Retrograde trans-synaptic retinal ganglion cell loss following retrogeniculate lesions of human visual pathway identified using optical coherence tomography

Introduction: Retrograde trans-synaptic degeneration (RTSD) in the human visual pathway has not been well clarified. Aims 1. To confirm the RTSD in human visual pathway. 2. To study the rate of RTSD. 3. To study the pupil function in the RTSD. Methods: 1. The peripapillary retinal nerve fibre layer (RNFL) thickness measured with optical coherence tomography was compared among patients with acquired and congenital retrogeniculate lesions and normal subjects. Humphrey perimetry and brain imaging were performed. 2. A relationship between the duration of the disease and the RNFL thickness measured at a single time point was evaluated. Additionally the RNFL thickness was measured in patients with homonymous hemianopia (HH) and smaller homonymous visual field defect serially following stroke. 3. Pupil responses were measured in HH patients and normal subjects, using achromatic and chromatic stimuli localised to the blind hemifield and compared with responses obtained in the sighted hemifield. Results: 1. The overall mean RNFL thickness of the patient groups was significantly less than that of the controls. The affected sectors respected the retinotopic organization. 2. There was a negative straight line relationship between the duration of disease (log years) and the mean thickness measured at a single point in time in HH patients. In the serial measurements the mean thickness had a decreasing trend over time in all HH cases in contrast to the small visual field defect group. The thinning occurred early in the first few months after the stroke. 3. In the acquired group, pupil responses from the blind hemifield were reduced in comparison with controls to all stimuli employed. However there was a greater deficit to the chromatic stimuli than to the luminance contrast stimuli. Discussions: We showed the RTSD in patients with acquired and congenital retrogeniculate lesion by using OCT. The degeneration was correlated to the duration and occurred early after stroke. The RTSD might occur in the pupil pathway

The OSCAR-IB Consensus Criteria for Retinal OCT Quality Assessment

Retinal optical coherence tomography (OCT) is an imaging biomarker for neurodegeneration in multiple sclerosis (MS). In order to become validated as an outcome measure in multicenter studies, reliable quality control (QC) criteria with high inter-rater agreement are required

Alzheimer's Disease: a Review of its Visual System Neuropathology. Optical Coherence Tomography-a Potential Role As a Study Tool in Vivo

Alzheimer's disease (AD) is a prevalent, long-term progressive degenerative disorder with great social impact. It is currently thought that, in addition to neurodegeneration, vascular changes also play a role in the pathophysiology of the disease. Visual symptoms are frequent and are an early clinical manifestation; a number of psychophysiologic changes occur in visual function, including visual field defects, abnormal contrast sensitivity, abnormalities in color vision, depth perception deficits, and motion detection abnormalities. These visual changes were initially believed to be solely due to neurodegeneration in the posterior visual pathway. However, evidence from pathology studies in both animal models of AD and humans has demonstrated that neurodegeneration also takes place in the anterior visual pathway, with involvement of the retinal ganglion cells' (RGCs) dendrites, somata, and axons in the optic nerve. These studies additionally showed that patients with AD have changes in retinal and choroidal microvasculature. Pathology findings have been corroborated in in-vivo assessment of the retina and optic nerve head (ONH), as well as the retinal and choroidal vasculature. Optical coherence tomography (OCT) in particular has shown great utility in the assessment of these changes, and it may become a useful tool for early detection and monitoring disease progression in AD. The authors make a review of the current understanding of retinal and choroidal pathological changes in patients with AD, with particular focus on in-vivo evidence of retinal and choroidal neurodegenerative and microvascular changes using OCT technology.info:eu-repo/semantics/publishedVersio

Metabolic Changes in the Visual Cortex Are Linked to Retinal Nerve Fiber Layer Thinning in Multiple Sclerosis

OBJECTIVE: To investigate the damage to the retinal nerve fiber layer as part of the anterior visual pathway as well as an impairment of the neuronal and axonal integrity in the visual cortex as part of the posterior visual pathway with complementary neuroimaging techniques, and to correlate our results to patients' clinical symptoms concerning the visual pathway. DESIGN, SUBJECTS AND METHODS: Survey of 86 patients with relapsing-remitting multiple sclerosis that were subjected to retinal nerve fiber layer thickness (RNFLT) measurement by optical coherence tomography, to a routine MRI scan including the calculation of the brain parenchymal fraction (BPF), and to magnetic resonance spectroscopy at 3 tesla, quantifying N-acetyl aspartate (NAA) concentrations in the visual cortex and normal-appearing white matter. RESULTS: RNFLT correlated significantly with BPF and visual cortex NAA, but not with normal-appearing white matter NAA. This was connected with the patients' history of a previous optic neuritis. In a combined model, both BPF and visual cortex NAA were independently associated with RNFLT. CONCLUSIONS: Our data suggest the existence of functional pathway-specific damage patterns exceeding global neurodegeneration. They suggest a strong interrelationship between damage to the anterior and the posterior visual pathway

Update on neuromyelitis optica: natural history and management

Panitha Jindahra1,2, Gordon T Plant1,21The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; 2St Thomas' Hospital, Westminster Bridge Road, London, UKAbstract: Neuromyelitis optica or Devic disease is an inflammatory disorder of the central nervous system. It is caused by antibodies that attack aquaporin 4 water channels in the cell membrane of astrocytic foot processes at the blood brain barrier. It can involve the optic nerve, the spinal cord and beyond. Here we review its pathophysiology, clinical features, and therapy.Keywords: Neuromyelitis optica, Devic disease, NMO-IgG, optic neuritis, transverse myelitis, NMO spectrum disorder

Imaging reveals optic tract degeneration in hemianopia.

PURPOSE: To investigate whether there is transsynaptic degeneration in the human optic tract in hemianopia. To consider how the degeneration varies with duration of hemianopia and location of insult. METHODS: Seven patients with damage to the primary visual cortex (V1), the lateral geniculate nucleus (LGN), or the optic tract were scanned with structural MRI. The volume and cross-sectional area of the left and right optic tracts were computed based on the intensity values of the T1-weighted image. High values correspond to voxels with high white matter content, and the values decrease as the white matter content drops (indicating degeneration). A laterality index to compare the tract size in the two hemispheres was calculated at different intensity values. RESULTS: The three hemianopic patients with longstanding damage to either V1 or LGN showed laterality indices greater than 0.5 at the highest intensity values, indicating significant optic tract degeneration. Those with recent damage to the optic tract had even higher laterality indices due to direct degeneration. Even 18 months after V1 lesion, there was a significant correlation between the cross-section and volume indices at different intensity thresholds, whereas no control subject showed any correlation. CONCLUSIONS: Transsynaptic degeneration had already begun 18 months after lesion. Although there was no visible decrease in volume at this stage, the white matter integrity was compromised. Significant decrease in volume could be visualized at longer durations of hemianopia. This method of objectively assessing structural images provides an effective, noninvasive approach to monitor the timescale of optic tract degeneration

Isolated Horner syndrome as a rare initial presentation of nasopharyngeal carcinoma: a case report

Tanyatuth Padungkiatsagul,1 Anuchit Poonyathalang,1 Panitha Jindahra,2 Piyaphon Cheecharoen,3 Kavin Vanikieti1 1Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Department of Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Background: Horner syndrome refers to a set of clinical presentations resulting from disruption of sympathetic innervation to the eye and adnexa. Classically, the clinical triad consists of ipsilateral blepharoptosis, pupillary miosis, and facial anhidrosis. Ocular sympathetic denervation may signify life-threatening causes. Timely investigation and accurate diagnosis are essential in patients with oculosympathetic denervation. Case presentation: A 33-year-old Asian man with a heavy smoking habit presented with a 3-week history of left ptosis and no other complaints. His visual acuity was 20/20 bilaterally. An ophthalmic examination was significant for mild ptosis of his left eyelid and anisocoria (smaller left pupil), which was greater in the dark. Both pupils reacted to light briskly without an afferent pupillary defect. Anhidrosis was found on the medial side of the left forehead. A 10% cocaine test was positive. At his first visit, neurologic examination was unremarkable. Comprehensive radiological investigations were scheduled for a left-sided isolated Horner syndrome. Two weeks after his first visit, he experienced a left-sided headache along with ipsilateral Horner syndrome. Neurologic examination revealed hypoesthesia in the left cranial nerve V1–3 territories. Emergent computed tomography angiography was suspected for petrous part of the left internal carotid artery (ICA) dissection. Magnetic resonance imaging demonstrated an enhancing infiltrative lesion with its epicenter at the left sphenoid bone. The lesion encased the left ICA and invaded the left Meckel cave. Rhinoscopy with incisional biopsy revealed squamous cell nasopharyngeal carcinoma. Conclusion: This case involved an unusual initial presentation of nasopharyngeal carcinoma: isolated Horner syndrome with clinical progression to adjacent structures. Infiltration involving the Meckel cave and ICA at the foramen lacerum can present as postganglionic Horner syndrome associated with trigeminal pain and hypoesthesia. These clinical findings may mimic carotid artery dissection on computed tomography angiography. Detailed magnetic resonance imaging with careful attention to the skull base should be performed. Keywords: Horner syndrome, nasopharyngeal carcinoma, trigemina