Clinical Experience with Ahmed M4 Tube-Shunt in Various Types of Glaucoma: A Pilot Study

Abstract

 

Purpose

 

To evaluate the safety and efficacy of the Ahmed Glaucoma Valve model M4 (AGV; New World Medical Inc., Rancho Cucamonga, CA). This device consists of a porous polythethiene shell, which was designed to reduce the fibrotic reaction around the plate. ¹

 

Methods

 

Patients’ charts who underwent implantation of the AGV model M4 from 12/1/12 to 8/31/13 were reviewed. Primary outcome: intraocular pressure (IOP) reduction; Secondary outcome: number of glaucoma medications and number of reoperations related to surgical complications or glaucoma. Clinical parameters were collected pre-operatively and on day 1, week 1 and 1-, 3- and 6- months post-operatively.

 

Results

 

Thirty-six eyes were included. Mean follow-up time was 136 ± 62 days. Preoperatively, subjects had a mean of 0.97 ± 1.0 prior glaucoma surgeries and a mean LogMAR visual acuity of 1.04 ± 0.89. Table 1 shows the mean IOP and number of glaucoma medications by pre- and post-operative visit. The percentage of IOP drop in day 1 and 3 month was 72% and 22% respectively. The average use of medications per patient was 2.9 ± 0.84 and 0.13 ± 0.43 before surgery and 3 months after, respectively. Thirty six percent of the patients had at least 1 complication; hyphema and shallow anterior chamber were the most prevalent early complications. Ten eyes underwent additional procedures to manage surgical complications. Four eyes needed reoperation for glaucoma 3 months post-operatively. No significant vision-threatening complications were recorded.

 

Conclusions

 

The AGV model M4 effectively reduced IOP during the first post-operative month. The IOP reduction at 1-month is comparable to published data. There was a trend toward higher IOP values after 3- and 6- months; however, this can be explained by a lower number of hypotensive drops used, compared to the previous report. Further studies are required to evaluate the long-term efficacy and safety of this device.

 

 

Keywords: 568 intraocular pressure