Relationship between ciliary sulcus diameter and anterior chamber diameter and corneal diameter

PURPOSE: To evaluate the relationship between the horizontal ciliary sulcus diameter and anterior chamber diameter measured by 35 MHz ultrasound biomicroscopy (UBM) and the horizontal corneal diameter (white to white [WTW]) measured by scanning-slit topography and to assess the repeatability (intraexaminer difference) of the 2 methods. SETTING: Department of Orthoptics and Visual Science, Kitasato University School, Sagamihara, Japan. METHODS: The repeatability and agreement of UBM and scanning-slit topography were assessed using the intraclass correlation (ICC) and the Bland and Altman method (ie, mean difference and 95% limits of agreement [LoA]). RESULTS: Thirty-one normal eyes of 31 subjects (mean age 22.6 years +/- 4.8 [SD]) were evaluated. The mean differences between the repeated measurements were as follows: ciliary sulcus diameter, -0.05 mm (95% LoA, -0.38 to 0.28 mm); anterior chamber diameter, 0.02 mm (95% LoA, -0.42 to 0.45 mm); and WTW diameter, -0.02 mm (95% LoA, -0.18 to 0.13 mm). The agreement between ciliary sulcus diameter and WTW diameter was poor (ICC, 0.679). The mean difference was 0.41 mm (95% LoA, -0.46 to 1.28 mm). The agreement between the ciliary sulcus diameter and anterior chamber diameter was high (ICC, 0.918). The mean difference was 0.13 mm (95% LoA, -0.41 to 0.67 mm). CONCLUSION: Results suggest that direct measurement of the ciliary sulcus by UBM would reduce the percentage of complications related to intraocular lens sizing over the percentage when sizing is based on WTW diameter.