A case of persistent hypotony following 23-gauge vitrectomy.

We report here a case in which ciliary detachment related to the preparation of a scleral wound was suspected as the cause of persistent hypotony following 23-gauge vitrectomy for proliferative diabetic retinopathy. Ultrasound biomicroscopy (UBM) was performed following injection of a viscoelastic substance into the anterior chamber to carefully investigate the treatment and cause of persistent hypotony. Deepening the anterior chamber by means of the viscoelastic substance enabled UBM identification of ciliary detachment that had not been detected in the shallow anterior chamber. The extent of ciliary detachment was approximately 8 degrees; however, the detachment could not be seen on gonioscopy. UBM showed no continuity between the anterior chamber and choroid, with findings suggesting that the two structures had been split by posterior traction. The ciliary detachment site was the same site at which a three-port system had been prepared. One advantage of a 23-gauge system is that few complications are associated with the insertion and retraction of instruments. However, the difference in level between the cannula and trocar may result in ciliary detachment even if no resistance is felt when the trocar is inserted.