Changes in filtering bleb morphology after bleb-related infection.

Abstract

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. 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. 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. 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.