Iris volume before and after pupillary dilation using ultrasound biomicroscopy

H. Ishikawa, R. Ritch, S. T. Hoh, J. M. Liebmann, D. S. Greenfield, Y. Uji

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Purpose. To evaluate changes in iris cross-sectional area and iris volume using ultrasound biomicroscopy (UBM). Methods. Patients were imaged before and after pupillary dilation. Images were exported to an IBM-compatible PC in PCX format. Iris volume and cross-sectional area were then measured using an automated software program of our own design capable of calculating iris volume with axial alignment using keratometry and corneal diameter. Results. 10 patients were enrolled (mean age, 45.5 ±19.0 yrs; mean refractive error, -2.4 ± 3.6 D; mean axial length, 24.1 ±1.6 mm). Mean iris volume was 41.21 ±2.64 mm3 before dilation and 35.88 ±3.92 mm3 after dilation (p=0.009, paired tTest) (12.5 ±11.4 % reduction). Cross-sectional iris area was 2.31 ±0.26 mm2 before dilation and 1.51 ±0.22 mm after dilation (p<0.0001, paired t-Test) (33.8 ±13.2 % reduction). Conclusion. Iris volume and cross-sectional iris area decrease with dilation. The decrease in iris volume represents loss of fluid from the stroma.

Original languageEnglish (US)
Pages (from-to)S166
JournalInvestigative Ophthalmology and Visual Science
Issue number4
StatePublished - Dec 1 1997
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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