[Surgical revision for hypotonia after glaucoma operation with mitomycin C]

Persistent hypotony with maculopathy is a severe complication of mitomycin C when used during filtration surgery. We wanted to know whether this complication can be controlled by a surgical reintervention yielding tight closure of the initial sclerostomy.

In our clinic, 52 eyes underwent filtering surgery with intraoperative application of mitomycin C. Seven of them required a reoperation owing to persistent hypotony with maculopathy. During this reoperation, the scleral flap was tightly sutured (5x) or, if necessary, was closed with dehydrated human dura mater (2x).

In all cases the intraocular pressure increased immediately (i.e., within less than 24 h) after reoperation. This intraocular pressure increase was accompanied by a simultaneous regression of the maculopathy. Further details: mean intraocular pressure (mmHg): before initial operation with mitomycin C: 38.5 +/- 2.9; after initial operation: 3.7 +/- 0.6; before reoperation (= 8 months after initial operation): 3.3 +/- 0.7; 24 h after reoperation: 22.0 +/- 2.9; 9 months after reoperation: 16.7 +/- 1.7. Mean visual acuity: before initial operation with mitomycin C: 0.72 +/- 0.1; after initial operation: 0.34 +/- 0.1; before reoperation (= 8 months after initial operation): 0.17 +/- 0.05; 24 h after reoperation: 0.28 +/- 0.05; 9 months after reoperation: 0.55 +/- 0.1.

(1) Since the interval between reoperation and intraocular pressure increase was very short in all cases, overfiltration is at least one major reason for hypotony, not only ciliary body failure; (2) in cases of persistent hypotony after filtering surgery with mitomycin C, surgical reintervation can be recommended. During this reoperation, the initial sclerostomy should be closed tightly.