• A modified filtering operation for neovascular glaucoma provided control of intraocular pressure after 12 to 23 months in ten of 13 eyes. After long-term follow-up, 23 to 54 months, seven of ten eyes still had controlled IOP. Two eyes were receiving no medication, two required miotics, and three required maximal medical therapy, including carbonic anhydrase inhibitors. One eye had undergone cyclocryotherapy four years after trabeculectomy. Four of seven eyes with diabetic neovascular glaucoma retained ambulatory vision. The eye with neovascular glaucoma from central retinal vein occlusion lost useful vision. The underlying disease process is an important determinant of surviving visual function.