Should patients with greatly restricted visual field defects from glaucoma be operated upon? Chandler and Grant in their recently published Lectures on Glaucoma raise the same question and ask that further data be published covering this problem. The purpose of this paper is to show our experience in facing this dilemma over the past 19 years. Fifty-two eyes with advanced glaucomatous field defects which have had filtration operations were evaluated. They were classifield into three categories according to the severity of the visual field loss. None was included whose field exceeded 20° in any meridian. They were also studied by age group, preoperative and postoperative pressures, central vision, and length of time followed after operation.