Trypan blue used to evaluate bleb

Trypan blue can be used to assess the functionality of a trabeculectomy bleb, according to a group of Indian surgeons.

Shishir Agrawal, MS, DNB, FRCS, and colleagues in Meerut reported their use of the technique in 15 eyes of 15 patients with trabeculectomy blebs who were undergoing phacoemulsification. IOP was controlled in all patients without medication, and their glaucoma was stabilized. Thirteen of the eyes had minimal, diffuse or well-formed blebs, and two patients had clinically absent or flat blebs.

The dye was injected into the anterior chamber during cataract surgery to stain the capsule and aid in capsulorrhexis. In all patients with blebs and one without, the trypan blue was transmitted into the bleb area. The dye progressively filled and concentrated in the bleb, the authors said. As the surgery progressed, the dye started to dilute and was washed away by the fluid flow into the bleb. By the time the surgery was completed, the bleb dye had diluted to almost half its original concentration. Within 12 to 24 hours, no trace of dye remained.

The study is published in the January issue of the Journal of Cataract & Refractive Surgery.