Optic-disc topography respresents a major parameter for assessing optic-nervehead damage in patients with glaucoma. For example, Kirsch and AndersonI have found that glaucoma patients generally evidence a totally cupped optic disc, a cup that extends upward or downward to touch the margin of the disc, or a cup that is vertically oval. By contrast, they note that normal discs have cups that are round or horizontally oval, with a rim of tissue along the entire disc circumference. Similarly, Kolker and Obstbaum have found an asymmetry in the cup/disc ratio in patients with asymmetric intraocular pressure. According to Kolker and Obstbaum, these findings suggest that progressive cupping may precede the development of field lo3ss in openangle glaucoma. Finally, Armaly has studied the correlation between opticcup appearance and visual function, and concluded the importance of using quantitative parameters to analyze opticcup configuration.