Outcome of functioning filtering blebs after pars plana vitrectomy

BACKGROUND AND OBJECTIVE: To determine the status of filtering bleb function following pars plana vitrectomy. PATIENTS AND METHODS: The authors retrospectively reviewed patients with functioning filtering blebs undergoing pars plana vitrectomy. RESULTS: Twenty-three eyes with functioning filtering blebs underwent pars plana vitrectomy. Postoperatively, 7/23 (30%) of the eyes had moderate (5 to 20 mm Hg) intraocular pressure (IOP), 8/23 of the eyes had IOP persistently greater than 20 mm Hg, and 7/23 of the eyes had IOP of less than 5 mm Hg. One of 7 eyes that underwent vitrectomy within 6 weeks after trabeculectomy maintained bleb function, whereas 6 of 16 eyes that underwent trabeculectomy 6 weeks or later maintained bleb function. Loss of bleb function occurred in the early postoperative period in the majority of the patients. Prior antimetabolite therapy was not associated with preservation of bleb function. CONCLUSION: There is a substantial risk of bleb failure following vitrectomy, which is in part related to the often severe nature of the diseases requiring vitreoretinal surgery.