Amaurosis

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Amaurosis (Greek meaning darkening, dark, or obscure) is vision loss or weakness that occurs without an apparent lesion affecting the eye. [1] It may result from either a medical condition or excess acceleration, as in flight. The term is the same as the Latin gutta serena, which means, in Latin, clear drop (or bright drop). Gutta serena is a condition of partial or complete blindness with a transparent, clear pupil. This term contrasts with suffusio nigra which means, in Latin, dark suffusion, indicating partial or complete blindness with a dark pupil, e.g., a cataract. Milton, already totally blind for twelve years (some scholars think from retinal detachment; others have diagnosed glaucoma) by the time he published Paradise Lost, refers to these terms in Book 3, lines 25–26. [2]

Contents

Types

Leber's congenital amaurosis

Leber's congenital amaurosis (LCA) is the most severe and earliest of the inherited retinal dystrophies that cause congenital blindness. It has an incidence of 2-3 per 100,000 births and accounts for 10-18% of cases of congenital blindness among children in blind institutes and 5% of all retinal dystrophies, a figure that is likely to be greater in countries with a greater percentage of consanguinity. [3]

In most cases, LCA is inherited in an autosomal recessive pattern, as established by Alström and Olson in 1957. Some patients only have retinal blindness, whereas others have multi-systemic involvement that includes renal, cardiac, skeletal, and, most notably, central nervous system anomalies. [3]

Theodor von Leber, a German ophthalmologist, described LCA in 1869 as a disorder characterized by profound visual loss present at or shortly after birth, nystagmus, sluggish pupillary reactions, and pigmentary retinopathy. [3]

Amaurosis fugax

Amaurosis fugax, also known as transient monocular blindness, is caused by a sudden, temporary decrease in blood flow to one eye. The loss of vision is abrupt, lasting only seconds or minutes. Blindness is total, though it is sometimes limited to a specific area of vision. Blindness frequently develops as if a shade was drawn upward or downward over the eye, rarely sideward. Single or multiple attacks are possible. Some patients experience hundreds, if not thousands, of episodes. Pain, scintillations, and diplopia are usually not present. The prognosis for retinal recovery is good in most patients; retinal infarction occurs in a few. [4]

Quinidine toxicity

Although amaurosis caused by quinine poisoning is now uncommon, it does occur on occasion. When quinine is used as an abortifacient, the initial history may be deceptive, but the presence of characteristic changes in the fundi usually allows certainty of a diagnosis. [5]

Management

Those experiencing amaurosis are usually advised to consult a physician immediately as any form of vision loss, even if temporary, is a symptom that may indicate the presence of a serious ocular or systemic problem.[ citation needed ]

In animals

This condition can also occur in ruminants suffering from a vitamin B1 (thiamine) deficiency due to thiamine-related cerebrocortical necrosis (CCN).[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Retina</span> Part of the eye

The retina is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera.

<span class="mw-page-title-main">Retinitis pigmentosa</span> Gradual retinal degeneration leading to progressive sight loss

Retinitis pigmentosa (RP) is a genetic disorder of the eyes that causes loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision. As peripheral vision worsens, people may experience "tunnel vision". Complete blindness is uncommon. Onset of symptoms is generally gradual and often begins in childhood.

<span class="mw-page-title-main">Amaurosis fugax</span> Medical condition

Amaurosis fugax is a painless temporary loss of vision in one or both eyes.

This is a partial list of human eye diseases and disorders.

Leber congenital amaurosis (LCA) is a rare inherited eye disease that appears at birth or in the first few months of life.

<span class="mw-page-title-main">Choroideremia</span> Medical condition

Choroideremia is a rare, X-linked recessive form of hereditary retinal degeneration that affects roughly 1 in 50,000 males. The disease causes a gradual loss of vision, starting with childhood night blindness, followed by peripheral vision loss and progressing to loss of central vision later in life. Progression continues throughout the individual's life, but both the rate of change and the degree of visual loss are variable among those affected, even within the same family.

Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye. Amaurosis fugax is a form of acute vision loss caused by reduced blood flow to the eye; it may be a warning sign of an impending stroke, as both stroke and retinal artery occlusion can be caused by thromboembolism due to atherosclerosis elsewhere in the body. Consequently, those with transient blurring of vision are advised to urgently seek medical attention for a thorough evaluation of the carotid artery. Anterior segment ischemic syndrome is a similar ischemic condition of anterior segment usually seen in post-surgical cases. Retinal artery occlusion leads to rapid death of retinal cells, thereby resulting in severe loss of vision.

<span class="mw-page-title-main">RPE65</span> Protein-coding gene in humans

Retinal pigment epithelium-specific 65 kDa protein, also known as retinoid isomerohydrolase, is an enzyme of the vertebrate visual cycle that is encoded in humans by the RPE65 gene. RPE65 is expressed in the retinal pigment epithelium and is responsible for the conversion of all-trans-retinyl esters to 11-cis-retinol during phototransduction. 11-cis-retinol is then used in visual pigment regeneration in photoreceptor cells. RPE65 belongs to the carotenoid oxygenase family of enzymes.

<span class="mw-page-title-main">AIPL1</span> Protein-coding gene in the species Homo sapiens

Aryl-hydrocarbon-interacting protein-like 1 is a protein that in humans is encoded by the AIPL1 gene.

<span class="mw-page-title-main">Foundation Fighting Blindness</span>

The mission of the Foundation Fighting Blindness is to fund research that will lead to the prevention, treatment and cures for the entire spectrum of retinal degenerative diseases, including retinitis pigmentosa, macular degeneration, Usher syndrome, Stargardt disease and related conditions. These diseases, which affect more than 10 million Americans and millions more throughout the world, often lead to severe vision loss or complete blindness.

<span class="mw-page-title-main">Retinal migraine</span> Medical condition

Retinal migraine is a retinal disease often accompanied by migraine headache and typically affects only one eye. It is caused by ischaemia or vascular spasm in or behind the affected eye.

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<span class="mw-page-title-main">The Llura Liggett Gund Award</span> Medical award

The Llura Liggett Gund Award honors researchers for career achievements that have significantly advanced the research and development of preventions, treatments and cures for eye disease.

<span class="mw-page-title-main">Cherry-red spot</span>

A cherry-red spot is a finding in the macula of the eye in a variety of lipid storage disorders and in central retinal artery occlusion. It describes the appearance of a small circular choroid shape as seen through the fovea centralis. Its appearance is due to a relative transparency of the macula; storage disorders cause the accumulation of storage material within the cell layers of the retina, however, the macula, which is relatively devoid of cellular layers, does not build up this material, and thus allows the eye to see through the macula to the red choroid below.

Retinal gene therapy holds a promise in treating different forms of non-inherited and inherited blindness.

<span class="mw-page-title-main">Childhood blindness</span> Medical condition

Childhood blindness is an important contribution to the national prevalence of the disability of blindness. Blindness in children can be defined as a visual acuity of <3/60 in the eye with better vision of a child under 16 years of age. This generally means that the child cannot see an object 10 feet away, that another child could see if it was 200 feet away.

<span class="mw-page-title-main">Robert MacLaren</span> British ophthalmologist

Robert E. MacLaren FMedSci FRCOphth FRCS FACS VR is a British ophthalmologist who has led pioneering work in the treatment of blindness caused by diseases of the retina. He is Professor of Ophthalmology at the University of Oxford and Honorary Professor of Ophthalmology at the UCL Institute of Ophthalmology. He is a Consultant Ophthalmologist at the Oxford Eye Hospital. He is also an Honorary Consultant Vitreo-retinal Surgeon at the Moorfields Eye Hospital. MacLaren is an NIHR Senior Investigator, or lead researcher, for the speciality of Ophthalmology. In addition, he is a member of the research committee of Euretina: the European Society of Retina specialists, Fellow of Merton College, in Oxford and a Fellow of the Higher Education Academy.

Voretigene neparvovec, sold under the brand name Luxturna, is a gene therapy medication for the treatment of Leber congenital amaurosis.

<span class="mw-page-title-main">Congenital blindness</span>

Congenital blindness refers to blindness present at birth. Congenital blindness is sometimes used interchangeably with "Childhood Blindness." However, current literature has various definitions of both terms. Childhood blindness encompasses multiple diseases and conditions present in ages up to 16 years old, which can result in permanent blindness or severe visual impairment over time. Congenital blindness is a hereditary disease and can be treated by gene therapy. Visual loss in children or infants can occur either at the prenatal stage or postnatal stage. There are multiple possible causes of congenital blindness. In general, 60% of congenital blindness cases are contributed from prenatal stage and 40% are contributed from inherited disease. However, most of the congenital blindness cases show that it can be avoidable or preventable with early treatment.

<span class="mw-page-title-main">Corneal opacity</span> Medical condition

Corneal opacification is a term used when the human cornea loses its transparency. The term corneal opacity is used particularly for the loss of transparency of cornea due to scarring. Transparency of the cornea is dependent on the uniform diameter and the regular spacing and arrangement of the collagen fibrils within the stroma. Alterations in the spacing of collagen fibrils in a variety of conditions including corneal edema, scars, and macular corneal dystrophy is clinically manifested as corneal opacity. The term corneal blindness is commonly used to describe blindness due to corneal opacity.

References

  1. "Dorlands Medical Dictionary". Archived from the original on 2008-03-03. Retrieved 2005-09-25.
  2. "Amaurosis". The Encyclopedia of World Problems. Retrieved 2023-11-04.
  3. 1 2 3 Fazzi, Elisa; Signorini, Sabrina Giovanna; Scelsa, Barbara; Bova, Stefania Maria; Lanzi, Giovanni (2003). "Leber's congenital amaurosis: an update". European Journal of Paediatric Neurology. Elsevier BV. 7 (1): 13–22. doi:10.1016/s1090-3798(02)00135-6. ISSN   1090-3798.
  4. Gautier, Jean-Claude (1993-08-05). "Amaurosis Fugax". New England Journal of Medicine. Massachusetts Medical Society. 329 (6): 426–428. doi:10.1056/nejm199308053290611. ISSN   0028-4793.
  5. Drance, S. M. (1955-03-01). "Quinine Amaurosis". British Journal of Ophthalmology. BMJ. 39 (3): 178–181. doi: 10.1136/bjo.39.3.178 . ISSN   0007-1161.