The extracellular matrix of the lamina cribrosa may be important in the changes in the optic nerve head associated with glaucoma. To investigate the cell biology of this tissue, human lamina cribrosa was explanted in tissue culture and two cell types grown from this tissue were characterized. The most common cell type obtained was a large, flat, polygonal cell which was negative for glial fibrillar acidic protein (GFAP) and could be serially subcultured. This cell type synthesized collagens type III and type IV, fibronectin and elastin. Much less commonly grown was a cell type with conspicuous long processes and which was positive for GFAP. This presumed astrocyte synthesized collagen type IV and fibronectin. Fibroblastic cells were not obtained from this tissue but were easily grown from sclera. The cells that we have cultured from the human lamina cribrosa may produce the extracellular matrix present in the cribriform plates of this tissue and be important in the glaucomatous process.