Hydration Changes in Cadaver Eyes Prepared for Practice and Experimental Surgery

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Abstract
Objectives: To identify reliable and efficient methods of thinning postmortem corneas for surgical experiments and to develop methods of maintaining stable corneal thickness. Methods: Three methods of corneal thinning were evaluated by group: group A, increased intraocular pressure; group B, exchange of anterior chamber fluid with dextran solution and immersion in dextran solution; and group C, immersion in dextran solution without aqueous replacement. The stability of the thinned central cornea was then evaluated by exposing 30 corneas thinned by methods used in groups B and C to air, Balanced Salt Solution drops (Alcon, Fort Worth, Tex), or dextran solution drops. Results: By 1 hour, the thinning method used in group A resulted in only three of 11 eyes achieving normal central corneal thickness. The method used in group B resulted in normal central thickness in 14 of 14 corneas and in group C, in nine of 15 corneas, at 1 hour. Once thinned by methods used in group B or C, air exposure further thinned the 30 additional corneas by 22% to 26%, Balanced Salt Solution drops thickened the corneas by 16% to 22%, and dextran solution drops stabilized the corneas with only 5% to 13% additional thinning. Conclusions: Hyperosmolar solutions were more efficient than pressure gradients in thinning the cadaver central cornea. Hydration shifts of the de-epithelialized cornea were dramatic with use of Balanced Salt Solution drops or drying and were minimized with use of hyperosmolar topical solutions.