Effect of Pilocarpine on the Iridocorneal Angle Following Phaco-Kahook Dual Blade Goniotomy in Japanese Glaucoma Patients.

PRCIS

Combined phacoemulsification and Kahook Dual Blade goniotomy significantly increased the iridocorneal angle dimensions in POAG/NTG, but postoperative pilocarpine instillation did not further increase the dimensions, suggesting that this postoperative therapy offers limited clinical benefit.

PURPOSE

Topical pilocarpine is frequently administered for months after Kahook Dual Blade goniotomy combined with phacoemulsification (phaco-KDB) to prevent peripheral anterior synechia formation. To clarify if it offers benefits, we investigated whether iridocorneal angle dimensions after phaco-KDB show further changes after topical pilocarpine instillation in the Japanese primary open angle glaucoma (POAG) or normal tension glaucoma (NTG) eyes.

MATERIALS AND METHODS

Thirty eyes of 30 consecutive Japanese POAG or NTG patients (age 69.4±12.4 y) undergoing phaco-KDB were investigated using anterior segment swept-source optical coherence tomography (CASIA2, Tomey). Angle opening distance (AOD) and trabecular-iris space area (TISA) were measured at 5 locations: 250 and 500 µm distance from the scleral spur on both the temporal and nasal sides. Measurements were taken preoperatively and within 1 month postoperatively before and 1 hour after the instillation of 2% pilocarpine.

RESULTS

The median spherical equivalent was -2.75 D (range: -18.5 D to +2.25 D). All postoperative AOD and TISA values (before pilocarpine instillation) increased clinically and statistically significantly at all 4 locations compared with the preoperative values ( P <0.001). One hour after pilocarpine instillation TISA in all and AOD in 3 of the 4 measurement locations remained unchanged ( P ≥0.135). AOD at the temporal 500 µm position increased significantly ( P <0.01) but the change was minimal (mean change=0.07 mm).

CONCLUSIONS

Phaco-KDB effectively widened the iridocorneal angle in this Japanese POAG and NTG cohort. However, angle widening did not increase further after pilocarpine instillation. This suggests that postoperative pilocarpine therapy after phaco-KDB offers limited benefit.