Neuro-ophthalmology

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Ravindran K, Schmalz P, Torun N, Ronthal M, Chang Y-M, Thomas AJ. Angiographic Findings in the Tolosa-Hunt Syndrome and Resolution after Corticosteroid Treatment. Neuroophthalmology 2018;42(3):159-163.Abstract
The Tolosa-Hunt syndrome is a rare clinical condition characterized by painful opthalmoparesis associated with idiopathic granulomatous inflammation of the orbital apex and cavernous sinus. Historically, this condition was thought to result from arteritic changes in the internal carotid artery and cavernous sinus. Modern digital angiographic techniques were unavailable when THS was initially described, and few reports exist on its high-resolution angiographic findings. Painful ophthalmoparesis, especially of the oculomotor nerve, warrants vascular imaging because of the concern for an underlying aneurysm. Here, we describe angiographic findings of THS which may be useful for clinicians when encountering patients presenting with painful ophthalmoplegia.
Redler Y, Levy M. Rodent Models of Optic Neuritis. Front Neurol 2020;11:580951.Abstract
Optic neuritis (ON) is an inflammatory attack of the optic nerve that leads to visual disability. It is the most common optic neuropathy affecting healthy young adults, most commonly women aged 20-45 years. It can be idiopathic and monophasic or as part of a neurologic disease such as multiple sclerosis with recurrence and cumulative damage. Currently, there is no therapy to repair the damage from optic neuritis. Animal models are an essential tool for the understanding of the pathogenesis of optic neuritis and for the development of potential treatment strategies. Experimental autoimmune encephalomyelitis (EAE) is the most commonly used experimental rodent model for human autoimmune inflammatory demyelinating diseases of the central nervous system (CNS). In this review, we discuss the latest rodent models regarding optic neuritis, focusing on EAE model, and on its recent achievements and developments.
Reshef ER, Schiff ND, Brown EN. A Neurologic Examination for Anesthesiologists: Assessing Arousal Level during Induction, Maintenance, and Emergence. Anesthesiology 2019;130(3):462-471.Abstract
Anesthetics have profound effects on the brain and central nervous system. Vital signs, along with the electroencephalogram and electroencephalogram-based indices, are commonly used to assess the brain states of patients receiving general anesthesia and sedation. Important information about the patient's arousal state during general anesthesia can also be obtained through use of the neurologic examination. This article reviews the main components of the neurologic examination focusing primarily on the brainstem examination. It details the components of the brainstem examination that are most relevant for patient management during induction, maintenance, and emergence from general anesthesia. The examination is easy to apply and provides important complementary information about the patient's arousal level that cannot be discerned from vital signs and electroencephalogram measures.
Resnick HH, Bear MF, Gaier ED. Partial Recovery of Amblyopia After Fellow Eye Ischemic Optic Neuropathy. J Neuroophthalmol 2023;43(1):76-81.Abstract
BACKGROUND: Recovery from amblyopia in adulthood after fellow eye (FE) vision loss is a well-known phenomenon. Incidence of recovery varies widely following different FE pathologies, and the rate of recovery after FE ischemic optic neuropathy (ION) has not been examined. We aimed to determine the frequency and degree of improvement in amblyopic eye (AE) visual function after ION in the FE. METHODS: We performed a retrospective chart review of patients between 2007 and 2021 confirmed to have amblyopia and ischemic optic neuropathy in different eyes. Patients with unstable ocular pathology potentially limiting vision were excluded. We compared the best-corrected visual acuity (VA) in each eye before and after FE ION over time. For patients with available data, we examined change in perimetric performance over time. RESULTS: Among the 12 patients who met the inclusion criteria (mean age 67 ± 8 years), 9 (75%) improved ≥1 line and 2 (17%) improved ≥3 lines. The median time from ION symptom onset to maximal improvement was 6 months (range: 2-101 months). Reliable perimetric data were available for 6 patients. Mean sensitivity improved in the AE for all patients, with mean improvement of 1.9 ± 1.1 dB. There was no correspondence between foci of ION-related field loss and gains in field sensitivity in the AE. CONCLUSIONS: A high proportion of patients with amblyopia and contralateral ION experience improvement in AEVA. Modest gains in perimetric sensitivity in the AE may accompany FE ION. These findings support the view that residual plasticity in the adult visual cortex can be tapped to support functional improvement in amblyopia.
Rinaldi L, Ciricugno A, Merabet LB, Vecchi T, Cattaneo Z. The Effect of Blindness on Spatial Asymmetries. Brain Sci 2020;10(10)Abstract
The human cerebral cortex is asymmetrically organized with hemispheric lateralization pervading nearly all neural systems of the brain. Whether the lack of normal visual development affects hemispheric specialization subserving the deployment of visuospatial attention asymmetries is controversial. In principle, indeed, the lack of early visual experience may affect the lateralization of spatial functions, and the blind may rely on a different sensory input compared to the sighted. In this review article, we thus present a current state-of-the-art synthesis of empirical evidence concerning the effects of visual deprivation on the lateralization of various spatial processes (i.e., including line bisection, mirror symmetry, and localization tasks). Overall, the evidence reviewed indicates that spatial processes are supported by a right hemispheric network in the blind, hence, analogously to the sighted. Such a right-hemisphere dominance, however, seems more accentuated in the blind as compared to the sighted as indexed by the greater leftward bias shown in different spatial tasks. This is possibly the result of the more pronounced involvement of the right parietal cortex during spatial tasks in blind individuals compared to the sighted, as well as of the additional recruitment of the right occipital cortex, which would reflect the cross-modal plastic phenomena that largely characterize the blind brain.
Rizzo JF. Festschrift for Simmons Lessell, MD. J Neuroophthalmol 2013;33(4):e26-7.
Rizzo JF, Sanders DT, Castelbuono AC. Orbital Vasculopathy With Unexpected Finding of Calcium Oxalosis in the Context of a Clinical Diagnosis of Optic Neuropathy. J Neuroophthalmol 2023;Abstract
BACKGROUND: There are few reports of histopathology of any form of optic neuropathy. This article provides histopathologic findings of an adult-onset, nonprogressive optic neuropathy that was diagnosed clinically as nonacute, nonarteritic anterior ischemic optic neuropathy (NAION) but which was found by a pathological study to be associated with diffuse calcium oxalosis that was confined in the involved orbit. METHODS: This is a case report that includes results of a neuro-ophthalmologic examination and histopathology of a complete autopsy, including en bloc removal of both orbits and the brain. The unaffected orbit/optic nerve served as a control. The affected orbit was serially sectioned into 2,550 increments each separated by 10 μm; the uninvolved orbit was sectioned into 150 equally spaced sections. The main outcome measures were derived from the autopsy, especially from the thin-section histopathologic study of both orbits that focused on blood vessels and the site of neural damage within the optic nerve. RESULTS: The neuro-ophthalmologic examination revealed a unilateral optic neuropathy with pallor of the left optic nerve head that had been documented just before death. The general autopsy showed acute bacterial endocarditis and a recent cerebral hematoma that caused death. Histopathology revealed sectoral loss of optic nerve axons in the left eye. Numerous arterial walls in the left orbit, including short posterior ciliary arteries and the central retinal artery, contained hundreds of crystals with anisotropic, colorful birefringence consistent with calcium oxalosis. Crystals were not found in the right, control orbit or elsewhere in the body. CONCLUSIONS: The patient developed an optic neuropathy late in life that was diagnosed by an experienced neuro-ophthalmologist as being most consistent with nonacute, nonarteritic anterior ischemic optic neuropathy. The autopsy identified sectoral loss of optic nerve fibers consistent with that diagnosis. However, the unexpected discovery of calcium oxalate crystals in blood vessels of the involved orbit, which curiously were not present elsewhere in the body, raises a question of their etiological role in this particular optic neuropathy. Whether the crystals were causal, epiphenomenal, or purely incidental to the optic neuropathy cannot be answered by our study.
Rizzo JF, Shah MP, Krasniqi D, Lu YR, Sinclair DA, Ksander BR. The Role of Epigenetics in Accelerated Aging: A Reconsideration of Later-Life Visual Loss After Early Optic Neuropathy. J Neuroophthalmol 2023;Abstract
BACKGROUND: In 2005, we reported 3 patients with bilateral optic nerve damage early in life. These patients had stable vision for decades but then experienced significant bilateral vision loss with no obvious cause. Our hypothesis, novel at that time, was that the late decline of vision was due to age-related attrition of retinal ganglion cells superimposed on a reduced neuronal population due to the earlier injury. EVIDENCE ACQUISITION: The field of epigenetics provides a new paradigm with which to consider the normal aging process and the impact of neuronal injury, which has been shown to accelerate aging. Late-in-life decline in function after early neuronal injury occurs in multiple sclerosis due to dysregulated inflammation and postpolio syndrome. Recent studies by our group in mice have also demonstrated the possibility of partial reversal of cellular aging and the potential to mitigate anatomical damage after injury and even improve visual function. RESULTS: The results in mice and nonhuman primates published elsewhere have shown enhanced neuronal survival and visual function after partial epigenetic reprogramming. CONCLUSIONS: Injury promotes epigenetic aging, and this finding can be observed in several clinically relevant scenarios. An understanding of the epigenetic mechanisms at play opens the opportunity to restore function in the nervous system and elsewhere with cellular rejuvenation therapies. Our earlier cases exemplify how reconsideration of previously established concepts can motivate inquiry of new paradigms.
Rizzo JF. Unraveling the Enigma of Nonarteritic Anterior Ischemic Optic Neuropathy. J Neuroophthalmol 2019;39(4):529-544.Abstract
Non-arteritic anterior ischemic optic neuropathy (NAON) is the second most common optic neuropathy in adults. Despite extensive study, the etiology of NAION is not definitively known. The best evidence suggests that NAION is caused by an infarction in the region of the optic nerve head (ONH), which is perfused by paraoptic short posterior ciliary arteries (sPCAs) and their branches. To examine the gaps in knowledge that defies our understanding of NAION, a historical review was performed both of anatomical investigations of the ONH and its relevant blood vessels and the evolution of clinical understanding of NAION. Notably, almost all of the in vitro vascular research was performed prior our current understanding of NAION, which has largely precluded a hypothesis-based laboratory approach to study the etiological conundrum of NAION. More recent investigative techniques, like fluorescein angiography, have provided valuable insight into vascular physiology, but such light-based techniques have not been able to image blood vessels located within or behind the dense connective tissue of the sclera and laminar cribrosa, sites that are likely culpable in NAION. The lingering gaps in knowledge clarify investigative paths that might be taken to uncover the pathogenesis of NAION and possibly glaucoma, the most common optic neuropathy for which evidence of a vascular pathology also exists.
Rosenvald OR, Lessell S. Pupillary sign of aberrant regeneration of the third nerve. Neurology 2016;86(18):1746.
Rossi A, Gnesi M, Montomoli C, Chirico G, Malerba L, Merabet LB, Merabet LB, Fazzi E. Neonatal Assessment Visual European Grid (NAVEG): Unveiling neurological risk. Infant Behav Dev 2017;49:21-30.
Rossin EJ, Gilbert AL, Koen N, Leslie-Mazwi TM, Cunnane ME, Rizzo JF. Site of Origin of the Ophthalmic Artery Influences the Risk for Retinal Versus Cerebral Embolic Events. J Neuroophthalmol 2021;41(1):24-28.Abstract
BACKGROUND: Embolic events leading to retinal ischemia or cerebral ischemia share common risk factors; however, it has been well documented that the rate of concurrent cerebral infarction is higher in patients with a history of transient ischemic attack (TIA) than in those with monocular vision loss (MVL) due to retinal ischemia. Despite the fact that emboli to the ophthalmic artery (OA) and middle cerebral artery share the internal carotid artery (ICA) as a common origin or transit for emboli, the asymmetry in their final destination has not been fully explained. We hypothesize that the anatomic location of the OA takeoff from the ICA may contribute to the differential flow of small emboli to the retinal circulation vs the cerebral circulation. METHODS: We report a retrospective, comparative, case-control study on 28 patients with retinal ischemia and 26 patients with TIA or cerebral infarction caused by embolic events. All subjects underwent either computed tomography angiography or MRA. The location of the ipsilateral OA origin off the ICA was then graded in a blinded fashion and compared between cohorts. Vascular risk factors were collected for all patients, including age, sex, hypertension, hyperlipidemia, arrhythmia, diabetes, coronary artery disease, and smoking. RESULTS: We find that in patients with retinal ischemia of embolic etiology, the ipsilateral OA takeoff from the ICA is more proximal than in patients with cerebral infarcts or TIA (P = 0.0002). We found no statistically significant differences in demographic, vascular, or systemic risk factors. CONCLUSIONS: We find that the mean anatomical location of the OA takeoff from the ICA is significantly more proximal in patients with MVL due to retinal ischemia compared with patients with TIA or cerebral ischemia. This finding contributes significantly to our understanding of a long observed but poorly understood phenomenon that patients with MVL are less likely to have concurrent cerebral ischemia than are patients with TIA.
Rothfield L, Falcone MM, Gaier ED, Heidary G, Gise R. Neuro-ophthalmic Complications in Pediatric Leukemia. J Neuroophthalmol 2023;43(4):520-524.Abstract
BACKGROUND: Optic neuropathy in childhood leukemia occurs through multiple direct and indirect mechanisms, including leukemic infiltration of the optic nerve, infection, blood dyscrasias, or adverse effects of treatment. We aimed to characterize visual outcomes in pediatric patients with leukemia-associated neuro-ophthalmic manifestations. METHODS: We retrospectively identified patients with leukemia and optic nerve pathology over 13 years by diagnostic billing codes. We collected information on demographics, presentation, treatment course, and visual outcomes directly from medical records. RESULTS: Of the 19 patients who met inclusion criteria, 17 (89.5%) had pseudotumor cerebri and 2 had direct optic nerve infiltration. Causes of increased intracranial pressure included central nervous system infiltration (6 of 17), hyperviscosity/leukemia (2 of 17), venous sinus thrombosis (3 of 17), medication induced (5 of 17), and bacterial meningitis (1 of 17). 47.1% (8 of 17) had papilledema at the time of leukemia diagnosis, and 94.1% (16 of 17) of patients with pseudotumor cerebri were treated with acetazolamide. At presentation, 3 patients had decreased vision secondary to macular ischemia, subhyaloid vitreous hemorrhage, or steroid induced glaucoma. Following treatment of pseudotumor cerebri, binocular visual acuity was ≥20/25 in all patients. One patient with optic nerve infiltration had a final visual acuity of count fingers in the affected eye. CONCLUSIONS: In our chart review, the most common mechanism of neuro-ophthalmic involvement in pediatric leukemia was elevated intracranial pressure from a myriad of causes. Visual outcomes from patients with elevated intracranial pressure were excellent. Understanding the mechanisms by which leukemia can cause optic nerve disease in pediatric patients can facilitate earlier diagnosis and treatment and potentially improve visual outcomes.
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Sabel BA, Flammer J, Merabet LB. Residual vision activation and the brain-eye-vascular triad: Dysregulation, plasticity and restoration in low vision and blindness - a review. Restor Neurol Neurosci 2018;Abstract
Vision loss due to ocular diseases such as glaucoma, optic neuropathy, macular degeneration, or diabetic retinopathy, are generally considered an exclusive affair of the retina and/or optic nerve. However, the brain, through multiple indirect influences, has also a major impact on functional visual impairment. Such indirect influences include intracerebral pressure, eye movements, top-down modulation (attention, cognition), and emotionally triggered stress hormone release affecting blood vessel dysregulation. Therefore, vision loss should be viewed as the result of multiple interactions within a "brain-eye-vascular triad", and several eye diseases may also be considered as brain diseases in disguise. While the brain is part of the problem, it can also be part of the solution. Neuronal networks of the brain can "amplify" residual vision through neuroplasticity changes of local and global functional connectivity by activating, modulating and strengthening residual visual signals. The activation of residual vision can be achieved by different means such as vision restoration training, non-invasive brain stimulation, or blood flow enhancing medications. Modulating brain functional networks and improving vascular regulation may offer new opportunities to recover or restore low vision by increasing visual field size, visual acuity and overall functional vision. Hence, neuroscience offers new insights to better understand vision loss, and modulating brain and vascular function is a promising source for new opportunities to activate residual vision to achieve restoration and recovery to improve quality of live in patients suffering from vision loss.
Saber Tehrani AS, Kattah JC, Kerber KA, Gold DR, Zee DS, Urrutia VC, Newman-Toker DE. Diagnosing Stroke in Acute Dizziness and Vertigo: Pitfalls and Pearls. Stroke 2018;49(3):788-795.
Saitakis G, Chwalisz BK. Optic perineuritis. Curr Opin Ophthalmol 2022;33(6):519-524.Abstract
PURPOSE OF REVIEW: This review paper aims at discussing pathogenesis, etiology, clinical features, management, and prognosis of OPN. RECENT FINDINGS: Optic perineuritis (OPN) is an inflammatory process primarily involving the optic nerve sheath. Clinically, OPN usually presents with unilateral, gradual decline of visual function, eye pain, and/or pain on eye movements, disc edema and various features of optic nerve dysfunction, including visual field defects. It can mimic typical optic neuritis. In most cases of OPN, the disease is isolated with no specific etiology being identified, however, it can also occur secondary to a wide range of underlying systemic diseases. OPN is clinically diagnosed and radiologically confirmed based on the finding of circumferential perineural enhancement of the optic nerve sheath on magnetic resonance imaging (MRI). SUMMARY: Unlike optic nerve, OPN is not typically self-limited without treatment. High-dose oral corticosteroids are the mainstay of treatment in OPN. The initiation of therapy usually causes rapid and dramatic improvement in signs and symptoms. In general, OPN usually has a relatively good visual prognosis, which is influenced by delays between the onset of visual loss and the initiation of steroid therapy as well as the presence of underlying systemic diseases.
Saitakis G, Chwalisz BK. The neurology of IGG4-related disease. J Neurol Sci 2021;424:117420.Abstract
PURPOSE OF REVIEW: IgG4-related disease (IgG4-RD) is emerging as a fibro-inflammatory entity affecting multiple organs, including manifold neurologic manifestations. This review discusses general characteristics of IgG4-RD neurologic disease including epidemiology, histology, clinical picture and treatment approaches. RECENT FINDINGS: IgG4-RD is increasingly recognized as an important underlying pathophysiology in multiple disorders of neurologic interest, including orbital inflammation, infundibulo-hypophysitis, hypertrophic pachymeningitis, and even in rare cases CNS parenchymal disease and cranial vascular involvement. These were previously considered idiopathic and unrelated to any systemic disease but now known to share a common histopathology. New knowledge regarding the pathogenesis, clinical features and epidemiology of IgG4 is emerging, and new neurological manifestations continue to be described. Diagnostic progress includes CT-PET imaging, the use of flow cytometry for plasmablast quantification, and the use of reverse passive latex agglutination aiming to overcome the prozone phenomenon. Histopathologic confirmation of IgG4-RD remains the gold standard method of diagnosis but new diagnostic criteria for systemic and organ-specific disease are being proposed. Though glucorticoids remain the mainstay of therapy, relapses and incomplete recovery are frequent. Rituximab is a promising treatment in IgG4-RD that is severe, refractory or glucocorticoid dependent. Initiation of immunosuppression at an early stage of disease should be considered in order to avoid development of refractory fibrosis. SUMMARY: The current review emphasizes the neurologic manifestations of IgG4-RD.
Sangaré LO, Yang N, Konstantinou EK, Lu D, Mukhopadhyay D, Young LH, Saeij JPJ. GRA15 Activates the NF-κB Pathway through Interactions with TNF Receptor-Associated Factors. MBio 2019;10(4)Abstract
The protozoan parasite secretes proteins from specialized organelles, the rhoptries, and dense granules, which are involved in the modulation of host cell processes. Dense granule protein GRA15 activates the nuclear factor kappa B (NF-κB) pathway, which plays an important role in cell death, innate immunity, and inflammation. Exactly how GRA15 activates the NF-κB pathway is unknown. Here we show that GRA15 interacts with tumor necrosis factor receptor-associated factors (TRAFs), which are adaptor proteins functioning upstream of the NF-κB transcription factor. We identified several TRAF binding sites in the GRA15 amino acid sequence and showed that these are involved in NF-κB activation. Furthermore, a TRAF2 knockout cell line has impaired GRA15-mediated NF-κB activation. Thus, we determined the mechanism for GRA15-dependent NF-κB activation. The parasite can cause birth defects and severe disease in immunosuppressed patients. Strain differences in pathogenicity exist, and these differences are due to polymorphic effector proteins that secretes into the host cell to coopt host cell functions. The effector protein GRA15 of some strains activates the nuclear factor kappa B (NF-κB) pathway, which plays an important role in cell death, innate immunity, and inflammation. We show that GRA15 interacts with TNF receptor-associated factors (TRAFs), which are adaptor proteins functioning upstream of the NF-κB transcription factor. Deletion of TRAF-binding sites in GRA15 greatly reduces its ability to activate the NF-κB pathway, and TRAF2 knockout cells have impaired GRA15-mediated NF-κB activation. Thus, we determined the mechanism for GRA15-dependent NF-κB activation.
Schoemaker D, Zuluaga Y, Viswanathan A, Shrimer M, Torrico-Teave H, Velilla L, Ospina C, Ospina GG, Lopera F, Arboleda-Velasquez JF, Quiroz YT. The INECO Frontal Screening for the Evaluation of Executive Dysfunction in Cerebral Small Vessel Disease: Evidence from Quantitative MRI in a CADASIL Cohort from Colombia. J Int Neuropsychol Soc 2020;26(10):1006-1018.Abstract
OBJECTIVES: Executive dysfunction is a predominant cognitive symptom in cerebral small vessel disease (SVD). The Institute of Cognitive Neurology Frontal Screening (IFS) is a well-validated screening tool allowing the rapid assessment of multiple components of executive function in Spanish-speaking individuals. In this study, we examined performance on the IFS in subjects with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), an inherited condition leading to the early onset of SVD. We further explored associations between performance on the IFS and magnetic resonance imaging (MRI) markers of SVD. METHODS: We recruited 24 asymptomatic CADASIL subjects and 23 noncarriers from Colombia. All subjects underwent a research MRI and a neuropsychological evaluation, including the IFS. Structural MRI markers of SVD were quantified in each subject, together with an SVD Sum Score representing the overall burden of cerebrovascular alterations. General linear model, correlation, and receiver operating characteristic curve analyses were used to explore group differences on the IFS and relationships with MRI markers of SVD. RESULTS: CADASIL subjects had a significantly reduced performance on the IFS Total Score. Performance on the IFS correlated with all quantified markers of SVD, except for brain atrophy and perivascular spaces enlargement. Finally, while the IFS Total Score was not able to accurately discriminate between carriers and noncarriers, it showed adequate sensitivity and specificity in detecting the presence of multiple MRI markers of SVD. CONCLUSIONS: These results suggest that the IFS may be a useful screening tool to assess executive function and disease severity in the context of SVD.
Schoemaker D, Quiroz YT, Torrico-Teave H, Arboleda-Velasquez JF. Clinical and research applications of magnetic resonance imaging in the study of CADASIL. Neurosci Lett 2019;698:173-179.Abstract
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is an inherited small vessel disease that leads to early cerebrovascular events and functional disability. It is the most common single-gene disorder leading to stroke. Magnetic resonance imaging (MRI) is a central component of the diagnosis and monitoring of CADASIL. Here we provide a descriptive review of the literature on three important aspects pertaining to the use of MRI in CADASIL. First, we review past research exploring MRI markers for this disease. Secondly, we describe results from studies investigating associations between neuroimaging abnormalities and neuropathology in CADASIL. Finally, we discuss previous findings relating MRI markers to clinical symptoms. This review thus provides a summary of the current state of knowledge regarding the use of MRI in CADASIL as well as suggestions for future research.

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