A Comparison of the Polypropylene Plate Ahmed Glaucoma Valve to the Silicone Plate Ahmed Glaucoma Flexible Valve

Purpose: To compare surgical outcomes following implantation of the polypropylene plate Ahmed glaucoma valve (AGV) (S-2) and the newer silicone plate AGV (FP-7) with minimum 12 months follow-up in patients with intractable glaucoma.

Design: Retrospective chart review of 25 eyes of 22 patients who underwent FP-7 and 26 eyes of 22 patients who underwent S-2 AGV implantation by a single surgeon. Main outcome measures included surgical outcomes in terms of intraocular pressure (IOP) control, hypertensive phase, and postoperative complications.

Results: There were no significant differences in diagnoses, pre-and postoperative IOP, pre- and postoperative visual acuities at all time points, and in the number of pre- and postoperative medications between the groups. Significant IOP reductions occurred after FP-7 implantation (29.6 +/- 13.1 to 12.1 +/- 3.4, p < 0.001) and S-2 implantation (31.4 +/- 11.7 to 16.1 +/- 5.7, p < 0.001). The FP-7 group had a statistically lower IOP compared to the S-2 group at 6 (p<0.05), 9 (p<0.01), and 12 months (p<0.01). There was no significant difference in the hypertensive phase between the two groups (p=0.41).

Conclusions: FP-7 model silicone plate AGV resulted in lower IOP compared to the older S-2 polypropylene plate AGV at 1 year. This may suggest that the plate material may influence clinical outcome.