Outcomes of sequential tube shunts in complicated glaucoma

OBJECTIVE: To evaluate intraocular pressure (IOP) control, change in visual acuity, and complications in eyes that have undergone a second glaucoma tube shunt procedure. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Twenty-two eyes of 22 patients that have undergone sequential tube implants for management of glaucoma. METHODS: Parameters analyzed included IOP, visual acuity, and number of hypotensive agent before each shunt procedure and at last follow-up visit. The overall IOP lowering effect attributable to each tube shunt was calculated. Any ocular complications after the second tube shunt were recorded. Success was defined as an IOP between 6 and 21 mm Hg and a 20% reduction in IOP from the second tube shunt procedure. Qualified successes met one of these two requirements at the last follow-up visit. Total failures did not meet any of the above criteria, required additional surgical intervention to lower IOP, or both. MAIN OUTCOME MEASURES: Intraocular pressure control, visual acuity preservation, and complications. RESULTS: At the last follow-up visit, the average percent reduction in IOP from both tube shunt procedures was 42+/-21%. The average percent IOP reduction from the second tube shunt was 33+/-17%. Eleven (50%) patients met the criteria for success, 8 (36.4%) patients were qualified successes, and 3 (13.6%) were failures. The median number of hypotensive agents decreased from two to one. Ten patients experienced new or worse pseudophakic bullous keratopathy after the second tube shunt, six of whom underwent penetrating keratoplasty. Thirteen (59%) patients maintained visual acuity within one line of their second tube shunt pre-operative Snellen visual acuity. Seven (32%) patients lost more than 2 lines, and one patient lost light perception. CONCLUSIONS: Although corneal morbidity is a common complication, a second tube shunt does not cause higher-than-expected rates of other complications associated with tube shunt surgery. Eyes that undergo a second tube shunt procedure can achieve pressure control, require fewer hypotensive agents, and may maintain stable visual acuity.