Visual impairment

Visual impairment, also known as vision impairment or vision loss, is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses. Some also include those who have a decreased ability to see because they do not have access to glasses or contact lenses. Visual impairment is often defined as a best corrected visual acuity of worse than either 20/40 or 20/60. The term blindness is used for complete or nearly complete vision loss. Visual impairment may cause people difficulties with normal daily activities such as driving, reading, socializing, and walking.

The most common causes of visual impairment globally are uncorrected refractive errors (43%), cataracts (33%), and glaucoma (2%). Refractive errors include near sighted, far sighted, presbyopia, and astigmatism. Cataracts are the most common cause of blindness. Other disorders that may cause visual problems include age related macular degeneration, diabetic retinopathy, corneal clouding, childhood blindness, and a number of infections. Visual impairment can also be caused by problems in the brain due to stroke, prematurity, or trauma among others. These cases are known as cortical visual impairment. Screening for vision problems in children may improve future vision and educational achievement. Screening adults may also be beneficial. Diagnosis is by an eye exam.

Blindness (disambiguation)

Blindness is a visual condition.

Blindness may also refer to:

See also

Blindness (novel)

Blindness (Portuguese: Ensaio sobre a cegueira, meaning Essay on Blindness) is a novel by Portuguese author José Saramago. It is one of his most famous novels, along with The Gospel According to Jesus Christ and Baltasar and Blimunda.

Plot summary

Blindness is the story of an unexplained mass epidemic of blindness afflicting nearly everyone in an unnamed city, and the social breakdown that swiftly follows. The novel follows the misfortunes of a handful of characters who are among the first to be stricken and centers on "the doctor's wife," her husband, several of his patients, and assorted others, thrown together by chance. After lengthy and traumatic quarantine in an asylum, the group bands together in a family-like unit to survive by their wits and by the unexplained good fortune that the doctor’s wife has escaped the blindness. The sudden onset and unexplained origin and nature of the blindness cause widespread panic, and the social order rapidly unravels as the government attempts to contain the apparent contagion and keep order via increasingly repressive and inept measures.

Dagger

A dagger is a knife with a very sharp point designed or capable of being used as a thrusting or stabbing weapon. The design dates to human prehistory, and daggers have been used throughout human experience to the modern day in close combat confrontations. Many ancient cultures used adorned daggers in ritual and ceremonial purposes, a trend which continues to the present time in the form of art knives. The distinctive shape and historic usage of the dagger have made it iconic and symbolic.

Over the years, the term has been used to describe a wide variety of thrusting knives, including knives that feature only a single cutting edge, such as the European rondel dagger or the Persian pesh-kabz, or, in some instances, no cutting edge at all, such as the stiletto of the Renaissance. However, over the last hundred years or so, authorities have recognized that the dagger, in its contemporary or mature form, has certain definable characteristics, including a short blade with a sharply tapered point, a central spine or fuller, and (usually) two cutting edges sharpened the full length of the blade, or nearly so.

Dagger (disambiguation)

A dagger is a short-bladed weapon.

Dagger or daggers also may refer to:

Film and television

Other media

People

Places

Sports

Theory

Conjugate transpose matrix, sometimes denoted with a superscript typographical dagger ()

Dagger (category theory), an involutive, identity-on-object functor

Logical NOR operator, sometimes known as Quine's dagger ()

Vehicles

Other uses

Cloak and Dagger (comics)

Cloak (Tyrone "Ty" Johnson) and Dagger (Tandy Bowen) are a fictional comic book superhero duo appearing in American comic books published by Marvel Comics. They were created by writer William "Bill" Mantlo and artist Edward Hannigan.

Concept and creation

The inspiration for Cloak and Dagger came to Bill Mantlo after a visit to Ellis Island. He recounted, "They came in the night, when all was silent and my mind was blank. They came completely conceived as to their powers and attributes, their origin and motivation. They embodied between them all that fear and misery, hunger and longing that had haunted me on Ellis Island."

Ed Hannigan, Mantlo's artist collaborator on Peter Parker, the Spectacular Spider-Man, recalled that he and Mantlo jointly came up with the characters' visual design: "Bill had a short page or two synopsis of the story that he showed me, and we discussed what the characters would look like. He gave me a lot of leeway, but it was fairly obvious that Cloak would be black and have a big ‘animated’ black cloak and Dagger would be white with a skintight leotard-type thing. I am not sure, but I think I might have come up with her ballet angle. I put the same kind of amulet/clasp on both costumes and came up with the dagger-shaped cutout on her costume, which was quite daring at the time."