Anterior chamber depth in plateau iris syndrome and pupillary block as measured by ultrasound biomicroscopy.

Abstract

To quantitatively analyze the anterior chamber depth (ACD) in patients with pupillary block and plateau iris syndrome. Retrospective, consecutive, observational case series. We measured the ACD in 318 eyes of 318 patients who had been diagnosed by ultrasound biomicroscopy as having either pupillary block or plateau iris syndrome. Pupillary block patients were all preiridotomy and plateau iris patients were all postiridotomy. Anterior chamber depth was measured axially from the internal corneal surface to the lens surface using the ultrasound instrument's internal measuring capability. The mean ACD in patients with plateau iris syndrome (n = 181) was significantly smaller than the hypothesized normal ACD (2.04 +/- 0.30 mm vs 3.0 mm, P =.0001). The mean ACD in patients with pupillary block (n = 137) was also significantly smaller than the hypothesized normal ACD (2.17 +/- 0.30 mm vs 3.0 mm, P =.0001). The mean ACD in patients with plateau iris syndrome was significantly smaller than the ACD in patients with pupillary block (2.04 +/- 0.30 mm vs 2.17 +/- 0.30 mm, P =.001). Review of the literature suggests that patients with plateau iris have a normal or deeper axial ACD compared with pupillary block. This study found that the ACD associated with plateau iris syndrome is shallower than normal and also shallower than in pupillary block.