A 56-year-old male presented with complaints of blurry vision and floaters in the right eye for a few days. He denied any past medical history of systemic disease but cited suffering from chronic headaches. Recently, a visual floater and blurred vision was noticed in the right eye. Visual acuity was 6/4 in the right eye and 6/5 in the left. He could identify only two plates OD and three plates OS with the Ishihara color test. Both anterior segments were normal. Fundoscopic examination revealed a moderate degree of disc edema with splinter hemorrhages in both eyes (Fig. 15.1). Fluorescein angiography showed capillary dilation over the optic disc in early phase, with dye staining at late phase (Fig. 15.2). Right homonymous hemianopia was found on visual field examination (Fig. 15.3). MRI showed a heterogeneously enhanced tumor measuring 6.6 × 4.0 × 5.1 cm in the left occipital region, with calcifications and necrotic components. In addition, an enlarged CSF space along the optic nerves was observed bilaterally on T2-weighted images (Fig. 15.4). The patient was confirmed to have lung cancer with brain metastasis and subsequently began whole brain radiotherapy and Iressa treatment.