Case-Matched Intraocular Pressure Results of Trabectome Ab Interno Trabeculectomy versus Ahmed Glaucoma Implant

Abstract

Purpose: To compare outcomes of ab interno trabeculectomy (T, Trabectome, Neomedix, Tustin, CA) to that of a valved glaucoma drainage device (AGI, Ahmed FP7, New World Medical, Rancho Cucamonga, CA) using an automated matching algorithm.

Methods: Retrospective, case-matched study of intraocular pressure (IOP) after T or AGI. Procedures were performed by the same surgeon group on similar patients for primary and secondary open-angle as well as primary angle-closure glaucomas. The only exclusion criterion was neovascular glaucoma. Cases were matched by age, gender, glaucoma type, number of preoperative medications, and whether prior phacoemulsification occurred. Weighted linear regression was significant when p<0.05. Reoperation was considered a complication.

Results: Prior to matching, T (n=103) had a preoperative IOP of 20.8±8.1 mmHg on 2.7±1.8 medications and AGI (n=41) had a preoperative IOP of 30.0±13.4 mmHg on 3.0±1.4 medications. After 1 year, the number of medications decreased to 1.9±1.7 for T and increased to 4.2±1.6 for AGI. For T, only 16% required further surgery vs. 41% for AGI.<br /> <br /> After matching, there was no significant difference between T and AGI at 1 week, 1 month, 3 months and 6 months (all p>0.05). The IOP reduction at 1 week was 7.7±10.4 mmHg for 31 T vs. 13.1±14.3 mmHg for 31 AGI, at 1 month 2.3±10.9 mmHg for 40 T vs. 10.0±14.9 mmHg for 32 AGI. At 3 months, 32 T had a baseline IOP of 26.4±9.1 mmHg that decreased to 15.7±4.1 mmHg vs. 33 AGI with a baseline of 27.1±10.9 mmHg that decreased to 14.8±8.1mmHg. At 6 months, 24 T had a baseline IOP of 26.4±9.4 mmHg that decreased to 17.1±5.8 mmHg vs. 19 AGI with a baseline of 26.7±10.2 mmHg that decreased to 15.5±5.5 mmHg.<br /> <br /> At 1 year, matched T (n=14) had a baseline IOP of 28.1±9.2 mmHg that decreased to 16.4±6.2 mmHg compared to AGI (n=11) with a baseline of 26.9±8.5 mmHg that decreased to 11.7±4.5 mmHg (p<0.01). AGI patients required twice as many medications to achieve this goal and had a more complicated postoperative course.

Conclusions: In this retrospective study of T matched to AGI, there was no difference in IOP lowering at 1 week and 1, 3, and 6 months. At 1 year, AGI patients achieved a lower IOP that required twice as many drops as T.