Changes in filtering bleb morphology after bleb-related infection.

Purpose: To verify, by use of data collected by the Japan Glaucoma Society Survey of Bleb-related Infection (JGSSBI), that bleb morphology changes within 12 months of the development of bleb-related infection.
Methods: JGSSBI data from 57 eyes of 57 patients with primary open-angle glaucoma and normal tension glaucoma who developed a bleb-related infection were analyzed. Morphological features of the blebs were graded by use of a predetermined grading system. Multiple logistic regression analysis was conducted to identify factors relating to bleb morphology which were associated with poor outcome.
Results: Bleb sizes, including both circumferential and tangential lengths, were significantly smaller for stage IIIa/IIIb infections than for stage I/II bleb infections (P = 0.009 and P = 0.026 for the circumferential and tangential lengths, respectively; Fisher's direct probability test). The bleb wall also became significantly thicker during stage IIIa/IIIb infections (P = 0.003). After infection, intraocular pressure (IOP) increased significantly for all cases but was no different in the three subgroups (i.e. stage I, stage II, and stage IIIa/IIIb bleb infections). Multiple logistic regression analysis revealed that a stage III infection was significantly associated with a poor outcome for the bleb.
Conclusions: This study revealed that the filtering bleb became smaller, both tangentially and circumferentially, and thicker, after stage III infections than after stage I or II infections.