Online Photo Diagnosis

By Gregory W. DeNaeyer, OD, FAAO

Nasal Bleb

Figure shows the left eye of a 77-year-old male patient who had an enlarged nasal bleb and secondary exotropia. The patient was being managed for primary open angle glaucoma and had a trabeculectomy approximately one year prior to his emergency visit. He complained of a large bubble in his eye, which was now turned out. The patient’s vision dropped from 20/60 to count fingers. Applanation pressure of his left eye was 16mm Hg.

Trabeculectomy is a glaucoma filtering procedure that allows aqueous to percolate into the subconjunctival space, where it is eventually absorbed. A raised dome, or filtering bleb, is formed as aqueous moves out of the anterior chamber, which results in decreased intraocular pressure. Filtering blebs are most commonly positioned behind the superior lid just above the limbus.

For this patient, the filtering bleb expanded nasally and became excessively large. The bleb was drained with a 22-gauge needle, and a 20mm bandage lens was placed on the eye to tamponade elevation. The nasal elevation returned, and the patient eventually had a bleb revision to decrease aqueous flow. Compression sutures over the nasal bleb were temporarily added to decrease the conjunctival elevation. Although the nasal bleb resolved, a dellen with 80% thinning resulted from poor tear coverage secondary to the bleb.

At his last follow-up visit, the patient’s vision was 20/25 and his intraocular pressure was stable using glaucoma medications.