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 $\ge$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 $\pm$ 10.8 years. The interval between the tube shunt and phacoemulsification was 28.8 $\pm$ 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 $\pm$ 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).Themean 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.