Abstract
Purpose:
Avascular bleb formation after trabeculectomy (Trab) with mitomycin C (MMC) is associated with undesirable side effects such as late-onset bleb leak and bleb infection. A fornix-based conjunctival flap is reported to be less likely to result in a thin avascular bleb than a limbus-based flap. However, the procedure cannot prevent bleb avascularity perfectly. As a first step to find out the factors associated with avascular bleb formation, we prospectively followed up the bleb morphology and evaluated the bleb avascularity quantitatively after trab with MMC using a fornix-based conjunctival flap.
Methods:
Consecutive patients who underwent trab with MMC (0.4mg/ml, 4 minutes) using a fornix-based conjunctival flap were enrolled. The eyes with insufficient intraocular pressure (IOP) reduction (IOP >21mmHg or >20% IOP reduction from baseline) or subsequent surgical bleb revision were excluded. Bleb photos were taken periodically (1, 3, 6, 12, 18 months postoperatively). Avascular area of the bleb were determined with bleb photos and expressed as a percentage of scleral flap size.
Results:
One hundred and nine eyes of 96 patients were analyzed. Sixty eyes (55%) showed avascular area in the bleb at the final follow-up visits. Postoperative avascular area at 1,3,6,12, and 18 months was 4±11%, 24±60%, 47±97%, 44±91%, and 53±102%, respectively. Avascular area after 6 months postoperatively was significantly larger than that at 1 month postoperatively (p<0.01). Avascular area became smaller (54±77%) in 17 eyes (28%). No bleb infections were observed during the follow-up periods.
Conclusions:
Avascular area in the bleb was observed in more than half of eyes after trab with MMC using a fornix-based conjunctival flap. The avascular area became significantly larger until 6 months postoperatively, while it regressed in some eyes.