Choroidal Thickness Decreased in Acute Primary Angle Closure Attacks with Elevated Intraocular Pressure

To study the choroidal thickness (CT) changes in patients having unilateral acute primary angle closure (APAC) attacks with elevated intraocular pressure (IOP).

This study included 23 patients with unilateral APAC attacked eyes. The CT at macular and peripapillary regions were measured in both eyes of the subjects using enhanced depth imaging-optical coherence tomography (EDI-OCT). We compared the CT difference between the two eyes in the same patients.

The average IOP of the attacked eyes was 39.4 ± 11.7 mmHg, significantly higher than the fellow eyes with IOP of 13.3 ± 3.8 mmHg (p < 0.001). Significant difference (p < 0.001) was also found in average subfoveal choroidal thickness (SFCT) of the attacked eyes (208.5 ± 80.6 μm) and the fellow eyes (258.4 ± 83.8 μm). In addition, the CT of the attacked eyes at all locations along the horizontal and vertical sections across the macular fovea was significantly smaller compared with the fellow eyes (p < 0.05). At the peripapillary region, the CT of the temporal, superotemporal and inferotemporal segments to the optic disk was significantly thinner than that in the fellow eyes (p < 0.05).

The CT of the APAC attacked eyes with extensive high IOP was significantly thinner than that of the fellow eyes with normal IOP. The changes have possibly resulted from the shrinkage of the blood vessel within the choroid and will lead to the ischemia of the retina.