Purpose: To evaluate the efficacy of argon laser peripheral iridoplasty (ALPI) on patients with severe acute primary angle closure (APAC), who have responded poorly to medical therapy.

Methods: Patients with APAC still had ocular pain, red eye, hazy cornea, closed anterior chamber (AC) angle, and IOP of ≥40 mmHg after two days or more of anti-glaucoma medication were enrolled. All patients underwent ophthalmologic examinations including measurement of visual acuity (VA), best corrected visual acuity (BCVA), intraocular pressure (IOP), biomicroscopy and gonioscopy followed by ALPI immediately and laser peripheral iridotomy (PI) when the cornea became clear. Main outcome measurements included VA, IOP, and post-treatment angle status.

Results: Thirty-six consecutive patients (8 men, 28 women) were identified as having medically unresponsive APAC, with mean age of 54.6±11.7 (range, 37-75). The average time for medical treatment before ALPI was 3.2±1.1 days (range, 2-5). The mean IOP value of the affected eyes dropped from 51.6±7.7 mmHg (range, 41-69) at enrollment to 17.1±4.6 mmHg (range, 10-27) two hours after ALPI. At follow-up day 7, the mean IOP value maintained at 14.8±4.2 mmHg (range, 9-25), which was significant (P=0.000) compared with baseline. The average decrease of IOP in the treated eyes was 36.8±7.4 mmHg (range, 22-51). VA improved in all APAC eyes when the IOP went down. After an average follow-up period of 34.5±1.0 months (range, 33-36), the mean IOP stabilized at 16.3±3.2 mmHg (range, 9-21).

Conclusions: ALPI lowers the IOP of medically refractory cases of APAC though they have responded poorly to anti-glaucoma medication.