The early flat anterior chamber after trabeculectomy: a randomized, prospective study of 3 methods of management.

PURPOSE: To evaluate prospectively 3 different approaches to the management of a flat anterior chamber (FAC) because of overfiltration in the early postoperative period after trabeculectomy.

MATERIALS AND METHODS: Thirty-six eyes diagnosed with a FAC with total iridocorneal touch, but no lenticular touch (grade II) because of overfiltration in the first 14 days after trabeculectomy were randomized prospectively into 3 groups: group 1--anterior chamber reformation with viscoelastic substance; group 2--anterior chamber reformation with balanced salt solution and concurrent drainage of choroidal effusion; and group 3--pharmacologic therapy with atropine, phenylephrine, and in select cases oral acetazolamide. Outcome measures were visual acuity, amount of intraocular pressure (IOP) reduction, and achievement of predetermined target IOP.

RESULTS: Treatment group 2 had a greater number of eyes with acuity decline of two or more lines relative to group 3 (P=0.04). Group 1 had more eyes with acuity decline of two or more lines relative to group 3, but this was not significant (P>0.05).

CONCLUSIONS: For grade II FACs because of overfiltration in the early postoperative period after trabeculectomy, reformation of the anterior chamber with drainage of choroidal effusion may be associated with greater long-term trabeculectomy success, but is associated with greater visual acuity loss relative to medicinal therapy alone. Reformation with viscoelastic resulted in a trend toward lowest final IOP in comparison to medicinal therapy alone.