title: Accommodation and iridotomy in the pigment dispersion syndrome.
abstract: OBJECTIVE
  Iris concavity has been noted in pigment dispersion syndrome, and could have a role in producing iris-zonule contact. Iris concavity is most likely caused by a relative increase in anterior chamber pressure. The method by which this occurs remains speculative. The authors used ultrasound biomicroscopy to examine the role of accommodation in producing iris concavity and to document changes that occur following iridotomy.
  
  
  METHODS
  Thirteen patients with clinically diagnosed pigmentary dispersion and pigmentary glaucoma underwent accommodation studies while being continuously imaged with ultrasound biomicroscopy. Anterior chamber depths were measured and iris configuration noted on distance and near fixation. These studies were repeated in 6 patients following laser iridotomy.
  
  
  RESULTS
  All patients showed a decrease in anterior chamber depth with accommodation. Ten patients had a planar iris configuration on distance fixation and 3 concave. Eleven of 13 patients showed increased concavity of the iris on near fixation as compared with distance fixation. Following iridotomy in 6 patients, the iris showed a planar configuration that remained unchanged on near fixation.
  
  
  CONCLUSIONS
  Accommodation increases iris concavity in some patients with pigment dispersion syndrome. The most likely explanation is an accommodation-induced relative increase in anterior chamber pressure secondary to anterior movement of the lens surface. Iridotomy prevents change in the iris profile with accommodation.
authors.affiliation: Department of Ophthalmology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: C J
authors.initials: CJ
authors.lastname: Pavlin
authors.forename: P
authors.initials: P
authors.lastname: Macken
authors.forename: G E
authors.initials: GE
authors.lastname: Trope
authors.forename: K
authors.initials: K
authors.lastname: Harasiewicz
authors.forename: F S
authors.initials: FS
authors.lastname: Foster
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000503:physiopathology; D017889:Exfoliation Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005902:Glaucoma, Open-Angle / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007498:Iris / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D053685:Laser Therapy; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography