atrophy of the optic disk which may be congenital or acquired. This condition indicates a deficiency in the number of nerve fibers which arise in the retina and converge to form the optic disk; optic nerve; optic chiasm; and optic tracts. glaucoma; ischemia; inflammation, a chronic elevation of intracranial pressure, toxins, optic nerve compression, and inherited conditions (see optic atrophies, hereditary) are relatively common causes of this condition.