What is the most appropriate next step for a patient experiencing prolonged hypotony following Ahmed glaucoma valve implantation and unsuccessful medical management?  

To reduce aqueous flow through the tube, a less invasive approach involves occluding the tube lumen using a 2-0 or 3-0 Prolene suture via an ab interno technique. For complete occlusion, a Supramid suture may be used instead of Prolene. The ab interno approach minimizes conjunctival disruption. Alte...

I agree, Dr. @Ullah, although I find that 3-0 Supramid does not usually result in complete occlusion but rather raises the resistance across the tube by 3-5 mm Hg. I use a 1 cm segment for this purpose. Just take care to leave a little bit protruding from the tube in the AC so you can remove it with...