Fig. 27. Glaucomatous disc with a crescent that nearly surrounds the entire disc circumference. The vessel configuration suggests thinning of tissue at the upper and lower disc sectors, and the pale base of the cup is taller than it is wide. With stereoscopic view the cup has a shape in which one can imagine a vertically oriented American football could be nestled. There may not be much visual field change, because an ample amount of tissue remains, but these signs suggesting a vertically oval configuration of the excavation should not be overlooked.