Effectiveness of laser peripheral iridoplasty in the treatment of acute primary angle closure

Summary Background Acute primary-angle closure (APAC) is a common condition in Asian populations due to pupillary block and anterior chamber angle closure. Argon laser peripheral iridoplasty (ALPI) involves laser impacts, the thermal effect of which is to retract the periphery of the iris, subsequently widening the iridocorneal angle and facilitating drainage. Purpose To evaluate the effectiveness and safety of ALPI as a treatment for APAC. Patients and methods An uncontrolled, interventional and prospective study was conducted including 26 eyes of 24 patients with APAC treated by ALPI at the Vietnam National Eye Hospital from December 2019 to August 2020. Intraocular pressure (IOP) before and after ALPI, visual acuity, cornea, pupil, and irido-cornea angle were analyzed. Angle width in Shaffer grades was assessed. Angle configuration was also evaluated using angle opening distance (AOD500), trabecular-iris angle (TIA) measured in UBM images. Results The mean IOP before ALPI of the group decreased from 44.8 ± 9.0 mm Hg to 27.6 ± 8.4 mm Hg at 15 min, 21.4 ± 8.7 mm Hg at 30 min, 16.5 ± 8.9 mm Hg at 60 min, and 13.1 ± 9.1 mm Hg at 120 min after the procedure. Before treatment, almost affected eyes had closed angles or very narrow angles. After the treatment, there was an increase in the angle width, and the mean TIA increased from 0.13 ± 0.68° to 17.2 ± 12.3°; the mean AOD500 increased from 0.5 ± 2 μm to 123.9 ± 92.5 μm ( p < 0.001). One eye had a peripheral corneal burn. Conclusion It appears that ALPI is effective and safe in controlling IOP in acute primary-angle closure.