Plateau iris in Asian subjects with primary angle closure glaucoma

Arch Ophthalmol. 2009 Oct;127(10):1269-72. doi: 10.1001/archophthalmol.2009.241.


Objective: To determine the prevalence of plateau iris in Asian eyes with primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM).

Methods: In this cross-sectional observational study, subjects older than 40 years with PACG who had a patent laser peripheral iridotomy underwent UBM in 1 eye. Ultrasound biomicroscopy images were qualitatively analyzed using standardized criteria. Plateau iris in a quadrant was defined by anteriorly directed ciliary body, absent ciliary sulcus, steep iris root from its point of insertion followed by a downward angulation, flat iris plane, and irido-angle contact. At least 2 quadrants had to fulfill these UBM criteria for an eye to be classified as having plateau iris.

Results: One hundred eleven subjects (70 from Singapore, 41 from Thailand) with PACG were recruited. The mean (SD) age was 65.6 (8.1) years, and 63.9% were female. Based on standardized UBM criteria, plateau iris was found in 36 of 111 eyes (32.4%; 95% confidence interval, 24.4%-41.6%). In these 36 eyes, quadrant-wise analysis showed 66.7% had plateau iris in 2 quadrants; 22.2%, in 3 quadrants; and 11.1%, in all quadrants.

Conclusions: About 30% of PACG eyes with a patent laser peripheral iridotomy were found to have plateau iris on UBM, highlighting the importance of non-pupil block mechanisms in Asian individuals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Asian People / ethnology*
  • Ciliary Body / diagnostic imaging
  • Cross-Sectional Studies
  • Eye Abnormalities / diagnostic imaging
  • Eye Abnormalities / ethnology*
  • Female
  • Glaucoma, Angle-Closure / diagnostic imaging
  • Glaucoma, Angle-Closure / ethnology*
  • Glaucoma, Angle-Closure / surgery
  • Gonioscopy
  • Humans
  • Intraocular Pressure
  • Iridectomy
  • Iris / abnormalities*
  • Iris / diagnostic imaging
  • Iris / surgery
  • Laser Therapy
  • Male
  • Microscopy, Acoustic
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Singapore / epidemiology
  • Thailand / epidemiology
  • Tonometry, Ocular
  • Trabecular Meshwork / diagnostic imaging