HYDRATION CHANGES IN CADAVER EYES PREPARED FOR PRACTICE AND EXPERIMENTAL SURGERY

Objectives: To identify reliable and efficient methods of thinning pos tmortem corneas for surgical experiments and to develop methods of mai ntaining stable corneal thickness. Methods: Three methods of corneal t hinning were evaluated by group: group A, increased intraocular pressu re; group B, exchange of anterior chamber fluid with dextran solution and immersion in dextran solution; and group C, immersion in dextran s olution without aqueous replacement. The stability of the thinned cent ral cornea was then evaluated by exposing 30 corneas thinned by method s 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 t hinning method used in group A resulted in only three of 11 eyes achie ving normal central corneal thickness. The method used in group B resu lted in normal central thickness in 14 of 14 corneas and in group C, i n 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 mor e efficient than pressure gradients in thinning the cadaver central co rnea. Hydration shifts of the de-epithelialized cornea were dramatic w ith use of Balanced Salt Solution drops or drying and were minimized w ith use of hyperosmolar topical solutions.