Fig. 20. Glaucomatous disc in which the thinner rim of tissue in the superior sector is more evident than in the previous example. As the initial physiologic cup be imagined in a disc of this size to have been one third to one half the disc diameter, the percentage of the total rim that has been lost is not great, and in keeping with this, the visual field loss consists of mild depression of the inferior hemifield with a detectable nasal step and three relative scotomas in the inferior arcuate region.