Fig. 5

Flat pigmented component of a tumor surrounding the ultrasonographically-measurable component. a Fundus photograph of tumor demonstrating area of flat pigment (blue dashed line) surrounding the elevated portion (red dashed line) of the tumor. b B scan ultrasound of the same tumor shown in part a, demonstrating that the area of choroidal tumor elevation measurable on B scan is approximately 4.7 mm away from the optic nerve (optic nerve shadow is seen at the bottom of the panel). c, d OCT imaging demonstrating that the distance from the optic nerve to the edge of the pigment is much less than to the edge of the elevated tumor. The OCT cut in part d is shown as a green line in the infrared image seen in part c. The yellow and blue lines in c and d represent the distance from the edge of the optic nerve head to the edge of the flat pigmented portion of the tumor (yellow lines) and to the edge of the elevated portion of the tumor (blue line). The distances shown in micrometers were calculated using the inbuilt Spectralis caliper measuring tool. Note how close the B scan measure of the distance from the elevated portion of the tumor (4.72 mm to the optic nerve head) is to the OCT measure of the distance from the elevated portion of the tumor (4.58 mm to the optic nerve head). This figure illustrates that the flat pigmented portions of the tumor may not be visible on ultrasound, and so they need to be added and incorporated into the overall determination of plaque size in clinical practice