Fig. 1. Ultrasound images from one volunteer using the I3B-scan. (A ) Image of the choroid layer taken in the supine position at the macula; the thickness is measured from the inner gray surface to the outer gray surface as shown by a + markers in the image. (B ) Image of the retrobulbar optic nerve in the supine position; the width is measured approximately 3 mm posterior to the globe between the + markers.