Corneal endothelial toxicity of different lidocaine concentrations.
OBJECTIVE
To examine the potential damaging effect on the corneal endothelium of unpreserved lidocaine in concentrations of 1%, 5%, and 10%.


METHODS
Department of Ophthalmology, Charité Medical Faculty, Humboldt University, Berlin, Germany.


METHODS
Experimental porcine corneas (n = 18) were exposed to 100 microL of unpreserved lidocaine hydrochloride at concentrations of 1%, 5%, and 10% for 60 minutes. Additional corneas (n = 6) were treated with lidocaine hydrochloride 1% for 30 minutes to simulate clinical conditions. Balanced salt solution (BSS((R))) served as a control to evaluate corneal endothelial cell damage using Janus Green photometry. Morphology, damage pattern, and changes in the ultrastructural appearance of corneal endothelial cells were examined by light and scanning electron microscopy.


RESULTS
Lidocaine 1% used for 30 or 60 minutes did not cause significantly more corneal endothelial damage (mean 3.00% +/- 0.76% [SD] and 3.26% +/- 1.00%, respectively) than in the control group (mean 3.32% +/- 0. 86%) (P >.01). Significant corneal endothelial cell loss was observed with lidocaine 5% (mean 10.7% +/- 6.4%) (P <.001) and lidocaine 10% (42.3% +/- 17.0%) (P <.001).


CONCLUSIONS
Experimental exposure of corneal endothelial cells to higher concentrations of lidocaine resulted in significant cell loss, indicating that the 1% concentration only should be used clinically.
Eggeling
P
P
Department of Ophthalmology, Charité Medical Faculty, Campus Virchow Hospital, Humboldt University Berlin, Berlin, Germany.
Pleyer
U
U
Hartmann
C
C
Rieck
P W
PW
D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000648:ultrastructure; D015353:Eye Enucleation; D066298:In Vitro Techniques; D008012:Lidocaine / Q000008:administration & dosage / Q000633:toxicity*; D010783:Photometry; D013552:Swine
D000779:Anesthetics, Local; D008012:Lidocaine