Ultrasound biomicroscopy in asymmetric pigment dispersion syndrome and pigmentary glaucoma.

OBJECTIVE To identify differences in anterior chamber anatomy among patients with asymmetric pigment dispersion syndrome and no other discernible cause for the asymmetry. METHODS Ultrasound biomicroscopy and A-scan biometry were performed on both eyes of 13 patients with asymmetric pigment dispersion syndrome without a known cause for asymmetric involvement. A radial perpendicular image in the horizontal temporal meridian detailing the scleral spur, angle anatomy, and iris configuration was obtained for each eye by 2 examiners. RESULTS There were no differences in lens thickness (P = .33), refractive error (P = .84), or axial length (P = .99) between more and less affected eyes. However, the mean +/- SD iris concavity (P<.001), iris-lens contact distance (P = .02), and distance from the scleral spur to the iris insertion (0.42 +/- 0.11 vs 0.29 +/- 0.06 mm) (P = .002) were greater in the more affected eye of each patient. CONCLUSION A more posterior iris insertion predisposes to the phenotypic expression of pigment dispersion syndrome.