Objective: Acetazolamide is preferred as the first-line drug for the medical treatment of idiopathic intracranial hypertension. In this study, the efficacy of different doses of the drug on visual functions; visual acuity, optic disc appearance- papilledema grade and visual field-mean deviation (VF-MD) were evaluated. Methods: The medical records of 73 patients diagnosed as idiopathic intracranial hypertension based on Modified Dandy Criteria and treated with acetazolamide who were on follow-up between 2010 and 2017 at the Neuro-ophthalmology Unit of Ege University Medical School, Department of Neurology were analyzed. Improvement in the visual functions at the end of the sixth month in three groups taking different doses of the drug; low (500, 750, 1000 mg/day), moderate (1500, 1750, 2000 mg/day) and high (3000, 4000 mg/day) were compared. Results: Improvement in visual acuity (p: 0.784), was not affected from different doses of the drug whereas papilledema grade (p: 0.014) and VF-MD (p<0.001) were affected. Binary comparisons revealed significant improvement in the high dose group when compared with the moderate and low dose groups both for the papilledema grade (low-high: p: 0.003, moderate-high: p: 0.024) and VF-MD (low-high: p<0.001, moderate-high: p: 0.001) Conclusion: Treatment with high doses of acetazolamide is associated with improvement in visual field defects and regression of optic disc edema in idiopathic intracranial hypertension.