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Oculogyric crisis (OGC) is a rare sudden, paroxysmal, dystonic reaction that may manifest in response to specific drugs, particularly neuroleptics, or medical conditions, such as movement disorders. This neurological phenomenon is characterized by a sustained dystonic, conjugate , involuntary upward deviation of both eyes lasting seconds to hours.
In most cases, the gaze palsy can simply be seen by inability to move both eyes in one direction. However, sometimes a patient exhibits an abduction nystagmus in both eyes, indicating evidence of a conjugate gaze palsy. [12] A nystagmus is a back and forth "jerk" of the eye when attempting to hold a gaze in one direction. [13]
Paralysis of upwards gaze: Downward gaze is usually preserved. This vertical palsy is supranuclear, so doll's head maneuver should elevate the eyes, but eventually all upward gaze mechanisms fail. In the extreme form, conjugate down gaze in the primary position, or the "setting-sun sign" is observed.
Color blindness is any deviation of color vision from normal trichromatic color vision (often as defined by the standard observer) that produces a reduced gamut. Mechanisms for color blindness are related to the functionality of cone cells , and often to the expression of photopsins , the photopigments that 'catch' photons and thereby convert ...
The term "fixation" can either be used to refer to the point in time and space of focus or the act of fixating. Fixation, in the act of fixating, is the point between any two saccades, during which the eyes are relatively stationary and virtually all visual input occurs.
Achromatopsia, also known as rod monochromacy, is a medical syndrome that exhibits symptoms relating to five conditions, most notably monochromacy.Historically, the name referred to monochromacy in general, but now typically refers only to an autosomal recessive congenital color vision condition.
The conjugate gaze is the motion of both eyes in the same direction at the same time, and conjugate gaze palsy refers to an impairment of this function. The conjugate gaze is controlled by four different mechanisms: [4] the saccadic system that allows for voluntary direction of the gaze; the pursuit system that allows the subject to follow a ...
Patients will move their heads to adjust for the loss of peripheral vision caused by inability to abduct or adduct the eye. All directions of gaze are affected; however, downward gaze appears to be best spared. This is in contrast to progressive supranuclear palsy (PSP), which typically affects vertical gaze and spares horizontal gaze.