Can medical conditions in the brain, excluding strokes or tumors, cause a visual field defect?

Yes. Other causes include multiple sclerosis, infection (e.g., abscess), and tumors in the pituitary gland that press on the brain. Visual field defects can also be seen with diseases of the retina or optic nerves. Also late in the course of some neurodegenerative disorders such as alzheimer's disease higher centers for vision can be affected and visual deficits can be seen.