Cutting Edge Glaucoma - Issue 2

CATARACT SURGERY IN PATIENTS WITH GLAUCOMA DRAINAGE IMPLANTS: THE HOOKED TUBE TECHNIQUE • 7  Temporary occlusion of the GDI tube during cataract surgery with a flexible iris retractor hook, i.e., the hooked tube technique, seems to avoid certain risks of earlier postoperative IOP fluctuations. Flexible iris hooks were originally developed to enlarge a small pupil intraopera- tively [7]. Nowadays, there are many commercially available disposable and flexible iris retractor hooks which can also be used in the hooked tube technique. In the present study, the GDI tube was occluded with an iris retractor hook before the anterior chamber was filled with viscoelastic material. This is important because otherwise the viscoelastic material may temporarily obstruct the GDI. The internal diameter of the silicone tube is 0.3 mm. After bending the GDI tube with the hook, the lumen of the soft tube is occluded at the site where the tube enters into the ante- rior chamber. This prevents the debris flow through the tube during the phacoemulsification. In addition, the iris hook itself with diameter of 0.1 mm inside the tube creates a mechanical barrier against to the lens debris during the surgery. The hooked tube technique seems to be a valuable tool for avoiding postoperative IOP spikes with minimal complications in cataract surgery patients with prior GDIs. Only one patient (6%), aged 86 years, had postoperative visual acuity reduced due to corneal decompensation. This is about the same rate as reported previously with phacoemulsification in GDI eyes without tem- porary intraoperative occlusion of the tube [2]. The bent tube may also give the cataract surgeon more working space in the anterior chamber in cases where the intracameral part of the GDI tube is quite long. In conclusion, I have successfully used the hooked tube technique in all patients where phacoemulsification cataract surgery was needed after previous GDI procedure. The limitations of this study are its retrospective design and small number of study patients. However, the hooked tube technique may help facilitate better IOP control, especially in advanced glaucoma patients with a GDI after cataract surgery. These patients are very sensitive to IOP spikes due to large visual field defects. None of the patients with the hooked tube technique required extra antiglaucoma medications or faced IOP spikes during the postoperative period. Compliance with Ethical Standards Conflict of interest The author declares that he has no conflict of interest. Ethical Standards: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed Consent: The study was a purely retrospective analysis and did not require informed consent from the participants. All patient data were deidentified and kept confidential. No identifiable patient data were collected. References 1. Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL (2012) Tube versus trabeculectomy study group. Treatment outcomes in the tube versus trabeculectomy (TVT) study after five years of follow-up. Am J Ophthalmol 153:789–803. 2. Gujral S, Nouri-Mahdavi K, Caprioli J (2005) Outcomes of small-incision cataract surgery in eyes with preexisting Ahmed glaucoma valves. Am J Ophthalmol 140:911–913. 3. Erie JC, Baratz KH, Mahr MA, Johnson DH (2006) Phacoemulsification in patients with Baerveldt tube shunts. J Cataract Refract Surg 32:1489–1491.