Correlation Between the Indiana Bleb Appearance Grading Scale and Intraocular Pressure After Phacotrabeculectomy

Abstract

To investigate the relationship between bleb morphology, recorded using the Indiana Bleb Appearance Grading Scale (IBAGS), and intraocular pressure (IOP) after phacotrabeculectomy. Two years postphacotrabeculectomy, a single observer compared bleb morphology to the IBAGS standard photographs in 76 eyes of 76 patients. In addition, the presence or absence of microcysts was recorded. IOP was also measured. On multivariate analysis increasing bleb height was associated with a low IOP (P=0.017). An increase in IBAGS height score by 1 U resulted in a reduction in IOP of 2.16 mm Hg (95% confidence interval=0.40-3.92 mm Hg). In this study, there was no association between vascularity, bleb extent or microcysts, and IOP. There were no cases of bleb leak in this series. Two years postphacotrabeculectomy increased bleb height, as measured by the IBAGS, was associated with a decrease in IOP, with a 1 point increase in IBAGS height score resulting in a decrease of 2.16 mm Hg. We found no association between bleb extent, vascularity, or the presence or absence of conjunctival microcysts. As there were no cases of bleb leak in this study this characteristic could not be evaluated.