Implantation of Second Glaucoma Drainage Devices After Failure of Primary Devices

BACKGROUND AND OBJECTIVE: To evaluate the efficacy and safety of implantation of a second glaucoma drainage device for eyes that have failed a primary device. PATIENTS AND METHODS: Medical records of patients receiving a primary glaucoma drainage device at Bascom Palmer Eye Institute from January 1987 to October 1998 were reviewed, of which 18 eyes of 18 patients were studied. Patients failing a primary glaucoma drainage procedure and receiving a second glaucoma drainage device were included in this study. The second eye in the same patient was excluded if a second drainage implant was required. All patients received a second device in a standardized fashion with the drainage tube inserted in the anterior chamber. Main outcome measures included: visual acuity, intraocular pressure (IOP), antiglaucomatous medication, length of follow up, and surface area of glaucoma drainage device. Success was defined as an IOP less than or equal to 2 1 mm Hg with or without medications, and at least a 20% reduction in IOP, without the need for additional glaucoma procedures. RESULTS: The mean postoperative IOP (19.6 ± 9.4 mm Hg; range, 8-50 mm Hg) was significantly (P = 0.006) lower than the mean preoperative IOP (29.5 ± 8. 1 mm Hg; range, 20-52 mm Hg) at last follow up (mean 19.6 ± 13.6 months; range, 6-47 months). The mean number of postoperative antiglaucomatous medications (2.2 ± 1.2; range 0-4) was statistically similar (P = 0.2) to mean preoperative number of antiglaucomatous medications (2.6 ± 1.2, range 1-4). Using Kaplan-Meier estimates, successful IOP reduction was observed in 89%, 83%, 63%, and 37% of eyes at 6 months, 1, 2, and 3 years, respectively. Four patients (21%) had a decline in visual acuity. CONCLUSIONS: Implantation of secondary glaucoma drainage devices may be useful in eyes that have failed primary devices. [Ophthalmic Surg Lasers 2002;33:37-43]