Optic gliomas are congenital in origin. Masses formed within the central nervous system in utero may influence the subsequent apoptosis of excess axons,6 in effect molding themselves in relative harmony with remaining axons to allow maximal visual function despite the presence of what may otherwise appear to be an impressive tumor. Nonetheless, following the final organization of visual pathways, subsequent growth could alter such an in utero–established arrangement. Optic gliomas are also intrinsic to the optic nerve. Thus, the hamartomatous overgrowth of glial cells with supporting tissue elements that normally surround each axon, should it occur in uniform fashion, may not necessarily impede axoplasmic flow and neuronal signaling. Neurons remain functional and viable with elevated pressures uniformly distributed.7,8 Pressure applied focally, on the other hand, particularly from tumors arising extrinsic to a nerve, can easily create pressure gradients that pinch axons and block axoplasmic flow, thus producing subsequent atrophy.8 As an analogy, just as a human can withstand high pressure evenly distributed, such as is generated by several tons of water when near the bottom of a swimming pool, it could nonetheless poorly tolerate even a fraction of such pressure were it to be applied focally, such as by an elephant resting its foot on a person's torso (Alfredo A. Sadun, MD, PhD, oral communication, February 2009).