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Flash blindness is an either temporary or permanent visual impairment during and following exposure of a varying length of time to a light flash of extremely high intensity, such as a nuclear explosion, flash photograph, lightning strike, or extremely bright light, i.e. a searchlight, laser pointer, landing lights or ultraviolet light. [1]
The Farnsworth Lantern Test, or FALANT, is a color vision test originally developed specifically to screen sailors for tasks requiring color vision, such as identifying signal lights at night. It screens for red-green deficiencies, but not the much rarer blue color deficiency.
For an adequate test, vision must not be entirely lost. In dim room light, the examiner notes the size of the pupils. The patient is asked to gaze into the distance, and the examiner swings the beam of a penlight back and forth from one pupil to the other, and observes the size of pupils and reaction in the eye that is lit.
Temporary blindness, a type of non-permanent vision loss, may refer to: Amaurosis fugax, or fleeting blindness; Conversion disorder, formerly called hysterical blindness; Flash blindness, caused by exposure to high-intensity light.
To give another example, of a more powerful laser—the type that might be used in an outdoor laser show: a 6-watt green (532 nm) laser with a 1.1 milliradian beam divergence is an eye hazard to about 1,600 feet (490 meters), can cause flash blindness to about 8,200 feet (1.5 mi/2.5 km), causes veiling glare to about 36,800 feet (7 mi; 11 km ...
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Color blindness, a color vision deficiency. Cortical blindness, a loss of vision caused by damage to the visual area in the brain. Flash blindness, a visual impairment following exposure to a light flash. Hysterical blindness (nowadays known as conversion disorder), the appearance of neurological symptoms without a neurological cause.
Beyond the question of physical injury to the eye from a laser pointer, several other undesirable effects are possible. These include short-lived flash blindness if the beam is encountered in darkened surroundings, as when driving at night. This may result in momentary loss of vehicular control.