Purpose. Previous studies demonstrated that corneas stored in hypertonic media with NaHCO3 remained thin and clear although endothelial degeneration occurred. It is speculated that the degeneration may be due, at least in part, to the instability of NaHCO3 buffer. We investigated whether preservation of the endothelium could be improved if NaHCO3 buffer is replaced by an internal HCO3 --generating system. Methods. The study was carried out using 13 donor corneas stored in two different media: Chen Medium (isotonic, without NaHCO3 buffer, with HCO3 - generated from oxidation of β-hydroxybutyrate) and Optisol (hypertonic, with NaHCO3 buffer). The study with corneas procured by Venice Eye Bank were paired, and those from Lions Eye Bank of Delaware Valley were not. The corneas had these characteristics: donor age: 47.3 ± 17.7 yr; postmortem time: 6.1±3.5 hr; and storage time: 3.1 ± 0.4 days. The study was monitored in terms of graft clarity and post-operative changes in corneal thickness and endothelial cell density estimated from specular micrographs. Results. Using the corneas stored in the NaHCO3 buffer-free media, the grafts became clear and thin in 1-2 weeks after surgery, with evidence of a well preserved endothelium at the first specular microscopic examination 2-4 months after surgery. Two years after surgery (paired study), endothelial cell density was 57.3 ± 53.8% higher than that grafted with the corneas stored in the media containing NaHCO3 buffer. All the grafts studied remained clear. Conclusions. The study showed that using β-hydroxybutyrate as substrate, the media without NaHCO3 buffer is at least as effective as Optisol for preservation of the endothelium. The findings suggest that HCO3 - generated from oxidation of high energy substrate is adequate for corneal storage. More studies are needed to determine whether a NaHCO3-free media may provide a better storage environment for the cornea.
|Journal||Investigative Ophthalmology and Visual Science|
|Publication status||Published - Feb 15 1996|
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