Argon laser peripheral iridoplasty (ALPI) versus systemic intraocular pressure lowering medications as the immediate management for phacomorphic angle closure

Abstract

Purpose: To compare the efficacy and safety of argon laser peripheral iridoplasty (ALPI) to systemic intraocular pressure (IOP) lowering medications in the immediate management of phacomorphic angle closure. Patients and methods: This was a prospective randomized controlled study conducted at a district hospital in Hong Kong, China. Consecutive cases of phacomorphic angle closure were recruited from December 2009 to December 2010. Patients received intravenous (IV) and oral carbonic anhydrase inhibitor or ALPI as the initial treatment. IV mannitol was administered in both groups for presenting IOP > 60 mmHg or IOP > 40 mmHg 2 hours post treatment. The following perimeters were compared between the 2 arms: Snellen best correct visual acuity (BCVA); duration of symptoms; presenting IOP; IOP at 15 minutes, 30minutes and hourly after treatment until IOP < 25 mmHg; post-op angle, retinal nerve fibre layer (RNFL), endothelial count, BCVA and IOP. Results: Ten consecutive cases were included in the study. Six cases received medication therapy and 4 received ALPI. The mean age was 79.7 ± 7.2 in the medical therapy group and 78.3 ± 11.0 in the ALPI group. The presenting IOP was 50.7 ± 8.4 mmHg and 50.25 ± 6.9 mmHg in the medical therapy and ALPI group respectively. The duration of phacomorphic glaucoma in the medical group was 2.8 ± 3.5 days and 0.9 ± 0.25 days in the ALPI group. In the medical therapy group, 50% (3/6) required IV mannitol and none in the ALPI group. The time taken to reduce the presenting IOP to < 25 mmHg was 115.0 ± 97.0 minutes in the medical therapy group and 18.8 ± 7.5 minutes in the ALPI group. Within the first 30minutes, the drop in IOP was 20.8 ± 13.5mmHg in the medical group and 34.8 ± 3.2mmHg in the ALPI group, representing a 41.0% and 69.3% drop in IOP respectively. The degree of peripheral anterior synechiae (PAS) formation at 3 months was 45 ± 45.3° and 22.5 ± 5° in the medical and ALPI group respectively. The RNFL, angle, endothelial count, post-op VA and IOP were comparable in both groups. Conclusion: ALPI is an effective and safe IOP lowering modality in acute phacomorphic angle closure, offering a more rapid reduction of IOP, avoiding the use of systemic carbonic anhydrase inhibitor and hyperosmotic agents, and with seemingly less PAS formation and comparable post-op results as compared to medical therapy. ALPI should replace medical therapy as first line treatment in phacomorphic angle closure especially in elderly patients cannot tolerable the side effects of systemic IOP-lowering medication.