Changes of anterior chamber architecture induced by laser peripheral iridotomy in acute angle closure crisis.

In acute angle closure crisis (AAC), a laser peripheral iridotomy (LPI) is performed to balance the pressure gradient between anterior and posterior chamber. The hereby induced changes in anterior chamber architecture were analyzed using Scheimpflug photography (SP). SP was performed in eyes with AAC and in fellow eyes (FE) before and after LPI. Intraocular pressure (IOP), anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle width (ACA), and central corneal thickness (CCT) were analyzed. The group consisted of 18 patients (14♀, 4♂; 69 ± 11 years) with unilateral AAC. Mean IOP in AAC eyes decreased from 49.3 ± 2.8 mmHg at presentation to 13.7 ± 1.6 mmHg after LPI (p = 0.001). Mean ACV increased from 48.2 ± 3.6 to 60.6 ± 2.4 mm(3) in AAC eyes (p < 0.001) and from 60.4 ± 4.6 to 74.1 ± 3.7 mm(3) in the FE (p < 0.001). Mean ACD increased from 1.27 ± 0.08 to 1.44 ± 0.06 mm (p = 0.01) in AAC eyes and decreased in FE from 1.72 ± 0.08 to 1.59 ± 0.04 mm (p = 0.5). Mean ACA increased from 16.8 ± 1.6 to 20.5 ± 1.5° in AAC eyes (p = 0.01) and from 18.5 ± 1.4 to 22.6 ± 1.5° in the FE (p = 0.01). Mean CCT did not change significantly in both groups after LPI (AAC p = 0.09; FE p = 0.9) but a statistically significant difference between the two groups was detectable before LPI (p = 0.04) which disappeared thereafter (p = 0.14). Using Scheimpflug photography, a significant difference of ACV, ACD, and ACA can be detected after LPI in eyes suffering from acute angle closure crisis which demonstrates the effectiveness of LPI.