[Incidence of encapsulated bleb after filtering surgery].

OBJECTIVE

To determine the incidence of encapsulated bleb (EB) after filtering surgery, and the risk factors for the development of this complication, especially those related with the surgical procedure.

METHODS

Ninety eyes that were submitted to trabeculectomy were prospectively studied. Lens extraction was associated in 56 eyes (62.9%). All patients were followed up for at least 3 months.

RESULTS

There were clinical characteristics of encapsulation in 29 eyes (32.3%) and EB with a peak IOP of 25 mmHg or higher in 14 eyes (15.7%). The incidence of EB formation was 20.5% in men and 11.8% in women (p.044). The incidence of EB was higher in the trabeculectomy group alone (24.2%) than in the group in which it was associated to cataract surgery (10.5%) (p.003). There were clinical characteristics of encapsulation in 40.7% of primary open angle glaucoma (p.041). EB was significantly associated with an increased failure rate (21.4%) when compared to normal blebs (5.55% failure rate) (p<.001).

CONCLUSIONS

The encapsulated bleb is significantly more frequent in the male gender and thick conjunctivas and in trabeculectomy alone versus trabeculectomy associated to cataract surgery. It means a significantly greater risk of failure after surgery in the short term.