The study is designed to evaluate the ability of optical coherence tomography and VCC scanning laser polarimetry to measure and identify the pattern of band atrophy of the optic nerve in patients with long standing chiasmal lesions. The hypothesis is that these new technologies are able to identify such pattern. The idea is that by using eyes with band atrophy one is able to investigate the ability of the new technologies in measuring the retinal nerve fiber layer particularly in the nasal and temporal portions of the optic nerve.