ABSTRACT: Idiopathic intracranial hypertension (IIH) is a disease of unknown cause typically affecting obese women in the childbearing years. Although headache is the most common symptom, the major morbidity of IIH is visual loss, with 5% to 10% of patients progressing to blindness. While about 95% of patients with IIH have visual loss documented by perimetry, only about one-third notice their visual loss because most loss occurs in the peripheral visual field. Since treatment decisions in IIH are made primarily by changes in visual field function, serial perimetry is the most critical test to obtain when following patients with IIH. This article describes the role of visual field testing in the monitoring of IIH patients in clinical practice, including its importance in communication among providers.