[An evaluation of blebs after filtering surgery with the in vivo confocal microscope]

To describe blebs after filtering surgery with a new in vivo confocal microscope.

We retrospectively evaluated 20 filtering blebs of 17 patients after trabeculectomy or deep nonpenetrating sclerectomy. Ophthalmological examinations included slit-lamp examination, applanation tonometry and in vivo confocal microscopy imaging (Heidelberg Retina Tomograph II Rostock Cornea Module). Eyes were classified into three groups: filtering blebs (eight eyes), nonfiltering blebs that were encapsulated or flat (seven eyes) and filtering blebs with mitomycin C (five eyes). In vivo confocal microscopy images were compared to the morphological and functional aspects of filtering blebs.

Filtering blebs had numerous intraepithelial microcysts, whereas nonfiltering blebs had none or few. However, few microcysts were seen in the encapsulated filtering blebs. The connective tissue of filtering blebs was arranged loosely, whereas it was dense in nonfiltering blebs. Filtering blebs with mitomycin C had numerous microcysts and loosely arranged subepithelial connective tissue.

By evaluating filtering blebs at the cellular level, this original method is highly consistent with ex vivo histological examination. In vivo confocal microscopy constitutes a new promising way to understand the wound healing mechanism in filtering surgery.