title: Ocular hypotony after trabeculectomy with mitomycin C.
abstract: Because mitomycin C reduces the resistance to aqueous outflow normally provided by postoperative subconjunctival fibrosis, we would expect to see more frequent hypotony after trabeculectomy with mitomycin C than after standard trabeculectomy. To evaluate the incidence of hypotony in trabeculectomy with intraoperative mitomycin C use, we performed a retrospective analysis on 52 eyes of 48 patients who underwent trabeculectomy with mitomycin C. Mitomycin C concentration was 0.4 mg/ml in all eyes, and treatment time ranged from 3 1/2 to seven minutes. We defined hypotony as intraocular pressure lower than 5 mm Hg on two examinations at least four weeks apart and six weeks or more postoperatively. Overall, average intraocular pressure was 22.7 +/- 10.7 mm Hg preoperatively and 10.4 +/- 5.0 mm Hg postoperatively (P < .001), a mean reduction in intraocular pressure of 12.3 +/- 11.5 mm Hg (47.0%). Hypotony occurred in 17 of 52 eyes (32.7%). Seven eyes required trabeculectomy revision for hypotony. Hypotonous eyes received longer treatment with mitomycin C intraoperatively, with a mean application time of 5.3 +/- 1.0 minutes for hypotonous eyes and 4.7 +/- 0.8 minutes for nonhypotonous eyes (P = .03). Sixteen of 43 eyes (37.2%) undergoing primary filtration became hypotonous, as compared to one of nine (11.1%) eyes that had previous filtering procedures (chi 2 = 2.30, P = .13). Nine of 17 hypotonous eyes (52.7%) and five of 35 nonhypotonous eyes (14.3%) had loss of two or more lines of Snellen visual acuity. Hypotony occurred in nearly one third of eyes treated with mitomycin C during trabeculectomy in our study. There was a statistically significant (P = .03) association of hypotony with longer application time of mitomycin C, and a trend toward increased incidence of hypotony in primary filtration.
authors.affiliation: New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts.
authors.forename: P T
authors.initials: PT
authors.lastname: Zacharia
authors.forename: S R
authors.initials: SR
authors.lastname: Deppermann
authors.forename: J S
authors.initials: JS
authors.lastname: Schuman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D005901:Glaucoma / Q000188:drug therapy / Q000601:surgery; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D015814:Ocular Hypotension / Q000139:chemically induced* / Q000503:physiopathology; D012189:Retrospective Studies; D014130:Trabeculectomy; D014792:Visual Acuity
chemical_list: D016685:Mitomycin