Hydration changes in cadaver eyes prepared for practice and experimental surgery
M. A. Terry, P. J. Ousley and M. L. Zjhra
Devers Eye Institute, Good Samaritan Hospital and Medical Center, Portland.
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.
