Clinical evaluation of intra-bleb pigmentation after trabeculectomy: a case-control study.

OBJECTIVE To evaluate the clinical status of a filtering bleb with visible pigment (intra-bleb pigmentation, IBP), in a case-controlled manner. MATERIAL AND METHOD Forty-one patients with IBP and 40 patients without visible pigment in blebs (controls) were enrolled from the authors' clinic. All patients underwent either trabeculectomy alone or combined cataract extraction with intraocular lens implantation and trabeculectomy. RESULTS Mean follow-up period was 22.8 months. Complete success (final IOP < 22 mmHg without additional treatment) was achieved more often in IBP patients (82.9%) than in controls (60%, p = 0.022). Median survival time was greater in IBP patients (49.9 +/- 0 months) than in controls (35.5 +/- 4.9 months, p = 0.013). Regression analysis revealed that IBP was associated with thin and cystic blebs (p = 0.023). Sex, age, eye, diagnosis, procedure, and mitomycin C had no effect on IBP development. IBP grading, location, and appearance did not relate to the success rate or bleb characteristics. CONCLUSION IBP appears to be a favorable sign in filtering blebs, in terms of complete success and survival time, because IBP is associated with thin-walled blebs. Clinicians should carefully observe patients for IBP when evaluating filtering blebs.