Clinical and Anterior Segment OCT Predictors of Intraocular Pressure After Phacoemulsification in Eyes with Prior Trabeculectomy.

PRCIS: Lower preoperative IOP, greater bleb height, and a shorter trabeculectomy-to-phacoemulsification interval are associated with greater postoperative IOP elevation in eyes with prior trabeculectomy. PURPOSE: To identify clinical factors and filtering bleb morphological features associated with intraocular pressure (IOP) changes after phacoemulsification in eyes with prior trabeculectomy. PATIENTS AND METHODS: This retrospective, consecutive case series included 76 eyes of 71 Japanese patients who underwent phacoemulsification following primary trabeculectomy. Bleb morphology was evaluated preoperatively using three-dimensional anterior segment optical coherence tomography (AS-OCT). The primary outcome was the change in IOP from baseline to one year after phacoemulsification. Associations between IOP change and pre-phacoemulsification AS-OCT parameters and clinical variables were assessed. For categorical analyses, eyes exhibiting both an IOP increase of >2 mmHg and a percentage IOP increase of >20% at one year were classified into the IOP increase group; the remaining eyes constituted the no IOP increase group. RESULTS: Fifty-one eyes were assigned to the no IOP increase group and 25 eyes to the IOP increase group. Pre-phacoemulsification IOP differed significantly between the groups (P=0.037). A shorter interval from trabeculectomy to phacoemulsification (rₛ=-0.320, P=0.005), lower pre-phacoemulsification IOP (rₛ=-0.424, P<0.001), and greater maximum bleb height (rₛ=0.284, P=0.013) were significantly associated with a larger IOP increase. Multivariable linear regression confirmed independent associations of IOP change with the interval (P=0.005), pre-phacoemulsification IOP (P=0.003), and maximum bleb height (P=0.022). CONCLUSIONS: IOP elevation after phacoemulsification in post-trabeculectomy eyes was associated with lower IOP and greater bleb height before phacoemulsification, as well as with a shorter trabeculectomy-phacoemulsification interval.