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Color blindness may also present itself as a symptom of degenerative diseases of the eye, such as cataract and age-related macular degeneration, and as part of the retinal damage caused by diabetes. Vitamin A deficiency may also cause color blindness. [47] Color blindness may be a side effect of prescription drug use.
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.
CVI is also sometimes known as cortical blindness, although most people with CVI are not totally blind. The term neurological visual impairment (NVI) covers both CVI and total cortical blindness. Delayed visual maturation, another form of NVI, is similar to CVI, except the child's visual difficulties resolve in a few months.
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.
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.
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.
Ophthalmoparesis refers to weakness (-paresis) or paralysis (-plegia) of one or more extraocular muscles which are responsible for eye movements.It is a physical finding in certain neurologic, ophthalmologic, and endocrine disease.
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]