A comparison of two approaches to managing acute primary angle closure in Asian eyes

Henrietta Ho,¹ Paul T Chew,² Chelvin Sng,^1,2 Huiqi Huang,¹ Tin Aung,^1,2 Shamira A Perera<sup>1,2

1</sup>Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; ²Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore

Purpose: To review the management regimes of acute primary angle closure (APAC) in two hospitals in Singapore, and to identify the incidence of and risk factors for progression to glaucomatous optic neuropathy.
Methods: We conducted a retrospective review of 40 patients from National University Hospital (NUH) and 52 patients from Singapore National Eye Centre (SNEC) who were diagnosed with APAC. Patients were treated with similar protocols of intensive medical therapy until laser peripheral iridotomy could be performed. In the event of failed medical treatment, patients at NUH only underwent laser iridoplasty. The 1-year outcomes were reviewed.
Results: The demographic features of patients and presenting intraocular pressures (IOP) were similar in both centers. More patients from NUH presented within 3 days of symptom onset, compared to those from SNEC (90.0% versus 71.2%, respectively) (P = 0.037). The mean ± standard deviation time to break the attack was 18.2 ± 32.9 hours at SNEC and 9.80 ± 10.6 hours at NUH (P = 0.11). The mean follow up duration was 18.8 ± 14.0 months. Nineteen patients (36.5%) from SNEC and six patients (22.5%) from NUH developed raised IOP (P = 0.032) within 1-year of the attack. Of these, glaucomatous optic neuropathy developed in thirteen patients (68.4%) from SNEC and all six patients (100%) from NUH. At final review, the mean IOP of the APAC eye was 14.8 ± 4.3 mmHg from SNEC and 13.4 ± 3.0 mmHg from NUH. There was no significant difference in final visual acuity or IOP between both groups.
Conclusion: Treatment strategies in both centers were effective in aborting an APAC attack. The development of raised IOP appears to be associated with a longer period of attack suggesting that greater urgency in aborting APAC attacks may entail better long term outcomes.

Keywords: acute primary angle closure, management, primary angle closure glaucoma