river blindness


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oc·u·lar on·cho·cer·ci·a·sis

ocular complications, such as keratitis, iridocyclitis, or retrobulbar neuritis, caused by the microfilariae of Onchocerca volvulus.
Synonym(s): river blindness

river blindness

blindness

(blind'nes)
Inability to see. The leading causes of blindness in the U.S. are age-related macular degeneration, diabetic retinopathy, and glaucoma.

Blindness may be caused by diseases of the lens, retina, or other eye structures; diseases of the optic nerve; or lesions of the visual cortex or pathways of the brain. A small number of infants are born blind, but far more people become blind during life. In the U.S., blindness due to infection is rare, but worldwide diseases like trachoma and onchocerciasis are relatively common causes of severe visual impairment. In malnourished people, vitamin A deficiency is an important cause of blindness.

A variety of free services are available for the blind and physically handicapped. Talking Books Topics, published bimonthly in large-print, cassette, and disc formats, is distributed free to the blind and physically handicapped who participate in the Library of Congress free reading program. It lists recorded books and magazines available through a national network of cooperating libraries and provides news of developments and activities in library services. Subscription requests may be sent to Talking Books Topics, CMLS, P.O. Box 9150, Melbourne, FL 32902-9150.

amnesic color blindness

Inability to remember the names of colors.
Enlarge picture
TEST FOR COLOR BLINDNESS

color blindness

A genetic or acquired abnormality of color perception. Complete color blindness, a rare disease, is called achromatopsia. Red-green color blindness, which affects about 8% of the male population, is an X-linked trait. Although color blindness is the term most commonly used, it is inaccurate:color deficiency and color vision deficiency are preferred. See: illustration

cortical blindness

Blindness due to lesions in the left and right occipital lobes of the brain. The eyes are still able to move, and the pupillary light reflexes remain, but the blindness is as if the optic nerves had been severed. The usual cause is occlusion of the posterior cerebral arteries. Transitory cortical blindness may follow head injury.
Synonym: cerebral visual impairment

day blindness

Hemeralopia.

eclipse blindness

Blindness due to burning the macula while viewing an eclipse without using protective lenses. Looking directly at the sun at any time can damage the eyes. Synonym: solar blindness; solar maculopathy

green blindness

Aglaucopsia.

hysterical blindness

An inaccurate term for functional blindness, i.e., blindness caused by psychological disorders rather than by demonstrable organic pathology.

legal blindness

A degree of loss of visual acuity that prevents a person from performing work requiring eyesight. In the U.S. this is defined as corrected visual acuity of 20/200 or less, or a visual field of 20° or less in the better eye. In the U.S. there are about three quarters of a million blind people, and about 8 or 9 million people with significant visual impairment.

letter blindness

A form of aphasia marked by an inability to understand the meaning of letters.

night blindness

Nyctalopia (1).

note blindness

The inability to recognize musical notes. It is due to a lesion of the central nervous system.

object blindness

A disorder in which the brain fails to recognize things even though the eyes function normally.
See: apraxia

psychic blindness

Sight without recognition due to a brain lesion.

red-green blindness

Red-green color blindness

red-green color blindness

Inability to see red hues. It is the most common kind of color blindness. Synonym: red-green blindness

river blindness

See: onchocerciasis

snow blindness

Blindness, usually temporary, due to the glare of sunlight on snow. It may result in photophobia and conjunctivitis, the latter resulting from effects of ultraviolet radiation.

solar blindness

Eclipse blindness.

taste blindness

An inability to taste certain substances such as phenylthiocarbamide. This inability is due to an autosomal recessive trait.

transient monocular blindness

A temporary loss of vision affecting one eye. In older adults it is usually a form of transient ischemic attack, caused by carotid atherosclerosis, and is therefore a harbinger of stroke. In young adults it may be caused by migraine. Synonym: amaurosis fugax

Etiology

In older adults, causes of carotid atherosclerosis include smoking, diabetes mellitus, hypertension, obesity, and hypercholesterolemia. When atherosclerotic plaques form within the carotid artery, they may ulcerate. The exposed endothelium within the artery becomes a focus of inflammation and blood clotting. Blindness occurs when tiny clots from the carotid arteries embolize to the ophthalmic arteries.

Symptoms

Patients often describe a dark shade descending into the field of vision. At the same time they may have other stroke symptoms, e.g., difficulty with speech or weakness of the hand on the side opposite the affected eye.

Treatment

A patient who may have carotid atherosclerosis should begin taking aspirin or other antiplatelet drugs if these are tolerated. Blood pressure and lipid levels should be controlled. The patient should be referred for noninvasive evaluation of blood flow through the carotid arteries, e.g., ultrasonography. If the carotid arteries are significantly blocked, the patient and physician should consider the risks and benefits of carotid endarterectomy.

violet blindness

Inability to see violet tints.

word blindness

Alexia.

river blindness

See ONCHOCERCIASIS.

onchocerciasis 

A disease caused by infestation with the filarial worm (Onchocerca volvulus) spread by blackflies. It is common in tropical Africa and Central America, especially in areas near rivers. Large numbers of microfilariae are present on the skin and often enter the eye. The patient initially complains of itching, but blindness occurs as a result of chorioretinitis and optic neuritis. The disease is treated successfully with ivermectin. Syn. onchocercosis; river blindness.
References in periodicals archive ?
The Fund is supported by in-kind contributions from GlaxoSmithKline plc, which will donate albendazole treatments over the next ten years to eliminate lymphatic filariasis and deworm school-age children in target countries, and MSD, which will donate ivermectin to eliminate lymphatic filariasis and river blindness through the Mectizan Donation Program, with co-investments from the UK Department for International Development (DfID) and United States Agency for International Development (USAID).
Neglected tropical diseases like river blindness stand in stark contrast to those like tuberculosis, which is estimated to affect (http://www.who.int/mediacentre/factsheets/fs104/en/) a third of the world's population  due to the increasing prevalence of highly antibiotic resistant strains.
To which anyone who has ever witnessed a person suffering the horrible effects of river blindness or elephantiasis might well reply, "So what?"
River blindness, or onchocerciasis, is caused by parasitic roundworms.
Parasites such as roundworms are the root cause of diseases like river blindness, which causes irreversible blindness; and elephantiasis which leads to huge swelling of limbs (hence the name for the disease).
Diseases such as malaria, tuberculosis and river blindness were not making the cut, since neither their sufferers nor their states had the resources to pay for expensive would-be drugs.
Irish-born Campbell and Japanese Omura won half of the prize for discovering a new drug, avermectin, that has helped the battle against river blindness and lymphatic filariasis, as well as showing effectiveness against other parasitic diseases.
They conducted a pilot study in Cameroon, where health officials have been battling the filarial, or parasitic worm, diseases onchocerciasis (river blindness) and lymphatic filariasis.
There are approximately 15mn people in the Americas with this disease which, although it doesn't kill victims rapidly, it causes years of debilitating symptoms; dengue fever, of which there are 50-100mn cases annually which can lead to a serious and potentially fatal form called severe dengue; echinococcosis, of which there are more than 1mn people infected; leishmaniasis, which is fatal if untreated and of which there are an estimated 12mn people infected and onchocerciasis, also known as "river blindness" of which there are 37mn people infected, just to mention a few of them.
Sicknesses covered include soil-transmitted helminth infections (such as hookworm infection), schistosomiasis (snail fever), tropical diseases that blind (such as river blindness and trachoma), mycobacterial infections, kinetoplastic infections (such as sleeping sickness and chagas disease), dengue, rabies, and much more.
It is termed as "river blindness" because it is spread by the bite of the blackfly vector that breads near oxygen-high fast-flowing streams and rivers people rely on for washing, drinking, and farming which results in depopulation of the fertile river valleys.
Together, we've covered leprosy, river blindness, malnutrition, breast-feeding and the Darfur genocide.