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.

Vapor

In physics a vapor (American English spelling) or vapour (British) is a substance in the gas phase at a temperature lower than its critical point, which means that the vapor can be condensed to a liquid by increasing the pressure on it without reducing the temperature. A vapor is a different substance than an aerosol. An aerosol is a suspension of tiny particles of liquid, solid or both within a gas.

For example, water has a critical temperature of 374 °C (647 K), which is the highest temperature at which liquid water can exist. In the atmosphere at ordinary temperatures, therefore, gaseous water (known as water vapor) will condense into a liquid if its partial pressure is increased sufficiently.

A vapor may co-exist with a liquid (or a solid). When this is true, the two phases will be in equilibrium, and the gas-partial pressure will be equal to the equilibrium vapor pressure of the liquid (or solid).

Properties

Vapor refers to a gas phase at a temperature where the same substance can also exist in the liquid or solid state, below the critical temperature of the substance. (For example, water has a critical temperature of 374 °C (647 K), which is the highest temperature at which liquid water can exist.) If the vapor is in contact with a liquid or solid phase, the two phases will be in a state of equilibrium. The term gas refers to a compressible fluid phase. Fixed gases are gases for which no liquid or solid can form at the temperature of the gas, such as air at typical ambient temperatures. A liquid or solid does not have to boil to release a vapor.

List of Cobra characters

The Cobra Organization is the fictional nemesis of the G.I. Joe Team in the Hasbro toylines and related media. This is an alphabetical listing of Cobra Command members with unique identities.

Baroness

Bayonet

Bayonet is a Cobra Snow Serpent serving as part of the organization's elite Plague Troopers. He wears a portable life support system due to having survived injuries to his chest by the G.I. Joe team.

Big Boa

Big Boa is Cobra's trainer, and was first released as an action figure in 1987. He was meant to be as an enemy to Rocky Balboa, from the Rocky films, even coming with boxing gloves, but the Rocky character was never released as an action figure. Big Boa is a brutal, unfeeling taskmaster who whips the unruly Cobra Troopers into shape, as these soldiers are not motivated by patriotism, unit loyalty, honor, or sense of duty. Cobra Troopers say he has a voice like a bullhorn, fists the size of frozen turkeys, and the disposition of a bear with a headache.

Big Boa appears in Devil's Due G.I. Joe series. He fights Bazooka, one of four Joes who had just discovered Cobra's influence in the small town of Delhi Hills. Bazooka defeats him in hand-to-hand combat, but Big Boa, like most signs of Cobra influence, is spirited away before the authorities arrive. He also makes an appearance in issue #24. Later, Big Boa is killed along with several Cobra troopers and South American operative Asa Negra in an attack by the Red Shadows. Their bodies are discovered by Joe members Hardball, Rampart, and Glenda. Moments later, the Red Shadows kill the Joes as well. These 'Shadows' are a militia group that seeks to destroy Cobra and G.I. Joe, by slaying key members on each side.

Vapor (disambiguation)

A vapor is a substance in the gas phase below its boiling point.

Vapor or vapour may also refer to:

See also