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Molecular Diagnosis & Therapy Jan 2022Achromatopsia (ACHM), also known as rod monochromatism or total color blindness, is an autosomal recessively inherited retinal disorder that affects the cones of the... (Review)
Review
Achromatopsia (ACHM), also known as rod monochromatism or total color blindness, is an autosomal recessively inherited retinal disorder that affects the cones of the retina, the type of photoreceptors responsible for high-acuity daylight vision. ACHM is caused by pathogenic variants in one of six cone photoreceptor-expressed genes. These mutations result in a functional loss and a slow progressive degeneration of cone photoreceptors. The loss of cone photoreceptor function manifests at birth or early in childhood and results in decreased visual acuity, lack of color discrimination, abnormal intolerance to light (photophobia), and rapid involuntary eye movement (nystagmus). Up to 90% of patients with ACHM carry mutations in CNGA3 or CNGB3, which are the genes encoding the alpha and beta subunits of the cone cyclic nucleotide-gated (CNG) channel, respectively. No authorized therapy for ACHM exists, but research activities have intensified over the past decade and have led to several preclinical gene therapy studies that have shown functional and morphological improvements in animal models of ACHM. These encouraging preclinical data helped advance multiple gene therapy programs for CNGA3- and CNGB3-linked ACHM into the clinical phase. Here, we provide an overview of the genetic and molecular basis of ACHM, summarize the gene therapy-related research activities, and provide an outlook for their clinical application.
Topics: Animals; Color Vision Defects; Cyclic Nucleotide-Gated Cation Channels; Genetic Therapy; Humans; Mutation; Retinal Cone Photoreceptor Cells
PubMed: 34860352
DOI: 10.1007/s40291-021-00565-z -
Journal of Neuro-ophthalmology : the... Mar 2019Photophobia is commonly associated with migraine, meningitis, concussion, and a variety of ocular diseases. Advances in our ability to trace multiple brain pathways... (Review)
Review
BACKGROUND
Photophobia is commonly associated with migraine, meningitis, concussion, and a variety of ocular diseases. Advances in our ability to trace multiple brain pathways through which light information is processed have paved the way to a better understanding of the neurobiology of photophobia and the complexity of the symptoms triggered by light.
PURPOSE
The purpose of this review is to summarize recent anatomical and physiological studies on the neurobiology of photophobia with emphasis on migraine.
RECENT FINDINGS
Observations made in blind and seeing migraine patients, and in a variety of animal models, have led to the discovery of a novel retino-thalamo-cortical pathway that carries photic signal from melanopsinergic and nonmelanopsinergic retinal ganglion cells (RGCs) to thalamic neurons. Activity of these neurons is driven by migraine and their axonal projections convey signals about headache and light to multiple cortical areas involved in the generation of common migraine symptoms. Novel projections of RGCs into previously unidentified hypothalamic neurons that regulate parasympathetic and sympathetic functions have also been discovered. Finally, recent work has led to a novel understanding of color preference in migraine-type photophobia and of the roles played by the retina, thalamus, and cortex.
SUMMARY
The findings provide a neural substrate for understanding the complexity of aversion to light in patients with migraine and neuro-ophthalmologic other disorders.
Topics: Animals; Cerebral Cortex; Humans; Migraine Disorders; Neural Pathways; Photophobia; Retinal Ganglion Cells; Thalamus
PubMed: 30762717
DOI: 10.1097/WNO.0000000000000766 -
Ugeskrift For Laeger Nov 2023This is a case report of a 3-year-old boy who presented with unilateral anterior uveitis and tonic pupil following varicella-zoster virus (VZV) Infection. The patient...
This is a case report of a 3-year-old boy who presented with unilateral anterior uveitis and tonic pupil following varicella-zoster virus (VZV) Infection. The patient had red and irritated eyes and photophobia. Ophthalmological findings included anterior uveitis and tonic pupil accompanied by reduced vision and accommodation. An MRI of the cerebrum was normal. To ease the symptoms the patient was prescribed photophobia glasses with correction of hyperopia. Tonic pupil due to VZV infection is a rare complication, but may have long-term consequences, why patients with eye-involving VZV infection need to be examined by an ophthalmologist.
Topics: Male; Humans; Child; Child, Preschool; Chickenpox; Tonic Pupil; Photophobia; Herpesvirus 3, Human; Uveitis, Anterior; Acute Disease
PubMed: 38018730
DOI: No ID Found -
Cephalalgia : An International Journal... Oct 2021Photophobia is one of the most common symptoms in migraine, and the underlying mechanism is uncertain. The discovery of the intrinsically-photosensitive retinal ganglion... (Review)
Review
Photophobia is one of the most common symptoms in migraine, and the underlying mechanism is uncertain. The discovery of the intrinsically-photosensitive retinal ganglion cells which signal the intensity of light on the retina has led to discussion of their role in the pathogenesis of photophobia. In the current review, we discuss the relationship between pain and discomfort leading to light aversion (traditional photophobia) and discomfort from flicker, patterns, and colour that are also common in migraine and cannot be explained solely by the activity of intrinsically-photosensitive retinal ganglion cells. We argue that, at least in migraine, a cortical mechanism provides a parsimonious explanation for discomfort from all forms of visual stimulation, and that the traditional definition of photophobia as pain in response to light may be too restrictive. Future investigation that directly compares the retinal and cortical contributions to photophobia in migraine with that in other conditions may offer better specificity in identifying biomarkers and possible mechanisms to target for treatment.
Topics: Humans; Migraine Disorders; Photic Stimulation; Photophobia; Retinal Ganglion Cells; Syndrome
PubMed: 33990148
DOI: 10.1177/03331024211014633 -
Frontiers in Neurology 2022Migraine is a highly prevalent neurological disease of varying attack frequency. Headache attacks that are accompanied by a combination of impact on daily activities,... (Review)
Review
Migraine is a highly prevalent neurological disease of varying attack frequency. Headache attacks that are accompanied by a combination of impact on daily activities, photophobia and/or nausea are most commonly migraine. The headache phase of a migraine attack has attracted more research, assessment tools and treatment goals than any other feature, characteristic, or phase of migraine. However, the migraine attack may encompass up to 4 phases: the prodrome, aura, headache phase and postdrome. There is growing recognition that the burden of migraine, including symptoms associated with the headache phase of the attack, may persist between migraine attacks, sometimes referred to as the "interictal phase." These include allodynia, hypersensitivity, photophobia, phonophobia, osmophobia, visual/vestibular disturbances and motion sickness. Subtle interictal clinical manifestations and a patient's trepidation to make plans or commitments due to the unpredictability of migraine attacks may contribute to poorer quality of life. However, there are only a few tools available to assess the interictal burden. Herein, we examine the recent advances in the recognition, description, and assessment of the interictal burden of migraine. We also highlight the value in patients feeling comfortable discussing the symptoms and overall burden of migraine when discussing migraine treatment needs with their provider.
PubMed: 36408525
DOI: 10.3389/fneur.2022.1032103