ULTRASOUND BIOMICROSCOPY IN PIGMENT DISPERSION SYNDROME

Purpose: To examine the positional relations of the iris, lens, ciliar y processes, and zonules in eyes with the pigment dispersion syndrome (PDS). Methods: High-resolution, anterior segment ultrasound biomicros copy was performed on 16 untreated eyes of 11 patients with PDS. Scann ing was repeated on four eyes after miotic treatment and four eyes aft er laser iridotomy. Results: Mid-peripheral iris concavity could be de monstrated in 56%, irido-zonular contact in 25%, and irido-ciliary pro cess contact in 75% of untreated eyes with PDS. Repeat scanning after laser iridotomy or pilocarpine therapy showed resolution of the iris c oncavity and irido-zonular contact in all eyes receiving these therapi es. Irido-ciliary process contact persisted in some eyes. Conclusion: The authors' findings demonstrate the structural relations among the i ris, lens, zonules, and ciliary processes in vivo that characterize th e PDS. Miotic therapy and laser iridotomy eliminate the iris concavity in all patients with this finding, supporting the hypothesis of rever se pupillary block. Irido-ciliary process contact may be another mecha nism causing release of pigment. This issue merits further clinical an d histologic study.