n. partial or complete loss of sight without evidence of organic abnormality of the affected eye or eyes. The cause is often damage to the optic nerve or the brain. The condition may be hereditary, as in Leber’s disease; transient (see amaurosis fugax); part of a syndrome, such as Tay–Sachs disease; or the result of complete destruction of the striate cortex (cortical amaurosis). See also functional blindness.