Fig. 4 General strategies of ocular surface reconstruction. Similar to growing a flowering plant in a garden, ocular surface reconstruction requires restoration of ocular surface defense to maintain a stable tear film (like rain), restoration of epithelial stem cells (SC; like seed), and restoration of stromal substrate (like soil). (Modified from Tseng SCG, Tsubota K: Important concepts for treating ocular surface and tear disorders. Am J Ophthalmol 124:825, 1997, with permission)