JUL 10, 2013
This prospective randomized clinical trial showed that both phacoemulsification alone and phacoemulsification combined with viscogonioplasty (phaco-VGP) resulted in opening of the drainage angle, deepening of the anterior chamber and reduction of peripheral anterior synechiae (PAS) extent in eyes with primary angle-closure glaucoma (PACG). However, eyes that underwent the combined procedure experienced a significantly greater reduction of PAS. While both procedures lead to significant reductions in the use of medications and in IOP, there was no statistically significant difference between the two.
Sixty-five eyes of 55 patients diagnosed with PACG were randomized to undergo phacoemulsification alone or phaco-VGP and completed the six-week trial. They underwent indentation gonioscopy and anterior segment optical coherence tomography (AS-OCT) preoperatively and six weeks after surgery.
The mean extent of PAS was significantly reduced from 127.7 to 95.0 degrees (P < 0.001) by phacoemulsification alone, and from 174.0 to 77.3 degrees (P < 0.001) by phaco-VGP. Angle-opening distance and trabecular-iris space-area measured by AS-OCT increased significantly after phacoemulsification alone and phaco-VGP (P < 0.001 for both). Although the change was greater in the phaco-VGP group, it did not reach statistical significance. Anterior chamber depth increased and lens vault decreased after both procedures, although the amount of change in each was not significantly different between the two groups.
While the study was not powered to detect a difference in IOP between the two surgical groups, the authors say the similarities in their effects suggest that IOP is not significantly improved by adding VGP when performing phacoemulsification. They conclude that a longer follow-up period and larger number of subjects are needed to determine the effect of adjunctive VGP on IOP.
They also note that the amount of increase in anterior chamber depth highly correlated with preoperative lens vault in both groups. Therefore, lens vault might be a determinant for long-term IOP control after phacoemulsification.