Ab Interno Occlusion of Ahmed Glaucoma Valve Tube with a 4-0 Polypropylene Suture in a Patient with Hypotony

Abstract

The objective is to present the clinical improvement observed after ab interno intraluminal occlusion of Ahmed glaucoma valve (AGV) tube with a 4-0 polypropylene suture in a patient with secondary hypotony following AGV implantation. A 47-year-old male patient with a history of retinitis pigmentosa, congenital cataract, and glaucoma had undergone ex-press glaucoma filtration device implantation and cyclophotocoagulation treatments in his left eye previously. The intraocular pressure (IOP) was not regulated with these treatments, and an AGV implantation was performed in our clinic. Due to the development of hypotony at the postoperative 1st week, ab interno intraluminal occlusion of the AGV tube was planned with a 4-0 polypropylene suture. Before AGV tube implantation, the best-corrected visual acuity (BCVA) was 0.05, and IOP was 40 mmHg (with maximum antiglaucoma medication) in the left eye of the patient. At the postoperative 1st week, BCVA regressed to the level of hand motion, and IOP was <5 mmHg. Findings such as corneal fold, hypotony maculopathy, and choroidal effusion were also observed. Since there was no response to anti-inflammatory medical treatment initiated to reduce hypotony, ab interno intraluminal occlusion of the AGV tube was performed. After revision surgery, it was observed that IOP increased to 10 mmHg and BCVA increased to 0.1. In cases with postoperative hypotony due to excessive filtration after glaucoma drainage device implantation, ab interno occlusion of the tube lumen with a 4-0 polypropylene suture is an effective, safe, and inexpensive alternative surgical method that can be performed without causing conjunctival damage or subconjunctival scarring.

Keywords: Ab interno tube occlusion; Ahmed glaucoma valve; Choroidal effusion; Hypotony maculopathy; Polypropylene suture.

Figure 1

Due to hypotony before revision surgery, it is seen that the cornea has lost its transparency, corneal folds are present, and the anterior chamber depth has become shallow.

Figure 2

(a) Optical coherence tomography (OCT) section of the posterior pole before Ahmed glaucoma valve implantation. (b) OCT image of hypotony maculopathy at postoperative 1^st week of Ahmed glaucoma valve implantation. (c) OCT section of the posterior pole at postoperative 2^nd week of revision surgery.

Figure 3

Ab interno occlusion of Ahmed glaucoma valve tube implant with a intraluminal 4.0 polypropylene suture.

Figure 4

View of the intraluminal 4.0 polypropylene suture.