Changes in the composition of stromal proteoglycans (PGs) have been previously demonstrated in corneal edema, wound healing, and disease. To examine if PGs are lost during corneal preservation, rabbit corneal PGs were radiolabeled in situ with 35S-sulfate and 3H-glucosamine, excised and stored in either modified McCarey-Kaufman medium (MMK), K-Sol (Coopervision-Cilco, Bellevue, WA, U.S.A.), corneal storage medium (CSM), or Dexsol (Chiron Ophthalmics, Irvine, CA, U.S.A.) for up to 14 days. The percentage of total radio-label lost was significantly greater from de-epithelialized corneas (p less than 0.05) and from corneas stored in CSM (p less than 0.05) or K-Sol (p less than 0.05). Corneas stored in CSM for 4 and 7 days were significantly more hydrated than corneas stored in MMK, K-Sol, or Dexsol. After 14 days of storage, all corneas were hydrated above control values with the Dexsol-stored cornea showing the least hydration. Results suggest that loss of stromal PGs during corneal storage is reduced with epithelial integrity and with preservation media containing dextran.