Abstract
Purpose:
To compare the surgical and visual outcomes of standard Ahmed valve with a new “wing” Ahmed valve in the treatment of advanced glaucoma. The plate of the wing valve has a surface area of approximately 450 mm-sq compared to a surface area of 180 mm-sq for the standard Ahmed valve.
Methods:
This was a retrospective nonrandomized comparative trial of 30 consecutive patients who underwent implantation of the Ahmed wing valve compared with an equal number of age and sex matched controls who had standard Ahmed valve implantation. All procedures were performed by a single surgeon (WEL). We compared vision and intraocular pressures preoperatively and at intervals of one day, one week, two weeks, six weeks, 10 to 12 weeks, 5 to 7 months, and 10 to 14 months. We also compared complication rates between the two groups.
Results:
By Students t-test, requiring p<0.05, intraocular pressures were statistically similar at all intervals except on postoperative day one when average IOP was 15 with the wing valve and 10.5 with the standard Ahmed valve (p=0.044). At the 10 to 14 month time point, average IOP with the wing valve was 15 compared to 19 with the standard valve, although this was not statistically significant (p = 0.099). The number of major complications (exposed valve with revision, explanted valve, or second valve implant) was 6 for the wing valve and 5 for the standard valve.
Conclusions:
Despite the larger surface area, the wing valve did not produce a statistically significant lower IOP at the one year time point. The rate of complications was similar.
Keywords: 568 intraocular pressure