Recovery from contact lens-induced edema is prolonged in the diabetic rabbit cornea

The recovery of the cornea from contact lens-induced edema has been proposed as a clinical test for the assessment of corneal hydration control, with prolonged times being seen in aged subjects and in conditions associated with endothelial dysfunction. Because diabetes is known to be associated with altered endothelial morphology, a study was performed to determine the influence of diabetes on recovery times from contact lens-induced edema. Corneal edema was produced in 10 normal and 10 diabetic rabbits by the monocular wear of a thick hydrogel contact lens on a closed eye for a period of 2 h. Corneal thicknesses measured by ultrasound pachometry at the end of the wearing period showed significantly (p less than 0.0001) more edema in the normal (75 +/- 11 microns) than in the diabetic group (56 +/- 11 microns). Open eye and closed eye recovery times from the induced edema were calculated for both groups using linear and nonlinear regression analysis. The calculated edema recovery rates for the diabetic cornea were significantly slower than those of the normal in both the open eye and closed eye deswelling conditions. The results of this study indicate that the cornea of a diabetic rabbit has a decreased ability to recover from contact lens-induced edema, and suggests that the practitioner should remain aware of the blood glucose levels of his poorly controlled diabetic contact lens patients.