Effects of enzymatic sterilization detergents on the corneal endothelium

Abstract

Objective: To evaluate the potential of enzymatic detergents to cause endothelial damage and anterior segment inflammation.

Methods: Paired rabbit corneas were mounted in an in vitro specular microscope. Endothelia were perfused either with the sterile irrigating solution BSS Plus (Alcon Laboratories Inc, Ft Worth, Tex) (control) or 0.1%, 0.4%, or 1.0% Medline Enzymatic Detergent (Medline Industries Inc, Mundelein, Ill) in BSS Plus. Swelling rates were determined by regression analysis. Human endothelia were perfused using 1.56% detergent. All corneas were fixed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Endothelial permeability was determined following perfusion of 0.78% detergent. Finally, in vivo intracameral injections with 1.56% or 3.9% detergent were performed to evaluate clinical changes and to correlate with histopathologic analysis.

Results: Dose-related corneal swelling rates were observed. Digital specular micrographs revealed greater endothelial cell damage when perfused with 1.0% detergent. The TEM of endothelia exposed to 1.0% solutions demonstrated abnormal vacuolization and dilated extracellular spaces, which manifested as an increased corneal permeability to 3 to 4 times that of controls. Human corneas swelled comparably to rabbit corneas but demonstrated increased sensitivity when evaluated by TEM and SEM. Histopathologic analysis after intracameral injection revealed thickened corneas with fewer endothelial cells and irises with increased inflammatory and fibrinous responses compared with controls.

Conclusions: Medline Enzymatic Detergent causes a dose-dependent corneal swelling, ultrastructural damage, increased corneal permeability, and increased inflammatory response in the iris after intracameral injection.

Clinical relevance: Failure to adequately rinse the detergent from surgical instruments may result in corneal edema and intraocular inflammation.