Toxic encephalopathy, vision loss, and memory disorder caused by acute acrylamide exposure.

Acrylamide (ACR) is an irritant that can cause damage to the eyes, skin, and nervous and reproductive systems. This study aims to illustrate a case of central nervous system and optic nerve damage from exposure to ACR. In this case, a 49-year-old male material handler was accidentally splashed with ACR solution on both of his upper limbs. Consequently, he was admitted to the hospital with toxic encephalopathy, characterized by cerebellar ataxia and slurred speech. Magnetic resonance imaging scan, a brain computed tomography scan blood sample analyses, optic coherence tomography, electroneuromyogram, and visual evoked potentials examination were performed. After 20 days of receiving symptomatic support treatment, the patient continued to experience disturbances in consciousness. Then, he developed vision loss, memory disorders, and symptoms of peripheral neuropathy such as skin peeling, extremity weakness, and absent tendon reflexes. This case report underscores the severe consequences of acute dermal exposure to high concentrations of ACR, resulting in toxic encephalopathy, visual impairment, and memory disorders, which will contribute to a broader understanding of ACR toxicity.

A randomized phase 2 clinical trial of phentolamine mesylate eye drops in patients with severe night vision disturbances.

PURPOSE: Dim light vision disturbances (DLD) comprise a wide range of symptoms affecting the quality of vision at low illumination including glare, halos, and starbursts. This exploratory study investigated 1.0% phentolamine mesylate ophthalmic solution (PMOS) as a treatment to improve vision and image quality for patients with DLD. METHODS: In this placebo-controlled, randomized, double-masked clinical trial, 24 adult patients with severe DLD were randomized in a 2:1 ratio to receive either one dose of PMOS or placebo. Subjects were eligible if they reported experiencing severe night vision difficulty that was not eliminated by distance spectacle correction and scored ≥0.3 log units below the normal range of contrast sensitivity assessed under mesopic conditions with glare at ≥2 spatial frequencies. Key efficacy outcomes were change from baseline in pupil diameter, contrast sensitivity, and visual acuity. Safety measures including intraocular pressure, conjunctival hyperemia, and systemic effects were also assessed. RESULTS: Eight subjects were randomized to placebo (63% female; mean age 47 years) and 16 were randomized to PMOS (75% female; mean age 42 years). Mean (SD) pupil diameter of PMOS-treated subjects decreased significantly - 1.3 mm (0 to - 2.8 mm) with p < 0.0001. Mean contrast sensitivity with glare in PMOS-treated subjects improved significantly post-treatment at spatial frequencies 3, 6, 12, and 18 cycles per degree (p ≤ 0.03). PMOS also demonstrated improvements in the numbers of letters read for mesopic and photopic, high- and low-contrast visual acuity (LCVA). Importantly, a statistically greater proportion of PMOS-treated eyes registered mesopic LCVA 5 letter (69% vs. 31%, p = 0.029) and 10 letter (34% vs. 6%, p = 0.04) improvement, with a trend at 15 letters (19% vs. 0%, p = 0.16). PMOS was well tolerated with the only reported side effect being a mild increase in conjunctival hyperemia. CONCLUSION: PMOS was well tolerated and effectively reduced pupil size with improvements in contrast sensitivity and visual acuity in adults with severe DLD. Future Phase 3 studies should be conducted to further evaluate its potential to treat DLD. TRIAL REGISTRATION: The trial registration number is NCT04004507 (02/07/2019). Retrospectively registered.

A 39-year-old woman with transient convulsions and vision disturbances: a case report.

BACKGROUND: Posterior reversible encephalopathy syndrome is a rare neurological syndrome that refers to reversible subcortical vasogenic brain edema disorder in patients with acute neurological symptoms. CASE PRESENTATION: Whether there is a direct causal relationship between pancreatitis and posterior reversible encephalopathy syndrome needs further study. We here report a 39-year-old Chinese woman who was diagnosed with pancreatitis followed by vision disturbance. The patient was finally diagnosed with posterior reversible encephalopathy syndrome. On the basis of this rare case, we analyzed the causes of visual disturbance and proposed diagnostic ideas. CONCLUSIONS: For posterior reversible encephalopathy syndrome, early identification and treatment of the primary disease are particularly important. Imaging and clinical characteristics in posterior reversible encephalopathy syndrome are usually reversible.

Intermittent Vertical Diplopia as a Rare Manifestation of a Rare Cerebral Infarct: Artery of Percheron Ischemic Infarct and Sidelights on the Phenotypic Variability of Thalamic Ocular Disorders.

The thalamus is a complex structure with over 40 named nuclei. Ischemic lesions of the thalamus exhibit a panorama of phenomena ranging from facial numbness to ocular and visual field disturbances to hemiplegia, behavioral disorders, and stupor. It is a dense neuronal hub with a bewildering variety of connections and functions. We present an intriguing case of intermittent vertical diplopia due to an artery of Percheron ischemic infarct of the bilateral paramedian thalami. We seize upon this opportunity to simplify the thalamic nuclei sub-divisions and their vascular supply. In this process, we outline the phenotypic variability of thalamic diplopia and ophthalmoplegia and their various underlying mechanisms.

Apperceptive Prosopagnosia Secondary to an Ischemic Infarct of the Lingual Gyrus: A Case Report and an Update on the Neuroanatomy, Neurophysiology, and Phenomenology of Prosopagnosia.

Phenomenology is the philosophical study of experience and its core feature of sentience, the very ability to be conscious of a sensation and how we perceive it. Nowhere is this idea more vivid, as in the phenomenon of vision and the ability to form and sense a visual percept. The clinical entity of prosopagnosia, the ability to sense but not recognize a face, strikes at the heart of this phenomenon. We describe a classic case of selective apperceptive prosopagnosia due to an ischemic infarct of the left occipital lobe with extension to the lingual gyrus. It is well-established that acquired prosopagnosia usually involves the right more than the left occipital cortex, with localization of lesions bilaterally more than unilaterally. The ischemic infarcts strategically involve the fusiform gyrus, inferior occipital gyrus, the fundus of the posterior temporal sulcus, parahippocampal gyrus, and, rarely, lingual gyrus, which is almost always not a solitary finding. We seize upon this opportunity to explore the concept of visual prosopagnosia and outline the latest ideas on the neuroanatomical localization, neurophysiology, and classification of this intriguing phenomenon.

An Analytic Dissection of a Case of Cerebral Diplopia: Is the Human Brain a Holographic Device?

We describe the case of a 70-year-old woman who developed a cerebral infarct of the striate cortex, V1, and associated visual association cortex, V2. She presented with the visual perception disorder of a duplicated image of objects, lower fidelity, and a diaphanous copy of the original (polyopia) that was eerily similar to a hologram. We seize upon this opportunity to explain the generation of these false images. This led us to no less than the spectacular holonomic brain theory, which explains the stupendously high entropy of the brain, the storage of data in the cerebral cortex, the equipotentiality of brain tissue, and the ability of the brain to compute algorithms and perceive sensation in unison. This remarkable ability of the human brain entails the deployment of mathematical Fourier transforms and the electrical slow potentials in the highly interconnected and dense dendritic trees of the cerebral cortex. The ideas explored here are sublime and deep. These machinations are thought to be deeply ingrained in the very fabric of nature; in no less than black holes and the cosmos itself. Our case provides evidence for the holographic model of brain function in a graphic and vivid manner.

The Biophysics of Visual Edge Detection: A Review of Basic Principles.

The mathematization of nature is an age-old concept. The Greeks sought harmony in the celestial spheres. The Arab geometers constructed a spherical geometry of the heavens. Later, Galileo Galilei arithmetized kinematics. As the centuries advanced, polymaths like the Dutchman Christiaan Huygens applied more advanced mathematics in order to understand natural phenomena. It was not until the turn of the twentieth century that a more comprehensive mathematical approach to understanding biological phenomena was sought by D'Arcy Wentworth Thompson. This leads us to our current review of the biophysics of visual edge detection. This is an unfolding saga of stunning experimental revelations in unison with an underlying mathematical edifice. The concept of visual contrast is a fundamental idea in order to understand the phenomenon of visual edge detection. We begin with contrast visual testing and the development of frequency tuning curves, which provided an insight into the multi-channel processing of selective spatial frequencies by the visual cortex. The single-cell recordings from the simple cells of the cat visual cortex unfolded the gamma distribution curves of different neuronal firing frequencies for different spatial frequencies. The theoretical construction of the convolution of Gabor wavelets with stimulus intensity goes hand-in-hand with the experimental observation of the separation of simple visual cortical cells into even and odd functions, a spectacular finding. In this review, we march the reader through the mathematical basics and the pathophysiologic correlates. Beginning with a simple Fourier analysis of a square wave, Weber's biophysical law, and the gamma distribution of contrast tuning curves, we gradually introduce Fourier transforms, the uncertainty principle of waveform analysis, the basics of wavelet theory, Gabor elementary signals and transforms, the concepts of coherence, and Weyl group representation theory. Group theory provides the symmetry operations necessary to preserve the fidelity of an image as it travels from the retina and cascades up the visual cortex. Unitary operators that allow a retinal displacement of an image to be reflected by a similar displacement in the visual cortex is also a fundamental principle. Along the way, we encounter the Convolution Theorem of Fourier transforms, which is critical in constructing a visual percept. We intermittently interject relevant clinical data as we unpack the mathematical complexities. The advanced mathematics deployed in the biophysics of vision makes for difficult reading. There is a paucity of step-by-step reviews of this subject. Our approach is heuristic and at the end of this review, one should be able to follow superficially the algorithmic steps in understanding visual edge detection using Gabor filters. Therefore, we will adopt the Socratic method of asking questions and providing answers to help us through the complex web of mathematics. In a nutshell, we will show that a Gabor filter is the inner product of a Gaussian distribution and the wave function. The Fourier transform of the convolution of the Gabor filter and the stimulus intensity function is what is recorded from simple visual cortical cells. This is not a coincidental observation, as nature economizes and utilizes a function that minimizes the uncertainty principle of signal extraction.

The Zeitraffer Phenomenon: A Strategic Ischemic Infarct of the Banks of the Parieto-Occipital Sulcus - A Unique Case Report and a Side Note on the Neuroanatomy of Visual Perception.

We describe the remarkable case of a medically healthy right-handed 15-year-old boy who developed an ischemic infarct of the banks of the right parieto-occipital sulcus (POs). The etiology of this infarct was undetermined, that is, cryptogenic. However, the focus of this article is functional neuroanatomy, as our patient developed a specific entity; an optic flow motion deficit characterized by slow self-motion of the left half of his body (egomotion) and slow motion of the surroundings (allocentric motion) together constituting the Zeitraffer phenomenon. We describe the neuroanatomy and neurophysiology of the dorsal visual stream and correlate the localization of this type of infarct in our patient with the known functional neuroanatomy. Although lesional studies in Macaque monkeys and functional MRI studies in humans have documented the clinical-functional correlations of POs lesions and perceived motion deficits, our case is one of the very first human cases in the literature that pinpoints the Zeitraffer phenomenon to a specific and strategic circumscribed ischemic stroke in the region of the POs.