Silicone versus poly(methyl methacrylate) lenses in combined phacoemulsification and trabeculectomy

To compare the outcome of phacotrabeculectomy with silicone or poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation over the first year.

Glaucoma Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom.

Two consecutive groups of 30 eyes each had phacotrabeculectomy with implantation of a foldable, plate-haptic silicone IOL (3.2 mm wide incision) or a PMMA IOL (5.2 mm wide incision) with a loosely or tightly sewn scleral flap, respectively. Early postoperative results and outcomes up to a mean of 1 year postoperatively in both groups were compared.

In the early postoperative period, eyes in the silicone IOL group had a lower incidence of postoperative intraocular pressure (IOP) spikes (more than 30 mm Hg) than those in the PMMA IOL group (two and six cases, respectively) but also showed an increase (eight and three cases, respectively) in incidence of ocular hypotony (less than 8 mm Hg). There was also an increased incidence, although not statistically significant, of early postoperative complications in the silicone group; for example, fibrinous reaction in the anterior chamber (26.6 versus 10.0%; P = .18), shallow anterior chamber (16.6 versus 3.3%, P = .20), and choroidal detachment (16.6 versus 3.3%, P = .20). These complications, often associated with ocular hypotony, resolved quickly without serious sequelae. One year after surgery, IOP control (less than 22 mm Hg) was attained without medication in 80.0% in the silicone group and 76.7% in the PMMA group (P = 1.00), and corrected visual acuity of 20/40 or better was attained in 70.0% in the silicone group and 73.3% in the PMMA group (P = 1.00).

The loosely sutured flap in the silicone group resulted in fewer early pressure spikes but at a cost of an increase in early postoperative hypotony with its associated complications. One year after surgery, there was no significant difference between the two groups in IOP control or visual acuity, showing that both procedures were effective in the surgical management of patients with cataract and glaucoma.