I am assuming you are interested in establishing cultures of corneal epithelial cells rather than stromal or endothelial cells?
In that case, the underlying basement membrane can be removed with Dispase and the collagenous stroma can be removed with collagenase. I peel off the corneal epithelial sheets after overnight digestion in 1X collagenase/Dispase in DMEM/F12 overnight at 4oC. The limbus region containing the corneal epithelial stem cells separates easily from the conjunctiva and stroma after enzyme treatment. The sheets can then be trypsinized within 10 minutes at 37oC. Purified human corneal epithelial cells can then be cultured in DMEM/F12 or CnT-50 medium without any serum.