Figure 2

Case illustration of BMO ovality index (0.82) and BMO rotation angle (72.4°) measurement in a highly myopic left eye (AL = 26.1 mm). The photograph (A) and OCT infrared image (B) of the optic disc are shown on the left and the corresponding BMO ovality and rotation measurement (C) is illustrated on the right image. The red dots indicate the BMO points. The red ellipse represents the fit ellipse based on the BMO points. The green vectors indicate the shortest and longest diameter of the BMO ellipse and are defined as major and minor axis to calculate the BMO ovality index. The BMO rotation angle is defined as the angle between the semimajor axis and the temporal axis (0°, horizontal axes of the en face OCT image), adjusted for variation in individual anatomies based on the FoBMOc angle. Abbreviations: BMO, Bruch’s membrane opening; FoBMOc, Fovea BMO center; OCT, optical coherence tomography.