The incidence of acute angle closure in Scotland: a prospective surveillance study

Purpose: To estimate the incidence, and describe the clinical features and short term clinical outcomes of acute angle closure (AAC).
Methods: Patients with newly diagnosed AAC were identified prospectively over a 12-month period (November 2011 to October 2012) by active surveillance through the Scottish Ophthalmic Surveillance Unit reporting system. Data were collected at case identification and at 6 months follow up.
 Results: There were 114 cases (108 patients) reported, giving an annual incidence of 2.2 cases (95% CI 1.8–2.6) or 2.0 patients (95% CI 1.7 - 2.4) per 100,000 in the whole population in Scotland. . Precipitating factors were identified in 40% of cases. Almost 1 in 5 cases was associated with topical dilating drops. Best corrected visual acuity (BCVA) at presentation ranged from 6/6 to perception of light. The mean presenting intraocular pressure (IOP) was 52 mmHg (SD 11). Almost 30% cases had a delayed presentation of 3 or more days. At 6 months follow up, 75% had BCVA of 6/12 or better and 30% were found to have glaucoma at follow up. Delayed presentation (≥3 days) was associated with higher rate of glaucoma at follow up (22.6% vs 60.8%, p<0.001), worse VA (0.34 vs 0.74 LogMAR, p<0.0001) and need for more topical medication (0.52 vs 1.2, p=0.003) to control IOP. 
Conclusion: The incidence of AAC in Scotland is relatively low compared to the Far East countries, but in line with previous European data. Almost 1 in 5 cases were associated with pupil dilation for retinal examination.