Chiasmal disorders

An 81-year-old man presented with four-month history of painless progressive bilateral loss of vision. He denied any history of headaches or other neurologic symptoms. The remainder of his past medical, surgical, social, family, and ocular history was negative. He was on no medication. His visual acuity was 20/20 in both eyes (OU). Ishihara color plate scoring was 0 out of 14 in the right eye (OD) and 2 out of 14 in the left eye (OS). Pupils were 3 mm in the dark and 2 mm in the light OU, and there was no relative afferent pupillary defect (RAPD) or light-near dissociation. Extraocular motility and intraocular pressure measurements were normal. Slit lamp biomicroscopy showed a posterior chamber intraocular lens OD and a mild nuclear sclerotic cataract OS. Automated (Humphrey 24-2) visual field testing is shown in (Fig. 16.1). The cup-to-disc ratio was 0.25 OU but there was significant temporal pallor OU. There was no disc edema. The rest of the funduscopic examination was normal. Magnetic resonance imaging (MRI) of the brain with and without contrast showed a large 4.6 cm × 2.9 cm × 3 cm mass with heterogeneous T2 signal, and enhancement in the sella, and suprasellar extension with compression of the optic chiasm from below (Fig. 16.2).