Documentation for techniques of surgical manipulation of a filtering bleb is meager in ophthalmological literature. Of particular interest in this matter is: (1) the management of loss of the filtering bleb after external filtering surgery for glaucoma, (2) management of external fistulization of a filtering bleb, (3) treatment of extension of a filtering bleb into the cornea with and without abnormal hypotony, and (4) the management of postoperative fistulization of the corneoscleral section in cataract surgery which results in the formation of a filtering bleb. It is the intent of this communication to present methods of treating these fortunately infrequent complications. Loss of the Filtering Bleb At the first dressing in the uncomplicated external filtering operation for glaucoma, one notes the presence of a bleb, a wellformed anterior chamber, and the absence of hyphema and choroidal detachment. Absence of or marked reduction in the size of the bleb may be