The role of YAG-laser iridotomy in pigment dispersion syndrome.

We determined iris configuration and posterior-chamber depth before and after YAG-laser iridotomy in 20 eyes with pigment dispersion syndrome using high-resolution ultrasound and measured the intraocular pressure after a mean of 9.1 months. The iris configuration and posterior-chamber depth of our patients were compared with those of an age- and refraction-matched control group of 20 eyes without pigment dispersion. In the patient group, 8 eyes had a concave iris configuration with shallow posterior chambers and 12 eyes had planar irides. In the former group the posterior-chamber depth increased significantly after treatment. In the latter group it did not change. In the normal control group, three subjects also had concave irides. There was a significant correlation between posterior-chamber depth and refraction in patients with pigment dispersion syndrome, but not in the normal control group. After the follow-up period the intraocular pressure of treated eyes was not significantly lower than that of untreated eyes. Iris concavity can also occur in normal individuals and may therefore be only a pathogenetic cofactor in the pigment dispersion syndrome. Laser iridotomy proved to flatten irides but did not significantly decrease the intraocular pressure.