Development of novel corneal storage medium: first report. Examinations of rabbit cornea.

PURPOSE To develop a new corneal storage medium with a simple formula and evaluate it by histological methods. METHODS Two corneal storage media containing minimum essential medium and 2.5% chondroitin sulfate (pH 7.33), with osmolarity of 320 mOsm/kg, were compared to Optisol-GS. The differences in the two media were the molecular weight (MW) and the source of chondroitin sulfate. The MW of Medium I was 27,500 and the MW of Medium II was 33,700. Japanese albino rabbits were used in this study. A cornea with scleral rim obtained from a rabbit was stored in either Medium I or Medium II and the fellow cornea was stored in Optisol-GS for 7 or 14 days at 4 degrees C. Histological examination of corneal endothelial cells was performed both by scanning electron microscopy and by transmission electron microscopy. RESULTS At day 7, there was no significant difference in histological findings among the rabbit corneas stored in Optisol-GS, Medium I, or Medium II. At day 14, corneas stored in Optisol-GS or Medium I showed similar histological findings. In Medium II, endothelial cells showed marked degeneration. CONCLUSIONS The results of experiments with rabbit cornea indicated that Optisol-GS and Medium I could preserve endothelial cellular structure better than Medium II. The difference between Medium I and Medium II was only the MW of the chondroitin sulfate used. The MW may be an important factor for determining suitable chondroitin sulfate for use in a corneal storage medium.