The purpose of this study was to compare the survival of epikeratophakia tissue lenses prepared with cryolathing and lyophilization (frozen lenses) and without (fresh lenses) in donor-sensitized recipients with vascularized corneas. Fresh lenses placed in vascularized corneas of immune recipients were subjected to immune attack. Frozen lenses placed in vascularized corneas of immunized recipients did not elicit an immune reaction. Neither fresh nor frozen lenses elicited immune reactions in nonvascularized corneas of immune recipients or in nonvascularized, nonimmune recipients. These results indicate that although the fresh lenses are more antigenic than the lenses in which the cells have been killed by freezing and lyophilization, the fresh lenses prepared using the BKS-1000 technique containing living stromal keratocytes are not likely to stimulate allograft immune reactions in unsensitized patients with avascular graft sites.