Diagnosis and clinical features of common optic neuropathies

Neutrophils in Ocular Diseases

Neutrophils, traditionally viewed as first responders to infection or tissue damage, exhibit dynamic and diverse roles in ocular health and disease. This review elaborates on previous findings that showed how neutrophils contribute to ocular diseases. In ocular infections, neutrophils play a pivotal role in host defense by orchestrating inflammatory responses to combat pathogens. Furthermore, in optic nerve neuropathies and retinal degenerative diseases like age-related macular degeneration (AMD) and diabetic retinopathy (DR), neutrophils are implicated in neuroinflammation and tissue damage owing to their ability to undergo neutrophil extracellular trap formation (NETosis) and secretion of inflammatory molecules. Targeting neutrophil-dependent processes holds promise as a therapeutic strategy, offering potential avenues for intervention in ocular infections, cancers, and retinal degenerative diseases. Understanding the multifaceted roles of neutrophils in ocular diseases is crucial for developing targeted therapies to improve patient outcomes.

Applying the 2022 optic neuritis criteria to noninflammatory optic neuropathies with optic nerve T2-hyperintensity: an observational study

INTRODUCTION

Recent diagnostic criteria for optic neuritis include T2-hyperintensity of the optic nerve (ON), even without associated contrast enhancement. However, isolated ON-T2-hyperintensity is a nonspecific finding found in any optic neuropathy or severe retinopathy. We applied the 2022 optic neuritis diagnostic criteria to a cohort of patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one eye, to assess the rate of optic neuritis misdiagnosis using these criteria.

METHODS

Retrospective study of consecutive patients who underwent brain/orbit MRI with/without contrast between 07/01/2019 and 06/30/2022. Patients with ON-T2-hyperintensity in at least one eye were included. The 2022 optic neuritis diagnostic criteria were applied to patients with noninflammatory optic neuropathies who had an ophthalmologic examination available for review.

RESULTS

Of 150 patients included, 85/150 had compressive optic neuropathy; 32/150 had glaucoma; 12/150 had papilledema; 8/150 had hereditary (3), radiation-induced (3), nutritional (1), traumatic (1) optic neuropathies (none fulfilled the criteria); 13/150 had ischemic optic neuropathy and 4 fulfilled the criteria as definite optic neuritis due to contrast enhancement of the ON head. Seven additional patients would have satisfied the diagnostic criteria if red flags for alternative diagnoses had been overlooked.

DISCUSSION

The application of the 2022 optic neuritis diagnostic criteria in patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one ON resulted in misdiagnosis of optic neuritis in only 4 patients because of ON head enhancement, all with nonarteritic anterior ischemic optic neuropathy. Neuro-ophthalmologic evaluation and exclusion of the ON head as a location in the MRI criteria would have prevented optic neuritis misdiagnosis in our study.

Application of a Deep Learning System to Detect Papilledema on Nonmydriatic Ocular Fundus Photographs in an Emergency Department

PURPOSE

The Fundus photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) studies showed that ED providers poorly recognized funduscopic findings in patients in the ED. We tested a modified version of the Brain and Optic Nerve Study Artificial Intelligence (BONSAI) deep learning system on nonmydriatic fundus photographs from the FOTO-ED studies to determine if the deep learning system could have improved the detection of papilledema had it been available to ED providers as a real-time diagnostic aid.

DESIGN

Retrospective secondary analysis of a cohort of patients included in the FOTO-ED studies.

METHODS

The testing data set included 1608 photographs obtained from 828 patients in the FOTO-ED studies. Photographs were reclassified according to the optic disc classification system used by the deep learning system ("normal optic discs," "papilledema," and "other optic disc abnormalities"). The system's performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity using a 1-vs-rest strategy, with reference to expert neuro-ophthalmologists.

RESULTS

The BONSAI deep learning system successfully distinguished normal from abnormal optic discs (AUC 0.92 [95% confidence interval {CI} 0.90-0.93]; sensitivity 75.6% [73.7%-77.5%] and specificity 89.6% [86.3%-92.8%]), and papilledema from normal and others (AUC 0.97 [0.95-0.99]; sensitivity 84.0% [75.0%-92.6%] and specificity 98.9% [98.5%-99.4%]). Six patients with missed papilledema in 1 eye were correctly identified by the deep learning system as having papilledema in the other eye.

CONCLUSIONS

The BONSAI deep learning system was able to reliably identify papilledema and normal optic discs on nonmydriatic photographs obtained in the FOTO-ED studies. Our deep learning system has excellent potential as a diagnostic aid in EDs and non-ophthalmology clinics equipped with nonmydriatic fundus cameras. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Enriching new transplantable RGC-like cells from retinal organoids for RGC replacement therapy

Optic neuropathies, such as glaucoma, are due to progressive retinal ganglion cells (RGCs) degeneration, result in irreversible vision loss. The promising RGCs replacement therapy for restoring vision are impeded by insufficient RGC-like cells sources. The present work was enriched one new type RGC-like cells using two surface markers CD184 and CD171 from human induced pluripotent stem cells (hiPSCs) by FACS sorting firstly. These new kind cells have well proliferation ability and possessed passage tolerance in vitro 2D or 3D spheroids culture, which kept expressing Pax6, Brn3b and βIII-Tubulin and so on. The transplanted CD184+CD171+ RGC-like cells could survive and integrate into the normal and optic nerve crush (ONC) mice retina, especially they were more inclined to across the optic nerve head and extend to the damaged optic nerve. These data support the feasible application for cell replacement therapy in RGC degenerative diseases, as well as help to develop new commercial cells sorting reagents and establish good manufacturing practice (GMP) grade RGC-like donor cells for further clinical application.

Optic Nerve MRI T2-Hyperintensity: A Nonspecific Marker of Optic Nerve Damage

BACKGROUND

MRI abnormalities are common in optic neuropathies, especially on dedicated orbital imaging. In acute optic neuritis, optic nerve T2-hyperintensity associated with optic nerve contrast enhancement is the typical imaging finding. In chronic optic neuropathies, optic nerve T2-hyperintensity and atrophy are regularly seen. Isolated optic nerve T2-hyperintensity is often erroneously presumed to reflect optic neuritis, frequently prompting unnecessary investigations and neuro-ophthalmology consultations. Our goal was to determine the significance of optic nerve/chiasm T2-hyperintensity and/or atrophy on MRI.

METHODS

Retrospective study of consecutive patients who underwent brain/orbital MRI with/without contrast at our institution between July 1, 2019, and June 6, 2022. Patients with optic nerve/chiasm T2-hyperintensity and/or atrophy were included. Medical records were reviewed to determine the etiology of the T2-hyperintensity and/or atrophy.

RESULTS

Four hundred seventy-seven patients (698 eyes) were included [mean age 52 years (SD ±18 years); 57% women]. Of the 364 of 698 eyes with optic nerve/chiasm T2-hyperintensity without atrophy, the causes were compressive (104), inflammatory (103), multifactorial (49), glaucoma (21), normal (19), and other (68); of the 219 of 698 eyes with optic nerve/chiasm T2-hyperintensity and atrophy, the causes were compressive (57), multifactorial (40), inflammatory (38), glaucoma (33), normal (7), and other (44); of the 115 of 698 eyes with optic nerve/chiasm atrophy without T2-hyperintensity, the causes were glaucoma (34), multifactorial (21), inflammatory (13), compressive (11), normal (10), and other (26). Thirty-six eyes with optic nerve/chiasm T2-hyperintensity or atrophy did not have evidence of optic neuropathy or retinopathy on ophthalmologic examination, and 17 eyes had clinical evidence of severe retinopathy without primary optic neuropathy.

CONCLUSIONS

Optic nerve T2-hyperintensity or atrophy can be found with any cause of optic neuropathy and with severe chronic retinopathy. These MRI findings should not automatically prompt optic neuritis diagnosis, workup, and treatment, and caution is advised regarding their use in the diagnostic criteria for multiple sclerosis. Cases of incidentally found MRI optic nerve T2-hyperintensity and/or atrophy without a known underlying optic neuropathy or severe retinopathy are rare. Such patients should receive an ophthalmologic examination before further investigations.

Autosomal recessive cerebellar ataxias: a diagnostic classification approach according to ocular features

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of neurodegenerative disorders affecting primarily the cerebellum and/or its afferent tracts, often accompanied by damage of other neurological or extra-neurological systems. Due to the overlap of clinical presentation among ARCAs and the variety of hereditary, acquired, and reversible etiologies that can determine cerebellar dysfunction, the differential diagnosis is challenging, but also urgent considering the ongoing development of promising target therapies. The examination of afferent and efferent visual system may provide neurophysiological and structural information related to cerebellar dysfunction and neurodegeneration thus allowing a possible diagnostic classification approach according to ocular features. While optic coherence tomography (OCT) is applied for the parametrization of the optic nerve and macular area, the eye movements analysis relies on a wide range of eye-tracker devices and the application of machine-learning techniques. We discuss the results of clinical and eye-tracking oculomotor examination, the OCT findings and some advancing of computer science in ARCAs thus providing evidence sustaining the identification of robust eye parameters as possible markers of ARCAs.

Optic neuropathy diagnosis in the emergency room - retrospective observational study of the last 18 years

INTRODUCTION

Optic neuropathies (ON), a broad spectrum of disorders of the optic nerve, are a frequent cause of visual loss, presenting either in isolation or associated to neurological or systemic disorders. They are often first evaluated in the Emergency Room (ER) and a rapid determination of the etiology is imperative for implementing timely and appropriate treatment. We aim to describe ER demographic data and clinical characteristics, as well as the performed imaging exams, of patients subsequently hospitalized and diagnosed with ON. Furthermore, we seek to explore the accuracy of ER discharge diagnosis and evaluate possible predictive factors that may influence it.

METHODS

We retrospectively reviewed the medical records of 192 patients admitted to the ward of the Neurology Department of Centro Hospitalar Universitário São João (CHUSJ), with a discharge diagnosis of ON. Subsequently, we selected those admitted from the ER, with clinical, laboratory and imaging data, between January 2004 and December 2021.

RESULTS

We included 171 patients. All participants were discharged from the ER and admitted in the ward with a main diagnostic suspicion of ON. Patients were stratified according to suspected etiology at the time of discharge: 99 inflammatory (57.9%), 38 ischemic (22.2%), 27 unspecified (15.8%) and 7 other (4.1%). By comparing with current follow-up diagnosis, 125 patients had an accurate ER diagnosis category (73.1%), 27 had an ON diagnosis of unspecified etiology that was defined only during follow-up (15.8%) and 19 had an inaccurate diagnosis category (11.1%). Diagnostic change was more common with ER ischemic diagnosis (21.1%) compared to inflammatory diagnosis (8.1%) (p = 0.034).

CONCLUSIONS

Our study reveals that most patients with ON can be accurately diagnosed in the ER through clinical history neurological and ophthalmological evaluation.

Optic nerve diseases and regeneration: How far are we from the promised land?

The retinal ganglion cells (RGCs) are the sole output neurons that connect information from the retina to the brain. Optic neuropathies such as glaucoma, trauma, inflammation, ischemia and hereditary optic neuropathy can cause RGC loss and axon damage, and lead to partial or total loss of vision, which is an irreversible process in mammals. The accurate diagnoses of optic neuropathies are crucial for timely treatments to prevent irrevocable RGCs loss. After severe ON damage in optic neuropathies, promoting RGC axon regeneration is vital for restoring vision. Clearance of neuronal debris, decreased intrinsic growth capacity, and the presence of inhibitory factors have been shown to contribute to the failure of post-traumatic CNS regeneration. Here, we review the current understanding of manifestations and treatments of various common optic neuropathies. We also summarise the current known mechanisms of RGC survival and axon regeneration in mammals, including specific intrinsic signalling pathways, key transcription factors, reprogramming genes, inflammation-related regeneration factors, stem cell therapy, and combination therapies. Significant differences in RGC subtypes in survival and regenerative capacity after injury have also been found. Finally, we highlight the developmental states and non-mammalian species that are capable of regenerating RGC axons after injury, and cellular state reprogramming for neural repair.

Deep Learning System Outperforms Clinicians in Identifying Optic Disc Abnormalities

BACKGROUND

The examination of the optic nerve head (optic disc) is mandatory in patients with headache, hypertension, or any neurological symptoms, yet it is rarely or poorly performed in general clinics. We recently developed a brain and optic nerve study with artificial intelligence-deep learning system (BONSAI-DLS) capable of accurately detecting optic disc abnormalities including papilledema (swelling due to elevated intracranial pressure) on digital fundus photographs with a comparable classification performance to expert neuro-ophthalmologists, but its performance compared to first-line clinicians remains unknown.

METHODS

In this international, cross-sectional multicenter study, the DLS, trained on 14,341 fundus photographs, was tested on a retrospectively collected convenience sample of 800 photographs (400 normal optic discs, 201 papilledema and 199 other abnormalities) from 454 patients with a robust ground truth diagnosis provided by the referring expert neuro-ophthalmologists. The areas under the receiver-operating-characteristic curves were calculated for the BONSAI-DLS. Error rates, accuracy, sensitivity, and specificity of the algorithm were compared with those of 30 clinicians with or without ophthalmic training (6 general ophthalmologists, 6 optometrists, 6 neurologists, 6 internists, 6 emergency department [ED] physicians) who graded the same testing set of images.

RESULTS

With an error rate of 15.3%, the DLS outperformed all clinicians (average error rates 24.4%, 24.8%, 38.2%, 44.8%, 47.9% for general ophthalmologists, optometrists, neurologists, internists and ED physicians, respectively) in the overall classification of optic disc appearance. The DLS displayed significantly higher accuracies than 100%, 86.7% and 93.3% of clinicians (n = 30) for the classification of papilledema, normal, and other disc abnormalities, respectively.

CONCLUSIONS

The performance of the BONSAI-DLS to classify optic discs on fundus photographs was superior to that of clinicians with or without ophthalmic training. A trained DLS may offer valuable diagnostic aid to clinicians from various clinical settings for the screening of optic disc abnormalities harboring potentially sight- or life-threatening neurological conditions.

Through the eyes into the brain, using artificial intelligence

Introduction: Detection of neurological conditions is of high importance in the current context of increasingly ageing populations. Imaging of the retina and the optic nerve head represents a unique opportunity to detect brain diseases, but requires specific human expertise. We review the current outcomes of artificial intelligence (AI) methods applied to retinal imaging for the detection of neurological and neuro-ophthalmic conditions. Method: Current and emerging concepts related to the detection of neurological conditions, using AI-based investigations of the retina in patients with brain disease were examined and summarised. Results: Papilloedema due to intracranial hypertension can be accurately identified with deep learning on standard retinal imaging at a human expert level. Emerging studies suggest that patients with Alzheimer’s disease can be discriminated from cognitively normal individuals, using AI applied to retinal images. Conclusion: Recent AI-based systems dedicated to scalable retinal imaging have opened new perspectives for the detection of brain conditions directly or indirectly affecting retinal structures. However, further validation and implementation studies are required to better understand their potential value in clinical practice. Keywords: Alzheimer’s disease, deep learning, dementia, optic neuropathy, papilloedema

Diagnosis of Optic Disc Oedema: Fundus Features, Ocular Imaging Findings, and Artificial Intelligence

Optic disc swelling is a manifestation of a broad range of processes affecting the optic nerve head and/or the anterior segment of the optic nerve. Accurately diagnosing optic disc oedema, grading its severity, and recognising its cause, is crucial in order to treat patients in a timely manner and limit vision loss. Some ocular fundus features, in light of a patient's history and visual symptoms, may suggest a specific mechanism or aetiology of the visible disc oedema, but current criteria can at most enable an educated guess as to the most likely cause. In many cases only the clinical evolution and ancillary testing can inform the exact diagnosis. The development of ocular fundus imaging, including colour fundus photography, fluorescein angiography, optical coherence tomography, and multimodal imaging, has provided assistance in quantifying swelling, distinguishing true optic disc oedema from pseudo-optic disc oedema, and differentiating among the numerous causes of acute optic disc oedema. However, the diagnosis of disc oedema is often delayed or not made in busy emergency departments and outpatient neurology clinics. Indeed, most non-eye care providers are not able to accurately perform ocular fundus examination, increasing the risk of diagnostic errors in acute neurological settings. The implementation of non-mydriatic fundus photography and artificial intelligence technology in the diagnostic process addresses these important gaps in clinical practice.

Understanding the molecular basis and pathogenesis of hereditary optic neuropathies: towards improved diagnosis and management

Hereditary optic neuropathies result from defects in the human genome, both nuclear and mitochondrial. The two main and most recognised phenotypes are dominant optic atrophy and Leber hereditary optic neuropathy. Advances in modern molecular diagnosis have expanded our knowledge of genotypes and phenotypes of inherited disorders that affect the optic nerve, either alone or in combination, with various forms of neurological and systemic degeneration. A unifying feature in the pathophysiology of these disorders appears to involve mitochondrial dysfunction, suggesting that the retinal ganglion cells and their axons are especially susceptible to perturbations in mitochondrial homoeostasis. As we better understand the pathogenesis behind these genetic diseases, aetiologically targeted therapies are emerging and entering into clinical trials, including treatments aimed at halting the cascade of neurodegeneration, replacing or editing the defective genes or their protein products, and potentially regenerating damaged optic nerves, as well as preventing generational disease transmission.

Diagnosis and classification of optic neuritis

There is no consensus regarding the classification of optic neuritis, and precise diagnostic criteria are not available. This reality means that the diagnosis of disorders that have optic neuritis as the first manifestation can be challenging. Accurate diagnosis of optic neuritis at presentation can facilitate the timely treatment of individuals with multiple sclerosis, neuromyelitis optica spectrum disorder, or myelin oligodendrocyte glycoprotein antibody-associated disease. Epidemiological data show that, cumulatively, optic neuritis is most frequently caused by many conditions other than multiple sclerosis. Worldwide, the cause and management of optic neuritis varies with geographical location, treatment availability, and ethnic background. We have developed diagnostic criteria for optic neuritis and a classification of optic neuritis subgroups. Our diagnostic criteria are based on clinical features that permit a diagnosis of possible optic neuritis; further paraclinical tests, utilising brain, orbital, and retinal imaging, together with antibody and other protein biomarker data, can lead to a diagnosis of definite optic neuritis. Paraclinical tests can also be applied retrospectively on stored samples and historical brain or retinal scans, which will be useful for future validation studies. Our criteria have the potential to reduce the risk of misdiagnosis, provide information on optic neuritis disease course that can guide future treatment trial design, and enable physicians to judge the likelihood of a need for long-term pharmacological management, which might differ according to optic neuritis subgroups.

Magnetic resonance imaging of the orbit, Part 2: Characterization of orbital pathologies

In this article we focus on a systematic approach to assess common orbital lesions on magnetic resonance imaging (MRI). The identification of the probable compartment or structure of origin helps narrow the differential diagnosis of a lesion. Analyzing the morphology, appearance, and signal intensity on various sequences, the pattern, and degree of contrast enhancement are key to characterize lesions on MRI. Imaging features suggesting cellularity and vascularity can also be determined to help plan for biopsy or surgery of these lesions. MRI can also distinguish active from chronic disease in certain pathologies and aids in selecting appropriate medical management. MRI may thus serve as a diagnostic tool and help in guiding therapeutic strategies and posttreatment follow-up.

Pediatric Optic Neuritis: Description of Four Cases and Review of the Literature

Pediatric optic neuritis (PON) may be a clinically isolated and self-limiting event or may present in the context of underlying neurologic, infective, or systemic disease. PON has a high impact on the quality of life as it may or may not evolve into other acquired demyelinating syndromes (ADSs), such as multiple sclerosis (MS), neuromyelitis optica (NMO), or other syndromes related to the myelin oligodendrocyte glycoprotein IgG antibodies (MOG-IgG). These different PON phenotypes present variable clinical and radiological features, plasma and liquor biomarkers, and prognosis. We describe four pediatric cases presenting clinically with ON, with different etiopathogenetic pictures: one case had a probable infective etiology, while the others were associated with different demyelinating disorders (MS, NMO, syndrome related to MOG-IgG). We discuss the possible evolution of presenting ON in other ADSs, based on recent literature. A careful evaluation of the clinical and investigation findings and the natural course of PON is necessary to define its pathogenic pathway and evolution. Further prolonged follow-up studies are needed to highlight the predictors of PON evolution, its potential sequelae, and the best treatment options.

Three "Red Lines" for Pattern Recognition-Based Differential Diagnosis Using Optical Coherence Tomography in Clinical Practice

BACKGROUND

Optical coherence tomography (OCT) devices for imaging of the eye are broadly available. The test is noninvasive, rapid, and well-tolerated by patients. This creates a large number of OCT images and patient referrals. Interpretation of OCT findings at the interface between neurological and ophthalmologic conditions has become a key skill in the neuro-ophthalmology service. Similar to the interpretation of visual fields, recogntion of the vertical and horizontal medians are helpful. A third "red line" is added, which will be reviewed here.

EVIDENCE

Levels 1a to 5 evidence.

ACQUISITION

Literature research.

RESULTS

There is level 1a evidence that neurodegeneration of the brain is associated with inner retinal layer atrophy. Predominantly, this is driven by retrograde (trans-synaptic) axonal degeneration from the brain to the eye. This process typically stops at the level of the inner nuclear layer (INL). Anterograde (Wallerian) axonal degeneration from the eye to the brain can trespass the INL. The geography of atrophy and swelling of individual macular retinal layers distinguishes prechiasmal from postchiasmal pathology. The emerging patterns are a front-back "red line" at the INL; a vertical "red line" through the macula for chiasmal/postchiasmal pathology; and a horizontal "red line" through the macular for pathology pointing to the optic disc. This is summarized by illustrative case vignettes.

CONCLUSIONS

The interpretation of patterns of individual retinal layer atrophy (3 "red lines") needs to be combined with recognition of localized layer thickening (edema, structural) at the macula. Certain macular patterns point to pathology at the level of the optic disc. This requires revision of the optic disc OCT and will guide need for further investigations. The 3 "red lines" proposed here may be found useful in clinical practice and the related mnemonics ("half moon," "sunset," "rainbow") for teaching.

Neuroglobin effectively halts vision loss in Harlequin mice at an advanced stage of optic nerve degeneration

Mitochondrial diseases are among the most prevalent groups of inherited neurological disorders, affecting up to 1 in 5000 adults. Despite the progress achieved on the identification of gene mutations causing mitochondrial pathologies, they cannot be cured so far. Harlequin mice, a relevant model of mitochondrial pathology due to apoptosis inducing factor depletion, suffer from progressive disappearance of retinal ganglion cells leading to optic neuropathy. In our previous work, we showed that administering adeno-associated virus encompassing the coding sequences for neuroglobin, (a neuroprotective molecule belonging to the globin family) or apoptosis-inducing factor, before neurodegeneration onset, prevented retinal ganglion cell loss and preserved visual function. One of the challenges to develop an effective treatment for optic neuropathies is to consider that by the time patients become aware of their handicap, a large amount of nerve fibers has already disappeared. Gene therapy was performed in Harlequin mice aged between 4 and 5 months with either a neuroglobin or an apoptosis-inducing factor vector to determine whether the increased abundance of either one of these proteins in retinas could preserve visual function at this advanced stage of the disease. We demonstrated that gene therapy, by preserving the connectivity of transduced retinal ganglion cells and optic nerve bioenergetics, results in the enhancement of visual cortex activity, ultimately rescuing visual impairment. This study demonstrates that: (a) An increased abundance of neuroglobin functionally overcomes apoptosis-inducing factor absence in Harlequin mouse retinas at a late stage of neuronal degeneration; (b) The beneficial effect for visual function could be mediated by neuroglobin localization to the mitochondria, thus contributing to the maintenance of the organelle homeostasis.

[Clinical and paraclinical examination of non-traumatic optic neuropathy in the adult population]

Optic neuropathies (ON) occur in a variety of clinical presentations depending on their pattern of occurrence, their topography and the amount of functional visual impairment. Management of an ON requires a sequence of steps: confirm its existence (positive diagnosis): the diagnosis of ON is usually clinical and must be considered in the case of decreased visual acuity, change in color vision, visual field defect, relative afferent pupillary defect (RAPD), and absence of macular pathology; rule out differential diagnoses: determine the cause; etiologic diagnosis is sometimes complex and takes shape from clinical and paraclinical building blocks. The etiology may be vascular, inflammatory or demyelinating, infectious, toxic, vitamin-deficient, compressive (neoplastic or non-neoplastic), hereditary, congenital, traumatic or even pressure-related (glaucoma or advanced intracranial hypertension). Cerebral and orbital imaging with fine cuts of the optic nerves is often a mandatory examination, which is sometimes useful to repeat; identify therapeutic emergencies.

Protective Effect of Total Panax Notoginseng Saponins on Retinal Ganglion Cells of an Optic Nerve Crush Injury Rat Model

Irreversible loss of retinal ganglion cells (RGCs) is a common pathological feature of various optic nerve degenerative diseases such as glaucoma and ischemic optic neuropathy. Effective protection of RGCs is the key to successful treatment of these diseases. Total Panax notoginseng saponins (TPNS) are the main active component of Panax notoginseng, which has an inhibitory effect on the apoptosis pathway. This study is aimed at assessing the protective effect of TPNS on RGCs of the optic nerve crush (ONC) model of rats and exploring the underlying mechanisms. The intraperitoneal or intravitreal injection of TPNS was used based on the establishment of the rat ONC model. Fifteen days after the injury, the cell membrane fluorescent probe (Fluoro-Gold) was applied to retrograde RGCs through the superior colliculus and obtain the number of surviving RGCs. TUNEL assay was also used to detect the number and density of RGC apoptosis after the ONC model. The expression and distribution of Bcl-2/Bax, c-Jun/P-c-Jun, and P-JNK in the retina were demonstrated by Western blot analysis. After the intervention of TPNS, the rate of cell survival increased in different retinal regions (p < 0.05) and the number of apoptosis cells decreased. Regarding the expression of Bcl-2/Bax, c-Jun/P-c-Jun, and P-JNK-related apoptotic proteins, TPNS can reduce the level of apoptosis and play a role in protecting RGCs (p < 0.05). These findings indicate that topical administration of TPNS can inhibit cell apoptosis and promote RGC survival in the crushed optic nerve.

Retinal changes associated with multivitamin deficiency before and after supplementation

BACKGROUND

Nutritional visual defects are apparently uncommon nowadays in developed nations. Retinal change-related visual defects caused by hypovitaminoses may be underdiagnosed.

AIM OF THE STUDY

To investigate the retinal structural and functional changes in a patient with multivitamin deficiency before and during vitamin supplementation.

METHODS

A 51-year-old female had been on vegetarian diet as a child, and on restrict vegan diet during the last 2 years, developing severe bilateral deterioration of visual function and polyneuropathy. Blood test revealed low levels of vitamin A, B6 and D. The patient underwent examinations with optical coherence tomography (OCT), computerized visual field examination (VF), electroretinography (ERG), visual evoked potentials (VEP) and neurography before and after vitamin supplementation.

RESULTS

Visual acuity (VA) was 20/1000 and VF examination showed central scotoma in both eyes. Color vision was significantly affected. Full-field ERG showed normal rod and cone function, but a clearly reduced central peak was registered in multifocal ERG (mf-ERG), indicating impaired fovea function. VEP showed delayed latency and low amplitude of P100 in both eyes. Neurography showed sensory polyneuropathy. OCT showed significant thinning of macular ganglion cell plus inner plexiform layer (GCIPL) with rapid progression. Retinal nerve fiber layer (RNFL) was preserved and normal, which is in contrast to neuroinflammatory conditions. After 2.5 years of multivitamin supplementation, the visual functions were improved. GCIPL thickness was stable without further deterioration.

CONCLUSIONS

Multivitamin deficiency results in progressive thinning of GCIPL with severe visual deterioration. In contrast to neuroinflammation, RNFL is preserved and normal. Stabilized GCIPL during vitamin supplementation was associated with improved visual function. OCT provides a sensitive and objective measure for differential diagnosis, monitoring retinal change and response to therapy.

Injury-induced Autophagy Delays Axonal Regeneration after Optic Nerve Damage in Adult Zebrafish

Optic neuropathies comprise a group of disorders in which the axons of retinal ganglion cells (RGCs), the retinal projection neurons conveying visual information to the brain, are damaged. This results in visual impairment or even blindness, which is irreversible as adult mammals lack the capacity to repair or replace injured or lost neurons. Despite intensive research, no efficient treatment to induce axonal regeneration in the central nervous system (CNS) is available yet. Autophagy, the cellular recycling response, was shown repeatedly to be elevated in animal models of optic nerve injury, and both beneficial and detrimental effects have been reported. In this study, we subjected spontaneously regenerating adult zebrafish to optic nerve damage (ONC) and revealed that autophagy is enhanced after optic nerve damage in zebrafish, both in RGC axons and somas, as well as in macroglial cells of the retina, the optic nerve and the visual target areas in the brain. Interestingly, the pattern of the autophagic response in the axons followed the spatiotemporal window of axonal regrowth, which suggests that autophagy is ongoing at the growth cones. Pharmacological inhibition of the recycling pathway resulted in accelerated RGC target reinnervation, possibly linked to increased mechanistic target of rapamycin (mTOR) activity, known to stimulate axonal regrowth. Taken together, these intriguing findings underline that further research is warranted to decipher if modulation of autophagy could be an effective therapeutic method to induce CNS regeneration.

Transplantation of miPSC/mESC-derived retinal ganglion cells into healthy and glaucomatous retinas

Optic neuropathies, including glaucoma, are a group of neurodegenerative diseases, characterized by the progressive loss of retinal ganglion cells (RGCs), leading to irreversible vision loss. While previous studies demonstrated the potential to replace RGCs with primary neurons from developing mouse retinas, their use is limited clinically. We demonstrate successful transplantation of mouse induced pluripotent stem cell (miPSC)/mouse embryonic stem cell (mESC)-derived RGCs into healthy and glaucomatous mouse retinas, at a success rate exceeding 65% and a donor cell survival window of up to 12 months. Transplanted Thy1-GFP+ RGCs were able to polarize within the host retina and formed axonal processes that followed host axons along the retinal surface and entered the optic nerve head. RNA sequencing of donor RGCs re-isolated from host retinas at 24 h and 1 week post-transplantation showed upregulation of cellular pathways mediating axonal outgrowth, extension, and guidance. Additionally, we provide evidence of subtype-specific diversity within miPSC-derived RGCs prior to transplantation.

Topical delivery of nerve growth factor for treatment of ocular and brain disorders

Neurotrophins are a family of proteins that support neuronal proliferation, survival, and differentiation in the central and peripheral nervous systems, and are regulators of neuronal plasticity. Nerve growth factor is one of the best-described neurotrophins and has advanced to clinical trials for treatment of ocular and brain diseases due to its trophic and regenerative properties. Prior trials over the past few decades have produced conflicting results, which have principally been ascribed to adverse effects of systemic nerve growth factor administration, together with poor penetrance of the blood-brain barrier that impairs drug delivery. Contrastingly, recent studies have revealed that topical ocular and intranasal nerve growth factor administration are safe and effective, suggesting that topical nerve growth factor delivery is a potential alternative to both systemic and invasive intracerebral delivery. The therapeutic effects of local nerve growth factor delivery have been extensively investigated for different ophthalmic diseases, including neurotrophic keratitis, glaucoma, retinitis pigmentosa, and dry eye disease. Further, promising pharmacologic effects were reported in an optic glioma model, which indicated that topically administered nerve growth factor diffused far beyond where it was topically applied. These findings support the therapeutic potential of delivering topical nerve growth factor preparations intranasally for acquired and degenerative brain disorders. Preliminary clinical findings in both traumatic and non-traumatic acquired brain injuries are encouraging, especially in pediatric patients, and clinical trials are ongoing. The present review will focus on the therapeutic effects of both ocular and intranasal nerve growth factor delivery for diseases of the brain and eye.

A multi-center case series of sarcoid optic neuropathy

OBJECTIVE

The diagnosis of sarcoid optic neuropathy is time-sensitive, as delayed treatment risks irreversible vision loss. We sought to analyze its characteristics and outcomes.

METHODS

We performed a multi-center retrospective study of sarcoid optic neuropathy among 5 USA medical centers. Inclusion criteria were: 1) clinical optic neuropathy; 2) optic nerve/sheath enhancement on neuroimaging; 3) pathological confirmation of systemic or nervous system sarcoidosis.

RESULTS

Fifty-one patients were included. The median onset age of sarcoid optic neuropathy was 50 years (range, 17-70 years) and 71% were female. The median visual acuity at nadir in the most affected eye was 20/80 (range, 20/20 to no-light-perception). Thirty-four of 50 (68%) patients had radiologic evidence of other nervous system involvement and 20 (39%) patients had symptoms/signs of other cranial nerve dysfunction. Cerebrospinal fluid analysis revealed an elevated white blood cell count in 22 of 31 (71%) patients (median: 14/μL; range: 1-643/μL). Pathologic confirmation of sarcoidosis was by biopsy of systemic/pulmonary site, 34 (67%); optic nerve/sheath, 9 (18%); or other nervous system region, 8 (16%). Forty patients improved with treatment (78%), 98% receiving corticosteroids and 65% receiving steroid-sparing immunosuppressants, yet 11/46 patients (24%) had a visual acuity of 20/200 or worse at last follow-up.

CONCLUSIONS

Sarcoid optic neuropathy frequently occurs with other clinical and radiologic abnormalities caused by neurosarcoidosis and diagnostic confirmation occasionally requires optic nerve/sheath biopsy. Improvement with treatment is common but most patients have some residual visual disability. Improved recognition and a more expeditious diagnosis and treatment may spare patients from permanent vision loss.

Remote Ischemic Post-Conditioning Therapy is Protective in Mouse Model of Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is characterized by visual dysfunction after indirect or direct injury to the optic nerve following blunt head trauma. TON is associated with increased oxidative stress and inflammation resulting in retinal ganglion cell (RGC) death. Remote ischemic post-conditioning (RIC) has been shown to enhance endogenous protective mechanisms in diverse disease models including stroke, vascular cognitive impairment (VCI), retinal injury and optic nerve injury. However, the protective mechanisms underlying the improvement of retinal function and RGC survival after RIC treatment remain unclear. Here, we hypothesized that RIC therapy may be protective following TON by preventing RGC death, oxidative insult and inflammation in the mouse retina. To carry out the study, mice were divided in three different groups (Control, TON and TON + RIC). We harvested retinal tissue 5 days after TON induction for western blotting and histochemical analysis. We observed increased TON-induced retinal cell death compared with controls by cleaved caspase-3 immunohistochemistry. Furthermore, the TON cohort demonstrated increased TUNEL positive cells which were significantly attenuated by RIC. Immunofluorescence data showed that oxidative stress markers dihydroethidium (DHE), NOX-2 and nitrotyrosine expression were elevated in the TON group relative to controls and RIC therapy significantly reduced the expression level of these markers. Next, we found that the proinflammatory cytokine TNF-α was increased and anti-inflammatory IL-10 was decreased in plasma of TON animals, and RIC therapy reversed this expression level. Interestingly, western blotting of retinal tissue showed that RGC marker Brn3a and tight junction proteins (ZO-1 and Occludin), and AMPKα1 expression were downregulated in the TON group compared to controls. However, RIC significantly increased the expression levels of these proteins. Together these data suggest that RIC therapy activates endogenous protective mechanisms which may attenuate TON-induced oxidative stress and inflammation, and improves BRB integrity.

Optic Disc Classification by Deep Learning versus Expert Neuro-Ophthalmologists

OBJECTIVE

To compare the diagnostic performance of an artificial intelligence deep learning system with that of expert neuro-ophthalmologists in classifying optic disc appearance.

METHODS

The deep learning system was previously trained and validated on 14,341 ocular fundus photographs from 19 international centers. The performance of the system was evaluated on 800 new fundus photographs (400 normal optic discs, 201 papilledema [disc edema from elevated intracranial pressure], 199 other optic disc abnormalities) and compared with that of 2 expert neuro-ophthalmologists who independently reviewed the same randomly presented images without clinical information. Area under the receiver operating characteristic curve, accuracy, sensitivity, and specificity were calculated.

RESULTS

The system correctly classified 678 of 800 (84.7%) photographs, compared with 675 of 800 (84.4%) for Expert 1 and 641 of 800 (80.1%) for Expert 2. The system yielded areas under the receiver operating characteristic curve of 0.97 (95% confidence interval [CI] = 0.96-0.98), 0.96 (95% CI = 0.94-0.97), and 0.89 (95% CI = 0.87-0.92) for the detection of normal discs, papilledema, and other disc abnormalities, respectively. The accuracy, sensitivity, and specificity of the system's classification of optic discs were similar to or better than the 2 experts. Intergrader agreement at the eye level was 0.71 (95% CI = 0.67-0.76) between Expert 1 and Expert 2, 0.72 (95% CI = 0.68-0.76) between the system and Expert 1, and 0.65 (95% CI = 0.61-0.70) between the system and Expert 2.

INTERPRETATION

The performance of this deep learning system at classifying optic disc abnormalities was at least as good as 2 expert neuro-ophthalmologists. Future prospective studies are needed to validate this system as a diagnostic aid in relevant clinical settings. ANN NEUROL 2020;88:785-795.

The latest diagnostic criteria and treatment options for neuromyelitis optica

Neuromyelitis optica, also known as Devic disease, is an autoimmune disorder that affects the spinal cord and optic nerve. This atypical demyelinating syndrome can be difficult to diagnose and responds poorly to treatments that are used for multiple sclerosis, a similar demyelinating disease. This article discusses the epidemiology, pathophysiology, clinical presentation, latest diagnostic criteria, and treatment options for neuromyelitis optica and neuromyelitis spectrum disorders.

[Giant cell arteritis: Ischemic complications]

GCA ischemic complications occur generally in patients with a yet undiagnosed or uncontrolled disease. When disease control is fair, ischemic complications may be due mostly to atheromatosis. Ophtalmic complications are most frequent and are dominated by anterior ischemic optic neuropathy. Vasculitic strokes occur essentially in the vertebrobasilar arterial territory. Overt vasculitic coronary disease is exceptional. The diagnosis of upper and lower limbs ischemic complications benefit from advances in echography (halo sign) and positron emission tomography imaging. Treatment relies on corticosteroids (initially 1mg/kg prednisone or more, preceded by intravenous methylprednisolone gigadoses if necessary), the control of cardiovascular risk factors and antiplatelet drugs; heparin may be indicated for threatening limbs ischemia.

The development of optic neuropathy after chronic rhinosinusitis: A population-based cohort study

Background

To evaluate the risk of developing optic neuropathy (ON) in patient with both non-surgery and surgery-indicated chronic rhinosinusitis (CRS) via the national health insurance research database in Taiwan.

Methodology/Principal findings

44,176 Patients with a diagnostic code of CRS was selected, which included 6,678 received functional endoscopic sinus surgery (FESS) regarded as the surgery-indicated CRS. Each individual in the study group was matched to two non-CRS patients by age and gender. The outcome was set as the occurrence of ON according to the diagnostic codes occurred after the index date. Poisson regression was used to calculate the adjusted relative risk (aRR) and conditional Cox proportional model was used to estimate the adjusted hazard ratio (aHR). There were 131 and 144 events of ON occurred in the study group and the control group respectively during the follow-up period. The whole study group, whether received FESS or not, demonstrated both significant aRR and aHR compared to the control group after adjusting demographic data, prominent ocular diseases, and systemic co-morbidities. In addition, both the aRR and aHR were higher in CRS patient received FESS than those with CRS but without FESS management.

Conclusion

The existence of CRS, especially the surgery-indicated CRS is a significant risk factor for the following ON using multivariable analysis.

Non-invasive measurement techniques for quantitative assessment of optic nerve head blood flow

Diseases of the optic nerve head involving changes in blood flow are common. However, the pathophysiology is not always fully understood. Several non-invasive methods for measuring optic nerve head blood flow are available, but currently no gold standard has been established. Methods for measuring blood flow in optic neuropathies including colour Doppler imaging, retinal function imager, optical coherence tomography angiography and laser speckle flowgraphy are reviewed. Ultrasound colour Doppler imaging is a fast measurement technique where several different parameters, especially the blood flow velocity, can be calculated. Though used for many years in ophthalmology, its use is not standardized and it requires significant observer skills. The retinal function imager is a direct method where the haemoglobin in erythrocytes is visualized and blood flow velocities in retinal vessels are calculated from a series of photos. The technique is not suitable for direct measurement of blood flow within the optic nerve head. Laser speckle flowgraphy uses a laser light which creates a light scatter pattern in the tissue. Particles moving in the area causes changes in the speckle pattern from which a relative blood flow can be estimated. It is, however, not known whether optic nerve head microcirculation is measurable with the technique. Optical coherence tomography angiography uses multiple scans to evaluate blood flow with good reproducibility but often problems with artefacts. The technique is continuously being refined and increasingly used in research as a tool for the study of blood flow in retinopathies and optic neuropathies. Most of the conducted studies are based on small sample sizes, but some of the methods show promising results in an optic nerve head blood flow research setting. Further and larger studies are required to provide standardized and comparable measurements before one or more of the methods can be considered clinical helpful in daily practice.

A Controlled Impact of Optic Nerve as a New Model of Traumatic Optic Neuropathy in Mouse

Purpose

Traumatic optic neuropathy (TON) is the most feared visual consequence of head and ocular trauma in both military and civilian communities, for which standard treatment does not exist. Animal models are critical for the development of novel TON therapies as well as the understanding of TON pathophysiology. However, the models currently used for TON have some limitations regarding consistency and mirroring the exact pathological progression of TON in closed ocular trauma. In this study, we modified the model of controlled cortical impact and adapted it for studying TON.

Methods

We defined new standardized procedures to induce TON in mice, wherein the optic nerve is reproducibly exposed to a graded controlled impact of known velocity to produce a graded deficit in retinal ganglion cell (RGC) electrophysiological functions.

Results

The key results of validating this newly modified model, “controlled orbital impact (COI),” included (1) the injury parameters (velocity as well as contusion depth and time), which were quantifiable and manageable to generate a wide range of TON severities; (2) a reproducible endpoint of diminished positive scotopic threshold response (pSTR) has been achieved without the interference of surgical variability and destruction of surrounding tissues; (3) the contralateral eyes showed no significant difference to the eyes of naïve mice, allowing them to be used as an internal control to minimize interindividual variability among mice; and (4) the occurrence of injury-associated mortality and/or ocular comorbidity was rare.

Conclusions

Taken together, this model overcomes some limitations of prior TON mouse models and provides an innovative platform to identify therapeutic targets for neuroprotection and/or neurorestoration following traumatic ocular injury.

Long-term neuronal survival, regeneration, and transient target reconnection after optic nerve crush and mesenchymal stem cell transplantation

Background

Retina and/or optic nerve injury may cause irreversible blindness, due to degeneration of retinal ganglion cells. We and others have previously shown that the intravitreal injection of mesenchymal stem cells (MSCs) protects injured retinal ganglion cells and stimulates their regeneration after optic nerve injury, but the long-term effects of this therapy are still unknown.

Methods

We injected rat MSC (rMSC) intravitreally in adult (3–5 months) Lister Hooded rats of either sex after optic nerve crush. Retinal ganglion cell survival, axonal regeneration, and reconnection were analyzed 60 and 240 days after crush by immunohistochemistry for Tuj1, anterograde labeling with cholera-toxin B and by immunohistochemistry for nerve growth factor-induced gene A (NGFI-A, driven by light stimulation) in the superior colliculus after a cycle of light deprivation-stimulation. Visual behaviors (optokinetic reflex, looming response, and preference for dark) were analyzed 70 days after crush.

Results

rMSC treatment doubled the number of surviving retinal ganglion cells, preferentially of a larger subtype, and of axons regenerating up to 0.5 mm. Some axons regenerated to the lateral geniculate nucleus and superior colliculus. NGFI-A+ cells were doubled in rMSC-treated animals 60 days after crush, but equivalent to vehicle-injected animals 240 days after crush, suggesting that newly formed synapses degenerated. Animals did not recover visual behaviors.

Conclusions

We conclude that rMSC-induced neuroprotection is sustained at longer time points. Although rMSCs promoted long-term neuroprotection and long-distance axon regeneration, the reconnection of retinal ganglion cells with their targets was transitory, indicating that they need additional stimuli to make stable reconnections.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1226-9) contains supplementary material, which is available to authorized users.

Diagnostic Utility of Optic Nerve Measurements with MRI in Patients with Optic Nerve Atrophy

BACKGROUND AND PURPOSE

No MR imaging measurement criteria are available for the diagnosis of optic nerve atrophy. We determined a threshold optic nerve area on MR imaging that predicts a clinical diagnosis of optic nerve atrophy and assessed the relationship between optic nerve area and retinal nerve fiber layer thickness measured by optical coherence tomography, an ancillary test used to evaluate optic nerve disorders.

MATERIALS AND METHODS

We evaluated 26 patients with suspected optic nerve atrophy (8 with unilateral, 13 with bilateral and 5 with suspected but not demonstrable optic nerve atrophy) who had both orbital MR imaging and optical coherence tomography examinations. Forty-five patients without optic nerve atrophy served as controls. Coronal inversion recovery images were used to measure optic nerve area on MR imaging. Retinal nerve fiber layer thickness was determined by optical coherence tomography. Individual eyes were treated separately; however, bootstrapping was used to account for clustering when appropriate. Correlation coefficients were used to evaluate relationships; receiver operating characteristic curves, to investigate predictive accuracy.

RESULTS

There was a significant difference in optic nerve area between patients' affected eyes with optic nerve atrophy (mean, 3.09 ± 1.09 mm²), patients' unaffected eyes (mean, 5.27 ± 1.39 mm²; P = .008), and control eyes (mean, 6.27 ± 2.64 mm²; P < .001). Optic nerve area ≤ 4.0 mm² had a sensitivity of 0.85 and a specificity of 0.83 in predicting the diagnosis of optic nerve atrophy. A significant relationship was found between optic nerve area and retinal nerve fiber layer thickness (r = 0.68, P < .001).

CONCLUSIONS

MR imaging-measured optic nerve area ≤ 4.0 mm² has moderately high sensitivity and specificity for predicting optic nerve atrophy, making it a potential diagnostic tool for radiologists.

Ophthalmoscopy in the 21st century: The 2017 H. Houston Merritt Lecture

Although the usefulness of viewing the ocular fundus is well-recognized, ophthalmoscopy is infrequently and poorly performed by most nonophthalmologist physicians, including neurologists. Barriers to the practice of ophthalmoscopy by nonophthalmologists include not only the technical difficulty related to direct ophthalmoscopy, but also lack of adequate training and discouragement by preceptors. Recent studies have shown that digital retinal fundus photographs with electronic transmission and remote interpretation of images by an ophthalmologist are an efficient and reliable way to allow examination of the ocular fundus in patients with systemic disorders such as diabetes mellitus. Ocular fundus photographs obtained without pharmacologic dilation of the pupil using nonmydriatic fundus cameras could be of great value in emergency departments (EDs) and neurologic settings. The Fundus Photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) study showed that ED providers consistently failed to correctly identify relevant ocular funduscopic findings using the direct ophthalmoscope, and that nonmydriatic fundus photography was an effective alternate way of providing access to the ocular fundus in the ED. Extrapolating these results to headache clinics, outpatient neurology clinics, and adult and pediatric primary care settings seems self-evident. As technology advances, nonmydriatic ocular fundus imaging systems will be of higher quality and more portable and affordable, thereby circumventing the need to master the use of the ophthalmoscope. Visualizing the ocular fundus is more important than the method used. Ocular fundus photography facilitates nonophthalmologists' performance of this essential part of the physical examination, thus helping to reestablish the value of doing so.

Optic Nerve Infiltration in Primary Central Nervous System Lymphoma

Importance

Visual impairment in primary central nervous system lymphoma (PCNSL) is caused mostly by intraocular lymphomatous involvement (vitritis and retinal infiltration), whereas optic nerve infiltration (ONI) is a rare condition.

Objective

To describe the clinical presentation of ONI, its imaging characteristics, and outcome.

Design, Setting and Participants

A total of 752 patients diagnosed with PCNSL were retrospectively identified from the databases of 3 French hospitals from January 1, 1998, through December 31, 2014. Of these, 7 patients had documented ONI. Exclusion criteria were intraocular involvement, orbital lymphoma, or other systemic lymphoma. Clinical presentation, neuroimaging, biological features, treatment, and outcomes were assessed.

Main Outcomes and Measures

Treatment response was evaluated clinically and radiologically on follow-up magnetic resonance imaging (MRI) according to the International PCNSL Collaborative Group response criteria.

Results

The 7 patients included 5 women and 2 men. Median age at diagnosis was 65 years (range, 49-78 years). Two patients had initial ONI at diagnosis, and 5 had ONI at relapse. Clinical presentation was marked by rapidly progressive and severe visual impairment for all patients. The MRI findings showed optic nerve enlargement in 3 patients and contrast enhancement of the optic nerve in all patients. Additional CNS lesions were seen in 4 patients. Examination of cerebrospinal fluid samples detected lymphomatous meningitis in 2 patients. Clinical outcome was poor and marked by partial recovery for 2 patients and persistent severe low visual acuity or blindness for 5 patients. Median progression-free survival after optic nerve infiltration was 11 months (95% CI, 9-13 months), and median overall survival was 18 months (95% CI, 9-27 months).

Conclusions and Relevance

Optic nerve infiltration is an atypical and challenging presentation of PCNSL. Its visual and systemic prognosis is particularly poor compared with vitreoretinal lymphomas even in response to chemotherapy. Although intraocular involvement is frequent in PCNSL and clinically marked by slowly progressive visual deterioration, lymphomatous ONI is rare and characterized by rapidly progressive severe visual impairment.

Age-related changes in the spatiotemporal responses to electrical stimulation in the visual cortex of rats with progressive vision loss

The Royal College of Surgeons (RCS) rat gradually loses vision due to retinal degeneration. Previous physiological studies have depicted the progressive loss of optical responses in the visual pathway, including the primary visual cortex (V1), over the course of retinal degeneration in the RCS rat. However, little is known about how the excitability of the V1 circuit changes during over the course of the gradual loss of visual signal input from the retina. We elucidated the properties of responses to electrical stimulations directly applied to V1 at different stages of vision input loss in the RCS rat in reference to those of the Long-Evans (LE) rat, using in vivo voltage-sensitive dye imaging. The V1 neuronal network of the RCS rat exhibited an excitatory response comparable to the LE rat. The excitatory response was maintained even long after total loss of the visual signal input from the retina. However, the response time-course suggested that the suppressive response was somewhat debilitated in the RCS rat. This is the first experiment demonstrating the long-term effect of retinal degeneration on cortical activities. Our findings provide the physiological fundamentals to enhance the preclinical research of cortical prostheses with the use of the RCS rat.

Longitudinal relationship between traumatic brain injury and the risk of incident optic neuropathy: A 10-year follow-up nationally representative Taiwan survey

Accumulating evidences had shown that traumatic brain injury was associated with visual impairment or vision loss. However, there were a limited number of empirical studies regarding the longitudinal relationship between traumatic brain injury and incident optic neuropathy. We studied a cohort from the Taiwanese National Health Insurance data comprising 553918 participants with traumatic brain injury and optic neuropathy-free in the case group and 1107836 individuals without traumatic brain injury in the control group from 1st January 2000. After the index date until the end of 2010, Cox proportional hazards analysis was used to compare the risk of incident optic neuropathy. During the follow-up period, case group was more likely to develop incident optic neuropathy (0.24%) than the control group (0.11%). Multivariate Cox regression analysis demonstrated that the case group had a 3-fold increased risk of optic neuropathy (HR = 3.017, 95% CI = 2.767-3.289, p < 0.001). After stratification by demographic information, traumatic brain injury remained a significant factor for incident optic neuropathy. Our study provided evidence of the increased risk of incident optic neuropathy after traumatic brain injury during a 10-year follow-up period. Patients with traumatic brain injury required periodic and thorough eye examinations for incident optic neuropathy to prevent potentially irreversible vision loss.