Filtering blebs functionality after trabeculectomy: a clinical and in vivo confocal microscopy study

Abstract

AbstractPurpose To evaluate macroscopic and microscopic morphological features of filtering blebs after trabeculectomy with Mitomycin C (MMC) or 5‐Fluorouracil (5‐FU) and correlate them with function.Methods Retrospective case control study of 28 eyes (21 patients) submitted to trabeculectomy (15 with MMC and 13 with 5‐FU) and 11 eyes (10 patients) treated medically. Ophthalmologic examinations included Goldmann applanation tonometry, slit‐lamp examination and photography (Moorfields bleb grading system classification) and in vivo confocal microscopy (Heidelberg Retina Tomograph II, Rostock Cornea Module). Eyes were classified into 3 groups: control, functioning blebs (Intraocular pressure (PIO)<21mmHg without therapy) and nonfunctioning blebs (PIO<21mmHg with therapy or ≥21mmHg).Results Biomicroscopically, functioning blebs, in comparison to nonfunctioning blebs, showed a significant increase in the central (p=0,009) and maximal (p=0,017) bleb area and a decrease in central (p=0,021) and maximal (p=0,028) bleb vascularization. When comparing successful with failed blebs, in vivo confocal microscopic showed a significant increased number of epithelial microcysts (p=0,014), a liquid content of epithelial microcysts (p=0,008), a lower density of stromal connective tissue (p=0,039) and a decreased number (p=0,041) and diameter (p=0,045) of the vessels. All morphological findings were similar when comparing the usage of MMC with the usage of 5‐FU (p>0,05).Conclusion This study suggests that both biomicroscopy and in vivo confocal microscopy findings can lead to a better understanding and management of filtering blebs.