The ability of rabbit corneas to undergo energy-dependent deturgescence was examined after the corneas were stored at 4°C in UW solution, M-K media, or selected modifications of these media. All corneas slowly increased in thickness during storage, despite the presence of colloidal osmotic agents. Corneas stored for 2.5 days in M-K became slightly thinner when cultured over a 24-hour period. Corneas stored in UW swelled quickly in culture and became too opaque to measure within three hours. Corneas stored in UW with 1.8 mM CaC12swelled transiently, then maintained their thickness and exhibited deturgescence in the latter stages of the culture period. Deturgescence of corneas stored for 7 days in M-K was only slightly worse than those stored for 2.5 days. Corneas stored for 7 days in UW, however, became opaque almost imnediately in culture and those stored in calcium-supplemented UW became opaque within 4.5 hours. Replacement of the dextran in M-K with hydroxyethyl starch produced a slower rate of corneal swelling during storage and a substantially better corneal deturgescence profile during culture. Use of high concentrations of potassium ion in the M-K formulation had no significant effect on post-storage deturgescence. Replacement of glucose in M-K with the impermeable sugar, raffinose had a slight deleterious effect on corneal deturgescence in subsequent culture. Use of the impermeable anions gluconate or lactobionate to replace chloride ion caused profound corneal swelling during culture, compared with those stored in M-K. These experiments show that UW solution is inferior to M-K at preserving post-storage corneal function. Furthermore, most of the components of uw solution are inferior to their analogous components of M-K at maintaining corneal function during storage. The hydroxyethyl starch used in UW solution, however, appears to have advantages over dextran during and after corneal storage.