Residual ethanol content of donor sclera after storage in 95% ethanol and saline rinse of various durations

PURPOSE : Some surgeons are wary of using alcohol-preserved sclera for allografts because they fear a toxic effect on surrounding tissue after placement. We set out to determine the amount of ethanol remaining in scleral allograft material after storage in 95% ethanol. METHODS : Sixty half scleras from 30 donors were preserved in 95% ethanol for an average of 31 ± 14 days (range, 11 to 50 days). Rehydration was performed by soaking each half sclera in 4 ounces of balanced salt solution. Half scleras were randomly assigned to six groups of 10 each. Assays for ethanol were performed on the following groups: no balanced salt solution soak and balanced salt solution soak for 10 minutes, 20 minutes, 30 minutes, 40 minutes, and 50 minutes. Ethanol assay was performed by Headspace Gas Space Chromatography at ChemaTox Laboratory, Inc, Boulder, Colorado. RESULTS : The 10 half scleras without balanced salt solution soak had a mean (± SD) ethanol level of 175 ± 14.1 mg per g of sclera. After 10 minutes of balanced salt solution soak, the level decreased to 7.57 ± 1.56 mg per g, then 3.77 ± 3.02 mg per g at 20 minutes, 1.59 ± 0.61 mg per g at 30 minutes, 1.07 ± 0.30 mg per g at 40 minutes, and 0.96 ± 0.26 mg per g at 50 minutes. Approximately 96% of the ethanol is leeched out of the half sclera by 10 minutes and 98% by 20 minutes. CONCLUSIONS : For sclera preserved in 95% ethanol, soaking in balanced salt solution for 20 minutes or longer leeches approximately 98% of the ethanol from the preserved donor sclera.