title: Direct measurement of the ciliary sulcus diameter by 35-megahertz ultrasound biomicroscopy.
abstract: OBJECTIVE
  To measure the ciliary sulcus diameters in 4 different axes and to determine the correlation with white-to-white distance.
  
  
  METHODS
  Cross-sectional observational study.
  
  
  METHODS
  Fourteen normal volunteers with no evidence of ocular disease.
  
  
  METHODS
  Twenty-eight eyes were scanned using a 35-megahertz (MHz) ultrasound biomicroscopy (UBM) in sequential meridional scan planes at 45 degrees increments. Horizontal white-to-white distance was measured using Orbscan IIz (Bausch & Lomb-Orbtek, Inc., Salt Lake City, UT).
  
  
  METHODS
  Ciliary sulcus diameter, anterior chamber diameter, white-to-white distance, and coefficient of variation.
  
  
  RESULTS
  The coefficient of variation for 35-MHz UBM was 0.90%. The mean diameters+/-standard deviations of ciliary sulci were 11.55+/-0.38 mm at 45 degrees, 11.99+/-0.36 mm at 90 degrees, 11.54+/-0.36 mm at 135 degrees, and 11.32+/-0.40 mm at 180 degrees. In all eyes, vertical diameters were greater than horizontal diameters. The mean difference between vertical and horizontal diameters was 0.67+/-0.26 mm (range, 0.36-1.13 mm), and this was statistically significant (P<0.001). Horizontal sulcus diameters and horizontal white-to-white distances were not correlated (r = 0.006; P = 0.976).
  
  
  CONCLUSIONS
  The posterior chamber appears to have a vertically oval shape. The white-to-white technique is inaccurate at predicting the horizontal diameter of the ciliary sulcus. The 35-MHz UBM may provide a good means of measuring the ciliary sulcus diameter for the implantation of a posterior chamber phakic intraocular lens.
authors.affiliation: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Jaeryung
authors.initials: J
authors.lastname: Oh
authors.forename: Hyung-Ho
authors.initials: HH
authors.lastname: Shin
authors.forename: Jun-Heon
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyo-Myung
authors.initials: HM
authors.lastname: Kim
authors.forename: Jong-Suk
authors.initials: JS
authors.lastname: Song
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000000981:diagnostic imaging; D001699:Biometry / Q000379:methods; D001837:Body Weights and Measures; D002924:Ciliary Body / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D033401:Microscopy, Acoustic