Purpose
To describe the demographics, efficacy, and complications of eyes that have undergone a second glaucoma tube shunt procedure.
Methods
A retrospective review of eyes that underwent a second glaucoma drainage implant (GDI) surgery from 2006 to 2013 was conducted. Eyes with a minimum follow up of at least three months were included. Primary outcome measures included intraocular pressure (IOP) reduction and failure rates. Secondary outcome measures included glaucoma medication use and number of reoperations. Success was defined as IOP<22 mmHg and IOP >5 mmHg with at least 25% reduction in IOP at three months follow up or more. Failure was defined as the lack of success, the need for another glaucoma surgical procedure or loss of light perception vision.
Results
Fifty eyes (48 patients) had a mean follow up of 25.1 ± 23.2 months. Sixty-four percent of second GDIs were an Ahmed-FP7 valve implant (New World Medical, Inc., Rancho Cucamonga, CA) and 24% were either a Baerveldt-350 or 250 implant (Abbott Medical Optics, Inc., Santa Ana, CA). Fifty percent of second GDIs were placed in the inferotemporal quadrant and 30% were place in the inferonasal quadrant. The average IOP reduction at one-year follow up was 43% (range 18-69%). The failure rate at one-year follow up was 42% (95% confidence level 29-57%) (Figure 1). The number of postoperative glaucoma medications at one-year follow up was reduced from 3.7 ± 1.2 preoperatively to 1.8 ± 1.3 medications postoperatively. Four eyes required reoperation for better IOP control and 6 eyes required reoperation for complications.
Conclusions
Most eyes undergoing a second GDI can achieve adequate IOP control with fewer hypotensive agents. Patients should be counseled for the possible need for another glaucoma surgery for IOP control or tube revision. This is the largest study to date documenting the postoperative course of sequential GDIs. The postoperative IOP control and reduction in hypotensive agents in this case series is similar to previous studies.
Keywords: 462 clinical (human) or epidemiologic studies: outcomes/complications