[Contribution to the problem of optic nerve excavation (author's transl)].

To study opinions on the formation of optic nerve head excavation we had the opportunity of examining microscopic sections of the papilla of a 10-month-old baby who showed bilateral considerable border excavation without the presence of hydrophthalmus or increased intraocular pressure. The thickened lamina cribrosa showed centrally no perforations so that the nerve fibres had to avoid the unperforated parts of the lamina. According to the size and position of such unperforated laminar areas, types of excavation with various defects on the optic nerve head resulted. By coincidence of both components in the optic nerve stem (increased connective tissue growth, and formation of a small vascular bundle), considerable collections of mesenchyme could occur which then resulted in a spreading apart of the optic nerve fibres. As long as neuroglia formation has not filled the gaps in the nervous tissue originally, a secondary growth of glial tissue can follow an original connective tissue-caused defect formation. Hence the deposits of glia in the excavated optic nerve head would be not the cause, but rather the effect of defect formation.