Effect of Phacoemulsification on Intraocular Pressure in Eyes with Functioning Tube Shunts

Purpose: To evaluate the effect of phacoemulsification on intraocular pressure (IOP) in eyes with functioning tube shunts. Methods: This was a retrospective chart review of primary open-angle glaucoma (POAG) patients with a functioning tube who underwent phacoemulsification and had ≥24 months of follow-up. The primary end point was defined as surgical failure (IOP 21 mmHg) at month 24, progression to no light perception (NLP) vision, glaucoma reoperation, or implant removal. Surgical failure defined as IOP 18 and 15 mmHg, changes in visual acuity (VA), IOP, and number of medications were assessed. Results: Twenty-seven eyes of 27 patients with moderate or severe POAG were included. The mean age of the patients was 64.2 ± 10.8 years. The interval between the tube shunt and phacoemulsification was 28.8 ± 25.0 months. At the end of the study, four (14.8%) eyes met the failure criteria; the average time to failure was 9.3 ± 3.8 months. The causes of failure were high IOP in two (50.0%) and glaucoma reoperation in two (50.0%) eyes; however, no eyes progressed to NLP vision. Surgical failure defined as IOP 18 and 15 mmHg showed an increasing failure rate (18.5% and 48.5%, respectively). The mean IOP and medications number remained stable at month 24 compared to baseline (P = 0.131 and P = 0.302, respectively). Initially, VA showed improvement, with the greatest improvement at 6 months (P = 0.001), but at 24 months the improvement was no longer significant (P = 0.430). Conclusion: Phacoemulsification in patients with functioning tubes did not change the mean IOP in most of the patients (86.2%); the number of medications also did not increase.