Battlefield Chemical Inhalation Injury
Jacob Loke in Pathophysiology and Treatment of Inhalation Injuries, 2020
Acute exposure with CS produces lacrimation with a peppery sensation in the eyes, as well as copious rhinorrhea and salivation. With increasing doses there is chest tightness, dyspnea, coughing, and sneezing (Owens and Punte, 1963). These symptoms remit spontaneously within 30 min after cessation of exposure (Ballantyne, 1977b), although a photophobia may persist up to 1 hr. At still higher concentrations, cyanosis may be present with severe respiratory distress followed by pulmonary edema. A case of an infant with a confined space exposure of 2-3 hr (unknown concentration) is reported. Initial examination showed only first-degree cheek burns; however, cyanosis was noted on day 2, resolving by day 3, only to be followed by pneumonia, which delayed hospital discharge to day 28 (Park and Giammona, 1972). Another child unable to escape a confined exposure in a bedroom (Londonderry riots) was found to be crying and gasping for breath. There was pallor and lacrimation but rapid recovery after removal from exposure (Himsworth, 1971a).
Photophobia and Anterior Uveitis
Amy-lee Shirodkar, Gwyn Samuel Williams, Bushra Thajudeen in Practical Emergency Ophthalmology Handbook, 2019
Photophobia implies a painful sensitivity to light, nothing more, nothing less. Some health professionals seem to automatically link photophobia with iritis, more properly termed anterior uveitis, but there are in fact several other important causes that need to be excluded before such a diagnosis can be made. Patients with sudden onset acute light sensitivity, particularly if this is the first ever episode, may present to accident and emergency. This is usually not so convenient as after a 4-hour wait the harried casualty officer usually has not much more ophthalmic experience than their week's worth of training in medical school. After using a broken down slit lamp to ascertain that, yes, the patient is photophobic will then call the on call ophthalmologist without a visual acuity test and without having performed a useful examination.
Ophthalmologic Side Effects
Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish in Retinoids in Dermatology, 2019
Photophobia (ocular discomfort or pain associated with light exposure) is a symptom that is associated with a wide spectrum of ocular or extraocular pathologies, such as migraine headaches. Photophobia is commonly seen in association with various ocular inflammatory conditions such as uveitis, keratitis, allergic conjunctivitis, and dry eye disease. UVA exposure of isotretinoin results with its photoisomerization to other retinoic acid products and photolysis to other degradation products which is a possible mechanism for explaining the photosensitivity (26). Development of dry eye disease is obviously an important contributing factor for the development of photophobia associated with this treatment; however, it is unclear whether the photosensitizing property of the isotretinoin molecule under UVA exposure is linked with photophobia in the eyes, as well. Management of this disturbing finding includes treatment of the underlying pathology (such as dry eye disease) and the use of sunglasses.
Photoaversion in inherited retinal diseases: clinical phenotypes, biological basis, and qualitative and quantitative assessment
Published in Ophthalmic Genetics, 2022
Serena Zaman, Thomas Kane, Mohamed Katta, Michalis Georgiou, Michel Michaelides
Photophobia is a broad term and can be taken to mean both avoidance of light as well as pain caused by a light stimulus (7). There may be benefit in subdivision by certain features. Photoallodynia (3,8) or photo-oculodynia (3), implies (peri)ocular pain or discomfort in an individual where exposure to a light stimulus of the same brightness would not elicit discomfort or pain in an unaffected individual. Disruption to vision in bright light can be an accompanying feature and is termed as day blindness. Hemeralopia as a term should be avoided, as it was often used incorrectly to describe both day and night blindness interchangeably in the literature, giving rise to confusion (9). Photo-cephalodynia (10) is described as the headache caused by or made worse by light, such as that seen in migraineurs. Photoaversion (PA) is the light avoidance response and can be measured and is therefore used to quantify photoallodynia in a research setting. When profound, as in many IRDs, photoallodynia can be debilitating, with huge emotional, psychological, social, and activities of daily living implications for affected individuals (11). At present, management largely consists of avoidance of problematic stimuli and/or wearing dark tinted spectacles or contact lenses (12,13)—which are helpful (albeit often making patients feel self-conscious), but do not fully address the PA, and moreover, result in further degrading the quality of vision in patients who already have severely compromised central vision.
Should “Retro-ocular Pain, Photophobia and Visual Acuity Loss” Be Recognised as a Distinct Entity? The ROPPVAL Syndrome
Published in Neuro-Ophthalmology, 2021
Francesco Pellegrini, Erika Mandarà, Daniele Brocca
Photophobia is defined as a painful sensation to light exposure. Recently, a novel population of retinal neurons, intrinsically photosensitive retinal ganglion cells (IPRGCs), have been identified as photophobia transducers in the eye.13 Notably, these IPRGCs project onto trigeminal neurons14 and pain nuclei in the thalamus,15,16 which are also involved in migraine pathogenesis. We believe that “stimuli”, like those involved in migraine, may trigger the trigeminal nerve fibres which collect painful light sensations from the eye when activated by IPRGCs. We believe that the ciliary ganglia located in orbital-fat behind the globe may play a major role in determining this stereotyped syndrome, because of the relief of symptoms when amitriptyline or cyclopentolate drops are administered. We can speculate that activated trigeminal pain-sensing fibres and light-activated fibres may affect parasympathetic neurons and/or vice versa. Cyclopentolate is an anticholinergic drug, thus paralyses the iris sphincter constrictor and ciliary body muscles. Cycloplegia is commonly used in ophthalmology to reduce inflammation and pain due to different ocular conditions such as iritis where the ciliary body over-contraction is the main cause of pain.
Neuro-Ophthalmic Literature Review
Published in Neuro-Ophthalmology, 2019
David Bellows, Noel Chan, John Chen, Hui-Chen Cheng, Michael Vaphiades, Konrad Weber
Photophobia is commonly associated with migraine, meningitis, concussion, and a variety of ocular diseases. Advances in the 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 symptoms triggered by light. The authors summarise the recent anatomical and physiological studies on the neurobiology of photophobia with emphasis on migraine. 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. The 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 colour preference in migraine-type photophobia and of the roles played by the retina, thalamus, and cortex. This article highlights the findings that provide a neural substrate for understanding the complexity of photophobia in patients with migraine and other neuro-ophthalmologic disorders.
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