Phaco following trabeculectomy causes increase in IOP, study indicates

MADRID — Phacoemulsification significantly increased intraocular pressure in eyes with functioning filtering blebs, a study here found. The number of glaucoma medications needed to control IOP following surgery also increased. But mean IOP after phaco was always lower than before trabeculectomy, the study authors said.

Gema Rebolleda, MD, PhD, and Francisco J. Muñoz-Negrete, MD, PhD, prospectively studied 49 eyes of 47 patients that underwent phacoemulsification after successful trabeculectomy in a nonrandomized comparative trial. Surgeons waited at least 1 year between procedures.

The mean IOP before phaco was 12 mm Hg. Mean IOP increased almost 4 mm Hg (P = .000) on the first postoperative day and was 2 mm Hg above baseline at 12 months (P = .01) and 1.6 mm Hg above baseline at the last follow-up visit (P = .01).

The authors note that mean IOP following phaco was always lower than before trabeculectomy (P = 0.000).

The number of glaucoma medications needed increased at all follow-up visits (P < 0.005), and glaucoma medications were required in 17 eyes (34.7%) at final follow-up.

Bleb size also decreased after phacoemulsification (P = 0.000). Bleb failure and the need for glaucoma medication were associated with higher IOP prior to phaco.

The report was published in Ophthalmology.