How to measure the largest basal dimension of choroidal melanoma: a mathematical study

Purpose: To identify the most accurate ultrasonographic technique to measure the largest basal dimension (LBD) of choroidal melanoma. Methods: B-scan ultrasound images were retrospectively reviewed in 99 eyes of 99 choroidal melanoma patients. The LBD was measured using one, two, and three straight lines along the inner and outer sclera. Theoretical arc length, calculated using trigonometry formulas based on the spherical model with the axial length as the sphere diameter, was used for comparisons with the actual measurements using straight lines. Results: For straight-line measurements in the inner sclera, the lowest error was found when using two straight-line measurements (P = 0.118). Differences in measurement using one-segment or three-segment measurements as compared with the theoretical arc length were found to be statistically significant (P
Source: RETINA - Category: Opthalmology Tags: Original Study Source Type: research