title: Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography.
abstract: OBJECTIVE
  To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.
  
  
  METHODS
  In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.
  
  
  RESULTS
  The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001), thicker lens (4.77mm vs. 5.11mm; p<0.001), shorter axial length (23.16mm vs. 22.63mm; p<0.001), smaller relative lens position (2.28 vs. 2.16; p<0.001) and larger lens/axial length factor (2.06 vs. 2.26; p<0.001). However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05).
  
  
  CONCLUSIONS
  Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.
authors.affiliation: Community Medicine Research Center and Institute of Public Health, National Yang-Ming University, Taipei, Taiwan; Department of Ophthalmology, Yang-Ming University Hospital, Ilan County, Taiwan.
authors.forename: Yu-Yen
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Community Medicine Research Center and Institute of Public Health, National Yang-Ming University, Taipei, Taiwan; Taipei City Hospital, Zhongxing Branch, Taipei, Taiwan.
authors.forename: Dachen
authors.initials: D
authors.lastname: Chu
authors.affiliation: Community Medicine Research Center and Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Pesus
authors.initials: P
authors.lastname: Chou
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007499:Iris Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011681:Pupil Disorders / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014463:Ultrasonography