Figure 2

Sample case (left eye) of eyeball asymmetry (group 2). (A₁) Disc photograph. The arrowhead indicates the location of the central retinal vascular trunk (CRVT). The dotted white line indicates the locations of the OCT scans. (A₂) Infrared image with demarcated Bruch’s membrane opening (BMO) margin (red dots). The CRVT position (yellow dot), the meridian of the longest externally oblique border (EOB, black dot), and the meridian of the maximal width of β-zone parapapillary atrophy (PPA, green dot) are marked on the same infrared image. (A₃) Measurement of lamina cribrosa (LC) / Bruch’s membrane opening (BMO) offset. The yellow arrow is drawn to show the direction and extent of CRVT (yellow dot) deviation from the BMO center (orange dot). (B) B-scan image. The red dots indicate the BMO margin and the yellow arrowhead indicates the CRVT. (C) Sagittal (C₁) and transverse (C₂) sectional images of three-dimensional (3D) MRI. Please note the asymmetric expansion of the eyeball on the inferior and nasal sides (red arrowheads). (D₁) 3D shape evaluated by optimal ellipsoid fitting. (D₂) The outermost protruded point (OPP) is on the inferonasal side (green arrow) from the fovea-BMO axis (dotted black line), which is in the direction opposite to the superotemporal LC/BMO offset (A₃, yellow arrow). The blue dots indicate the location of fovea, and the yellow dots that of the BMO. The red squares indicate the outermost protruded points, and the blue squares indicate the reciprocal innermost depressed points. (D₃) From the best-fitted ellipsoid (black dashed line), the average distance was calculated for the outward protrusion (red line) and inward depression (blue line) as a ratio relative to the radius (gray dotted line) in each direction, respectively, and their summation was defined as the protrusion depth. The entire 3D shape of the eyeball is available in Supplemental Video 2.