Scanning laser polarimetry in patients with acute attack of primary angle closure

To compare the retinal nerve fiber layer measurements of attacked eyes with their fellow eyes after a single unilateral attack of acute primary angle closure (APAC). Patients with a single episode of APAC in 1 eye, successfully treated with laser peripheral iridotomy, were recruited. Eyes with persistently raised intraocular pressure (IOP) after resolution of the acute attack were excluded. Scanning laser polarimetry was carried out at 6 months after remission of the acute attack. The various parameters between the attacked and the fellow eyes were compared using the Student t-test. Twenty-six patients (24 female and 2 male, mean age 66.9±8.1 years) were recruited. The duration of the APAC ranged from 5 to 98 hours (mean, 36.3 hours). The mean presenting IOP during the acute attack was 62.0±9.4 mm Hg. Only the mean inferior ratio and the ellipse modulation showed a statistically significant difference between the attacked and the fellow eyes among the 12 standard scanning laser polarimetry measurement parameters. No severe retinal nerve fiber layer damage was documented in eyes that suffered a single episode of APAC with duration of attack up to 48 hours. With duration of attack longer than 48 hours, retinal nerve fiber layer damage was detected.