Objective To observe the results of visual functional MRI(fMRI)of injury side with those of uninjured side,in patients with visual field defects and retrochiasmastic tumor.The potential clinical usefulness of visual fMRI data during functional examination on visual centre,defining the tumor field and surgery,was evaluated in patients with occipital lobe tumour.Design Case series.Participants Two patients with occipital lobe tumor and homonymous visual field defects,injury sides contrast with uninjured ones.Methods Patients were studied with fMRI using monocular checker stimulation(5Hz).The data obtained were analyzed with statistical parametric maps software(P