Management of chronic hypotony following trabeculectomy with mitomycin C

Chronic hypotony is marked by decreased vision and late-onset leaking bleb after filtration surgery using topical mitomycin C; to manage this condition we followed a three-step approach: first, intrableb autologous blood injection; second, surgical exploration and additional suturing of the scleral flap; third, excision of the cystic bleb and advancement of a fornical conjunctival flap. For the avascular flap cystic blebs of five patients. In three of the six eyes, there was no increase of intraocular pressure (IOP); two eyes showed massive hyphema and were mildly resistant to the injection of autologous blood, and in one, a leaking hole was seen in the bleb wall two days after the injection of blood. Two eyes of three in which blood injection had failed, and another, in which the bleb had spread over more than half the eyeball, and which was the patient's only sighted eye, underwent the second step of the procedure. The remaining leaking eye, in which blood injection had been complicated, and another, in which spontaneous leakage from a thin avascular bleb had occurred, were subjected to the third step. After each of the three approaches, IOP increased on average from 1.67 to 5.67 mmHg, from 2.33 to 11.33 mmHg, and from 1.5 to 7 mmHg, respectively; each approach successfully improved vision. Intrableb autologous blood injection is a simple procedure for the management of chronic overfiltration and a way of determining whether excessive filtration is occurring through the scleral flap, in which case additional suturing is required, or in another way. Depending on the status of the bleb, additional suturing or excision of the cystic bleb and advancement of the fornical conjunctival flap are useful modalities for the treatment of late-onset leaking filtration bleb.