Blindness (redirected from ablepsia)

blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in systemic disorders (e.g., diabetes) and by cataract, glaucoma, or retinal detachment. Blindness caused by infectious diseases, such as trachoma, and by dietary deficiencies is common in underdeveloped countries where medical care is inadequate. River blindness, caused by a parasitic worm transmitted by black flies, results in severe itching and disfiguring lesions. Infection of the eye area can destroy vision. An estimated 18 million people in Africa, Latin America, South America, and Yemen are infected with the parasite; 1 million of those infected are expected to become blind or severely impaired. Until recently, pesticides have been used to eradicate the flies. Two new drugs, ivermectin and amocarzine, have proved effective when used together. Most infectious diseases of the eye can be prevented or cured.

A major cause of congenital blindness in the United States, ophthalmia neonatorum, which is caused by gonorrhea organisms in the maternal birth canal, is now prevented by placing silver nitrate solution in all newborn infants' eyes. Retinitis pigmentosis, a hereditary and degenerative eye disease, affects 100,000 people in the United States. An early sign is night blindness which progresses to total blindness. Color blindness, an hereditary problem, is an inability to distinguish colors, most commonly red and green. Snow blindness is a temporary condition resulting from a burn of the cornea caused by the reflection of sunlight on snow. Night blindness results from a deficiency of vitamin A. See eye.

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blindness

Inability to see with one or both eyes. Transient blindness (blackout) can result from vertical acceleration causing high gravitational forces, glomerulonephritis (a kidney disease), or a clot in a blood vessel of the eye. Continuing blindness may arise from injuries or diseases of the eye (e.g., cataract, glaucoma), including the retina, the optic nerve, or the brain's visual centres. Many infectious, noninfectious, and parasitic systemic diseases can cause blindness. Sexually transmitted diseases and rubella in pregnant women can cause blindness in their infants. See also macular degeneration; visual-field defect.

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blindness [′blīnd·nəs]

(medicine)

Loss or absence of the ability to perceive visual images.

The condition of a person having less than 1/10 (20/200 on the Snellen test) normal vision.

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Blindness

Agib

dervish who lost an eye. [Arab. Lit.: Arabian Nights]

Anchises

blinded by lightning. [Gk. Myth.: Walsh Classical, 22]

Blind Pew David,

the blind beggar. [Br. Lit.: Treasure Island]

Braille, Louis (1809–1852)

teacher of blind; devised raised printing which is read by touch. [Fr. Hist.: NCE, 354]

Cratus

Titan who blinded Prometheus. [Gk. Myth.: Kravitz, 67–68]

Demodocus

blind bard rewarded by Odysseus. [Gk. Lit.: Odyssey VIII]

Ephialtes

giant deprived of his left eye by Apollo and of his right eye by Hercules. [Gk. Myth.: Brewer Dictionary, 333]

Gloucester

cruelly blinded by those he served. [Br. Lit.: King Lear]

the Graeae

share one eye among them. [Gk. Myth.: Gayley, 208–210]

Heldar, Dick

artist who gradually goes blind and is abandoned by his sweetheart. [Br. Lit.: The Light that Failed in Benét, 586]

Homer

sightless writer of Iliad and Odyssey. [Gr. Hist.: Wallechinsky, 13]

Justice

personified as a blindfolded goddess, token of impartiality. [Rom. Tradition: Jobes II, 898]

Keller, Helen

(1880–1968) Achieved greatness despite blindness and deafness. [Am. Hist.: Wallechinsky, 13]

Lucy, St.

vision restored after gouging out of eyes. [Christian Hagiog.: Brewster, 20–21]

mole

said to lack eyes. [Medieval Animal Symbolism: White, 95–96]

Nydia

beautiful flower girl lacks vision but “sees” love. [Br. Lit.: The Last Days of Pompeii, Magill I, 490–492]

Odilia, St.

recovered vision; shrine, pilgrimage for visually afflicted. [Christian Hagiog.: Attwater, 257]

Oedipus

blinded self on learning he had married his mother. [Gk. Lit.: Oedipus Rex]

Paul, St.

blinded by God on road to Damascus. [N.T.: Acts 9:1–19]

Peeping Tom

stricken blind for peeping as the naked Lady Godiva rode by. [Br. Legend: Brewer Dictionary]

Plutus

blind god of Wealth. [Gk. Lit.: Plutus]

Polyphemus

Cyclops blinded by Odysseus. [Gk. Myth.: Odyssey]

Rochester, Edward

blinded when his home burns down, depends on the care of Jane Eyre. [Br. Lit.: Charlotte Bronte Jane Eyre]

Samson

Israelite hero treacherously blinded by Philistines. [O.T.: Judges 16:4–21]

Stagg

sightless roomkeeper. [Br. Lit.: Barnaby Rudge]

three blind mice

sightless rodents; lost tails to farmer’s wife. [Nurs. Rhyme: Opie, 306]

Tiresias

made sightless by Athena for viewing her nakedness. [Gk. Myth.: Brewer Dictionary, 1086]

Tobit

sparrow guano falls into his eyes while sleeping. [Apocrypha: Tobit 2:10]

Zedekiah

eyes put out for revolting against Nebuchadnezzar. [O.T.: II Kings 25:7]

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Blindness 

in the strictly scientific sense, the permanent and irreversible loss of vision in both eyes, the inability to distinguish light from darkness. In cases of total blindness visual acuity is equal to 0.

In the practical and social sense, blindness has a much broader definition. A person is considered to be blind when he cannot see well enough to orient himself in his surroundings or get around outside his home without help. A blind person may be photoreceptive, that is, able to distinguish light and the direction it is coming from, and may be able to see the outlines of large objects. The legally blind include persons who are practically sightless, possessing extremely low visual acuity (to 0.02). An individual who does not see well enough to work even when wearing glasses is said to be industrially blind. A person whose vision has deteriorated to the point that he cannot do his customary work is considered occupationally blind. For example, individuals engaged in intellectual work are said to be occupationally blind when they can no longer see well enough to read.

According to the World Health Organization (WHO), there were 10 to 15 million blind persons in the world in 1972. The main causes of blindness are glaucoma, trachoma, and traumatism of the eyes. The causes of blindness and the number of blind persons vary from country to country. For example, pox diseases caused many cases of blindness in prerevolutionary Russia, whereas no such incidences have been reported in the USSR. In economically developed countries blindness is primarily caused by progressive myopia, traumatism, or vascular lesions of the retina, including those produced by diabetes mellitus. In developing countries infectious and parasitic diseases are the main causes of blindness. Of the approximately 500 million persons with trachoma, approximately 2 million are blind. The disease is widespread in Asia, Africa, and Latin America. Prior to the October Revolution of 1917,21.5 percent of all incidences of blindness were caused by trachoma. By 1968 trachoma had been eradicated as a major disease in the USSR. In industrial countries, where occupational injuries are fairly common, most of the blind are men.

Blindness can be controlled by preventing certain eye injuries and diseases. In the USSR, for example, glaucoma is diagnosed early, and those suffering from the disease have regular checkups. Recent advances in eye surgery have restored some degree of vision to many blind persons.

The All-Russian Society for the Blind was organized in 1925; similar societies have been organized in other Union republics. A network of specialized secondary and eight-year schools has been established for the education of children who are blind or have poor eyesight. Textbooks, literary works, and magazines are published in Braille. Special sound-recording studios and record and tape libraries have been established.

Blind adolescents and adults receive occupational training at special industrial enterprises organized by societies for the blind. After finishing their studies they may work at these enterprises or at enterprises in other localities.

In capitalist countries philanthropic societies are the chief organizations involved in finding work for the blind. The World Council for the Welfare of the Blind, which works in cooperation with UNESCO and other agencies of the UN, was established in Paris in 1951.

REFERENCES

Golovin, S. S. O slepote v Rossii. Odessa, 1910.
Averbakh, M. I. “Uchenie o slepote, ocherk 1.” In his book Oftal’mologicheskie ocherki. Moscow, 1949.
Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 1, book 2. Edited by V. N. Arkhangel’skii. Moscow, 1962.
Shoev, F. I. Vserossiiskoe obshchestvo slepykh i ego deiatel’nost’. Moscow, 1965.