Normally sized and shaped optic nerve head (ONH). The average ONH has a slightly vertical and oval form and represents the anatomical structure where all axons of the retinal ganglion cells are joined together. Its surface is approx. 2.5 mm2 and the neuroretinal rim is to be recognized without difficulty. In small ONH (micropapilla), the neuroretinal rim fills the optic cup and may be confused with an edema of the ONH. In large ONH (macropapilla), the central optic cup appears enlarged and may be confused with a glaucomatous optic neuropathy. In this picture, the physiological course of the vessels over the neuroretinal rim of the ONH can be well observed. |