Rabbit endothelial response to ophthalmic preservatives

Area of Science:

• Ophthalmology
• Toxicology
• Corneal Science

Background:

• Benzalkonium chloride (BAC) and cetylpyridinium chloride (CPC) are common surfactants in ophthalmic solutions.
• Their potential toxicity to the corneal endothelium requires thorough investigation.

Purpose of the Study:

• To determine the threshold concentrations and exposure times for BAC and CPC to induce physiological and ultrastructural changes in rabbit corneal endothelium.
• To assess the reversibility of these effects and evaluate the safety of topical BAC application on deepithelialized corneas.

Main Methods:

• Isolated rabbit corneas were perfused with varying concentrations of BAC and CPC for three hours.
• Corneal endothelium was examined for physiological and ultrastructural alterations.
• In vivo studies involved topical application of BAC to deepithelialized rabbit corneas.

Main Results:

• The threshold for endothelial alteration was approximately 0.0001% for BAC and 0.01 mM for CPC.
• Effects were observed after 15-minute exposures without subsequent recovery.
• Topical application of 0.133% BAC to deepithelialized corneas did not cause endothelial damage.

Conclusions:

• Ophthalmic solutions containing BAC and CPC pose potential hazards to the corneal endothelium due to their toxicity at low concentrations and short exposure times.
• The corneal endothelium shows no recovery after damage induced by these surfactants.
• BAC may be safe for topical use on deepithelialized corneas at the tested concentration.