Stage III is divided into stages IIIA, IIIB, and IIIC. In stage IIIA, the tumor (1) may have spread to the ciliary body and is size category 2 (12.1 to 18 millimeters wide and not more than 3 millimeters thick; or 9.1 to 15 millimeters wide and 3.1 to 6 millimeters thick; or not more than 12 millimeters wide and 6.1 to 9 millimeters thick). The tumor has spread through the sclera to the outside of the eyeball. The part of the tumor outside the eyeball is not more than 5 millimeters thick; or (2) has spread to the ciliary body and is size category 3 (15.1 to 18 millimeters wide and 3.1 to 6 millimeters thick; or 12.1 to 18 millimeters wide and 6.1 to 9 millimeters thick; or 3.1 to 18 millimeters wide and 9.1 to 12 millimeters thick; or 9.1 to 15 millimeters wide and 12.1 to 15 millimeters thick); or (3) is size category 3 and has spread through the sclera to the outside of the eyeball. The part of the tumor outside the eyeball is not more than 5 millimeters thick. The tumor has not spread to the ciliary body; or (4) is in the choroid only and is size category 4 (more than 18 millimeters wide and may be any thickness; or 15.1 to 18 millimeters wide and more than 12 millimeters thick; or 12.1 to 15 millimeters wide and more than 15 millimeters thick).