANTE T1-SPACE sequences was associated with circumpapillary retinal nerve fiber layer thickness at the initial visit, eye pain, and the time interval from symptom onset to MRI scan. CONCLUSION: Contrast-enhanced DANTE T1-SPACE was better than other sequences of MRI for diagnosing optic neuritis.
Spotlight on Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts (HDBSCC).
Kozak I, Mochida GH, Lin DDM … +2 more , Ali SM, Bosley TM
Eye Brain · 2024 · PMID 39464599 · Full text
Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts (HDBSCC) is a rare syndrome caused by biallelic mutations in the JAM3 gene with significant intrafamilial variability in clinical...
Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts (HDBSCC) is a rare syndrome caused by biallelic mutations in the JAM3 gene with significant intrafamilial variability in clinical presentation and brain imaging phenotypes. The clinical presentation of HDBSCC includes severe recurrent hemorrhages involving the brain parenchyma and the ventricles beginning in utero and continuing in infancy together with dense central cataracts present at birth. This comprehensive review documents reported cases on this unique condition and describes its genetic, neuroradiologic and ophthalmic features. It should be included in the differential diagnosis of children with congenital cataracts and neurodevelopmental abnormalities. Unique clinical, imaging findings and genetic testing can help the diagnosis.
Differences and Similarities Between Primary Open Angle Glaucoma and Primary Angle-Closure Glaucoma.
Wang Y, Guo Y, Zhang Y … +2 more , Huang S, Zhong Y
Eye Brain · 2024 · PMID 39309574 · Full text
Glaucoma is the leading cause of irreversible blindness worldwide. It is an ocular disease characterized by an increase in intraocular pressure or, in some cases, normal intraocular pressure, which leads to optic nerve d...
Glaucoma is the leading cause of irreversible blindness worldwide. It is an ocular disease characterized by an increase in intraocular pressure or, in some cases, normal intraocular pressure, which leads to optic nerve damage and progressive constriction of the visual field (VF). Primary Open-Angle Glaucoma (POAG) and Primary Angle-Closure Glaucoma (PACG) represent the predominant forms of glaucoma. Numerous hypotheses have been posited to elucidate the pathogenic mechanisms underlying these conditions. There is an emerging understanding of the distinct pathological processes that differentiate the various types of glaucoma. While some similarities in the mechanisms between PACG and POAG have been suggested, evidence indicates that there are also significant differences between the two. This review synthesizes the similarities and differences in the etiology of optic neuropathy caused by POAG and PACG, considering their respective pathophysiological mechanisms, the morphology of the optic disc and surrounding tissues, genetic characteristics, optical coherence tomography angiography, optical coherence tomography, and structural and functional features from VF examinations. These characteristics may contribute to a deeper comprehension of the underlying pathogenesis of glaucoma and enhance the management of different types of this ocular condition.
Retina-Brain Homology: The Correlation Between Ophthalmic or Retinal Artery Occlusion and Ischemic Stroke.
Yao Y, Song Q, Zhang J … +2 more , Wen Y, Dou X
Eye Brain · 2024 · PMID 39156910 · Full text
The retina's similar structure and function to the brain make it a unique visual "window" for studying cerebral disorders. Ophthalmic artery occlusion (OAO) or retinal artery occlusion (RAO) is a severe ophthalmic emerge...
The retina's similar structure and function to the brain make it a unique visual "window" for studying cerebral disorders. Ophthalmic artery occlusion (OAO) or retinal artery occlusion (RAO) is a severe ophthalmic emergency that significantly affects visual acuity. Studies have demonstrated that patients with OAO or RAO face a notably higher risk of future acute ischemic stroke (AIS). However, ophthalmologists often overlook multidisciplinary approach involving the neurologist, to evaluate the risk of AIS and devise clinical treatment strategies for patients with OAO or RAO. Unlike the successful use of thrombolysis in AIS, the application of thrombolysis for OAO or RAO remains limited and controversial due to insufficient reliable evidence. In this review, we aim to summarize the anatomical and functional connections between the retina and the brain, and the clinical connection between OAO or RAO and AIS, compare and review recent advances in the effectiveness and safety of intravenous and intra-arterial thrombolysis therapy in patients with OAO or RAO, and discuss future research directions for OAO or RAO. Our goal is to advance the development of multidisciplinary diagnosis and treatment strategies for the disease, as well as to establish expedited pathways or thrombolysis guidelines for vascular intervention.
A Comprehensive Review of Leber Hereditary Optic Neuropathy and Its Association with Multiple Sclerosis-Like Phenotypes Known as Harding's Disease.
Alorainy J, Alorfi Y, Karanjia R … +1 more , Badeeb N
Eye Brain · 2024 · PMID 39100385 · Full text
Leber Hereditary Optic Neuropathy (LHON) stands as a distinctive maternally inherited mitochondrial disorder marked by painless, subacute central vision loss, primarily affecting young males. This review covers the possi...
Leber Hereditary Optic Neuropathy (LHON) stands as a distinctive maternally inherited mitochondrial disorder marked by painless, subacute central vision loss, primarily affecting young males. This review covers the possible relationship between LHON and multiple sclerosis (MS), covering genetic mutations, clinical presentations, imaging findings, and treatment options. LHON is associated with mutations in mitochondrial DNA (mtDNA), notably m.11778G>A, m.3460G>A, and m.14484T>C, affecting complex I subunits. Beyond ocular manifestations, LHON can go beyond the eye into a multi-systemic disorder, showcasing extraocular abnormalities. Clinical presentations, varying in gender prevalence and outcomes, underscore the nature of mitochondrial optic neuropathies. Hypotheses exploring the connection between LHON and MS encompass mitochondrial DNA mutations triggering neurological diseases, immunologically mediated responses inducing demyelination, and the possibility of coincidental diseases. The research on mtDNA mutations among MS patients sheds light on potential associations with specific clinical subgroups, offering a unique perspective into the broader landscape of MS. Imaging findings, ranging from white matter alterations to cerebrospinal fluid biomarkers, further emphasize shared pathological processes between LHON-MS and classical MS. This comprehensive review contributes to the understanding of the complex relationship between LHON and MS.
Detecting Abnormal Eye Movements in Patients with Neurodegenerative Diseases - Current Insights.
Sekar A, Panouillères MTN, Kaski D
Eye Brain · 2024 · PMID 38617403 · Full text
This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's Disease (PD), atypical parkinsonism, and...
This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's Disease (PD), atypical parkinsonism, and others, leveraging advancements in eye-tracking technology for enhanced diagnostic precision. We delve into the different classes of eye movements, their clinical assessment, and specific abnormalities manifesting in these diseases, highlighting the nuanced differences and shared patterns. For instance, AD and ADRD are characterized by increased saccadic latencies and instability in fixation, while PD features saccadic hypometria and mild smooth pursuit impairments. Atypical parkinsonism, notably Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS), presents with distinct ocular motor signatures such as vertical supranuclear gaze palsy and saccadic apraxia, respectively. Our review underscores the diagnostic value of eye movement analysis in differentiating between these disorders and also posits the existence of underlying common pathological mechanisms. We discuss how eye movements have potential as biomarkers for neurodegenerative diseases but also some of the existing limitations.
A Fond Farewell.
Wong-Riley M
Eye Brain · 2024 · PMID 38322779 · Full text
Abstract loading — click title to view on PubMed.
Spotlight on Trans-Synaptic Degeneration in the Visual Pathway in Multiple Sclerosis.
Filippatou AG, Calabresi PA, Saidha S … +1 more , Murphy OC
Eye Brain · 2023 · PMID 38169913 · Full text
A putative mechanism of neurodegeneration in multiple sclerosis (MS) is trans-synaptic degeneration (TSD), whereby injury to a neuron leads to degeneration of synaptically connected neurons. The visual system is commonly...
A putative mechanism of neurodegeneration in multiple sclerosis (MS) is trans-synaptic degeneration (TSD), whereby injury to a neuron leads to degeneration of synaptically connected neurons. The visual system is commonly involved in MS and provides an ideal model to study TSD given its well-defined structure. TSD may occur in an anterograde direction (optic neuropathy causing degeneration in the posterior visual pathway including the optic radiations and occipital gray matter) and/or retrograde direction (posterior visual pathway lesions causing retinal degeneration). In the current review, we discuss evidence supporting the presence of anterograde and retrograde TSD in the visual system in MS.
GGT1 Suppresses the Development of Ferroptosis and Autophagy in Mouse Retinal Ganglion Cell Through Targeting GCLC.
Xu G, Wang J, Zhang Y … +2 more , Chen Z, Deng R
Eye Brain · 2023 · PMID 38020723 · Full text
BACKGROUND: Glaucoma is a neurodegenerative disorder characterized with optic nerve injury and the loss of retinal ganglion cells (RGCs). Ferroptosis has been proved to be associated with the degradation of RGCs. The aim...
BACKGROUND: Glaucoma is a neurodegenerative disorder characterized with optic nerve injury and the loss of retinal ganglion cells (RGCs). Ferroptosis has been proved to be associated with the degradation of RGCs. The aim of this study is to elucidate the relationship between ferroptosis and glaucoma pathogenesis, and unveil the underlying mechanism. METHODS: Methyl thiazolyl tetrazolium (MTT) assay was used to evaluate the proliferation of RGCs. The accumulation of cellular iron was measured by Iron assay kit, and the level of reactive oxygen species (ROS) was detected by fluorescence probe. The mitochondrial morphology and autophagosomes were analysed by using transmission electron microscopy (TEM). The contents of glutathione (GSH) and malondialdehyde (MDA) were tested by a GSH assay kit and an MDA detection kit, respectively. The expression of autophagy-related proteins was detected by Western blotting. RESULTS: A serious cell damage, aberrant iron homeostasis, and oxidative stress was shown in RGC-5 after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment and gamma-Glutamyl transpeptidase 1 (GGT1) knockdown, but these effects were significantly alleviated by overexpression of GGT1 or ferroptosis inhibitors. The TEM and immunofluorescent results indicated that mitochondria impairment and autophagosome accumulation in OGD/R-treated cells was improved after GGT1 overexpression, while the phenomenon in GGT1-silenced cells was aggravated. Furthermore, we found that GGT1 can interact with glutamate cysteine ligase catalytic subunit (GCLC) to inhibit autophagy and ferroptosis in RGC-5 cells. CONCLUSION: GGT1 represses autophagy in RGC-5 cells by targeting GCLC, which further restrains the development of ferroptosis in cells.
Neuromodulation: Actions of Dopamine, Retinoic Acid, Nitric Oxide, and Other Substances on Retinal Horizontal Cells.
McMahon DG, Dowling JE
Eye Brain · 2023 · PMID 37928979 · Full text
Whereas excitation and inhibition of neurons are well understood, it is clear that neuromodulatory influences on neurons and their synapses play a major role in shaping neural activity in the brain. Memory and learning,...
Whereas excitation and inhibition of neurons are well understood, it is clear that neuromodulatory influences on neurons and their synapses play a major role in shaping neural activity in the brain. Memory and learning, emotional and other complex behaviors, as well as cognitive disorders have all been related to neuromodulatory mechanisms. A number of neuroactive substances including monoamines such as dopamine and neuropeptides have been shown to act as neuromodulators, but other substances thought to play very different roles in the body and brain act as neuromodulators, such as retinoic acid. We still understand little about how neuromodulatory substances exert their effects, and the present review focuses on how two such substances, dopamine and retinoic acid, exert their effects. The emphasis is on the underlying neuromodulatory mechanisms down to the molecular level that allow the second order bipolar cells and the output neurons of the retina, the ganglion cells, to respond to different environmental (ie lighting) conditions. The modulation described affects a simple circuit in the outer retina, involves several neuroactive substances and is surprisingly complex and not fully understood.
A Neuro-Ophthalmologist's Guide to Advances in Intracranial Pressure Measurements.
Mollan SP, Momin SNA, Khatkar PS … +3 more , Grech O, Sinclair AJ, Tsermoulas G
Eye Brain · 2023 · PMID 37790122 · Full text
Cerebrospinal fluid disorders have a wide-ranging impact on vision, headache, cognition and a person's quality of life. Due to advances in technology and accessibility, intracranial pressure measurement and monitoring, u...
Cerebrospinal fluid disorders have a wide-ranging impact on vision, headache, cognition and a person's quality of life. Due to advances in technology and accessibility, intracranial pressure measurement and monitoring, usually managed by neurosurgeons, are being employed more widely in clinical practice. These developments are of direct importance for Ophthalmologists and Neurologists because the ability to readily measure intracranial pressure can aide management decisions. The aim of this review is to present the emerging evidence for intracranial pressure measurement methods and interpretation that is relevant to Neuro-ophthalmologists.
Monitoring Eye Movement in Patients with Parkinson's Disease: What Can It Tell Us?
Sun YR, Beylergil SB, Gupta P … +2 more , Ghasia FF, Shaikh AG
Eye Brain · 2023 · PMID 37519412 · Full text
Parkinson's disease (PD) affects approximately 10 million individuals worldwide. Visual impairments are a common feature of PD. Patients report difficulties with visual scanning, impaired depth perception and spatial nav...
Parkinson's disease (PD) affects approximately 10 million individuals worldwide. Visual impairments are a common feature of PD. Patients report difficulties with visual scanning, impaired depth perception and spatial navigation, and blurry and double vision. Examination of PD patients reveals abnormal fixational saccades, strabismus, impaired convergence, and abnormal visually-guided saccades. This review aims to describe objective features of abnormal eye movements in PD and to discuss the structures and pathways through which these abnormalities may manifest.
Neuro-Ophthalmological Manifestations of Horner's Syndrome: Current Perspectives.
Maamouri R, Ferchichi M, Houmane Y … +2 more , Gharbi Z, Cheour M
Eye Brain · 2023 · PMID 37465361 · Full text
Horner's syndrome (HS) is caused by a damage to the oculosympathetic pathway. HS may be congenital, but it is usually acquired and may reveal a life-threatening condition. According to the anatomic location of the underl...
Horner's syndrome (HS) is caused by a damage to the oculosympathetic pathway. HS may be congenital, but it is usually acquired and may reveal a life-threatening condition. According to the anatomic location of the underlying pathologic process, HS is classified as central, pre- or postganglionic, when the lesion affects the first, second or third-order neuron, respectively. Pharmacological testing, if available, can be used to differentiate HS from « pseudo-HS » in patients with mild symptoms. Given the financial burden that imaging of the entire oculosympathetic pathway represents, a targeted imaging approach is advised. Although in the majority of cases, clinical examination may predict etiology, in other cases pharmacological testing can help in the localization process. We searched PubMed data base for papers published before December 2022 that concerned Horner's syndrome, its neuro-ophthalmological manifestations and diagnosis. In this article, we describe the main neuro-ophthalmological manifestations of the three types of HS, the most common etiologies, and a targeted diagnostic strategy in each type.
Effects of Stimulus Luminance, Stimulus Color and Intra-Stimulus Color Contrast on Visual Field Mapping in Neurologically Impaired Adults Using Flicker Pupil Perimetry.
Portengen BL, Porro GL, Bergsma D … +3 more , Veldman EJ, Imhof SM, Naber M
Eye Brain · 2023 · PMID 37287993 · Full text
PURPOSE: We improve pupillary responses and diagnostic performance of flicker pupil perimetry through alterations in global and local color contrast and luminance contrast in adult patients suffering from visual field de...
PURPOSE: We improve pupillary responses and diagnostic performance of flicker pupil perimetry through alterations in global and local color contrast and luminance contrast in adult patients suffering from visual field defects due to cerebral visual impairment (CVI). METHODS: Two experiments were conducted on patients with CVI (Experiment 1: 19 subjects, age M and SD 57.9 ± 14.0; Experiment 2: 16 subjects, age M and SD 57.3 ± 14.7) suffering from absolute homonymous visual field (VF) defects. We altered global color contrast (stimuli consisted of white, yellow, cyan and yellow-equiluminant-to-cyan colored wedges) in Experiment 1, and we manipulated luminance and local color contrast with bright and dark yellow and multicolor wedges in a 2-by-2 design in Experiment 2. Stimuli consecutively flickered across 44 stimulus locations within the inner 60 degrees of the VF and were offset to a contrasting (opponency colored) dark background. Pupil perimetry results were compared to standard automated perimetry (SAP) to assess diagnostic accuracy. RESULTS: A bright stimulus with global color contrast using yellow (= 0.009) or white (= 0.006) evoked strongest pupillary responses as opposed to stimuli containing local color contrast and lower brightness. Diagnostic accuracy, however, was similar across global color contrast conditions in Experiment 1 (= 0.27) and decreased when local color contrast and less luminance contrast was introduced in Experiment 2 (= 0.02). The bright yellow condition resulted in highest performance (AUC M = 0.85 ± 0.10, Mdn = 0.85). CONCLUSION: Pupillary responses and pupil perimetry's diagnostic accuracy both benefit from high luminance contrast and global but not local color contrast.
Meridional Attentional Asymmetries in Astigmatic Eyes.
de Lestrange-Anginieur E
Eye Brain · 2023 · PMID 37200891 · Full text
PURPOSE: To investigate the impact of attention orientation in young myopic adults with astigmatism. METHODS: The effect of attention on foveal meridional performance and anisotropy was measured in corrected myopes with...
PURPOSE: To investigate the impact of attention orientation in young myopic adults with astigmatism. METHODS: The effect of attention on foveal meridional performance and anisotropy was measured in corrected myopes with various levels of astigmatism (with-the-rule astigmatism ≤ -0.75D, Axis: 180 ± 20) using orientation-based attention. Attention was manipulated by instructing subjects to attend to either the horizontal or the vertical line of a central pre-stimulus (a pulsed cross) along separate blocks of trials. For each attention condition, meridional acuity and reaction times were measured via an annulus Gabor target situated remotely from the cross and presented at random horizontally and vertically in a two-alternative forced-choice employing two interleaved staircase procedures (one-up/one-down). Attention modulations were estimated by the difference in performance between horizontal and vertical attention. RESULTS: Foveal meridional performance and anisotropy were strongly affected by the orientation of attention, which appeared critical for the enhancement of reaction times and resolution. Under congruent orienting of attention, foveal meridional anisotropy was correlated with the amount of defocus for both reaction time and resolution, demonstrating greater vertical performance than horizontal performance as myopia increased. Compatible with an attentional compensation of blur through optimal orienting of attention, vertical attention enhanced reaction times compared to horizontal attention and was accompanied by an increase in overall acuity when myopia increased. Increased astigmatism was associated with smaller attention effects and asymmetry, suggesting potential deficits in the compensation of blur in astigmatic eyes. CONCLUSION: Collectively, attention to orientation plays a significant role in horizontal-vertical foveal meridional anisotropy and can modulate the asymmetry of foveal perception imposed by the optics of the eye in episodes of uncorrected vision. Further work is necessary to understand how attention and refractive errors interact during visual development. These results may have practical implications for methods to enhance vision with attention training in myopic astigmats.
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