Q. A 65-year-old man presents to the emergency room with a complaint of "walking into walls." He reports that yesterday, he walked into the side of the wall at work and hit his left shoulder against the door frame. When he was driving home, he didn't see a car at the intersection and almost got into an accident. He has a history of migraines and has had visual issues from them before but normally they resolve within 20 minutes. He awoke this morning and still has issues with walking into things, so he decided to come in. His vital signs are normal and his general medical exam is normal. On neurological exam, visual field testing demonstrates a left hemianopia (loss of vision). Which of the following lobes of the brain is primarily responsible for visual processing?