The correlation between ultrasound biomicroscopy of filtering blebs, with or without mitomycin C, and intraocular pressure

摘要

Purpose: To evaluate the presence or absence of filtering blebs, its cavities, differences in diameter, height, wall thickness, seen on ultrasound biomicroscopy (UBM) of eyes submited to trabeculectomy, with or without using mitomicyn C (MMC), and to evaluate the effect of these caracteristics on the intraocular pressure (IOP). Methods: In a nonrandomized fashion, a six-month cohort study of 61 eyes of 44 glaucoma patients examined by UBM, all of which underwent trabeculectomy. Of these, 38 received MMC and 23 did not. All eyes were examined and evaluated post-operatively by UBM, with a 50 mHz probe, using the technique described by Pavlin in 1991 (Pavlin et al., 1991). Results: Bleb height was 1.80 ± 0.74 mm in eyes with MMC and 1.40 ± 0.53 mm in the ones without MMC. The thickness of the bleb wall was 0.91 ± 0.59 mm in eyes with MMC and 0.51 ± 0.45 mm in the ones without MMC. IOP measured was 12.37 ± 5.45 mmHg in eyes with MMC and 14.91 ± 5.48 mm in the ones without MMC. Conclusions: UBM study showed that bleb height was the main influencing factor in lowering IOP. The bleb wall was significantly thicker in eyes with MMC than in the ones without MMC. Decrease of IOP was significantly higher in eyes with MMC, with an average difference of 2.54 mmHg.