Repeatability of the ciliary sulcus-to-sulcus diameter measurement using wide-scanning-field ultrasound biomicroscopy

Abstract

Purpose: To evaluate the interexaminer and intraexaminer variance in ciliary sulcus-to-sulcus (STS) diameter measurements using wide-scanning-field ultrasound biomicroscopy (UBM) (Vumax II).

Setting: Nagoya Eye Clinic, Nagoya, Japan.

Design: Evaluation of diagnostic test or technology.

Method: Two examiners measured the STS diameter 10 times in each subject. Intraexaminer and interexaminer variances were calculated. To determine interexaminer variance at each UBM measurement step, the examiner was changed every 2 steps when the STS diameter was measured. The Bland-Altman plot test was used to analyze each step of measurement variance.

Results: Thirty eyes of 15 volunteers (9 men, 6 women; mean age 29.6 years ± 6.2 [SD]) were enrolled. The mean coefficient of variation was 0.62% ± 0.20% for intraexaminer measurements and 3.4% ± 2.4% for interexaminer measurements. There were statistically significant differences between the 2 examiners in the step of extracting images and determining and measuring the STS diameter (P=.02). The 95% confidence intervals in all steps were relatively high (recordings, -1.02 to 1.08 mm; extracting images and determining and measuring STS; -0.79 to 1.25 mm).

Conclusion: Interexaminer variance in STS measurement should be considered if the STS diameter is used for selecting the size of posterior chamber phakic intraocular lenses.