Clinical Evaluation of Intra-Bleb Pigmentation after Trabeculectomy: A Case-Control Study
Boonsong Wanichwecharungruang MD*, Worawan Narumitchai MD*, Somporn Chantra MD*
Affiliation : * Department of Ophthalmology, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand
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.
Keywords : Asian continental ancestry group, Glaucoma, Pigmentation disorders, Trabeculectomy, Treatment outcome
