- A bladder-like structure more than 5 mm in diameter with thin walls that may be full of fluid. Also called a bulla.
* * *1. A large flaccid vesicle. 2. An acquired lung cyst, usually less than 1 cm in diameter, similar to but smaller than a bulla, which is thought to be the most common cause of spontaneous pneumothorax. Blebs occur mainly in the apex of the lung.- filtering b. a blister of conjunctiva resulting from glaucoma surgery by which a flap of sclera is created in the eye wall, allowing aqueous humor to percolate out of the eye and underneath the conjunctiva, thus lowering intraocular pressure. SYN: filtering cicatrix.- pulmonary b. air-filled alveolar dilation less than 1 cm in diameter on the edge of the lung at the apex of upper lobe or superior segment of lower lobe; usually occurs in young people and can rupture, producing primary pneumothorax. Cf.:pulmonary bulla.
* * *bleb 'bleb n2) something resembling a bleb esp a vesicular outpocketing of a plasma or nuclear membranebleb·bing -iŋ nbleb·by 'bleb-ē adj
* * *n.a blister or large vesicle. A filtering bleb is a blister-like cyst underneath the conjunctiva resulting from trabeculectomy, a surgical procedure commonly used in the treatment of glaucoma.
* * *(bleb) bulla (def. 1).
Medical dictionary. 2011.