Fig. 2

Sonographic appearance of the structures of the normal eye. The cornea (1) is visualized as the most superficial echogenic curved line; the anterior chamber (2) is anechoic. The iris (3) appears as a thin echogenic line. The lens (4) is defined by anterior and posterior boundary echoes, but the lens itself is echo-free. The vitreous chamber (5) is filled with a clear gel-like substance that is normally echo-free, although the formation of spots and linear echoes with aging is considered normal. The RCS complex (6) forms the wall of the posterior ocular segment; it is seen as an echogenic concave line extending from the iris plane to the optic nerve (ON; 7). The ON is seen as a hypoechoic band surrounded by echogenic retrobulbar fat (8). The circular area where the ON connects to the retina is the optic disc or papilla (9)